Denys Vlasenko [Thu, 3 May 2012 05:44:19 +0000 (15:44 +1000)]
vsprintf-further-optimize-decimal-conversion-v2
Here is a new version. I also plugged a hole in num_to_str() -
it was assuming it's safe to call put_dec() for num=0.
(We never tripped over it before because the single caller
of num_to_str() takes care of that case).
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Denys Vlasenko [Thu, 3 May 2012 05:44:19 +0000 (15:44 +1000)]
vsprintf: further optimize decimal conversion
Previous code was using optimizations which were developed to work well
even on narrow-word CPUs (by today's standards). But Linux runs only on
32-bit and wider CPUs. We can use that.
First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly
divide by 10 much larger numbers, and thus we can print groups of 9 digits
instead of groups of 5 digits.
Next: there are two algorithms to print larger numbers. One is generic:
divide by 1000000000 and repeatedly print groups of (up to) 9 digits.
It's conceptually simple, but requires an (unsigned long long) / 1000000000 division.
Second algorithm splits 64-bit unsigned long long into 16-bit chunks,
manipulates them cleverly and generates groups of 4 decimal digits. It so
happens that it does NOT require long long division.
If long is > 32 bits, division of 64-bit values is relatively easy, and we
will use the first algorithm. If long long is > 64 bits (strange
architecture with VERY large long long), second algorithm can't be used,
and we again use the first one.
Else (if long is 32 bits and long long is 64 bits) we use second one.
And third: there is a simple optimization which takes fast path not only
for zero as was done before, but for all one-digit numbers.
In all tested cases new code is faster than old one, in many cases by 30%,
in few cases by more than 50% (for example, on x86-32, conversion of 12345678). Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit
case.
This patch is based upon an original from Michal Nazarewicz.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Cc: Douglas W Jones <jones@cs.uiowa.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Oleg Nesterov [Thu, 3 May 2012 05:44:17 +0000 (15:44 +1000)]
keys: kill the dummy key_replace_session_keyring()
After the previouse change key_replace_session_keyring() becomes a nop.
Remove the dummy definition in key.h and update the callers in
arch/*/kernel/signal.c.
Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Alexander Gordeev <agordeev@redhat.com> Cc: Chris Zankel <chris@zankel.net> Cc: David Smith <dsmith@redhat.com> Cc: "Frank Ch. Eigler" <fche@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Oleg Nesterov [Thu, 3 May 2012 05:44:16 +0000 (15:44 +1000)]
keys: change keyctl_session_to_parent() to use task_work_add()
Change keyctl_session_to_parent() to use task_work_add() and move
key_replace_session_keyring() logic into task_work->func().
Note that we do task_work_cancel() before task_work_add() to ensure that
only one work can be pending at any time. This is important, we must not
allow user-space to abuse the parent's ->task_works list.
The callback, replace_session_keyring(), checks PF_EXITING. I guess this
is not really needed but looks better.
As a side effect, this fixes the (unlikely) race. The callers of
key_replace_session_keyring() and keyctl_session_to_parent() lack the
necessary barriers, the parent can miss the request.
Now we can remove task_struct->replacement_session_keyring and related
code.
Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Alexander Gordeev <agordeev@redhat.com> Cc: Chris Zankel <chris@zankel.net> Cc: David Smith <dsmith@redhat.com> Cc: "Frank Ch. Eigler" <fche@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Oleg Nesterov [Thu, 3 May 2012 05:44:15 +0000 (15:44 +1000)]
task_work_add: generic process-context callbacks
Provide a simple mechanism that allows running code in the (nonatomic)
context of the arbitrary task.
The caller does task_work_add(task, task_work) and this task executes
task_work->func() either from do_notify_resume() or from do_exit(). The
callback can rely on PF_EXITING to detect the latter case.
"struct task_work" can be embedded in another struct, still it has "void
*data" to handle the most common/simple case.
This allows us to kill the ->replacement_session_keyring hack, and
potentially this can have more users.
Performance-wise, this adds 2 "unlikely(!hlist_empty())" checks into
tracehook_notify_resume() and do_exit(). But at the same time we can
remove the "replacement_session_keyring != NULL" checks from
arch/*/signal.c and exit_creds().
