At one single place in the code, the specified number of bytes to read and
the actual number of bytes read differ by one. This one-liner patch fixes
that inconsistency.
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Cc: Nicolas Boichat <nicolas@boichat.ch>
Cc: Riki Oktarianto <rkoktarianto@gmail.com>
Cc: Mark M. Hoffman <mhoffman@lightlink.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adds therm-min/max/crit-alarm callbacks, sensor-device-attribute
declarations, and refs to those new decls in the macro used to initialize
the therm_group (of sysfs files)
The thermistors use voltage channels to measure; so they don't have a
fault-alarm, but unlike the other voltages, they do have an overtemp,
which we call crit (by convention).
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
temp and vin status register values may be set by chip specifications, set
again by bios, or by this previously loaded driver. Debug output nicely
displays modprobe init=\d actions.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Driver handles 3 logical devices in fixed length array. Give this a
define-d constant.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adds temp-min/max/crit/fault-alarm callbacks, sensor-device-attribute
declarations, and refs to those new decls in the macro used to initialize
the temp_group (of sysfs files)
[akpm@linux-foundation.org: cleanups]
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adds vin-min/max-alarm callbacks, sensor-device-attribute declarations,
and refs to those new decls in the macro used to initialize the vin_group
(of sysfs files)
[akpm@linux-foundation.org: cleanups]
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bring hwmon/pc87360 into agreement with
Documentation/hwmon/sysfs-interface.
Patchset adds separate limit alarms for voltages and temps, it also adds
temp[123]_fault files. On my Soekris, temps 1,2 are unused/unconnected,
so temp[123]_fault = 1,1,0 respectively. This agrees with
/usr/bin/sensors, which has always shown them as OPEN. Temps 4,5,6 are
thermistor based, and dont have a fault bit in their status register.
This patch:
2 different kinds of constants added:
- CHAN_ALM_* constants for (later) vin, temp alarm callbacks.
- CHAN_* conversion constants, used in _init_device, partly for RW1C bits
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix for a typo and and replacing incorrect word in the comment.
Signed-off-by: Ameya Palande <2ameya@gmail.com>
Cc: "Ashok Raj" <ashok.raj@intel.com>
Cc: "Shaohua Li" <shaohua.li@intel.com>
Cc: "Anil S Keshavamurthy" <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These comments are useless, remove them.
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On my HP 2510, pressing the (i) button generates an unknown keycode:
0x213b. So here is a patch adding support for it. However, as it seems
there is already support for a similar button connected to 0x231b as
keycode, I wonder if it could be a typo in the driver?
Signed-off-by: Eric Piel <eric.piel@tremplin-utc.net>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I fell into the trap recently that it only dumps hrtimers instead of
all timers. Fix the documentation.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix
arch/um/sys-i386/signal.c: In function 'copy_sc_from_user':
arch/um/sys-i386/signal.c:182: warning: dereferencing 'void *' pointer
arch/um/sys-i386/signal.c:182: error: request for member '_fxsr_env' in something not a structure or union
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Describe why we need the freezer subsystem and how to use it in a
documentation file. Since the cgroups.txt file is focused on the
subsystem-agnostic portions of cgroups make a directory and move the old
cgroups.txt file at the same time.
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: containers@lists.linux-foundation.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
check_if_frozen() sounds like it should return something when in fact it's
just updating the freezer state.
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename cgroup freezer states to be less generic to avoid any name
collisions while also better describing what each state is.
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Don't let frozen tasks or cgroups change. This means frozen tasks can't
leave their current cgroup for another cgroup. It also means that tasks
cannot be added to or removed from a cgroup in the FROZEN state. We
enforce these rules by checking for frozen tasks and cgroups in the
can_attach() function.
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a system is resumed after a suspend, it will also unfreeze frozen
cgroups.
This patchs modifies the resume sequence to skip the tasks which are part
of a frozen control group.
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch implements a new freezer subsystem in the control groups
framework. It provides a way to stop and resume execution of all tasks in
a cgroup by writing in the cgroup filesystem.
The freezer subsystem in the container filesystem defines a file named
freezer.state. Writing "FROZEN" to the state file will freeze all tasks
in the cgroup. Subsequently writing "RUNNING" will unfreeze the tasks in
the cgroup. Reading will return the current state.
