Every cache that is considered a root cache (basically the "original"
caches, tied to the root memcg/no-memcg) will have an array that should be
large enough to store a cache pointer per each memcg in the system.
Theoreticaly, this is as high as 1 << sizeof(css_id), which is currently
in the 64k pointers range. Most of the time, we won't be using that much.
What goes in this patch, is a simple scheme to dynamically allocate such
an array, in order to minimize memory usage for memcg caches. Because we
would also like to avoid allocations all the time, at least for now, the
array will only grow. It will tend to be big enough to hold the maximum
number of kmem-limited memcgs ever achieved.
We'll allocate it to be a minimum of 64 kmem-limited memcgs. When we have
more than that, we'll start doubling the size of this array every time the
limit is reached.
Because we are only considering kmem limited memcgs, a natural point for
this to happen is when we write to the limit. At that point, we already
have set_limit_mutex held, so that will become our natural synchronization
mechanism.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow a memcg parameter to be passed during cache creation. When the slub
allocator is being used, it will only merge caches that belong to the same
memcg. We'll do this by scanning the global list, and then translating
the cache to a memcg-specific cache
Default function is created as a wrapper, passing NULL to the memcg
version. We only merge caches that belong to the same memcg.
A helper is provided, memcg_css_id: because slub needs a unique cache name
for sysfs. Since this is visible, but not the canonical location for slab
data, the cache name is not used, the css_id should suffice.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We can use static branches to patch the code in or out when not used.
Because the _ACTIVE bit on kmem_accounted is only set after the increment
is done, we guarantee that the root memcg will always be selected for kmem
charges until all call sites are patched (see memcg_kmem_enabled). This
guarantees that no mischarges are applied.
Static branch decrement happens when the last reference count from the
kmem accounting in memcg dies. This will only happen when the charges
drop down to 0.
When that happens, we need to disable the static branch only on those
memcgs that enabled it. To achieve this, we would be forced to complicate
the code by keeping track of which memcgs were the ones that actually
enabled limits, and which ones got it from its parents.
It is a lot simpler just to do static_key_slow_inc() on every child
that is accounted.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce infrastructure for tracking kernel memory pages to a given
memcg. This will happen whenever the caller includes the flag
__GFP_KMEMCG flag, and the task belong to a memcg other than the root.
In memcontrol.h those functions are wrapped in inline acessors. The idea
is to later on, patch those with static branches, so we don't incur any
overhead when no mem cgroups with limited kmem are being used.
Users of this functionality shall interact with the memcg core code
through the following functions:
memcg_kmem_newpage_charge: will return true if the group can handle the
allocation. At this point, struct page is not
yet allocated.
memcg_kmem_commit_charge: will either revert the charge, if struct page
allocation failed, or embed memcg information
into page_cgroup.
memcg_kmem_uncharge_page: called at free time, will revert the charge.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While profiling numa/core v16 with cgroup_disable=memory on the command
line, I noticed mem_cgroup_count_vm_event() still showed up as high as
0.60% in perftop.
This occurs because the function is called extremely often even when memcg
is disabled.
To fix this, inline the check for mem_cgroup_disabled() so we avoid the
unnecessary function call if memcg is disabled.
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit e1aab161e0 ("socket: initial cgroup code.") causes a build
error when CONFIG_INET is disabled in Linus' tree:
net/built-in.o: In function `sk_update_clone':
net/core/sock.c:1336: undefined reference to `sock_update_memcg'
sock_update_memcg() is only defined when CONFIG_INET is enabled, so fix
it by defining the dummy function without this option.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It really should return a boolean for match/no match. And since it takes
a memcg, not a cgroup, fix that parameter name as well.
[akpm@linux-foundation.org: mm_match_cgroup() is not a macro]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Compaction (and page migration in general) can currently be hindered
through pages being owned by memory cgroups that are at their limits and
unreclaimable.
The reason is that the replacement page is being charged against the limit
while the page being replaced is also still charged. But this seems
unnecessary, given that only one of the two pages will still be in use
after migration finishes.
This patch changes the memcg migration sequence so that the replacement
page is not charged. Whatever page is still in use after successful or
failed migration gets to keep the charge of the page that was going to be
replaced.
The replacement page will still show up temporarily in the rss/cache
statistics, this can be fixed in a later patch as it's less urgent.
Reported-by: David Rientjes <rientjes@google.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Wanpeng Li <liwp.linux@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
By globally defining check_panic_on_oom(), the memcg oom handler can be
moved entirely to mm/memcontrol.c. This removes the ugly #ifdef in the
oom killer and cleans up the code.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The global oom killer is serialized by the per-zonelist
try_set_zonelist_oom() which is used in the page allocator. Concurrent
oom kills are thus a rare event and only occur in systems using
mempolicies and with a large number of nodes.
Memory controller oom kills, however, can frequently be concurrent since
there is no serialization once the oom killer is called for oom conditions
in several different memcgs in parallel.
This creates a massive contention on tasklist_lock since the oom killer
requires the readside for the tasklist iteration. If several memcgs are
calling the oom killer, this lock can be held for a substantial amount of
time, especially if threads continue to enter it as other threads are
exiting.
Since the exit path grabs the writeside of the lock with irqs disabled in
a few different places, this can cause a soft lockup on cpus as a result
of tasklist_lock starvation.
The kernel lacks unfair writelocks, and successful calls to the oom killer
usually result in at least one thread entering the exit path, so an
alternative solution is needed.
This patch introduces a seperate oom handler for memcgs so that they do
not require tasklist_lock for as much time. Instead, it iterates only
over the threads attached to the oom memcg and grabs a reference to the
selected thread before calling oom_kill_process() to ensure it doesn't
prematurely exit.
This still requires tasklist_lock for the tasklist dump, iterating
children of the selected process, and killing all other threads on the
system sharing the same memory as the selected victim. So while this
isn't a complete solution to tasklist_lock starvation, it significantly
reduces the amount of time that it is held.
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Sha Zhengju <handai.szj@taobao.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mem_cgroup_out_of_memory() is defined in mm/oom_kill.c, so declare it in
linux/oom.h rather than linux/memcontrol.h.
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Take lruvec further: pass it instead of zone to add_page_to_lru_list() and
del_page_from_lru_list(); and pagevec_lru_move_fn() pass lruvec down to
its target functions.
This cleanup eliminates a swathe of cruft in memcontrol.c, including
mem_cgroup_lru_add_list(), mem_cgroup_lru_del_list() and
mem_cgroup_lru_move_lists() - which never actually touched the lists.
In their place, mem_cgroup_page_lruvec() to decide the lruvec, previously
a side-effect of add, and mem_cgroup_update_lru_size() to maintain the
lru_size stats.
Whilst these are simplifications in their own right, the goal is to bring
the evaluation of lruvec next to the spin_locking of the lrus, in
preparation for a future patch.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Konstantin just introduced mem_cgroup_get_lruvec_size() and
get_lruvec_size(), I'm about to add mem_cgroup_update_lru_size(): but
we're dealing with the same thing, lru_size[lru]. We ought to agree on
the naming, and I do think lru_size is the more correct: so rename his
ones to get_lru_size().
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If memory cgroup is enabled we always use lruvecs which are embedded into
struct mem_cgroup_per_zone, so we can reach lru_size counters via
container_of().
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch kills mem_cgroup_lru_del(), we can use
mem_cgroup_lru_del_list() instead. On 0-order isolation we already have
right lru list id.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With mem_cgroup_disabled() now explicit, it becomes clear that the
zone_reclaim_stat structure actually belongs in lruvec, per-zone when
memcg is disabled but per-memcg per-zone when it's enabled.
We can delete mem_cgroup_get_reclaim_stat(), and change
update_page_reclaim_stat() to update just the one set of stats, the one
which get_scan_count() will actually use.
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The rmap walker checking page table references has historically ignored
references from VMAs that were not part of the memcg that was being
reclaimed during memcg hard limit reclaim.
When transitioning global reclaim to memcg hierarchy reclaim, I missed
that bit and now references from outside a memcg are ignored even during
global reclaim.
Reverting back to traditional behaviour - count all references during
global reclaim and only mind references of the memcg being reclaimed
during limit reclaim would be one option.
However, the more generic idea is to ignore references exactly then when
they are outside the hierarchy that is currently under reclaim; because
only then will their reclamation be of any use to help the pressure
situation. It makes no sense to ignore references from a sibling memcg
and then evict a page that will be immediately refaulted by that sibling
which contributes to the same usage of the common ancestor under
reclaim.
The solution: make the rmap walker ignore references from VMAs that are
not part of the hierarchy that is being reclaimed.
Flat limit reclaim will stay the same, hierarchical limit reclaim will
mind the references only to pages that the hierarchy owns. Global
reclaim, since it reclaims from all memcgs, will be fixed to regard all
references.