Note: task_work_add/task_work_run abuses ->pi_lock. This is only because
this lock is already used by lookup_pi_state() to synchronize with
do_exit() setting PF_EXITING. Fortunately the scope of this lock in
task_work.c is really tiny, and the code is unlikely anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Alexander Gordeev <agordeev@redhat.com> Cc: Chris Zankel <chris@zankel.net> Cc: David Smith <dsmith@redhat.com> Cc: "Frank Ch. Eigler" <fche@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sameer Nanda [Thu, 3 May 2012 05:44:13 +0000 (15:44 +1000)]
NMI watchdog: fix for lockup detector breakage on resume
On the suspend/resume path the boot CPU does not go though an
offline->online transition. This breaks the NMI detector post-resume
since it depends on PMU state that is lost when the system gets suspended.
Fix this by forcing a CPU offline->online transition for the lockup
detector on the boot CPU during resume.
To provide more context, we enable NMI watchdog on Chrome OS. We have
seen several reports of systems freezing up completely which indicated
that the NMI watchdog was not firing for some reason.
Debugging further, we found a simple way of repro'ing system freezes --
issuing the command 'tasket 1 sh -c "echo nmilockup > /proc/breakme"'
after the system has been suspended/resumed one or more times.
With this patch in place, the system freeze result in panics, as expected.
These panics provide a nice stack trace for us to debug the actual issue
causing the freeze.
Signed-off-by: Sameer Nanda <snanda@chromium.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Don Zickus <dzickus@redhat.com> Cc: Mandeep Singh Baines <msb@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sasikantha babu [Thu, 3 May 2012 05:44:13 +0000 (15:44 +1000)]
sethostname/setdomainname: notify userspace when there is a change in uts_kern_table
sethostname() and setdomainname() notify userspace on failure (without
modifying uts_kern_table). Change things so that we only notify userspace
on success, when uts_kern_table was actually modified.
Signed-off-by: Sasikantha babu <sasikanth.v19@gmail.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: WANG Cong <amwang@redhat.com> Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Xi Wang [Thu, 3 May 2012 05:44:13 +0000 (15:44 +1000)]
introduce SIZE_MAX
ULONG_MAX is often used to check for integer overflow when calculating
allocation size. While ULONG_MAX happens to work on most systems, there
is no guarantee that `size_t' must be the same size as `long'.
This patch introduces SIZE_MAX, the maximum value of `size_t', to improve
portability and readability for allocation size validation.
Signed-off-by: Xi Wang <xi.wang@gmail.com> Acked-by: Alex Elder <elder@dreamhost.com> Cc: David Airlie <airlied@linux.ie> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Matt Fleming [Thu, 3 May 2012 05:44:12 +0000 (15:44 +1000)]
parisc: use set_current_blocked() and block_sigmask()
As described in e6fa16ab ("signal: sigprocmask() should do
retarget_shared_pending()") the modification of current->blocked is
incorrect as we need to check whether the signal we're about to block is
pending in the shared queue.
Also, use the new helper function introduced in commit 5e6292c0f28f
("signal: add block_sigmask() for adding sigmask to current->blocked")
which centralises the code for updating current->blocked after
successfully delivering a signal and reduces the amount of duplicate code
across architectures. In the past some architectures got this code wrong,
so using this helper function should stop that from happening again.
Xi Wang [Thu, 3 May 2012 05:44:12 +0000 (15:44 +1000)]
CodingStyle: add kmalloc_array() to memory allocators
Add the new kmalloc_array() to the list of general-purpose memory
allocators in chapter 14.
Signed-off-by: Xi Wang <xi.wang@gmail.com> Acked-by: Jesper Juhl <jj@chaosbits.net> Acked-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andi Kleen [Thu, 3 May 2012 05:44:11 +0000 (15:44 +1000)]
checkpatch: check for spin_is_locked()
spin_is_locked() is usually misued. In checkpatch.pl:
- warn when it is used at all
- error out when it is asserted on free, because that's usually broken
(e.g. doesn't work on on uni processor builds). Recommend
lockdep_assert_held() instead.