* Examples of usage :
# mkdir /containers/freezer
# mount -t cgroup -ofreezer freezer /containers
# mkdir /containers/0
# echo $some_pid > /containers/0/tasks
to get status of the freezer subsystem :
# cat /containers/0/freezer.state
RUNNING
to freeze all tasks in the container :
# echo FROZEN > /containers/0/freezer.state
# cat /containers/0/freezer.state
FREEZING
# cat /containers/0/freezer.state
FROZEN
to unfreeze all tasks in the container :
# echo RUNNING > /containers/0/freezer.state
# cat /containers/0/freezer.state
RUNNING
This is the basic mechanism which should do the right thing for user space
task in a simple scenario.
It's important to note that freezing can be incomplete. In that case we
return EBUSY. This means that some tasks in the cgroup are busy doing
something that prevents us from completely freezing the cgroup at this
time. After EBUSY, the cgroup will remain partially frozen -- reflected
by freezer.state reporting "FREEZING" when read. The state will remain
"FREEZING" until one of these things happens:
1) Userspace cancels the freezing operation by writing "RUNNING" to
the freezer.state file
2) Userspace retries the freezing operation by writing "FROZEN" to
the freezer.state file (writing "FREEZING" is not legal
and returns EIO)
3) The tasks that blocked the cgroup from entering the "FROZEN"
state disappear from the cgroup's set of tasks.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: export thaw_process]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that the TIF_FREEZE flag is available in all architectures, extract
the refrigerator() and freeze_task() from kernel/power/process.c and make
it available to all.
The refrigerator() can now be used in a control group subsystem
implementing a control group freezer.
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Tested-by: Matt Helsley <matthltc@us.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch series introduces a cgroup subsystem that utilizes the swsusp
freezer to freeze a group of tasks. It's immediately useful for batch job
management scripts. It should also be useful in the future for
implementing container checkpoint/restart.
The freezer subsystem in the container filesystem defines a cgroup file
named freezer.state. Reading freezer.state will return the current state
of the cgroup. Writing "FROZEN" to the state file will freeze all tasks
in the cgroup. Subsequently writing "RUNNING" will unfreeze the tasks in
the cgroup.
* Examples of usage :
# mkdir /containers/freezer
# mount -t cgroup -ofreezer freezer /containers
# mkdir /containers/0
# echo $some_pid > /containers/0/tasks
to get status of the freezer subsystem :
# cat /containers/0/freezer.state
RUNNING
to freeze all tasks in the container :
# echo FROZEN > /containers/0/freezer.state
# cat /containers/0/freezer.state
FREEZING
# cat /containers/0/freezer.state
FROZEN
to unfreeze all tasks in the container :
# echo RUNNING > /containers/0/freezer.state
# cat /containers/0/freezer.state
RUNNING
This patch:
The first step in making the refrigerator() available to all
architectures, even for those without power management.
The purpose of such a change is to be able to use the refrigerator() in a
new control group subsystem which will implement a control group freezer.
[akpm@linux-foundation.org: fix sparc]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Acked-by: Pavel Machek <pavel@suse.cz>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Nigel Cunningham <nigel@tuxonice.net>
Tested-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To prepare the chunking, move the sys_move_pages() code that is used when
nodes!=NULL into do_pages_move(). And rename do_move_pages() into
do_move_page_to_node_array().
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
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>
do_pages_stat() does not need any page_to_node entry for real. Just pass
the pointers to the user-space page address array and to the user-space
status array, and have do_pages_stat() traverse the former and fill the
latter directly.
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
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>
A patchset reworking sys_move_pages(). It removes the possibly large
vmalloc by using multiple chunks when migrating large buffers. It also
dramatically increases the throughput for large buffers since the lookup
in new_page_node() is now limited to a single chunk, causing the quadratic
complexity to have a much slower impact. There is no need to use any
radix-tree-like structure to improve this lookup.
sys_move_pages() duration on a 4-quadcore-opteron 2347HE (1.9Gz),
migrating between nodes #2 and #3:
length move_pages (us) move_pages+patch (us)
4kB 126 98
40kB 198 168
400kB 963 937
4MB 12503 11930
40MB 246867 11848
Patches #1 and #4 are the important ones:
1) stop returning -ENOENT from sys_move_pages() if nothing got migrated
2) don't vmalloc a huge page_to_node array for do_pages_stat()
3) extract do_pages_move() out of sys_move_pages()
4) rework do_pages_move() to work on page_sized chunks
5) move_pages: no need to set pp->page to ZERO_PAGE(0) by default
This patch:
There is no point in returning -ENOENT from sys_move_pages() if all pages
were already on the right node, while we return 0 if only 1 page was not.
