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>
mem_cgroup_charge_statisics() was designed for charging a page but now, we
have transparent hugepage. To fix problems (in following patch) it's
required to change the function to get the number of pages as its
arguments.
The new function gets following as argument.
- type of page rather than 'pc'
- size of page which is accounted.
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>
Up until 3e7d344 ("mm: vmscan: reclaim order-0 and use compaction instead
of lumpy reclaim"), compaction skipped calculating the fragmentation index
of a zone when compaction was explicitely requested through the procfs
knob.
However, when compaction_suitable was introduced, it did not come with an
extra check for order == -1, set on explicit compaction requests, and
passed this order on to the fragmentation index calculation, where it
overshifts the number of requested pages, leading to a division by zero.
This patch makes sure that order == -1 is recognized as the flag it is
rather than passing it along as valid order parameter.
[akpm@linux-foundation.org: add comment, per Mel]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memblock_is_region_memory() uses reserved memblocks to search for the
given region, while it should use the memory memblocks.
I encountered the problem with OMAP's framebuffer ram allocation.
Normally the ram is allocated dynamically, and this function is not
called. However, if we want to pass the framebuffer from the bootloader
to the kernel (to retain the boot image), this function is used to check
the validity of the kernel parameters for the framebuffer ram area.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "H. Peter Anvin" <hpa@zytor.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>
Two users reported THP-related crashes on 32-bit x86 machines. Their oops
reports indicated an invalid pte, and subsequent code inspection showed
that the highpte is actually used after unmap.
The fix is to unmap the pte only after all operations against it are
finished.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Ilya Dryomov <idryomov@gmail.com>
Reported-by: werner <w.landgraf@ru.ru>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Ilya Dryomov <idryomov@gmail.com>
Tested-by: Steven Rostedt <rostedt@goodmis.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pmdp_get_and_clear/pmdp_clear_flush/pmdp_splitting_flush were trapped as
BUG() and they were defined only to diminish the risk of build issues on
not-x86 archs and to be consistent with the generic pte methods previously
defined in include/asm-generic/pgtable.h.
But they are causing more trouble than they were supposed to solve, so
it's simpler not to define them when THP is off.
This is also correcting the export of pmdp_splitting_flush which is
currently unused (x86 isn't using the generic implementation in
mm/pgtable-generic.c and no other arch needs that [yet]).
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Sam Ravnborg <sam@ravnborg.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (59 commits)
ACPI / PM: Fix build problems for !CONFIG_ACPI related to NVS rework
ACPI: fix resource check message
ACPI / Battery: Update information on info notification and resume
ACPI: Drop device flag wake_capable
ACPI: Always check if _PRW is present before trying to evaluate it
ACPI / PM: Check status of power resources under mutexes
ACPI / PM: Rename acpi_power_off_device()
ACPI / PM: Drop acpi_power_nocheck
ACPI / PM: Drop acpi_bus_get_power()
Platform / x86: Make fujitsu_laptop use acpi_bus_update_power()
ACPI / Fan: Rework the handling of power resources
ACPI / PM: Register power resource devices as soon as they are needed
ACPI / PM: Register acpi_power_driver early
ACPI / PM: Add function for updating device power state consistently
ACPI / PM: Add function for device power state initialization
ACPI / PM: Introduce __acpi_bus_get_power()
ACPI / PM: Introduce function for refcounting device power resources
ACPI / PM: Add functions for manipulating lists of power resources
ACPI / PM: Prevent acpi_power_get_inferred_state() from making changes
ACPICA: Update version to 20101209
...
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>
Commit b1dd693e ("memcg: avoid deadlock between move charge and
try_charge()") can cause another deadlock about mmap_sem on task migration
if cpuset and memcg are mounted onto the same mount point.
After the commit, cgroup_attach_task() has sequence like:
cgroup_attach_task()
ss->can_attach()
cpuset_can_attach()
mem_cgroup_can_attach()
down_read(&mmap_sem) (1)
ss->attach()
cpuset_attach()
mpol_rebind_mm()
down_write(&mmap_sem) (2)
up_write(&mmap_sem)
cpuset_migrate_mm()
do_migrate_pages()
down_read(&mmap_sem)
up_read(&mmap_sem)
mem_cgroup_move_task()
mem_cgroup_clear_mc()
up_read(&mmap_sem)
We can cause deadlock at (2) because we've already aquire the mmap_sem at (1).
But the commit itself is necessary to fix deadlocks which have existed
before the commit like:
Ex.1)
move charge | try charge
--------------------------------------+------------------------------
mem_cgroup_can_attach() | down_write(&mmap_sem)
mc.moving_task = current | ..
mem_cgroup_precharge_mc() | __mem_cgroup_try_charge()
mem_cgroup_count_precharge() | prepare_to_wait()
down_read(&mmap_sem) | if (mc.moving_task)
-> cannot aquire the lock | -> true
| schedule()
| -> move charge should wake it up
Ex.2)
move charge | try charge
--------------------------------------+------------------------------
mem_cgroup_can_attach() |
mc.moving_task = current |
mem_cgroup_precharge_mc() |
mem_cgroup_count_precharge() |
down_read(&mmap_sem) |
.. |
up_read(&mmap_sem) |
| down_write(&mmap_sem)
mem_cgroup_move_task() | ..
mem_cgroup_move_charge() | __mem_cgroup_try_charge()
down_read(&mmap_sem) | prepare_to_wait()
-> cannot aquire the lock | if (mc.moving_task)
| -> true
| schedule()
| -> move charge should wake it up
This patch fixes all of these problems by:
1. revert the commit.