[joe@perches.com: some improvements] Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Andy Whitcroft <apw@canonical.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andi Kleen [Thu, 3 May 2012 05:44:10 +0000 (15:44 +1000)]
drivers/net/ethernet/smsc/smsc911x.h: use lockdep_assert_held() instead of home grown buggy construct
Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Steve Glendinning <steve.glendinning@smsc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It's hard to imagine how this spin_is_locked() debugging check is not
totally racy. Remove it.
Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Samuel Ortiz <samuel@sortiz.org> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andi Kleen [Thu, 3 May 2012 05:44:09 +0000 (15:44 +1000)]
futex: use lockdep_assert_held() for lock checking
Use lockdep_assert_held() for lock checking instead of a strange homegrown
variant. This removes the return for this case, but that is unlikely to
be useful anyway.
Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Darren Hart <dvhart@linux.intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kautuk Consul [Thu, 3 May 2012 05:44:07 +0000 (15:44 +1000)]
um/kernel/trap.c: port OOM changes to handle_page_fault()
Commit d065bd810b6deb6 ("mm: retry page fault when blocking on disk
transfer") and commit 37b23e0525 ("x86,mm: make pagefault killable")
The above commits introduced changes into the x86 pagefault handler
for making the page fault handler retryable as well as killable.
These changes reduce the mmap_sem hold time, which is crucial
during OOM killer invocation.
Port these changes to um.
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Matt Fleming [Thu, 3 May 2012 05:44:07 +0000 (15:44 +1000)]
frv: use set_current_blocked() and block_sigmask()
As described in e6fa16ab ("signal: sigprocmask() should do
retarget_shared_pending()") the modification of current->blocked is
incorrect as we need to check whether the signal we're about to block is
pending in the shared queue.
Also, use the new helper function introduced in commit 5e6292c0f28f
("signal: add block_sigmask() for adding sigmask to current->blocked")
which centralises the code for updating current->blocked after
successfully delivering a signal and reduces the amount of duplicate code
across architectures. In the past some architectures got this code wrong,
so using this helper function should stop that from happening again.
Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This allocation may be large. The code is probing to see if it will
succeed and if not, it falls back to vmalloc(). We should suppress any
page-allocation failure messages when the fallback happens.
Reported-by: Dave Jones <davej@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/vmscan: replace zone_nr_lru_pages() with get_lruvec_size()
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>
mm/vmscan: push zone pointer into shrink_page_list()
It doesn't need a pointer to the cgroup - pointer to the zone is enough.
This patch also kills the "mz" argument of page_check_references() - it is
unused after "mm: memcg: count pte references from every member of the
reclaimed hierarch"
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>
mm/vmscan: store "priority" in struct scan_control
In memory reclaim some function have too many arguments - "priority" is
one of them. It can be stored in struct scan_control - we construct them
on the same level. Instead of an open coded loop we set the initial
sc.priority, and do_try_to_free_pages() decreases it down to zero.
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>
Ying Han [Thu, 3 May 2012 05:44:01 +0000 (15:44 +1000)]
memcg: add mlock statistic in memory.stat
We have the nr_mlock stat both in meminfo as well as vmstat system wide,
this patch adds the mlock field into per-memcg memory stat. The stat
itself enhances the metrics exported by memcg since the unevictable lru
includes more than mlock()'d page like SHM_LOCK'd.
Why we need to count mlock'd pages while they are unevictable and we can
not do much on them anyway?
This is true. The mlock stat I am proposing is more helpful for system
admin and kernel developer to understand the system workload. The same
information should be helpful to add into OOM log as well. Many times in
the past that we need to read the mlock stat from the per-container
meminfo for different reason. Afterall, we do have the ability to read
the mlock from meminfo and this patch fills the info in memcg.
Note:
Here are the places where I didn't add the hook:
1. in the mlock_migrate_page() since the owner of oldpage and newpage
is the same.
2. in the freeing path since page shouldn't get to there at the first
place.
1. Run memtoy in B and mlock 512m file pages:
memtoy>file /export/hda3/file_512m private
memtoy>map file_512m 0 512m
memtoy>lock file_512m
memtoy: mlock of file_512m [131072 pages] took 5.296secs.