Most application don't know where their pages are allocated, so it's not
an error to try to migrate them anyway.
Just return 0 and let the status array in user-space be checked if the
application needs details.
It will make the upcoming chunked-move_pages() support much easier.
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
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>
During hotplug memory remove, memory regions should be released on a
PAGES_PER_SECTION size chunks. This mirrors the code in add_memory where
resources are requested on a PAGES_PER_SECTION size.
Attempting to release the entire memory region fails because there is not
a single resource for the total number of pages being removed. Instead
the resources for the pages are split in PAGES_PER_SECTION size chunks as
requested during memory add.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current documentation of dirty_ratio and dirty_background_ratio is a
bit misleading.
In the documentation we say that they are "a percentage of total system
memory", but the current page writeback policy, intead, is to apply the
percentages to the dirtyable memory, that means free pages + reclaimable
pages.
Better to be more explicit to clarify this concept.
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.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>
This attribute just has a write operation.
[akpm@linux-foundation.org: use S_IWUSR as suggested by Randy]
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This replaces zone->lru_lock in setup_per_zone_pages_min() with zone->lock.
There seems to be no need for the lru_lock anymore, but there is a need for
zone->lock instead, because that function may call move_freepages() via
setup_zone_migrate_reserve().
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Presently hugepage doesn't use zero page at all because zero page is only
used for coredumping and hugepage can't core dump.
However we have now implemented hugepage coredumping. Therefore we should
implement the zero page of hugepage.
Implementation note:
o Why do we only check VM_SHARED for zero page?
normal page checked as ..
static inline int use_zero_page(struct vm_area_struct *vma)
{
if (vma->vm_flags & (VM_LOCKED | VM_SHARED))
return 0;
return !vma->vm_ops || !vma->vm_ops->fault;
}
First, hugepages are never mlock()ed. We aren't concerned with VM_LOCKED.
Second, hugetlbfs is a pseudo filesystem, not a real filesystem and it
doesn't have any file backing. Thus ops->fault checking is meaningless.
o Why don't we use zero page if !pte.
!pte indicate {pud, pmd} doesn't exist or some error happened. So we
shouldn't return zero page if any error occurred.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Kawai Hidehiro <hidehiro.kawai.ez@hitachi.com>
Cc: Mel Gorman <mel@skynet.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Presently hugepage's vma has a VM_RESERVED flag in order not to be
swapped. But a VM_RESERVED vma isn't core dumped because this flag is
often used for some kernel vmas (e.g. vmalloc, sound related).
Thus hugepages are never dumped and it can't be debugged easily. Many
developers want hugepages to be included into core-dump.
However, We can't read generic VM_RESERVED area because this area is often
IO mapping area. then these area reading may change device state. it is
definitly undesiable side-effect.
So adding a hugepage specific bit to the coredump filter is better. It
will be able to hugepage core dumping and doesn't cause any side-effect to
any i/o devices.
In additional, libhugetlb use hugetlb private mapping pages as anonymous
page. Then, hugepage private mapping pages should be core dumped by
default.
Then, /proc/[pid]/core_dump_filter has two new bits.
- bit 5 mean hugetlb private mapping pages are dumped or not. (default: yes)
- bit 6 mean hugetlb shared mapping pages are dumped or not. (default: no)
I tested by following method.
% ulimit -c unlimited
% ./crash_hugepage 50
% ./crash_hugepage 50 -p
% ls -lh
% gdb ./crash_hugepage core
%
% echo 0x43 > /proc/self/coredump_filter
% ./crash_hugepage 50
% ./crash_hugepage 50 -p
% ls -lh
% gdb ./crash_hugepage core
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
#include <string.h>
#include "hugetlbfs.h"
int main(int argc, char** argv){
char* p;
int ch;
int mmap_flags = MAP_SHARED;
int fd;
int nr_pages;
while((ch = getopt(argc, argv, "p")) != -1) {
switch (ch) {
case 'p':
mmap_flags &= ~MAP_SHARED;
mmap_flags |= MAP_PRIVATE;
break;
default:
/* nothing*/
break;
}
}
argc -= optind;
argv += optind;
if (argc == 0){
printf("need # of pages\n");
exit(1);
}
nr_pages = atoi(argv[0]);
if (nr_pages < 2) {
printf("nr_pages must >2\n");
exit(1);
}
fd = hugetlbfs_unlinked_fd();
p = mmap(NULL, nr_pages * gethugepagesize(),
PROT_READ|PROT_WRITE, mmap_flags, fd, 0);
sleep(2);
*(p + gethugepagesize()) = 1; /* COW */
sleep(2);
/* crash! */
*(int*)0 = 1;
return 0;
}
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Kawai Hidehiro <hidehiro.kawai.ez@hitachi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: William Irwin <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/hugetlb.c:265:17: warning: symbol 'resv_map_alloc' was not declared. Should it be static?