[akpm@linux-foundation.org: name the args in the declaration]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Konstantin Khlebnikov<khlebnikov@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mem_cgroup_begin_update_page_stat() should be very fast because it's
called very frequently. Now, it needs to look up page_cgroup and its
memcg....this is slow.
This patch adds a global variable to check "any memcg is moving or not".
With this, the caller doesn't need to visit page_cgroup and memcg.
Here is a test result. A test program makes page faults onto a file,
MAP_SHARED and makes each page's page_mapcount(page) > 1, and free the
range by madvise() and page fault again. This program causes 26214400
times of page fault onto a file(size was 1G.) and shows shows the cost of
mem_cgroup_begin_update_page_stat().
Before this patch for mem_cgroup_begin_update_page_stat()
[kamezawa@bluextal test]$ time ./mmap 1G
real 0m21.765s
user 0m5.999s
sys 0m15.434s
27.46% mmap mmap [.] reader
21.15% mmap [kernel.kallsyms] [k] page_fault
9.17% mmap [kernel.kallsyms] [k] filemap_fault
2.96% mmap [kernel.kallsyms] [k] __do_fault
2.83% mmap [kernel.kallsyms] [k] __mem_cgroup_begin_update_page_stat
After this patch
[root@bluextal test]# time ./mmap 1G
real 0m21.373s
user 0m6.113s
sys 0m15.016s
In usual path, calls to __mem_cgroup_begin_update_page_stat() goes away.
Note: we may be able to remove this optimization in future if
we can get pointer to memcg directly from struct page.
[akpm@linux-foundation.org: don't return a void]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Greg Thelen <gthelen@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now, page-stat-per-memcg is recorded into per page_cgroup flag by
duplicating page's status into the flag. The reason is that memcg has a
feature to move a page from a group to another group and we have race
between "move" and "page stat accounting",
Under current logic, assume CPU-A and CPU-B. CPU-A does "move" and CPU-B
does "page stat accounting".
When CPU-A goes 1st,
CPU-A CPU-B
update "struct page" info.
move_lock_mem_cgroup(memcg)
see pc->flags
copy page stat to new group
overwrite pc->mem_cgroup.
move_unlock_mem_cgroup(memcg)
move_lock_mem_cgroup(mem)
set pc->flags
update page stat accounting
move_unlock_mem_cgroup(mem)
stat accounting is guarded by move_lock_mem_cgroup() and "move" logic
(CPU-A) doesn't see changes in "struct page" information.
But it's costly to have the same information both in 'struct page' and
'struct page_cgroup'. And, there is a potential problem.
For example, assume we have PG_dirty accounting in memcg.
PG_..is a flag for struct page.
PCG_ is a flag for struct page_cgroup.
(This is just an example. The same problem can be found in any
kind of page stat accounting.)
CPU-A CPU-B
TestSet PG_dirty
(delay) TestClear PG_dirty
if (TestClear(PCG_dirty))
memcg->nr_dirty--
if (TestSet(PCG_dirty))
memcg->nr_dirty++
Here, memcg->nr_dirty = +1, this is wrong. This race was reported by Greg
Thelen <gthelen@google.com>. Now, only FILE_MAPPED is supported but
fortunately, it's serialized by page table lock and this is not real bug,
_now_,
If this potential problem is caused by having duplicated information in
struct page and struct page_cgroup, we may be able to fix this by using
original 'struct page' information. But we'll have a problem in "move
account"
Assume we use only PG_dirty.
CPU-A CPU-B
TestSet PG_dirty
(delay) move_lock_mem_cgroup()
if (PageDirty(page))
new_memcg->nr_dirty++
pc->mem_cgroup = new_memcg;
move_unlock_mem_cgroup()
move_lock_mem_cgroup()
memcg = pc->mem_cgroup
new_memcg->nr_dirty++
accounting information may be double-counted. This was original reason to
have PCG_xxx flags but it seems PCG_xxx has another problem.
I think we need a bigger lock as
move_lock_mem_cgroup(page)
TestSetPageDirty(page)
update page stats (without any checks)
move_unlock_mem_cgroup(page)
This fixes both of problems and we don't have to duplicate page flag into
page_cgroup. Please note: move_lock_mem_cgroup() is held only when there
are possibility of "account move" under the system. So, in most path,
status update will go without atomic locks.
This patch introduces mem_cgroup_begin_update_page_stat() and
mem_cgroup_end_update_page_stat() both should be called at modifying
'struct page' information if memcg takes care of it. as
mem_cgroup_begin_update_page_stat()
modify page information
mem_cgroup_update_page_stat()
=> never check any 'struct page' info, just update counters.
mem_cgroup_end_update_page_stat().
This patch is slow because we need to call begin_update_page_stat()/
end_update_page_stat() regardless of accounted will be changed or not. A
following patch adds an easy optimization and reduces the cost.
[akpm@linux-foundation.org: s/lock/locked/]
[hughd@google.com: fix deadlock by avoiding stat lock when anon]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Greg Thelen <gthelen@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The oom killer typically displays the allocation order at the time of oom
as a part of its diangostic messages (for global, cpuset, and mempolicy
ooms).
The memory controller may also pass the charge order to the oom killer so
it can emit the same information. This is useful in determining how large
the memory allocation is that triggered the oom killer.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When moving tasks from old memcg (with move_charge_at_immigrate on new
memcg), followed by removal of old memcg, hit General Protection Fault in
mem_cgroup_lru_del_list() (called from release_pages called from
free_pages_and_swap_cache from tlb_flush_mmu from tlb_finish_mmu from
exit_mmap from mmput from exit_mm from do_exit).
Somewhat reproducible, takes a few hours: the old struct mem_cgroup has
been freed and poisoned by SLAB_DEBUG, but mem_cgroup_lru_del_list() is
still trying to update its stats, and take page off lru before freeing.
A task, or a charge, or a page on lru: each secures a memcg against
removal. In this case, the last task has been moved out of the old memcg,
and it is exiting: anonymous pages are uncharged one by one from the
memcg, as they are zapped from its pagetables, so the charge gets down to
0; but the pages themselves are queued in an mmu_gather for freeing.
Most of those pages will be on lru (and force_empty is careful to
lru_add_drain_all, to add pages from pagevec to lru first), but not
necessarily all: perhaps some have been isolated for page reclaim, perhaps
some isolated for other reasons. So, force_empty may find no task, no
charge and no page on lru, and let the removal proceed.
There would still be no problem if these pages were immediately freed; but
typically (and the put_page_testzero protocol demands it) they have to be
added back to lru before they are found freeable, then removed from lru
and freed. We don't see the issue when adding, because the
mem_cgroup_iter() loops keep their own reference to the memcg being
scanned; but when it comes to mem_cgroup_lru_del_list().
I believe this was not an issue in v3.2: there, PageCgroupAcctLRU and
PageCgroupUsed flags were used (like a trick with mirrors) to deflect view
of pc->mem_cgroup to the stable root_mem_cgroup when neither set.
38c5d72f3e ("memcg: simplify LRU handling by new rule") mercifully
removed those convolutions, but left this General Protection Fault.
But it's surprisingly easy to restore the old behaviour: just check
PageCgroupUsed in mem_cgroup_lru_add_list() (which decides on which lruvec
to add), and reset pc to root_mem_cgroup if page is uncharged. A risky
change? just going back to how it worked before; testing, and an audit of
uses of pc->mem_cgroup, show no problem.
And there's a nice bonus: with mem_cgroup_lru_add_list() itself making
sure that an uncharged page goes to root lru, mem_cgroup_reset_owner() no
longer has any purpose, and we can safely revert 4e5f01c2b9 ("memcg:
clear pc->mem_cgroup if necessary").
Calling update_page_reclaim_stat() after add_page_to_lru_list() in swap.c
is not strictly necessary: the lru_lock there, with RCU before memcg
structures are freed, makes mem_cgroup_get_reclaim_stat_from_page safe
without that; but it seems cleaner to rely on one dependency less.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparation before removing a flag PCG_ACCT_LRU in page_cgroup
and reducing atomic ops/complexity in memcg LRU handling.
In some cases, pages are added to lru before charge to memcg and pages
are not classfied to memory cgroup at lru addtion. Now, the lru where
the page should be added is determined a bit in page_cgroup->flags and
pc->mem_cgroup. I'd like to remove the check of flag.
To handle the case pc->mem_cgroup may contain stale pointers if pages
are added to LRU before classification. This patch resets
pc->mem_cgroup to root_mem_cgroup before lru additions.
[akpm@linux-foundation.org: fix CONFIG_CGROUP_MEM_CONT=n build]
[hughd@google.com: fix CONFIG_CGROUP_MEM_RES_CTLR=y CONFIG_CGROUP_MEM_RES_CTLR_SWAP=n build]
[akpm@linux-foundation.org: ksm.c needs memcontrol.h, per Michal]
[hughd@google.com: stop oops in mem_cgroup_reset_owner()]
[hughd@google.com: fix page migration to reset_owner]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In split_huge_page(), mem_cgroup_split_huge_fixup() is called to handle
page_cgroup modifcations. It takes move_lock_page_cgroup() and modifies
page_cgroup and LRU accounting jobs and called HPAGE_PMD_SIZE - 1 times.