2) Create 20g memcg and run single thread page fault test (pft) w/ 10g
mlock memory, here it measures faults/cpu/second:
x before.txt
+ after.txt
+--------------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 10 346345.92 349113.01 347470.52 347651.93 819.71411
+ 10 345934.67 348973.58 347677.9 347495.33 833.58657
No difference proven at 95.0% confidence
Signed-off-by: Ying Han <yinghan@google.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sha Zhengju [Thu, 3 May 2012 05:43:59 +0000 (15:43 +1000)]
memcg: make threshold index in the right position
Index current_threshold may point to threshold that just equal to usage
after last call of __mem_cgroup_threshold. But after registering a new
event, it will change (pointing to threshold just below usage). So make
it consistent here.
mm: remove lru type checks from __isolate_lru_page()
After patch "mm: forbid lumpy-reclaim in shrink_active_list()" we can
completely remove anon/file and active/inactive lru type filters from
__isolate_lru_page(), because isolation for 0-order reclaim always
isolates pages from right lru list. And pages-isolation for lumpy
shrink_inactive_list() or memory-compaction anyway allowed to isolate
pages from all evictable lru lists.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
GCC sometimes ignores "inline" directives even for small and simple functions.
This supposed to be fixed in gcc 4.7, but it was released only yesterday.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: 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>
Hugh Dickins [Thu, 3 May 2012 05:43:56 +0000 (15:43 +1000)]
mm/memcg: move reclaim_stat into lruvec
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>
Hugh Dickins [Thu, 3 May 2012 05:43:55 +0000 (15:43 +1000)]
mm/memcg: scanning_global_lru means mem_cgroup_disabled
Although one has to admire the skill with which it has been concealed,
scanning_global_lru(mz) is actually just an interesting way to test
mem_cgroup_disabled(). Too many developer hours have been wasted on
confusing it with global_reclaim(): just use mem_cgroup_disabled().
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: 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>
memcg: fix/change behavior of shared anon at moving task
This patch changes memcg's behavior at task_move().
At task_move(), the kernel scans a task's page table and move the changes
for mapped pages from source cgroup to target cgroup. There has been a
bug at handling shared anonymous pages for a long time.
Before patch:
- The spec says 'shared anonymous pages are not moved.'
- The implementation was 'shared anonymoys pages may be moved'.
If page_mapcount <=2, shared anonymous pages's charge were moved.
After patch:
- The spec says 'all anonymous pages are moved'.
- The implementation is 'all anonymous pages are moved'.
Considering usage of memcg, this will not affect user's experience.
'shared anonymous' pages only exists between a tree of processes which
don't do exec(). Moving one of process without exec() seems not sane.
For example, libcgroup will not be affected by this change. (Anyway, no
one noticed the implementation for a long time...)
Below is a discussion log:
- current spec/implementation are complex
- Now, shared file caches are moved
- It adds unclear check as page_mapcount(). To do correct check,
we should check swap users, etc.
- No one notice this implementation behavior. So, no one get benefit
from the design.
- In general, once task is moved to a cgroup for running, it will not
be moved....
- Finally, we have control knob as memory.move_charge_at_immigrate.
Here is a patch to allow moving shared pages, completely. This makes
memcg simpler and fix current broken code.
Suggested-by: Hugh Dickins <hughd@google.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Glauber Costa <glommer@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
is_vma_temporary_stack() isn't referenced in huge_mm.h, so it has compile
errors:
arch/x86/mm/tlb.c: In function `flush_tlb_range':
arch/x86/mm/tlb.c:324:4: error: implicit declaration of function `is_vma_temporary_stack' [-Werror=implicit-function-declaration]
Since is_vma_temporay_stack() is just used in rmap.c and huge_memory.c, it
is better to move it to huge_mm.h from rmap.h to avoid such errors.
Signed-off-by: Alex Shi <alex.shi@intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ulrich Drepper [Thu, 3 May 2012 05:43:54 +0000 (15:43 +1000)]
tools/vm/page-types.c: cleanups
Compiling page-type.c with a recent compiler produces many warnings,
mostly related to signed/unsigned comparisons. This patch cleans up most
of them.
One remaining warning is about an unused parameter. The <compiler.h> file
doesn't define a __unused macro (or the like) yet. This can be addressed
later.
Ulrich Drepper [Thu, 3 May 2012 05:43:53 +0000 (15:43 +1000)]
kbuild: install kernel-page-flags.h
Programs using /proc/kpageflags need to know about the various flags. The
<linux/kernel-page-flags.h> provides them and the comments in the file
indicate that it is supposed to be used by user-level code. But the file
is not installed.
