lkml is added to all CC lists via pattern matching on "THE REST"
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These file patterns match all sources.
By default, scripts/get_maintainers.pl excludes Linus Torvalds
from the CC: list. Option --git-chief-penguins will include him.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fixes git send-email with a cover letter
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixed bug introduced after using rfc822 address checking.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
support older versions of grep (use -E not -P)
no need to return data in routine recent_git_signoffs
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Moved linux-kernel@vger.kernel.org to MAINTAINERS
lkml will be added to all CC lists via F: pattern match
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix mailing lists that are described, but not "(subscriber-only)"
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a call to write_lock() in gen_pool_destroy which is not balanced
by any corresponding write_unlock(). This causes problems with preemption
because the preemption-disable counter is incremented in the write_lock()
call, but never decremented by any call to write_unlock(). This bug is
gen_pool_destroy, and one of them is non-x86 arch-specific code.
Signed-off-by: Zygo Blaxell <zygo.blaxell@xandros.com>
Cc: Jiri Kosina <trivial@kernel.org>
Cc: Steve Wise <swise@opengridcomputing.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CONFIG_FILE_LOCKING should not depend on CONFIG_BLOCK.
This makes it possible to run complete systems out of a CONFIG_BLOCK=n
initramfs on current kernels again (this last worked on 2.6.27.*).
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add support for the TI VLYNQ high-speed, serial and packetized bus.
This bus allows external devices to be connected to the System-on-Chip and
appear in the main system memory just like any memory mapped peripheral.
It is widely used in TI's networking and multimedia SoC, including the AR7
SoC.
Signed-off-by: Eugene Konev <ejka@imfi.kspu.ru>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The console blank timer is currently hardcoded to 10*60 seconds which
might be annoying on systems with no input devices attached to wake up the
console again. Especially during development, disabling the screen saver
can be handy - for example when debugging the root fs mount mechanism or
other scenarios where no userspace program could be started to do that at
runtime from userspace.
This patch defines a core_param for the variable in charge which allows
users to entirely disable the blank feature at boot time by setting it 0.
The value can still be overwritten at runtime using the standard ioctl
call - this just allows to conditionally change the default.
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
list_add() lost a parameter in sample code.
Signed-off-by: Figo.zhang <figo1802@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add EISA IDs for Network Peripherals FDDI boards. Descriptions taken from
the respective EISA configuration files.
It's unlikely we'll ever support these cards, the problem being the lack
of documentation. Assuming the policy for the EISA ID database is the
same as for PCI I'm sending these entries for the sake of completeness.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Marc Zyngier <maz@misterjones.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert most arches to use asm-generic/kmap_types.h.
Move the KM_FENCE_ macro additions into asm-generic/kmap_types.h,
controlled by __WITH_KM_FENCE from each arch's kmap_types.h file.
Would be nice to be able to add custom KM_types per arch, but I don't yet
see a nice, clean way to do that.
Built on x86_64, i386, mips, sparc, alpha(tonyb), powerpc(tonyb), and
68k(tonyb).
Note: avr32 should be able to remove KM_PTE2 (since it's not used) and
then just use the generic kmap_types.h file. Get avr32 maintainer
approval.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: <linux-arch@vger.kernel.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Bryan Wu <cooloney@kernel.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: "Luck Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix compilation warning:
Documentation/accounting/getdelays.c: In function `main':
Documentation/accounting/getdelays.c:249: warning: `cmd_type' may be used uninitialized in this function
This is in fact a false positive.
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Acked-by: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For example:
hex_dump_to_buffer("AB", 2, 16, 1, buf, 100, 0);
pr_info("[%s]\n", buf);
I'd expect the output to be "[41 42]", but actually it's "[41 42 ]"
This patch also makes the required buf to be minimum. To print the hex
format of "AB", a buf with size 6 should be sufficient, but
hex_dump_to_buffer() required at least 8.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are some places to be able to use printk_once instead of hard coding.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
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>
Round the slow work queue's cull and OOM timeouts to whole second boundary
with round_jiffies(). The slow work queue uses a pair of timers to cull
idle threads and, after OOM, to delay new thread creation.