But thinking again,
- compound_lock() is held at move_accout...then, it's not necessary
to take move_lock_page_cgroup().
- LRU is locked and all tail pages will go into the same LRU as
head is now on.
- page_cgroup is contiguous in huge page range.
This patch fixes mem_cgroup_split_huge_fixup() as to be called once per
hugepage and reduce costs for spliting.
[akpm@linux-foundation.org: fix typo, per Michal]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that all code that operated on global per-zone LRU lists is
converted to operate on per-memory cgroup LRU lists instead, there is no
reason to keep the double-LRU scheme around any longer.
The pc->lru member is removed and page->lru is linked directly to the
per-memory cgroup LRU lists, which removes two pointers from a
descriptor that exists for every page frame in the system.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Ying Han <yinghan@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memory cgroup limit reclaim and traditional global pressure reclaim will
soon share the same code to reclaim from a hierarchical tree of memory
cgroups.
In preparation of this, move the two right next to each other in
shrink_zone().
The mem_cgroup_hierarchical_reclaim() polymath is split into a soft
limit reclaim function, which still does hierarchy walking on its own,
and a limit (shrinking) reclaim function, which relies on generic
reclaim code to walk the hierarchy.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Ying Han <yinghan@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit ef6a3c6311 ("mm: add replace_page_cache_page() function") added a
function replace_page_cache_page(). This function replaces a page in the
radix-tree with a new page. WHen doing this, memory cgroup needs to fix
up the accounting information. memcg need to check PCG_USED bit etc.
In some(many?) cases, 'newpage' is on LRU before calling
replace_page_cache(). So, memcg's LRU accounting information should be
fixed, too.
This patch adds mem_cgroup_replace_page_cache() and removes the old hooks.
In that function, old pages will be unaccounted without touching
res_counter and new page will be accounted to the memcg (of old page).
WHen overwriting pc->mem_cgroup of newpage, take zone->lru_lock and avoid
races with LRU handling.
Background:
replace_page_cache_page() is called by FUSE code in its splice() handling.
Here, 'newpage' is replacing oldpage but this newpage is not a newly allocated
page and may be on LRU. LRU mis-accounting will be critical for memory cgroup
because rmdir() checks the whole LRU is empty and there is no account leak.
If a page is on the other LRU than it should be, rmdir() will fail.
This bug was added in March 2011, but no bug report yet. I guess there
are not many people who use memcg and FUSE at the same time with upstream
kernels.
The result of this bug is that admin cannot destroy a memcg because of
account leak. So, no panic, no deadlock. And, even if an active cgroup
exist, umount can succseed. So no problem at shutdown.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> net/core/sock.c: In function 'sk_update_clone':
> net/core/sock.c:1278:3: error: implicit declaration of function 'sock_update_memcg'
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
They need to be available for other protocols as well, since
they are used in sock.c openly
Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch introduces memory pressure controls for the tcp
protocol. It uses the generic socket memory pressure code
introduced in earlier patches, and fills in the
necessary data in cg_proto struct.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The goal of this work is to move the memory pressure tcp
controls to a cgroup, instead of just relying on global
conditions.
To avoid excessive overhead in the network fast paths,
the code that accounts allocated memory to a cgroup is
hidden inside a static_branch(). This branch is patched out
until the first non-root cgroup is created. So when nobody
is using cgroups, even if it is mounted, no significant performance
penalty should be seen.
This patch handles the generic part of the code, and has nothing
tcp-specific.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtsu.com>
CC: Kirill A. Shutemov <kirill@shutemov.name>
CC: David S. Miller <davem@davemloft.net>
CC: Eric W. Biederman <ebiederm@xmission.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reclaim decides to skip scanning an active list when the corresponding
inactive list is above a certain size in comparison to leave the assumed
working set alone while there are still enough reclaim candidates around.
The memcg implementation of comparing those lists instead reports whether
the whole memcg is low on the requested type of inactive pages,
considering all nodes and zones.
This can lead to an oversized active list not being scanned because of the
state of the other lists in the memcg, as well as an active list being
scanned while its corresponding inactive list has enough pages.
Not only is this wrong, it's also a scalability hazard, because the global
memory state over all nodes and zones has to be gathered for each memcg
and zone scanned.
Make these calculations purely based on the size of the two LRU lists
that are actually affected by the outcome of the decision.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memcg code sometimes uses "struct mem_cgroup *mem" and sometimes uses
"struct mem_cgroup *memcg". Rename all mem variables to memcg in source
file.
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change ISOLATE_XXX macro with bitwise isolate_mode_t type. Normally,
macro isn't recommended as it's type-unsafe and making debugging harder as
symbol cannot be passed throught to the debugger.
Quote from Johannes
" Hmm, it would probably be cleaner to fully convert the isolation mode
into independent flags. INACTIVE, ACTIVE, BOTH is currently a
tri-state among flags, which is a bit ugly."
This patch moves isolate mode from swap.h to mmzone.h by memcontrol.h
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Revert the post-3.0 commit 82f9d486e5 ("memcg: add
memory.vmscan_stat").
The implementation of per-memcg reclaim statistics violates how memcg
hierarchies usually behave: hierarchically.
The reclaim statistics are accounted to child memcgs and the parent
hitting the limit, but not to hierarchy levels in between. Usually,
hierarchical statistics are perfectly recursive, with each level
representing the sum of itself and all its children.
Since this exports statistics to userspace, this may lead to confusion
and problems with changing things after the release, so revert it now,
we can try again later.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove mem_cgroup_shmem_charge_fallback(): it was only required when we
had to move swappage to filecache with GFP_NOWAIT.
Remove the GFP_NOWAIT special case from mem_cgroup_cache_charge(), by
moving its call out from shmem_add_to_page_cache() to two of thats three
callers. But leave it doing mem_cgroup_uncharge_cache_page() on error:
although asymmetrical, it's easier for all 3 callers to handle.
These two changes would also be appropriate if anyone were to start
using shmem_read_mapping_page_gfp() with GFP_NOWAIT.
Remove mem_cgroup_get_shmem_target(): mc_handle_file_pte() can test
radix_tree_exceptional_entry() to get what it needs for itself.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The commit log of 0ae5e89c60 ("memcg: count the soft_limit reclaim
in...") says it adds scanning stats to memory.stat file. But it doesn't
because we considered we needed to make a concensus for such new APIs.
This patch is a trial to add memory.scan_stat. This shows
- the number of scanned pages(total, anon, file)
- the number of rotated pages(total, anon, file)
- the number of freed pages(total, anon, file)
- the number of elaplsed time (including sleep/pause time)
for both of direct/soft reclaim.
The biggest difference with oringinal Ying's one is that this file
can be reset by some write, as
# echo 0 ...../memory.scan_stat
Example of output is here. This is a result after make -j 6 kernel
under 300M limit.
[kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.scan_stat
[kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.vmscan_stat
scanned_pages_by_limit 9471864
scanned_anon_pages_by_limit 6640629
scanned_file_pages_by_limit 2831235
rotated_pages_by_limit 4243974
rotated_anon_pages_by_limit 3971968
rotated_file_pages_by_limit 272006
freed_pages_by_limit 2318492
freed_anon_pages_by_limit 962052
freed_file_pages_by_limit 1356440
elapsed_ns_by_limit 351386416101
scanned_pages_by_system 0
scanned_anon_pages_by_system 0
scanned_file_pages_by_system 0
rotated_pages_by_system 0
rotated_anon_pages_by_system 0
rotated_file_pages_by_system 0
freed_pages_by_system 0
freed_anon_pages_by_system 0
freed_file_pages_by_system 0
elapsed_ns_by_system 0
scanned_pages_by_limit_under_hierarchy 9471864
scanned_anon_pages_by_limit_under_hierarchy 6640629
scanned_file_pages_by_limit_under_hierarchy 2831235
rotated_pages_by_limit_under_hierarchy 4243974
rotated_anon_pages_by_limit_under_hierarchy 3971968
rotated_file_pages_by_limit_under_hierarchy 272006
freed_pages_by_limit_under_hierarchy 2318492
freed_anon_pages_by_limit_under_hierarchy 962052
freed_file_pages_by_limit_under_hierarchy 1356440
elapsed_ns_by_limit_under_hierarchy 351386416101
scanned_pages_by_system_under_hierarchy 0
scanned_anon_pages_by_system_under_hierarchy 0
scanned_file_pages_by_system_under_hierarchy 0
rotated_pages_by_system_under_hierarchy 0
rotated_anon_pages_by_system_under_hierarchy 0
rotated_file_pages_by_system_under_hierarchy 0
freed_pages_by_system_under_hierarchy 0
freed_anon_pages_by_system_under_hierarchy 0
freed_file_pages_by_system_under_hierarchy 0
elapsed_ns_by_system_under_hierarchy 0
total_xxxx is for hierarchy management.