Install the headers and mark the unstable flags as out-of-bounds. The
page-type tool is also adjusted to not duplicate the definitions
bug: completely remove code generated by disabled VM_BUG_ON()
Even if CONFIG_DEBUG_VM=n gcc genereates code for some VM_BUG_ON()
for example VM_BUG_ON(!PageCompound(page) || !PageHead(page)); in
do_huge_pmd_wp_page() generates 114 bytes of code.
But they mostly disappears when I split this VM_BUG_ON into two:
-VM_BUG_ON(!PageCompound(page) || !PageHead(page));
+VM_BUG_ON(!PageCompound(page));
+VM_BUG_ON(!PageHead(page));
weird... but anyway after this patch code disappears completely.
Sometimes we want to check some expressions correctness at compile time.
"(void)(e);" or "if (e);" can be dangerous if the expression has
side-effects, and gcc sometimes generates a lot of code, even if the
expression has no effect.
This patch introduces macro BUILD_BUG_ON_INVALID() for such checks, it
forces a compilation error if expression is invalid without any extra
code.
[Cast to "long" required because sizeof does not work for bit-fields.]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Rientjes [Thu, 3 May 2012 05:43:50 +0000 (15:43 +1000)]
mm, thp: drop page_table_lock to uncharge memcg pages
mm->page_table_lock is hotly contested for page fault tests and isn't
necessary to do mem_cgroup_uncharge_page() in do_huge_pmd_wp_page().
Signed-off-by: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Thu, 3 May 2012 05:43:49 +0000 (15:43 +1000)]
mm: memcg: count pte references from every member of the reclaimed hierarchy
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.
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> Cc: 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>
Johannes Weiner [Thu, 3 May 2012 05:43:48 +0000 (15:43 +1000)]
kernel: cgroup: push rcu read locking from css_is_ancestor() to callsite
Library functions should not grab locks when the callsites can do it, even
if the lock nests like the rcu read-side lock does.
Push the rcu_read_lock() from css_is_ancestor() to its single user,
mem_cgroup_same_or_subtree() in preparation for another user that may
already hold the rcu read-side lock.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: 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>
Larry Woodman [Thu, 3 May 2012 05:43:47 +0000 (15:43 +1000)]
mm: do_migrate_pages() calls migrate_to_node() even if task is already on a correct node
While running an application that moves tasks from one cpuset to another I
noticed that it takes much longer and moves many more pages than expected.
The reason for this is do_migrate_pages() does its best to preserve the
relative node differential from the first node of the cpuset because the
application may have been written with that in mind. If memory was
interleaved on the nodes of the source cpuset by an application
do_migrate_pages() will try its best to maintain that interleaving on the
nodes of the destination cpuset. This means copying the memory from all
source nodes to the destination nodes even if the source and destination
nodes overlap.
This is a problem for userspace NUMA placement tools. The amount of time
spent doing extra memory moves cancels out some of the NUMA performance
improvements. Furthermore, if the number of source and destination nodes
are to maintain the previous interleaving layout anyway.
This patch changes do_migrate_pages() to only preserve the relative layout
inside the program if the number of NUMA nodes in the source and
destination mask are the same. If the number is different, we do a much
more efficient migration by not touching memory that is in an allowed
node.
This preserves the old behaviour for programs that want it, while allowing
a userspace NUMA placement tool to use the new, faster migration. This
improves performance in our tests by up to a factor of 7.