mm/hugetlb.c:277:6: warning: symbol 'resv_map_release' was not declared. Should it be static?
mm/hugetlb.c:292:9: warning: Using plain integer as NULL pointer
mm/hugetlb.c:1750:5: warning: symbol 'unmap_ref_private' was not declared. Should it be static?
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rewrite the vmap allocator to use rbtrees and lazy tlb flushing, and
provide a fast, scalable percpu frontend for small vmaps (requires a
slightly different API, though).
The biggest problem with vmap is actually vunmap. Presently this requires
a global kernel TLB flush, which on most architectures is a broadcast IPI
to all CPUs to flush the cache. This is all done under a global lock. As
the number of CPUs increases, so will the number of vunmaps a scaled
workload will want to perform, and so will the cost of a global TLB flush.
This gives terrible quadratic scalability characteristics.
Another problem is that the entire vmap subsystem works under a single
lock. It is a rwlock, but it is actually taken for write in all the fast
paths, and the read locking would likely never be run concurrently anyway,
so it's just pointless.
This is a rewrite of vmap subsystem to solve those problems. The existing
vmalloc API is implemented on top of the rewritten subsystem.
The TLB flushing problem is solved by using lazy TLB unmapping. vmap
addresses do not have to be flushed immediately when they are vunmapped,
because the kernel will not reuse them again (would be a use-after-free)
until they are reallocated. So the addresses aren't allocated again until
a subsequent TLB flush. A single TLB flush then can flush multiple
vunmaps from each CPU.
XEN and PAT and such do not like deferred TLB flushing because they can't
always handle multiple aliasing virtual addresses to a physical address.
They now call vm_unmap_aliases() in order to flush any deferred mappings.
That call is very expensive (well, actually not a lot more expensive than
a single vunmap under the old scheme), however it should be OK if not
called too often.
The virtual memory extent information is stored in an rbtree rather than a
linked list to improve the algorithmic scalability.
There is a per-CPU allocator for small vmaps, which amortizes or avoids
global locking.
To use the per-CPU interface, the vm_map_ram / vm_unmap_ram interfaces
must be used in place of vmap and vunmap. Vmalloc does not use these
interfaces at the moment, so it will not be quite so scalable (although it
will use lazy TLB flushing).
As a quick test of performance, I ran a test that loops in the kernel,
linearly mapping then touching then unmapping 4 pages. Different numbers
of tests were run in parallel on an 4 core, 2 socket opteron. Results are
in nanoseconds per map+touch+unmap.
threads vanilla vmap rewrite
1 14700 2900
2 33600 3000
4 49500 2800
8 70631 2900
So with a 8 cores, the rewritten version is already 25x faster.
In a slightly more realistic test (although with an older and less
scalable version of the patch), I ripped the not-very-good vunmap batching
code out of XFS, and implemented the large buffer mapping with vm_map_ram
and vm_unmap_ram... along with a couple of other tricks, I was able to
speed up a large directory workload by 20x on a 64 CPU system. I believe
vmap/vunmap is actually sped up a lot more than 20x on such a system, but
I'm running into other locks now. vmap is pretty well blown off the
profiles.