This will be useful for further memcg developments and need to be
developped before we do some complicated rework on LRU/softlimit
management.
This patch adds a new struct memcg_scanrecord into scan_control struct.
sc->nr_scanned at el is not designed for exporting information. For
example, nr_scanned is reset frequentrly and incremented +2 at scanning
mapped pages.
To avoid complexity, I added a new param in scan_control which is for
exporting scanning score.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Andrew Bresticker <abrestic@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In mm/memcontrol.c, there are many lru stat functions as..
mem_cgroup_zone_nr_lru_pages
mem_cgroup_node_nr_file_lru_pages
mem_cgroup_nr_file_lru_pages
mem_cgroup_node_nr_anon_lru_pages
mem_cgroup_nr_anon_lru_pages
mem_cgroup_node_nr_unevictable_lru_pages
mem_cgroup_nr_unevictable_lru_pages
mem_cgroup_node_nr_lru_pages
mem_cgroup_nr_lru_pages
mem_cgroup_get_local_zonestat
Some of them are under #ifdef MAX_NUMNODES >1 and others are not.
This seems bad. This patch consolidates all functions into
mem_cgroup_zone_nr_lru_pages()
mem_cgroup_node_nr_lru_pages()
mem_cgroup_nr_lru_pages()
For these functions, "which LRU?" information is passed by a mask.
example:
mem_cgroup_nr_lru_pages(mem, BIT(LRU_ACTIVE_ANON))
And I added some macro as ALL_LRU, ALL_LRU_FILE, ALL_LRU_ANON.
example:
mem_cgroup_nr_lru_pages(mem, ALL_LRU)
BTW, considering layout of NUMA memory placement of counters, this patch seems
to be better.
Now, when we gather all LRU information, we scan in following orer
for_each_lru -> for_each_node -> for_each_zone.
This means we'll touch cache lines in different node in turn.
After patch, we'll scan
for_each_node -> for_each_zone -> for_each_lru(mask)
Then, we'll gather information in the same cacheline at once.
[akpm@linux-foundation.org: fix warnigns, build error]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, memcg reclaim can disable swap token even if the swap token mm
doesn't belong in its memory cgroup. It's slightly risky. If an admin
creates very small mem-cgroup and silly guy runs contentious heavy memory
pressure workload, every tasks are going to lose swap token and then
system may become unresponsive. That's bad.
This patch adds 'memcg' parameter into disable_swap_token(). and if the
parameter doesn't match swap token, VM doesn't disable it.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Rik van Riel<riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Two new stats in per-memcg memory.stat which tracks the number of page
faults and number of major page faults.
"pgfault"
"pgmajfault"
They are different from "pgpgin"/"pgpgout" stat which count number of
pages charged/discharged to the cgroup and have no meaning of reading/
writing page to disk.
It is valuable to track the two stats for both measuring application's
performance as well as the efficiency of the kernel page reclaim path.
Counting pagefaults per process is useful, but we also need the aggregated
value since processes are monitored and controlled in cgroup basis in
memcg.
Functional test: check the total number of pgfault/pgmajfault of all
memcgs and compare with global vmstat value:
$ cat /proc/vmstat | grep fault
pgfault 1070751
pgmajfault 553
$ cat /dev/cgroup/memory.stat | grep fault
pgfault 1071138
pgmajfault 553
total_pgfault 1071142
total_pgmajfault 553
$ cat /dev/cgroup/A/memory.stat | grep fault
pgfault 199
pgmajfault 0
total_pgfault 199
total_pgmajfault 0
Performance test: run page fault test(pft) wit 16 thread on faulting in
15G anon pages in 16G container. There is no regression noticed on the
"flt/cpu/s"
Sample output from pft:
TAG pft:anon-sys-default:
Gb Thr CLine User System Wall flt/cpu/s fault/wsec
15 16 1 0.67s 233.41s 14.76s 16798.546 266356.260
+-------------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 10 16682.962 17344.027 16913.524 16928.812 166.5362
+ 10 16695.568 16923.896 16820.604 16824.652 84.816568
No difference proven at 95.0% confidence
[akpm@linux-foundation.org: fix build]
[hughd@google.com: shmem fix]
Signed-off-by: Ying Han <yinghan@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The caller of the function has been renamed to zone_nr_lru_pages(), and
this is just fixing up in the memcg code. The current name is easily to
be mis-read as zone's total number of pages.
Signed-off-by: Ying Han <yinghan@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Presently, memory cgroup's direct reclaim frees memory from the current
node. But this has some troubles. Usually when a set of threads works in
a cooperative way, they tend to operate on the same node. So if they hit
limits under memcg they will reclaim memory from themselves, damaging the
active working set.
For example, assume 2 node system which has Node 0 and Node 1 and a memcg
which has 1G limit. After some work, file cache remains and the usages
are
Node 0: 1M
Node 1: 998M.
and run an application on Node 0, it will eat its foot before freeing
unnecessary file caches.
This patch adds round-robin for NUMA and adds equal pressure to each node.
When using cpuset's spread memory feature, this will work very well.
But yes, a better algorithm is needed.
[akpm@linux-foundation.org: comment editing]
[kamezawa.hiroyu@jp.fujitsu.com: fix time comparisons]
Signed-off-by: Ying Han <yinghan@google.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The global kswapd scans per-zone LRU and reclaims pages regardless of the
cgroup. It breaks memory isolation since one cgroup can end up reclaiming
pages from another cgroup. Instead we should rely on memcg-aware target
reclaim including per-memcg kswapd and soft_limit hierarchical reclaim under
memory pressure.
In the global background reclaim, we do soft reclaim before scanning the
per-zone LRU. However, the return value is ignored. This patch is the first
step to skip shrink_zone() if soft_limit reclaim does enough work.
This is part of the effort which tries to reduce reclaiming pages in global
LRU in memcg. The per-memcg background reclaim patchset further enhances the
per-cgroup targetting reclaim, which I should have V4 posted shortly.
Try running multiple memory intensive workloads within seperate memcgs. Watch
the counters of soft_steal in memory.stat.
$ cat /dev/cgroup/A/memory.stat | grep 'soft'
soft_steal 240000
soft_scan 240000
total_soft_steal 240000
total_soft_scan 240000
This patch:
In the global background reclaim, we do soft reclaim before scanning the
per-zone LRU. However, the return value is ignored.
We would like to skip shrink_zone() if soft_limit reclaim does enough
work. Also, we need to make the memory pressure balanced across per-memcg
zones, like the logic vm-core. This patch is the first step where we
start with counting the nr_scanned and nr_reclaimed from soft_limit
reclaim into the global scan_control.
Signed-off-by: Ying Han <yinghan@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
commit 3f58a82943 ("move memcg reclaimable page into tail of inactive
list") added inline keyword twice in its prototype.
CC arch/x86/kernel/asm-offsets.s
In file included from include/linux/swap.h:8,
from include/linux/suspend.h:4,
from arch/x86/kernel/asm-offsets.c:12:
include/linux/memcontrol.h:220: error: duplicate `inline'
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add checks at allocating or freeing a page whether the page is used (iow,
charged) from the view point of memcg.
This check may be useful in debugging a problem and we did similar checks
before the commit 52d4b9ac(memcg: allocate all page_cgroup at boot).
This patch adds some overheads at allocating or freeing memory, so it's
enabled only when CONFIG_DEBUG_VM is enabled.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The rotate_reclaimable_page function moves just written out pages, which
the VM wanted to reclaim, to the end of the inactive list. That way the
VM will find those pages first next time it needs to free memory.
This patch applies the rule in memcg. It can help to prevent unnecessary
working page eviction of memcg.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This function basically does:
remove_from_page_cache(old);
page_cache_release(old);
add_to_page_cache_locked(new);
Except it does this atomically, so there's no possibility for the "add" to
fail because of a race.
If memory cgroups are enabled, then the memory cgroup charge is also moved
from the old page to the new.
This function is currently used by fuse to move pages into the page cache
on read, instead of copying the page contents.
[minchan.kim@gmail.com: add freepage() hook to replace_page_cache_page()]
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now, under THP:
at charge:
- PageCgroupUsed bit is set to all page_cgroup on a hugepage.
....set to 512 pages.
at uncharge
- PageCgroupUsed bit is unset on the head page.
So, some pages will remain with "Used" bit.
This patch fixes that Used bit is set only to the head page.
Used bits for tail pages will be set at splitting if necessary.
This patch adds this lock order:
compound_lock() -> page_cgroup_move_lock().
[akpm@linux-foundation.org: fix warning]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In the current implementation mem_cgroup_end_migration() decides whether
the page migration has succeeded or not by checking "oldpage->mapping".
But if we are tring to migrate a shmem swapcache, the page->mapping of it
is NULL from the begining, so the check would be invalid. As a result,
mem_cgroup_end_migration() assumes the migration has succeeded even if
it's not, so "newpage" would be freed while it's not uncharged.