Without this change migrating tasks from a cpuset containing nodes 0-7 to
a cpuset containing nodes 3-4, we migrate from ALL the nodes even if they
are in the both the source and destination nodesets:
Migrating 7 to 4
Migrating 6 to 3
Migrating 5 to 4
Migrating 4 to 3
Migrating 1 to 4
Migrating 3 to 4
Migrating 0 to 3
Migrating 2 to 3
With this change we only migrate from nodes that are not in the
destination nodesets:
Migrating 7 to 4
Migrating 6 to 3
Migrating 5 to 4
Migrating 2 to 3
Migrating 1 to 4
Migrating 0 to 3
Yet if we move from a cpuset containing nodes 2,3,4 to a cpuset
containing 3,4,5 we still
do move everything so that we preserve the desired NUMA offsets:
Migrating 4 to 5
Migrating 3 to 4
Migrating 2 to 3
As far as performance is concerned this simple patch improves the time it
takes to move 14, 20 and 26 large tasks from a cpuset containing nodes 0-7
to a cpuset containing nodes 1 & 3 by up to a factor of 7. Here are the
timings with and without the patch:
BEFORE PATCH -- Move times: 59, 140, 651 seconds
============
Moving 14 tasks from nodes (0-7) to nodes (1,3)
numad(8780) do_migrate_pages (mm=0xffff88081d414400
from_nodes=0xffff880818c81d28 to_nodes=0xffff880818c81ce8 flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x7 dest=0x3
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x6 dest=0x1
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x5 dest=0x3
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x4 dest=0x1
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x2 dest=0x1
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x1 dest=0x3
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d414400 source=0x0 dest=0x1
flags=0x4)
(Above moves repeated for each of the 14 tasks...)
PID 8890 moved to node(s) 1,3 in 59.2 seconds
Moving 20 tasks from nodes (0-7) to nodes (1,4-5)
numad(8780) do_migrate_pages (mm=0xffff88081d88c700
from_nodes=0xffff880818c81d28 to_nodes=0xffff880818c81ce8 flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x7 dest=0x4
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x6 dest=0x1
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x3 dest=0x1
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x2 dest=0x5
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x1 dest=0x4
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d88c700 source=0x0 dest=0x1
flags=0x4)
(Above moves repeated for each of the 20 tasks...)
PID 8962 moved to node(s) 1,4-5 in 139.88 seconds
Moving 26 tasks from nodes (0-7) to nodes (1-3,5)
numad(8780) do_migrate_pages (mm=0xffff88081d5bc740
from_nodes=0xffff880818c81d28 to_nodes=0xffff880818c81ce8 flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x7 dest=0x5
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x6 dest=0x3
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x5 dest=0x2
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x3 dest=0x5
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x2 dest=0x3
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x1 dest=0x2
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x0 dest=0x1
flags=0x4)
numad(8780) migrate_to_node (mm=0xffff88081d5bc740 source=0x4 dest=0x1
flags=0x4)
(Above moves repeated for each of the 26 tasks...)
PID 9058 moved to node(s) 1-3,5 in 651.45 seconds
AFTER PATCH -- Move times: 42, 56, 93 seconds
===========
Moving 14 tasks from nodes (0-7) to nodes (5,7)
numad(33209) do_migrate_pages (mm=0xffff88101d5ff140
from_nodes=0xffff88101e7b5d28 to_nodes=0xffff88101e7b5ce8 flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x6 dest=0x5
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x4 dest=0x5
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x3 dest=0x7
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x2 dest=0x5
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x1 dest=0x7
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d5ff140 source=0x0 dest=0x5
flags=0x4)
(Above moves repeated for each of the 14 tasks...)
PID 33221 moved to node(s) 5,7 in 41.67 seconds
Moving 20 tasks from nodes (0-7) to nodes (1,3,5)
numad(33209) do_migrate_pages (mm=0xffff88101d6c37c0
from_nodes=0xffff88101e7b5d28 to_nodes=0xffff88101e7b5ce8 flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d6c37c0 source=0x7 dest=0x3
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d6c37c0 source=0x6 dest=0x1
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d6c37c0 source=0x4 dest=0x3
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d6c37c0 source=0x2 dest=0x5
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d6c37c0 source=0x0 dest=0x1
flags=0x4)
(Above moves repeated for each of the 20 tasks...)
PID 33289 moved to node(s) 1,3,5 in 56.3 seconds
Moving 26 tasks from nodes (0-7) to nodes (1,3,5,7)
numad(33209) do_migrate_pages (mm=0xffff88101d924400
from_nodes=0xffff88101e7b5d28 to_nodes=0xffff88101e7b5ce8 flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d924400 source=0x6 dest=0x5
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d924400 source=0x4 dest=0x1
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d924400 source=0x2 dest=0x5
flags=0x4)
numad(33209) migrate_to_node (mm=0xffff88101d924400 source=0x0 dest=0x1
flags=0x4)
(Above moves repeated for each of the 26 tasks...)