2. To fix the Ex.1, we set mc.moving_task after mem_cgroup_count_precharge()
has released the mmap_sem.
3. To fix the Ex.2, we use down_read_trylock() instead of down_read() in
mem_cgroup_move_charge() and, if it has failed to aquire the lock, cancel
all extra charges, wake up all waiters, and retry trylock.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reported-by: Ben Blum <bblum@andrew.cmu.edu>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Paul Menage <menage@google.com>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.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>
Adding the number of swap pages to the byte limit of a memory control
group makes no sense. Convert the pages to bytes before adding them.
The only user of this code is the OOM killer, and the way it is used means
that the error results in a higher OOM badness value. Since the cgroup
limit is the same for all tasks in the cgroup, the error should have no
practical impact at the moment.
But let's not wait for future or changing users to trip over it.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: David Rientjes <rientjes@google.com>
Acked-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>
Introduce a new bit spin lock, PCG_MOVE_LOCK, to synchronize the page
accounting and migration code. This reworks the locking scheme of
_update_stat() and _move_account() by adding new lock bit PCG_MOVE_LOCK,
which is always taken under IRQ disable.
1. If pages are being migrated from a memcg, then updates to that
memcg page statistics are protected by grabbing PCG_MOVE_LOCK using
move_lock_page_cgroup(). In an upcoming commit, memcg dirty page
accounting will be updating memcg page accounting (specifically: num
writeback pages) from IRQ context (softirq). Avoid a deadlocking
nested spin lock attempt by disabling irq on the local processor when
grabbing the PCG_MOVE_LOCK.
2. lock for update_page_stat is used only for avoiding race with
move_account(). So, IRQ awareness of lock_page_cgroup() itself is not
a problem. The problem is between mem_cgroup_update_page_stat() and
mem_cgroup_move_account_page().
Trade-off:
* Changing lock_page_cgroup() to always disable IRQ (or
local_bh) has some impacts on performance and I think
it's bad to disable IRQ when it's not necessary.
* adding a new lock makes move_account() slower. Score is
here.
Performance Impact: moving a 8G anon process.
Before:
real 0m0.792s
user 0m0.000s
sys 0m0.780s
After:
real 0m0.854s
user 0m0.000s
sys 0m0.842s
This score is bad but planned patches for optimization can reduce
this impact.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Greg Thelen <gthelen@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Andrea Righi <arighi@develer.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.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>
The zone->lru_lock is heavily contented in workload where activate_page()
is frequently used. We could do batch activate_page() to reduce the lock
contention. The batched pages will be added into zone list when the pool
is full or page reclaim is trying to drain them.
For example, in a 4 socket 64 CPU system, create a sparse file and 64
processes, processes shared map to the file. Each process read access the
whole file and then exit. The process exit will do unmap_vmas() and cause
a lot of activate_page() call. In such workload, we saw about 58% total
time reduction with below patch. Other workloads with a lot of
activate_page also benefits a lot too.
I tested some microbenchmarks:
case-anon-cow-rand-mt 0.58%
case-anon-cow-rand -3.30%
case-anon-cow-seq-mt -0.51%
case-anon-cow-seq -5.68%
case-anon-r-rand-mt 0.23%
case-anon-r-rand 0.81%
case-anon-r-seq-mt -0.71%
case-anon-r-seq -1.99%
case-anon-rx-rand-mt 2.11%
case-anon-rx-seq-mt 3.46%
case-anon-w-rand-mt -0.03%
case-anon-w-rand -0.50%
case-anon-w-seq-mt -1.08%
case-anon-w-seq -0.12%
case-anon-wx-rand-mt -5.02%
case-anon-wx-seq-mt -1.43%
case-fork 1.65%
case-fork-sleep -0.07%
case-fork-withmem 1.39%
case-hugetlb -0.59%
case-lru-file-mmap-read-mt -0.54%
case-lru-file-mmap-read 0.61%
case-lru-file-mmap-read-rand -2.24%
case-lru-file-readonce -0.64%
case-lru-file-readtwice -11.69%
case-lru-memcg -1.35%
case-mmap-pread-rand-mt 1.88%
case-mmap-pread-rand -15.26%
case-mmap-pread-seq-mt 0.89%
case-mmap-pread-seq -69.72%
case-mmap-xread-rand-mt 0.71%
case-mmap-xread-seq-mt 0.38%
The most significent are:
case-lru-file-readtwice -11.69%
case-mmap-pread-rand -15.26%
case-mmap-pread-seq -69.72%
which use activate_page a lot. others are basically variations because
each run has slightly difference.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
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>