This patch fixes it by passing mem_cgroup_end_migration() the result of
the page migration.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace usage of the mem_cgroup_update_file_mapped() memcg
statistic update routine with two new routines:
* mem_cgroup_inc_page_stat()
* mem_cgroup_dec_page_stat()
As before, only the file_mapped statistic is managed. However, these more
general interfaces allow for new statistics to be more easily added. New
statistics are added with memcg dirty page accounting.
Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrea Righi <arighi@develer.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mem_cgroup_soft_limit_reclaim() has zone, nid and zid argument. but nid
and zid can be calculated from zone. So remove it.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This a complete rewrite of the oom killer's badness() heuristic which is
used to determine which task to kill in oom conditions. The goal is to
make it as simple and predictable as possible so the results are better
understood and we end up killing the task which will lead to the most
memory freeing while still respecting the fine-tuning from userspace.
Instead of basing the heuristic on mm->total_vm for each task, the task's
rss and swap space is used instead. This is a better indication of the
amount of memory that will be freeable if the oom killed task is chosen
and subsequently exits. This helps specifically in cases where KDE or
GNOME is chosen for oom kill on desktop systems instead of a memory
hogging task.
The baseline for the heuristic is a proportion of memory that each task is
currently using in memory plus swap compared to the amount of "allowable"
memory. "Allowable," in this sense, means the system-wide resources for
unconstrained oom conditions, the set of mempolicy nodes, the mems
attached to current's cpuset, or a memory controller's limit. The
proportion is given on a scale of 0 (never kill) to 1000 (always kill),
roughly meaning that if a task has a badness() score of 500 that the task
consumes approximately 50% of allowable memory resident in RAM or in swap
space.
The proportion is always relative to the amount of "allowable" memory and
not the total amount of RAM systemwide so that mempolicies and cpusets may
operate in isolation; they shall not need to know the true size of the
machine on which they are running if they are bound to a specific set of
nodes or mems, respectively.
Root tasks are given 3% extra memory just like __vm_enough_memory()
provides in LSMs. In the event of two tasks consuming similar amounts of
memory, it is generally better to save root's task.
Because of the change in the badness() heuristic's baseline, it is also
necessary to introduce a new user interface to tune it. It's not possible
to redefine the meaning of /proc/pid/oom_adj with a new scale since the
ABI cannot be changed for backward compatability. Instead, a new tunable,
/proc/pid/oom_score_adj, is added that ranges from -1000 to +1000. It may
be used to polarize the heuristic such that certain tasks are never
considered for oom kill while others may always be considered. The value
is added directly into the badness() score so a value of -500, for
example, means to discount 50% of its memory consumption in comparison to
other tasks either on the system, bound to the mempolicy, in the cpuset,
or sharing the same memory controller.
/proc/pid/oom_adj is changed so that its meaning is rescaled into the
units used by /proc/pid/oom_score_adj, and vice versa. Changing one of
these per-task tunables will rescale the value of the other to an
equivalent meaning. Although /proc/pid/oom_adj was originally defined as
a bitshift on the badness score, it now shares the same linear growth as
/proc/pid/oom_score_adj but with different granularity. This is required
so the ABI is not broken with userspace applications and allows oom_adj to
be deprecated for future removal.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since 2.6.28 zone->prev_priority is unused. Then it can be removed
safely. It reduce stack usage slightly.
Now I have to say that I'm sorry. 2 years ago, I thought prev_priority
can be integrate again, it's useful. but four (or more) times trying
haven't got good performance number. Thus I give up such approach.
The rest of this changelog is notes on prev_priority and why it existed in
the first place and why it might be not necessary any more. This information
is based heavily on discussions between Andrew Morton, Rik van Riel and
Kosaki Motohiro who is heavily quotes from.
Historically prev_priority was important because it determined when the VM
would start unmapping PTE pages. i.e. there are no balances of note within
the VM, Anon vs File and Mapped vs Unmapped. Without prev_priority, there
is a potential risk of unnecessarily increasing minor faults as a large
amount of read activity of use-once pages could push mapped pages to the
end of the LRU and get unmapped.
There is no proof this is still a problem but currently it is not considered
to be. Active files are not deactivated if the active file list is smaller
than the inactive list reducing the liklihood that file-mapped pages are
being pushed off the LRU and referenced executable pages are kept on the
active list to avoid them getting pushed out by read activity.
Even if it is a problem, prev_priority prev_priority wouldn't works
nowadays. First of all, current vmscan still a lot of UP centric code. it
expose some weakness on some dozens CPUs machine. I think we need more and
more improvement.
The problem is, current vmscan mix up per-system-pressure, per-zone-pressure
and per-task-pressure a bit. example, prev_priority try to boost priority to
other concurrent priority. but if the another task have mempolicy restriction,
it is unnecessary, but also makes wrong big latency and exceeding reclaim.
per-task based priority + prev_priority adjustment make the emulation of
per-system pressure. but it have two issue 1) too rough and brutal emulation
2) we need per-zone pressure, not per-system.
Another example, currently DEF_PRIORITY is 12. it mean the lru rotate about
2 cycle (1/4096 + 1/2048 + 1/1024 + .. + 1) before invoking OOM-Killer.
but if 10,0000 thrreads enter DEF_PRIORITY reclaim at the same time, the
system have higher memory pressure than priority==0 (1/4096*10,000 > 2).
prev_priority can't solve such multithreads workload issue. In other word,
prev_priority concept assume the sysmtem don't have lots threads."
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michael Rubin <mrubin@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
FILE_MAPPED per memcg of migrated file cache is not properly updated,
because our hook in page_add_file_rmap() can't know to which memcg
FILE_MAPPED should be counted.
Basically, this patch is for fixing the bug but includes some big changes
to fix up other messes.
Now, at migrating mapped file, events happen in following sequence.
1. allocate a new page.
2. get memcg of an old page.
3. charge ageinst a new page before migration. But at this point,
no changes to new page's page_cgroup, no commit for the charge.
(IOW, PCG_USED bit is not set.)
4. page migration replaces radix-tree, old-page and new-page.
5. page migration remaps the new page if the old page was mapped.
6. Here, the new page is unlocked.
7. memcg commits the charge for newpage, Mark the new page's page_cgroup
as PCG_USED.
Because "commit" happens after page-remap, we can count FILE_MAPPED
at "5", because we should avoid to trust page_cgroup->mem_cgroup.
if PCG_USED bit is unset.
(Note: memcg's LRU removal code does that but LRU-isolation logic is used
for helping it. When we overwrite page_cgroup->mem_cgroup, page_cgroup is
not on LRU or page_cgroup->mem_cgroup is NULL.)
We can lose file_mapped accounting information at 5 because FILE_MAPPED
is updated only when mapcount changes 0->1. So we should catch it.
BTW, historically, above implemntation comes from migration-failure
of anonymous page. Because we charge both of old page and new page
with mapcount=0, we can't catch
- the page is really freed before remap.
- migration fails but it's freed before remap
or .....corner cases.
New migration sequence with memcg is:
1. allocate a new page.
2. mark PageCgroupMigration to the old page.
3. charge against a new page onto the old page's memcg. (here, new page's pc
is marked as PageCgroupUsed.)
4. page migration replaces radix-tree, page table, etc...
5. At remapping, new page's page_cgroup is now makrked as "USED"
We can catch 0->1 event and FILE_MAPPED will be properly updated.
And we can catch SWAPOUT event after unlock this and freeing this
page by unmap() can be caught.
7. Clear PageCgroupMigration of the old page.
So, FILE_MAPPED will be correctly updated.
Then, for what MIGRATION flag is ?
Without it, at migration failure, we may have to charge old page again
because it may be fully unmapped. "charge" means that we have to dive into
memory reclaim or something complated. So, it's better to avoid
charge it again. Before this patch, __commit_charge() was working for
both of the old/new page and fixed up all. But this technique has some
racy condtion around FILE_MAPPED and SWAPOUT etc...
Now, the kernel use MIGRATION flag and don't uncharge old page until
the end of migration.
I hope this change will make memcg's page migration much simpler. This
page migration has caused several troubles. Worth to add a flag for
simplification.
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reported-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For now, we have global isolation vs. memory control group isolation, do
not allow the reclaim entry function to set an arbitrary page isolation
callback, we do not need that flexibility.
And since we already pass around the group descriptor for the memory
control group isolation case, just use it to decide which one of the two
isolator functions to use.
The decisions can be merged into nearby branches, so no extra cost there.
In fact, we save the indirect calls.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In current page-fault code,
handle_mm_fault()
-> ...
-> mem_cgroup_charge()
-> map page or handle error.
-> check return code.
If page fault's return code is VM_FAULT_OOM, page_fault_out_of_memory() is
called. But if it's caused by memcg, OOM should have been already
invoked.
Then, I added a patch: a636b327f7. That
patch records last_oom_jiffies for memcg's sub-hierarchy and prevents
page_fault_out_of_memory from being invoked in near future.