Before:
1352059 total 0.1401
798784 _write_lock 8320.6667 <- vmlist_lock
529313 default_idle 1181.5022
15242 smp_call_function 15.8771 <- vmap tlb flushing
2472 __get_vm_area_node 1.9312 <- vmap
1762 remove_vm_area 4.5885 <- vunmap
316 map_vm_area 0.2297 <- vmap
312 kfree 0.1950
300 _spin_lock 3.1250
252 sn_send_IPI_phys 0.4375 <- tlb flushing
238 vmap 0.8264 <- vmap
216 find_lock_page 0.5192
196 find_next_bit 0.3603
136 sn2_send_IPI 0.2024
130 pio_phys_write_mmr 2.0312
118 unmap_kernel_range 0.1229
After:
78406 total 0.0081
40053 default_idle 89.4040
33576 ia64_spinlock_contention 349.7500
1650 _spin_lock 17.1875
319 __reg_op 0.5538
281 _atomic_dec_and_lock 1.0977
153 mutex_unlock 1.5938
123 iget_locked 0.1671
117 xfs_dir_lookup 0.1662
117 dput 0.1406
114 xfs_iget_core 0.0268
92 xfs_da_hashname 0.1917
75 d_alloc 0.0670
68 vmap_page_range 0.0462 <- vmap
58 kmem_cache_alloc 0.0604
57 memset 0.0540
52 rb_next 0.1625
50 __copy_user 0.0208
49 bitmap_find_free_region 0.2188 <- vmap
46 ia64_sn_udelay 0.1106
45 find_inode_fast 0.1406
42 memcmp 0.2188
42 finish_task_switch 0.1094
42 __d_lookup 0.0410
40 radix_tree_lookup_slot 0.1250
37 _spin_unlock_irqrestore 0.3854
36 xfs_bmapi 0.0050
36 kmem_cache_free 0.0256
35 xfs_vn_getattr 0.0322
34 radix_tree_lookup 0.1062
33 __link_path_walk 0.0035
31 xfs_da_do_buf 0.0091
30 _xfs_buf_find 0.0204
28 find_get_page 0.0875
27 xfs_iread 0.0241
27 __strncpy_from_user 0.2812
26 _xfs_buf_initialize 0.0406
24 _xfs_buf_lookup_pages 0.0179
24 vunmap_page_range 0.0250 <- vunmap
23 find_lock_page 0.0799
22 vm_map_ram 0.0087 <- vmap
20 kfree 0.0125
19 put_page 0.0330
18 __kmalloc 0.0176
17 xfs_da_node_lookup_int 0.0086
17 _read_lock 0.0885
17 page_waitqueue 0.0664
vmap has gone from being the top 5 on the profiles and flushing the crap
out of all TLBs, to using less than 1% of kernel time.
[akpm@linux-foundation.org: cleanups, section fix]
[akpm@linux-foundation.org: fix build on alpha]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__vma_link_file and expand_downwards functions are not small, yeat they
are marked inline. They probably had one callsite sometime in the past,
but now they have more. In order to prevent similar thing, I also
deinlined expand_upwards, despite it having only pne callsite. Nowadays
gcc auto-inlines such static functions anyway. In find_extend_vma, I
removed one extra level of indirection.
Patch is deliberately generated with -U $BIGNUM to make
it easier to see that functions are big.
Result:
# size */*/mmap.o */vmlinux
text data bss dec hex filename
9514 188 16 9718 25f6 0.org/mm/mmap.o
9237 188 16 9441 24e1 deinline/mm/mmap.o
6124402 858996 389480 7372878 70804e 0.org/vmlinux
6124113 858996 389480 7372589 707f2d deinline/vmlinux
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.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>
trylock_buffer and unlock_buffer open and close a critical section.
Hence, we can use the lock bitops to get the desired memory ordering.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
trylock_page, unlock_page open and close a critical section. Hence,
we can use the lock bitops to get the desired memory ordering.
Also, mark trylock as likely to succeed (and remove the annotation from
callers).
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
unlock_page is fairly expensive. It can be avoided in page reclaim
success path. By definition if we have any other references to the page
it would be a bug anyway.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Reviewed-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>
Setting and clearing the page locked when inserting it into swapcache /
pagecache when it has no other references can use non-atomic page flags
operations because no other CPU may be operating on it at this time.
This saves one atomic operation when inserting a page into pagecache.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rework Posix error return for mlock().
Posix requires error code for mlock*() system calls for some conditions
that differ from what kernel low level functions, such as
get_user_pages(), return for those conditions. For more info, see:
http://marc.info/?l=linux-kernel&m=121750892930775&w=2
This patch provides the same translation of get_user_pages()
error codes to posix specified error codes in the context
of the mlock rework for unevictable lru.