This patch also extracts the mod_timer() logic for the cull timer into a
separate helper function.
By rounding non-time-critical timers such as these to whole seconds, they
will be batched up to fire at the same time rather than being spread out.
This allows the CPU wake up less, which saves power.
Signed-off-by: Chris Peterson <cpeterso@cpeterso.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
radix_tree_lookup() and radix_tree_lookup_slot() have much the
same code except for the return value.
Introduce radix_tree_lookup_element() to do the real work.
/*
* is_slot == 1 : search for the slot.
* is_slot == 0 : search for the node.
*/
static void * radix_tree_lookup_element(struct radix_tree_root *root,
unsigned long index, int is_slot);
Signed-off-by: Huang Shijie <shijie8@gmail.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
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>
Move supplementary groups implementation to kernel/groups.c .
kernel/sys.c already accumulated quite a few random stuff.
Do strictly copy/paste + add required headers to compile. Compile-tested
on many configs and archs.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
put_cpu_no_resched() is an optimization of put_cpu() which unfortunately
can cause high latencies.
The nfs iostats code uses put_cpu_no_resched() in a code sequence where a
reschedule request caused by an interrupt between the get_cpu() and the
put_cpu_no_resched() can delay the reschedule for at least HZ.
The other users of put_cpu_no_resched() optimize correctly in interrupt
code, but there is no real harm in using the put_cpu() function which is
an alias for preempt_enable(). The extra check of the preemmpt count is
not as critical as the potential source of missing a reschedule.
Debugged in the preempt-rt tree and verified in mainline.
Impact: remove a high latency source
[akpm@linux-foundation.org: build fix]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since we have had a LANANA major number for years, and it is documented in
devices.txt, I think that this first patch can go upstream.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
They're in linux/bug.h at present, which causes include order tangles. In
particular, linux/bug.h cannot be used by linux/atomic.h because,
according to Nikanth:
linux/bug.h pulls in linux/module.h => linux/spinlock.h => asm/spinlock.h
(which uses atomic_inc) => asm/atomic.h.
bug.h is a pretty low-level thing and module.h is a higher-level thing,
IMO.
Cc: Nikanth Karthikesan <knikanth@novell.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After introduction of keyed wakeups Davide Libenzi did on epoll, we are
able to avoid spurious wakeups in poll()/select() code too.
For example, typical use of poll()/select() is to wait for incoming
network frames on many sockets. But TX completion for UDP/TCP frames call
sock_wfree() which in turn schedules thread.
When scheduled, thread does a full scan of all polled fds and can sleep
again, because nothing is really available. If number of fds is large,
this cause significant load.
This patch makes select()/poll() aware of keyed wakeups and useless
wakeups are avoided. This reduces number of context switches by about 50%
on some setups, and work performed by sofirq handlers.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
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>
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Cc: Anton Altaparmakov <aia21@cantab.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
_atomic_dec_and_lock() should not unconditionally take the lock before
calling atomic_dec_and_test() in the UP case. For consistency reasons it
should behave exactly like in the SMP case.
Besides that this works around the problem that with CONFIG_DEBUG_SPINLOCK
this spins in __spin_lock_debug() if the lock is already taken even if the
counter doesn't drop to 0.
Signed-off-by: Jan Blunck <jblunck@suse.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Cc: Valerie Aurora <vaurora@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The members of the new_utsname structure are defined with magic numbers
that *should* correspond to the constant __NEW_UTS_LEN+1. Everywhere
else, code assumes this and uses the constant, so this patch makes the
structure match.
Originally suggested by Serge here:
https://lists.linux-foundation.org/pipermail/containers/2009-March/016258.html
Signed-off-by: Dan Smith <danms@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
`ELF_CORE_COPY_REGS(x, y)' will make expansions like:
`(y)[0] = (x)->x.gp[0]' but correct is `(y)[0] = (x)->regs.gp[0]'
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: WANG Cong <amwang@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When compiling uml on x86_64:
MODPOST vmlinux.o
WARNING: vmlinux.o (.__syscall_stub.2): unexpected non-allocatable section.
Did you forget to use "ax"/"aw" in a .S file?