But Nishimura-san reported that check by jiffies is not enough when the
system is terribly heavy.
This patch changes memcg's oom logic as.
* If memcg causes OOM-kill, continue to retry.
* remove jiffies check which is used now.
* add memcg-oom-lock which works like perzone oom lock.
* If current is killed(as a process), bypass charge.
Something more sophisticated can be added but this pactch does
fundamental things.
TODO:
- add oom notifier
- add permemcg disable-oom-kill flag and freezer at oom.
- more chances for wake up oom waiter (when changing memory limit etc..)
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (34 commits)
HWPOISON: Remove stray phrase in a comment
HWPOISON: Try to allocate migration page on the same node
HWPOISON: Don't do early filtering if filter is disabled
HWPOISON: Add a madvise() injector for soft page offlining
HWPOISON: Add soft page offline support
HWPOISON: Undefine short-hand macros after use to avoid namespace conflict
HWPOISON: Use new shake_page in memory_failure
HWPOISON: Use correct name for MADV_HWPOISON in documentation
HWPOISON: mention HWPoison in Kconfig entry
HWPOISON: Use get_user_page_fast in hwpoison madvise
HWPOISON: add an interface to switch off/on all the page filters
HWPOISON: add memory cgroup filter
memcg: add accessor to mem_cgroup.css
memcg: rename and export try_get_mem_cgroup_from_page()
HWPOISON: add page flags filter
mm: export stable page flags
HWPOISON: limit hwpoison injector to known page types
HWPOISON: add fs/device filters
HWPOISON: return 0 to indicate success reliably
HWPOISON: make semantics of IGNORED/DELAYED clear
...
In global VM, FILE_MAPPED is used but memcg uses MAPPED_FILE. This makes
grep difficult. Replace memcg's MAPPED_FILE with FILE_MAPPED
And in global VM, mapped shared memory is accounted into FILE_MAPPED.
But memcg doesn't. fix it.
Note:
page_is_file_cache() just checks SwapBacked or not.
So, we need to check PageAnon.
Cc: Balbir Singh <balbir@in.ibm.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In massive parallel enviroment, res_counter can be a performance
bottleneck. One strong techinque to reduce lock contention is reducing
calls by coalescing some amount of calls into one.
Considering charge/uncharge chatacteristic,
- charge is done one by one via demand-paging.
- uncharge is done by
- in chunk at munmap, truncate, exit, execve...
- one by one via vmscan/paging.
It seems we have a chance to coalesce uncharges for improving scalability
at unmap/truncation.
This patch is a for coalescing uncharge. For avoiding scattering memcg's
structure to functions under /mm, this patch adds memcg batch uncharge
information to the task. A reason for per-task batching is for making use
of caller's context information. We do batched uncharge (deleyed
uncharge) when truncation/unmap occurs but do direct uncharge when
uncharge is called by memory reclaim (vmscan.c).
The degree of coalescing depends on callers
- at invalidate/trucate... pagevec size
- at unmap ....ZAP_BLOCK_SIZE
(memory itself will be freed in this degree.)
Then, we'll not coalescing too much.
On x86-64 8cpu server, I tested overheads of memcg at page fault by
running a program which does map/fault/unmap in a loop. Running
a task per a cpu by taskset and see sum of the number of page faults
in 60secs.
[without memcg config]
40156968 page-faults # 0.085 M/sec ( +- 0.046% )
27.67 cache-miss/faults
[root cgroup]
36659599 page-faults # 0.077 M/sec ( +- 0.247% )
31.58 miss/faults
[in a child cgroup]
18444157 page-faults # 0.039 M/sec ( +- 0.133% )
69.96 miss/faults
[child with this patch]
27133719 page-faults # 0.057 M/sec ( +- 0.155% )
47.16 miss/faults
We can see some amounts of improvement.
(root cgroup doesn't affected by this patch)
Another patch for "charge" will follow this and above will be improved more.
Changelog(since 2009/10/02):
- renamed filed of memcg_batch (as pages to bytes, memsw to memsw_bytes)
- some clean up and commentary/description updates.
- added initialize code to copy_process(). (possible bug fix)
Changelog(old):
- fixed !CONFIG_MEM_CGROUP case.
- rebased onto the latest mmotm + softlimit fix patches.
- unified patch for callers
- added commetns.
- make ->do_batch as bool.
- removed css_get() at el. We don't need it.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
So that the hwpoison injector can get mem_cgroup for arbitrary page
and thus know whether it is owned by some mem_cgroup task(s).
[AK: Merged with latest git tree]
CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Hugh Dickins <hugh.dickins@tiscali.co.uk>
CC: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
CC: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Implement reclaim from groups over their soft limit
Permit reclaim from memory cgroups on contention (via the direct reclaim
path).
memory cgroup soft limit reclaim finds the group that exceeds its soft
limit by the largest number of pages and reclaims pages from it and then
reinserts the cgroup into its correct place in the rbtree.
Add additional checks to mem_cgroup_hierarchical_reclaim() to detect long
loops in case all swap is turned off. The code has been refactored and
the loop check (loop < 2) has been enhanced for soft limits. For soft
limits, we try to do more targetted reclaim. Instead of bailing out after
two loops, the routine now reclaims memory proportional to the size by
which the soft limit is exceeded. The proportion has been empirically
determined.
[akpm@linux-foundation.org: build fix]
[kamezawa.hiroyu@jp.fujitsu.com: fix softlimit css refcnt handling]
[nishimura@mxp.nes.nec.co.jp: refcount of the "victim" should be decremented before exiting the loop]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add file RSS tracking per memory cgroup
We currently don't track file RSS, the RSS we report is actually anon RSS.
All the file mapped pages, come in through the page cache and get
accounted there. This patch adds support for accounting file RSS pages.
It should
1. Help improve the metrics reported by the memory resource controller
2. Will form the basis for a future shared memory accounting heuristic
that has been proposed by Kamezawa.
Unfortunately, we cannot rename the existing "rss" keyword used in
memory.stat to "anon_rss". We however, add "mapped_file" data and hope to
educate the end user through documentation.
[hugh.dickins@tiscali.co.uk: fix mem_cgroup_update_mapped_file_stat oops]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.cn>
Cc: Paul Menage <menage@google.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the file LRU lists are dominated by streaming IO pages, evict those
pages first, before considering evicting other pages.
This should be safe from deadlocks or performance problems
because only three things can happen to an inactive file page:
1) referenced twice and promoted to the active list
2) evicted by the pageout code
3) under IO, after which it will get evicted or promoted
The pages freed in this way can either be reused for streaming IO, or
allocated for something else. If the pages are used for streaming IO,
this pageout pattern continues. Otherwise, we will fall back to the
normal pageout pattern.
Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Elladan <elladan@eskimo.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current mem_cgroup_shrink_usage() has two problems.
1. It doesn't call mem_cgroup_out_of_memory and doesn't update
last_oom_jiffies, so pagefault_out_of_memory invokes global OOM.
2. Considering hierarchy, shrinking has to be done from the
mem_over_limit, not from the memcg which the page would be charged to.
mem_cgroup_try_charge_swapin() does all of these things properly, so we
use it and call cancel_charge_swapin when it succeeded.
The name of "shrink_usage" is not appropriate for this behavior, so we
change it too.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.cn>
Cc: Paul Menage <menage@google.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, mem_cgroup_calc_mapped_ratio() is unused at all. it can be
removed and KAMEZAWA-san suggested it.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add RSS and swap to OOM output from memcg
Display memcg values like failcnt, usage and limit when an OOM occurs due
to memcg.
Thanks to Johannes Weiner, Li Zefan, David Rientjes, Kamezawa Hiroyuki,
Daisuke Nishimura and KOSAKI Motohiro for review.
Sample output
-------------
Task in /a/x killed as a result of limit of /a
memory: usage 1048576kB, limit 1048576kB, failcnt 4183
memory+swap: usage 1400964kB, limit 9007199254740991kB, failcnt 0
[akpm@linux-foundation.org: compilation fix]
[akpm@linux-foundation.org: fix kerneldoc and whitespace]
[akpm@linux-foundation.org: add printk facility level]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now, you can see following even when swap accounting is enabled.
1. Create Group 01, and 02.
2. allocate a "file" on tmpfs by a task under 01.
3. swap out the "file" (by memory pressure)
4. Read "file" from a task in group 02.
5. the charge of "file" is moved to group 02.
This is not ideal behavior. This is because SwapCache which was loaded
by read-ahead is not taken into account..
This is a patch to fix shmem's swapcache behavior.
- remove mem_cgroup_cache_charge_swapin().
- Add SwapCache handler routine to mem_cgroup_cache_charge().
By this, shmem's file cache is charged at add_to_page_cache()
with GFP_NOWAIT.
- pass the page of swapcache to shrink_mem_cgroup.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After previous patch, mem_cgroup_try_charge is not used by anyone, so we
can remove it.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, inactive_ratio of memcg is calculated at setting limit.
because page_alloc.c does so and current implementation is straightforward
porting.