[akpm@linux-foundation.org: fix build]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change is intended to make mlock() error returns correct.
make_page_present() is a lower level function used by more than mlock().
Subsequent patch[es] will add this error return fixup in an mlock specific
path.
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During each reclaim scan we accumulate scan pressure on unrelated lists
which will result in bogus scans and unwanted reclaims eventually.
Scanning lists with few reclaim candidates results in a lot of rotation
and therefor also disturbs the list balancing, putting even more
pressure on the wrong lists.
In a test-case with much streaming IO, and therefor a crowded inactive
file page list, swapping started because
a) anon pages were reclaimed after swap_cluster_max reclaim
invocations -- nr_scan of this list has just accumulated
b) active file pages were scanned because *their* nr_scan has also
accumulated through the same logic. And this in return created a
lot of rotation for file pages and resulted in a decrease of file
list priority, again increasing the pressure on anon pages.
The result was an evicted working set of anon pages while there were
tons of inactive file pages that should have been taken instead.
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
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>
Several LRU manupuration function are not used now. So they can be
removed.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.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>
Allow free of mlock()ed pages. This shouldn't happen, but during
developement, it occasionally did.
This patch allows us to survive that condition, while keeping the
statistics and events correct for debug.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-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>
This patch adds a function to scan individual or all zones' unevictable
lists and move any pages that have become evictable onto the respective
zone's inactive list, where shrink_inactive_list() will deal with them.
Adds sysctl to scan all nodes, and per node attributes to individual
nodes' zones.
Kosaki: If evictable page found in unevictable lru when write
/proc/sys/vm/scan_unevictable_pages, print filename and file offset of
these pages.
[akpm@linux-foundation.org: fix one CONFIG_MMU=n build error]
[kosaki.motohiro@jp.fujitsu.com: adapt vmscan-unevictable-lru-scan-sysctl.patch to new sysfs API]
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>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.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>
In the fault paths that install new anonymous pages, check whether the
page is evictable or not using lru_cache_add_active_or_unevictable(). If
the page is evictable, just add it to the active lru list [via the pagevec
cache], else add it to the unevictable list.
This "proactive" culling in the fault path mimics the handling of mlocked
pages in Nick Piggin's series to keep mlocked pages off the lru lists.
Notes:
1) This patch is optional--e.g., if one is concerned about the
additional test in the fault path. We can defer the moving of
nonreclaimable pages until when vmscan [shrink_*_list()]
encounters them. Vmscan will only need to handle such pages
once, but if there are a lot of them it could impact system
performance.
2) The 'vma' argument to page_evictable() is require to notice that
we're faulting a page into an mlock()ed vma w/o having to scan the
page's rmap in the fault path. Culling mlock()ed anon pages is
currently the only reason for this patch.
3) We can't cull swap pages in read_swap_cache_async() because the
vma argument doesn't necessarily correspond to the swap cache
offset passed in by swapin_readahead(). This could [did!] result
in mlocking pages in non-VM_LOCKED vmas if [when] we tried to
cull in this path.
4) Move set_pte_at() to after where we add page to lru to keep it
hidden from other tasks that might walk the page table.
We already do it in this order in do_anonymous() page. And,
these are COW'd anon pages. Is this safe?
[riel@redhat.com: undo an overzealous code cleanup]
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add NR_MLOCK zone page state, which provides a (conservative) count of
mlocked pages (actually, the number of mlocked pages moved off the LRU).
Reworked by lts to fit in with the modified mlock page support in the
Reclaim Scalability series.
[kosaki.motohiro@jp.fujitsu.com: fix incorrect Mlocked field of /proc/meminfo]
[lee.schermerhorn@hp.com: mlocked-pages: add event counting with statistics]
Signed-off-by: Nick Piggin <npiggin@suse.de>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Originally by Nick Piggin <npiggin@suse.de>
Remove mlocked pages from the LRU using "unevictable infrastructure"
during mmap(), munmap(), mremap() and truncate(). Try to move back to
normal LRU lists on munmap() when last mlocked mapping removed. Remove
PageMlocked() status when page truncated from file.