Note that for example <linux/init.h> contains
section definitions for use in .S files.
Because modpost checks for missing SHF_ALLOC section flag. So just add
it.
Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The defines and typedefs (hw_interrupt_type, no_irq_type, irq_desc_t) have
been kept around for migration reasons. After more than two years it's
time to remove them finally.
This patch cleans up one of the remaining users. When all such patches
hit mainline we can remove the defines and typedefs finally.
Impact: cleanup
Convert the last remaining users to struct irq_chip and remove the
define.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
See ancient discussion at
http://marc.info/?l=user-mode-linux-devel&m=101990155831279&w=2
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=7854
Signed-off-by: Alan Cox <alan@linux.intel.com>
Reported-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Roland Kletzing <devzero@web.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The defines and typedefs (hw_interrupt_type, no_irq_type, irq_desc_t) have
been kept around for migration reasons. After more than two years it's
time to remove them finally.
This patch cleans up one of the remaining users. When all such patches
hit mainline we can remove the defines and typedefs finally.
Impact: cleanup
Convert the last remaining users to struct irq_chip and remove the
define.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
`for_each_mem_cluster(x, y, z)' will expand to
`for ((x) = (y)->x ...' but correct is `for ((x) = (y)->cluster ...'
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The defines and typedefs (hw_interrupt_type, no_irq_type, irq_desc_t) have
been kept around for migration reasons. After more than two years it's
time to remove them finally.
This patch cleans up one of the remaining users. When all such patches
hit mainline we can remove the defines and typedefs finally.
Impact: cleanup
Convert the last remaining users to struct irq_chip and remove the
define.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At lumpy reclaim, a page failed to be taken by __isolate_lru_page() can be
pushed back to "src" list by list_move(). But the page may not be from
"src" list. This pushes the page back to wrong LRU. And list_move()
itself is unnecessary because the page is not on top of LRU. Then, leave
it as it is if __isolate_lru_page() fails.
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
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>
On NUMA machines, the administrator can configure zone_reclaim_mode that
is a more targetted form of direct reclaim. On machines with large NUMA
distances for example, a zone_reclaim_mode defaults to 1 meaning that
clean unmapped pages will be reclaimed if the zone watermarks are not
being met.
There is a heuristic that determines if the scan is worthwhile but it is
possible that the heuristic will fail and the CPU gets tied up scanning
uselessly. Detecting the situation requires some guesswork and
experimentation so this patch adds a counter "zreclaim_failed" to
/proc/vmstat. If during high CPU utilisation this counter is increasing
rapidly, then the resolution to the problem may be to set
/proc/sys/vm/zone_reclaim_mode to 0.
[akpm@linux-foundation.org: name things consistently]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On NUMA machines, the administrator can configure zone_reclaim_mode that
is a more targetted form of direct reclaim. On machines with large NUMA
distances for example, a zone_reclaim_mode defaults to 1 meaning that
clean unmapped pages will be reclaimed if the zone watermarks are not
being met. The problem is that zone_reclaim() failing at all means the
zone gets marked full.
This can cause situations where a zone is usable, but is being skipped
because it has been considered full. Take a situation where a large tmpfs
mount is occuping a large percentage of memory overall. The pages do not
get cleaned or reclaimed by zone_reclaim(), but the zone gets marked full
and the zonelist cache considers them not worth trying in the future.
This patch makes zone_reclaim() return more fine-grained information about
what occured when zone_reclaim() failued. The zone only gets marked full
if it really is unreclaimable. If it's a case that the scan did not occur
or if enough pages were not reclaimed with the limited reclaim_mode, then
the zone is simply skipped.
There is a side-effect to this patch. Currently, if zone_reclaim()
successfully reclaimed SWAP_CLUSTER_MAX, an allocation attempt would go
ahead. With this patch applied, zone watermarks are rechecked after
zone_reclaim() does some work.
This bug was introduced by commit 9276b1bc96
("memory page_alloc zonelist caching speedup") way back in 2.6.19 when the
zonelist_cache was introduced. It was not intended that zone_reclaim()
aggressively consider the zone to be full when it failed as full direct
reclaim can still be an option. Due to the age of the bug, it should be
considered a -stable candidate.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A bug was brought to my attention against a distro kernel but it affects
mainline and I believe problems like this have been reported in various
guises on the mailing lists although I don't have specific examples at the
moment.