However, memcg introduced hierarchy feature recently. In hierarchy
restriction, memory limit is not only decided memory.limit_in_bytes of
current cgroup, but also parent limit and sibling memory usage.
Then, The optimal inactive_ratio is changed frequently. So, everytime
calculation is better.
Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now, get_scan_ratio() return correct value although memcg reclaim. Then,
mem_cgroup_calc_reclaim() can be removed.
So, memcg reclaim get the same capability of anon/file reclaim balancing
as global reclaim now.
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The inactive_anon_is_low() is key component of active/inactive anon
balancing on reclaim. However current inactive_anon_is_low() function
only consider global reclaim.
Therefore, we need following ugly scan_global_lru() condition.
if (lru == LRU_ACTIVE_ANON &&
(!scan_global_lru(sc) || inactive_anon_is_low(zone))) {
shrink_active_list(nr_to_scan, zone, sc, priority, file);
return 0;
it cause that memcg reclaim always deactivate pages when shrink_list() is
called. To make mem_cgroup_inactive_anon_is_low() improve active/inactive
anon balancing of memcgroup.
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: "Pekka Enberg" <penberg@cs.helsinki.fi>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
My patch, memcg-fix-gfp_mask-of-callers-of-charge.patch changed gfp_mask
of callers of charge to be GFP_HIGHUSER_MOVABLE for showing what will
happen at memory reclaim.
But in recent discussion, it's NACKed because it sounds ugly.
This patch is for reverting it and add some clean up to gfp_mask of
callers of charge. No behavior change but need review before generating
HUNK in deep queue.
This patch also adds explanation to meaning of gfp_mask passed to charge
functions in memcontrol.h.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current mmtom has new oom function as pagefault_out_of_memory(). It's
added for select bad process rathar than killing current.
When memcg hit limit and calls OOM at page_fault, this handler called and
system-wide-oom handling happens. (means kernel panics if panic_on_oom is
true....)
To avoid overkill, check memcg's recent behavior before starting
system-wide-oom.
And this patch also fixes to guarantee "don't accnout against process with
TIF_MEMDIE". This is necessary for smooth OOM.
[akpm@linux-foundation.org: build fix]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Jan Blunck <jblunck@suse.de>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm_match_cgroup() calls cgroup_subsys_state().
We must use rcu_read_lock() to protect cgroup_subsys_state().
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We check mem_cgroup is disabled or not by checking
mem_cgroup_subsys.disabled. I think it has more references than expected,
now.
replacing
if (mem_cgroup_subsys.disabled)
with
if (mem_cgroup_disabled())
give us good look, I think.
[kamezawa.hiroyu@jp.fujitsu.com: fix typo]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A big patch for changing memcg's LRU semantics.
Now,
- page_cgroup is linked to mem_cgroup's its own LRU (per zone).
- LRU of page_cgroup is not synchronous with global LRU.
- page and page_cgroup is one-to-one and statically allocated.
- To find page_cgroup is on what LRU, you have to check pc->mem_cgroup as
- lru = page_cgroup_zoneinfo(pc, nid_of_pc, zid_of_pc);
- SwapCache is handled.
And, when we handle LRU list of page_cgroup, we do following.
pc = lookup_page_cgroup(page);
lock_page_cgroup(pc); .....................(1)
mz = page_cgroup_zoneinfo(pc);
spin_lock(&mz->lru_lock);
.....add to LRU
spin_unlock(&mz->lru_lock);
unlock_page_cgroup(pc);
But (1) is spin_lock and we have to be afraid of dead-lock with zone->lru_lock.
So, trylock() is used at (1), now. Without (1), we can't trust "mz" is correct.
This is a trial to remove this dirty nesting of locks.
This patch changes mz->lru_lock to be zone->lru_lock.
Then, above sequence will be written as
spin_lock(&zone->lru_lock); # in vmscan.c or swap.c via global LRU
mem_cgroup_add/remove/etc_lru() {
pc = lookup_page_cgroup(page);
mz = page_cgroup_zoneinfo(pc);
if (PageCgroupUsed(pc)) {
....add to LRU
}
spin_lock(&zone->lru_lock); # in vmscan.c or swap.c via global LRU
This is much simpler.
(*) We're safe even if we don't take lock_page_cgroup(pc). Because..
1. When pc->mem_cgroup can be modified.
- at charge.
- at account_move().
2. at charge
the PCG_USED bit is not set before pc->mem_cgroup is fixed.
3. at account_move()
the page is isolated and not on LRU.
Pros.
- easy for maintenance.
- memcg can make use of laziness of pagevec.
- we don't have to duplicated LRU/Active/Unevictable bit in page_cgroup.
- LRU status of memcg will be synchronized with global LRU's one.
- # of locks are reduced.
- account_move() is simplified very much.
Cons.
- may increase cost of LRU rotation.
(no impact if memcg is not configured.)
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch implements per cgroup limit for usage of memory+swap. However
there are SwapCache, double counting of swap-cache and swap-entry is
avoided.
Mem+Swap controller works as following.
- memory usage is limited by memory.limit_in_bytes.
- memory + swap usage is limited by memory.memsw_limit_in_bytes.
This has following benefits.
- A user can limit total resource usage of mem+swap.
Without this, because memory resource controller doesn't take care of
usage of swap, a process can exhaust all the swap (by memory leak.)
We can avoid this case.
And Swap is shared resource but it cannot be reclaimed (goes back to memory)
until it's used. This characteristic can be trouble when the memory
is divided into some parts by cpuset or memcg.
Assume group A and group B.
After some application executes, the system can be..
Group A -- very large free memory space but occupy 99% of swap.
Group B -- under memory shortage but cannot use swap...it's nearly full.
Ability to set appropriate swap limit for each group is required.
Maybe someone wonder "why not swap but mem+swap ?"
- The global LRU(kswapd) can swap out arbitrary pages. Swap-out means
to move account from memory to swap...there is no change in usage of
mem+swap.
In other words, when we want to limit the usage of swap without affecting
global LRU, mem+swap limit is better than just limiting swap.
Accounting target information is stored in swap_cgroup which is
per swap entry record.
Charge is done as following.
map
- charge page and memsw.
unmap
- uncharge page/memsw if not SwapCache.
swap-out (__delete_from_swap_cache)
- uncharge page
- record mem_cgroup information to swap_cgroup.
swap-in (do_swap_page)
- charged as page and memsw.
record in swap_cgroup is cleared.
memsw accounting is decremented.
swap-free (swap_free())
- if swap entry is freed, memsw is uncharged by PAGE_SIZE.
There are people work under never-swap environments and consider swap as
something bad. For such people, this mem+swap controller extension is just an
overhead. This overhead is avoided by config or boot option.
(see Kconfig. detail is not in this patch.)
TODO:
- maybe more optimization can be don in swap-in path. (but not very safe.)
But we just do simple accounting at this stage.
[nishimura@mxp.nes.nec.co.jp: make resize limit hold mutex]
[hugh@veritas.com: memswap controller core swapcache fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Config and control variable for mem+swap controller.
This patch adds CONFIG_CGROUP_MEM_RES_CTLR_SWAP
(memory resource controller swap extension.)
For accounting swap, it's obvious that we have to use additional memory to
remember "who uses swap". This adds more overhead. So, it's better to
offer "choice" to users. This patch adds 2 choices.
This patch adds 2 parameters to enable swap extension or not.
- CONFIG
- boot option
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now, management of "charge" under page migration is done under following
manner. (Assume migrate page contents from oldpage to newpage)
before
- "newpage" is charged before migration.
at success.
- "oldpage" is uncharged at somewhere(unmap, radix-tree-replace)
at failure
- "newpage" is uncharged.
- "oldpage" is charged if necessary (*1)
But (*1) is not reliable....because of GFP_ATOMIC.
This patch tries to change behavior as following by charge/commit/cancel ops.
before
- charge PAGE_SIZE (no target page)
success
- commit charge against "newpage".
failure
- commit charge against "oldpage".
(PCG_USED bit works effectively to avoid double-counting)
- if "oldpage" is obsolete, cancel charge of PAGE_SIZE.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a small race in do_swap_page(). When the page swapped-in is
charged, the mapcount can be greater than 0. But, at the same time some
process (shares it ) call unmap and make mapcount 1->0 and the page is
uncharged.
CPUA CPUB
mapcount == 1.
(1) charge if mapcount==0 zap_pte_range()
(2) mapcount 1 => 0.
(3) uncharge(). (success)
(4) set page's rmap()
mapcount 0=>1
Then, this swap page's account is leaked.
For fixing this, I added a new interface.
- charge
account to res_counter by PAGE_SIZE and try to free pages if necessary.
- commit
register page_cgroup and add to LRU if necessary.
- cancel
uncharge PAGE_SIZE because of do_swap_page failure.
CPUA
(1) charge (always)
(2) set page's rmap (mapcount > 0)
(3) commit charge was necessary or not after set_pte().