[akpm@linux-foundation.org: cleanup]
[kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()]
[kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework]
[lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block]
[akpm@linux-foundation.org: remove bogus kerneldoc token]
Signed-off-by: Nick Piggin <npiggin@suse.de>
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>
Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We need to hold the mmap_sem for write to initiatate mlock()/munlock()
because we may need to merge/split vmas. However, this can lead to very
long lock hold times attempting to fault in a large memory region to mlock
it into memory. This can hold off other faults against the mm
[multithreaded tasks] and other scans of the mm, such as via /proc. To
alleviate this, downgrade the mmap_sem to read mode during the population
of the region for locking. This is especially the case if we need to
reclaim memory to lock down the region. We [probably?] don't need to do
this for unlocking as all of the pages should be resident--they're already
mlocked.
Now, the caller's of the mlock functions [mlock_fixup() and
mlock_vma_pages_range()] expect the mmap_sem to be returned in write mode.
Changing all callers appears to be way too much effort at this point.
So, restore write mode before returning. Note that this opens a window
where the mmap list could change in a multithreaded process. So, at least
for mlock_fixup(), where we could be called in a loop over multiple vmas,
we check that a vma still exists at the start address and that vma still
covers the page range [start,end). If not, we return an error, -EAGAIN,
and let the caller deal with it.
Return -EAGAIN from mlock_vma_pages_range() function and mlock_fixup() if
the vma at 'start' disappears or changes so that the page range
[start,end) is no longer contained in the vma. Again, let the caller deal
with it. Looks like only sys_remap_file_pages() [via mmap_region()]
should actually care.
With this patch, I no longer see processes like ps(1) blocked for seconds
or minutes at a time waiting for a large [multiple gigabyte] region to be
locked down. However, I occassionally see delays while unlocking or
unmapping a large mlocked region. Should we also downgrade the mmap_sem
for the unlock path?
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-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>
Documentation for unevictable lru list and its usage.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@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>
Make sure that mlocked pages also live on the unevictable LRU, so kswapd
will not scan them over and over again.
This is achieved through various strategies:
1) add yet another page flag--PG_mlocked--to indicate that
the page is locked for efficient testing in vmscan and,
optionally, fault path. This allows early culling of
unevictable pages, preventing them from getting to
page_referenced()/try_to_unmap(). Also allows separate
accounting of mlock'd pages, as Nick's original patch
did.
Note: Nick's original mlock patch used a PG_mlocked
flag. I had removed this in favor of the PG_unevictable
flag + an mlock_count [new page struct member]. I
restored the PG_mlocked flag to eliminate the new
count field.
2) add the mlock/unevictable infrastructure to mm/mlock.c,
with internal APIs in mm/internal.h. This is a rework
of Nick's original patch to these files, taking into
account that mlocked pages are now kept on unevictable
LRU list.
3) update vmscan.c:page_evictable() to check PageMlocked()
and, if vma passed in, the vm_flags. Note that the vma
will only be passed in for new pages in the fault path;
and then only if the "cull unevictable pages in fault
path" patch is included.
4) add try_to_unlock() to rmap.c to walk a page's rmap and
ClearPageMlocked() if no other vmas have it mlocked.
Reuses as much of try_to_unmap() as possible. This
effectively replaces the use of one of the lru list links
as an mlock count. If this mechanism let's pages in mlocked
vmas leak through w/o PG_mlocked set [I don't know that it
does], we should catch them later in try_to_unmap(). One
hopes this will be rare, as it will be relatively expensive.
Original mm/internal.h, mm/rmap.c and mm/mlock.c changes:
Signed-off-by: Nick Piggin <npiggin@suse.de>
splitlru: introduce __get_user_pages():
New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS.
because current get_user_pages() can't grab PROT_NONE pages theresore it
cause PROT_NONE pages can't munlock.
[akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch]
[akpm@linux-foundation.org: untangle patch interdependencies]
[akpm@linux-foundation.org: fix things after out-of-order merging]
[hugh@veritas.com: fix page-flags mess]
[lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm']
[kosaki.motohiro@jp.fujitsu.com: build fix]
[kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments]
[kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Matt Mackall <mpm@selenic.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>
Henrik Rydberg
Jim Cromie
Ameya Palande
WANG Cong
Eric Piel
Andi Kleen
Huang Weiyi
Matt Helsley
Brice Goglin
Nathan Fontenot
Andrea Righi
Shaohua Li
Gerald Schaefer
KOSAKI Motohiro
Yinghai Lu
Harvey Harrison
Nick Piggin
Denys Vlasenko
Lee Schermerhorn
Johannes Weiner
Rik van Riel