The reported problem was that malloc() stalled for a long time (minutes in
some cases) if a large tmpfs mount was occupying a large percentage of
memory overall. The pages did not get cleaned or reclaimed by
zone_reclaim() because the zone_reclaim_mode was unsuitable, but the lists
are uselessly scanned frequencly making the CPU spin at near 100%.
This patchset intends to address that bug and bring the behaviour of
zone_reclaim() more in line with expectations which were noticed during
investigation. It is based on top of mmotm and takes advantage of
Kosaki's work with respect to zone_reclaim().
Patch 1 fixes the heuristics that zone_reclaim() uses to determine if the
scan should go ahead. The broken heuristic is what was causing the
malloc() stall as it uselessly scanned the LRU constantly. Currently,
zone_reclaim is assuming zone_reclaim_mode is 1 and historically it
could not deal with tmpfs pages at all. This fixes up the heuristic so
that an unnecessary scan is more likely to be correctly avoided.
Patch 2 notes that zone_reclaim() returning a failure automatically means
the zone is marked full. This is not always true. It could have
failed because the GFP mask or zone_reclaim_mode were unsuitable.
Patch 3 introduces a counter zreclaim_failed that will increment each
time the zone_reclaim scan-avoidance heuristics fail. If that
counter is rapidly increasing, then zone_reclaim_mode should be
set to 0 as a temporarily resolution and a bug reported because
the scan-avoidance heuristic is still broken.
This patch:
On NUMA machines, the administrator can configure zone_reclaim_mode that
is a more targetted form of direct reclaim. On machines with large NUMA
distances for example, a zone_reclaim_mode defaults to 1 meaning that
clean unmapped pages will be reclaimed if the zone watermarks are not
being met.
There is a heuristic that determines if the scan is worthwhile but the
problem is that the heuristic is not being properly applied and is
basically assuming zone_reclaim_mode is 1 if it is enabled. The lack of
proper detection can manfiest as high CPU usage as the LRU list is scanned
uselessly.
Historically, once enabled it was depending on NR_FILE_PAGES which may
include swapcache pages that the reclaim_mode cannot deal with. Patch
vmscan-change-the-number-of-the-unmapped-files-in-zone-reclaim.patch by
Kosaki Motohiro noted that zone_page_state(zone, NR_FILE_PAGES) included
pages that were not file-backed such as swapcache and made a calculation
based on the inactive, active and mapped files. This is far superior when
zone_reclaim==1 but if RECLAIM_SWAP is set, then NR_FILE_PAGES is a
reasonable starting figure.
This patch alters how zone_reclaim() works out how many pages it might be
able to reclaim given the current reclaim_mode. If RECLAIM_SWAP is set in
the reclaim_mode it will either consider NR_FILE_PAGES as potential
candidates or else use NR_{IN}ACTIVE}_PAGES-NR_FILE_MAPPED to discount
swapcache and other non-file-backed pages. If RECLAIM_WRITE is not set,
then NR_FILE_DIRTY number of pages are not candidates. If RECLAIM_SWAP is
not set, then NR_FILE_MAPPED are not.
[kosaki.motohiro@jp.fujitsu.com: Estimate unmapped pages minus tmpfs pages]
[fengguang.wu@intel.com: Fix underflow problem in Kosaki's estimate]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joe Perches
Zygo Blaxell
Tomas Szepe
Florian Fainelli
Daniel Mack
Figo.zhang
Maciej W. Rozycki
Masatake YAMATO
Randy Dunlap
Jaswinder Singh Rajput
Li Zefan
Minchan Kim
Chris Peterson
Huang Shijie
Alexey Dobriyan
Thomas Gleixner
Philipp Reisner
Andrew Morton
Eric Dumazet
Robert P. J. Day
Jan Blunck
Dan Smith
Roel Kluin
Amerigo Wang
Alan Cox
KAMEZAWA Hiroyuki
Mel Gorman