This protocol uses PCG_USED bit on page_cgroup for avoiding over accounting.
Usual mem_cgroup_charge_common() does charge -> commit at a time.
And this patch also adds following function to clarify all charges.
- mem_cgroup_newpage_charge() ....replacement for mem_cgroup_charge()
called against newly allocated anon pages.
- mem_cgroup_charge_migrate_fixup()
called only from remove_migration_ptes().
we'll have to rewrite this later.(this patch just keeps old behavior)
This function will be removed by additional patch to make migration
clearer.
Good for clarifying "what we do"
Then, we have 4 following charge points.
- newpage
- swap-in
- add-to-cache.
- migration.
[akpm@linux-foundation.org: add missing inline directives to stubs]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allocate all page_cgroup at boot and remove page_cgroup poitner from
struct page. This patch adds an interface as
struct page_cgroup *lookup_page_cgroup(struct page*)
All FLATMEM/DISCONTIGMEM/SPARSEMEM and MEMORY_HOTPLUG is supported.
Remove page_cgroup pointer reduces the amount of memory by
- 4 bytes per PAGE_SIZE.
- 8 bytes per PAGE_SIZE
if memory controller is disabled. (even if configured.)
On usual 8GB x86-32 server, this saves 8MB of NORMAL_ZONE memory.
On my x86-64 server with 48GB of memory, this saves 96MB of memory.
I think this reduction makes sense.
By pre-allocation, kmalloc/kfree in charge/uncharge are removed.
This means
- we're not necessary to be afraid of kmalloc faiulre.
(this can happen because of gfp_mask type.)
- we can avoid calling kmalloc/kfree.
- we can avoid allocating tons of small objects which can be fragmented.
- we can know what amount of memory will be used for this extra-lru handling.
I added printk message as
"allocated %ld bytes of page_cgroup"
"please try cgroup_disable=memory option if you don't want"
maybe enough informative for users.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the system contains lots of mlocked or otherwise unevictable pages,
the pageout code (kswapd) can spend lots of time scanning over these
pages. Worse still, the presence of lots of unevictable pages can confuse
kswapd into thinking that more aggressive pageout modes are required,
resulting in all kinds of bad behaviour.
Infrastructure to manage pages excluded from reclaim--i.e., hidden from
vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to
maintain "unevictable" pages on a separate per-zone LRU list, to "hide"
them from vmscan.
Kosaki Motohiro added the support for the memory controller unevictable
lru list.
Pages on the unevictable list have both PG_unevictable and PG_lru set.
Thus, PG_unevictable is analogous to and mutually exclusive with
PG_active--it specifies which LRU list the page is on.
The unevictable infrastructure is enabled by a new mm Kconfig option
[CONFIG_]UNEVICTABLE_LRU.
A new function 'page_evictable(page, vma)' in vmscan.c tests whether or
not a page may be evictable. Subsequent patches will add the various
!evictable tests. We'll want to keep these tests light-weight for use in
shrink_active_list() and, possibly, the fault path.
To avoid races between tasks putting pages [back] onto an LRU list and
tasks that might be moving the page from non-evictable to evictable state,
the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()'
-- tests the "evictability" of a page after placing it on the LRU, before
dropping the reference. If the page has become unevictable,
putback_lru_page() will redo the 'putback', thus moving the page to the
unevictable list. This way, we avoid "stranding" evictable pages on the
unevictable list.
[akpm@linux-foundation.org: fix fallout from out-of-order merge]
[riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build]
[nishimura@mxp.nes.nec.co.jp: remove redundant mapping check]
[kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework]
[kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c]
[kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure]
[kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch]
[kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch]
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Split the LRU lists in two, one set for pages that are backed by real file
systems ("file") and one for pages that are backed by memory and swap
("anon"). The latter includes tmpfs.
The advantage of doing this is that the VM will not have to scan over lots
of anonymous pages (which we generally do not want to swap out), just to
find the page cache pages that it should evict.
This patch has the infrastructure and a basic policy to balance how much
we scan the anon lists and how much we scan the file lists. The big
policy changes are in separate patches.
[lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset]
[kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru]
[kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page]
[hugh@veritas.com: memcg swapbacked pages active]
[hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED]
[akpm@linux-foundation.org: fix /proc/vmstat units]
[nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration]
[kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo]
[kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()]
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we are defining explicit variables for the inactive and active
list. An indexed array can be more generic and avoid repeating similar
code in several places in the reclaim code.
We are saving a few bytes in terms of code size:
Before:
text data bss dec hex filename
4097753 573120 4092484 8763357 85b7dd vmlinux
After:
text data bss dec hex filename
4097729 573120 4092484 8763333 85b7c5 vmlinux
Having an easy way to add new lru lists may ease future work on the
reclaim code.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A new call, mem_cgroup_shrink_usage() is added for shmem handling and
relacing non-standard usage of mem_cgroup_charge/uncharge.
Now, shmem calls mem_cgroup_charge() just for reclaim some pages from
mem_cgroup. In general, shmem is used by some process group and not for
global resource (like file caches). So, it's reasonable to reclaim pages
from mem_cgroup where shmem is mainly used.
[hugh@veritas.com: shmem_getpage release page sooner]
[hugh@veritas.com: mem_cgroup_shrink_usage css_put]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch changes page migration under memory controller to use a
different algorithm. (thanks to Christoph for new idea.)
Before:
- page_cgroup is migrated from an old page to a new page.
After:
- a new page is accounted , no reuse of page_cgroup.
Pros:
- We can avoid compliated lock depndencies and races in migration.
Cons:
- new param to mem_cgroup_charge_common().
- mem_cgroup_getref() is added for handling ref_cnt ping-pong.
This version simplifies complicated lock dependency in page migraiton
under memory resource controller.
new refcnt sequence is following.
a mapped page:
prepage_migration() ..... +1 to NEW page
try_to_unmap() ..... all refs to OLD page is gone.
move_pages() ..... +1 to NEW page if page cache.
remap... ..... all refs from *map* is added to NEW one.
end_migration() ..... -1 to New page.
page's mapcount + (page_is_cache) refs are added to NEW one.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the mem_cgroup member from mm_struct and instead adds an owner.
This approach was suggested by Paul Menage. The advantage of this approach
is that, once the mm->owner is known, using the subsystem id, the cgroup
can be determined. It also allows several control groups that are
virtually grouped by mm_struct, to exist independent of the memory
controller i.e., without adding mem_cgroup's for each controller, to
mm_struct.
A new config option CONFIG_MM_OWNER is added and the memory resource
controller selects this config option.
This patch also adds cgroup callbacks to notify subsystems when mm->owner
changes. The mm_cgroup_changed callback is called with the task_lock() of
the new task held and is called just prior to changing the mm->owner.
I am indebted to Paul Menage for the several reviews of this patchset and
helping me make it lighter and simpler.
This patch was tested on a powerpc box, it was compiled with both the
MM_OWNER config turned on and off.
After the thread group leader exits, it's moved to init_css_state by
cgroup_exit(), thus all future charges from runnings threads would be
redirected to the init_css_set's subsystem.
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>,
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nothing uses mem_cgroup_uncharge apart from mem_cgroup_uncharge_page, (a
trivial wrapper around it) and mem_cgroup_end_migration (which does the same
as mem_cgroup_uncharge_page). And it often ends up having to lock just to let
its caller unlock. Remove it (but leave the silly locking until a later
patch).
Moved mem_cgroup_cache_charge next to mem_cgroup_charge in memcontrol.h.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace free_hot_cold_page's VM_BUG_ON(page_get_page_cgroup(page)) by a "Bad
page state" and clear: most users don't have CONFIG_DEBUG_VM on, and if it
were set here, it'd likely cause corruption when the page is reused.
Don't use page_assign_page_cgroup to clear it: that should be private to
memcontrol.c, and always called with the lock taken; and memmap_init_zone
doesn't need it either - like page->mapping and other pointers throughout the
kernel, Linux assumes pointers in zeroed structures are NULL pointers.
Instead use page_reset_bad_cgroup, added to memcontrol.h for this only.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Each caller of mem_cgroup_move_lists is having to use page_get_page_cgroup:
it's more convenient if it acts upon the page itself not the page_cgroup; and
in a later patch this becomes important to handle within memcontrol.c.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Glauber Costa
David Rientjes
Johannes Weiner
Andrew Morton
Hugh Dickins
Konstantin Khlebnikov
KAMEZAWA Hiroyuki
Johannes Weiner
David S. Miller
Raghavendra K T
Minchan Kim
KOSAKI Motohiro
Ying Han
Eric Dumazet
Daisuke Nishimura
Miklos Szeredi
Greg Thelen
Linus Torvalds
Wu Fengguang
Balbir Singh
Rik van Riel
Lai Jiangshan
Hirokazu Takahashi
Lee Schermerhorn
Christoph Lameter
Hugh Dickins