PID 33372 moved to node(s) 1,3,5,7 in 92.67 seconds
Signed-off-by: Larry Woodman <lwoodman@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <mkosaki@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Rientjes [Thu, 3 May 2012 05:43:47 +0000 (15:43 +1000)]
thp, memcg: split hugepage for memcg oom on cow
On COW, a new hugepage is allocated and charged to the memcg. If the
system is oom or the charge to the memcg fails, however, the fault handler
will return VM_FAULT_OOM which results in an oom kill.
Instead, it's possible to fallback to splitting the hugepage so that the
COW results only in an order-0 page being allocated and charged to the
memcg which has a higher liklihood to succeed. This is expensive because
the hugepage must be split in the page fault handler, but it is much
better than unnecessarily oom killing a process.
Signed-off-by: David Rientjes <rientjes@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm: correctly synchronize rss-counters at exit/exec
mm->rss_stat counters have per-task delta: task->rss_stat. Before
changing task->mm pointer the kernel must flush this delta with
sync_mm_rss().
do_exit() already calls sync_mm_rss() to flush the rss-counters before
committing the rss statistics into task->signal->maxrss, taskstats, audit
and other stuff. Unfortunately the kernel does this before calling
mm_release(), which can call put_user() for processing
task->clear_child_tid. So at this point we can trigger page-faults and
task->rss_stat becomes non-zero again. As a result mm->rss_stat becomes
inconsistent and check_mm() will print something like this:
This patch moves sync_mm_rss() into mm_release(), and moves mm_release()
out of do_exit() and calls it earlier. After mm_release() there should be
no pagefaults.
[akpm@linux-foundation.org: tweak comment] Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Cc: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sasikantha babu [Thu, 3 May 2012 05:43:46 +0000 (15:43 +1000)]
mm/vmstat.c: remov debug fs entries on failure of file creation and made extfrag_debug_root dentry local
Removed debug fs files and directory on failure. Since no one using
"extfrag_debug_root" dentry outside of function extfrag_debug_init made it
local to the function.
Signed-off-by: Sasikantha babu <sasikanth.v19@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/fork: fix overflow in vma length when copying mmap on clone
The vma length in dup_mmap is calculated and stored in a unsigned int,
which is insufficient and hence overflows for very large maps (beyond
16TB). The following program demonstrates this:
The if(mm) check is not required in find_vma, as the kernel code calls
find_vma only when it is absolutely sure that the mm_struct arg to it is
non-NULL.
Remove the if(mm) check and adding the a WARN_ONCE(!mm) for now. This
will serve the purpose of mandating that the execution
context(user-mode/kernel-mode) be known before find_vma is called. Also
fixed 2 checkpatch.pl errors in the declaration of the rb_node and vma_tmp
local variables.
I was browsing through the internet and read a discussion at
https://lkml.org/lkml/2012/3/27/342 which discusses removal of the
validation check within find_vma. Since no-one responded, I decided to
send this patch with Andrew's suggestions.
Thomas Meyer [Thu, 3 May 2012 05:43:44 +0000 (15:43 +1000)]
mm: use kcalloc() instead of kzalloc() to allocate array
The advantage of kcalloc is, that will prevent integer overflows which
could result from the multiplication of number of elements and size and it
is also a bit nicer to read.
The semantic patch that makes this change is available
in https://lkml.org/lkml/2011/11/25/107
Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryota Ozaki [Thu, 3 May 2012 05:43:44 +0000 (15:43 +1000)]
mm: fix off-by-one bug in print_nodes_state()
/sys/devices/system/node/{online,possible} outputs a garbage byte because
print_nodes_state() returns content size + 1. To fix the bug, the patch
changes the use of cpuset_sprintf_cpulist to follow the use at other
places, which is clearer and safer.
hugetlb: migrate memcg info from oldpage to new page during migration
With HugeTLB pages, memcg is uncharged in compound page destructor. Since
we are holding a hugepage reference, we can be sure that old page won't
get uncharged till the last put_page(). On successful migrate, we can
move the memcg information to new page's page_cgroup and mark the old
page's page_cgroup unused.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
projects / karo-tx-linux.git / log