drtracing.org Git - deliverable/linux.git/log

powerpc: implement arch_reserved_kernel_pages

Currently significant amount of memory is reserved only in kernel booted
to capture kernel dump using the fa_dump method.

Kernels compiled with CONFIG_DEFERRED_STRUCT_PAGE_INIT will initialize
only certain size memory per node.  The certain size takes into account
the dentry and inode cache sizes.  Currently the cache sizes are
calculated based on the total system memory including the reserved memory.
However such a kernel when booting the same kernel as fadump kernel will
not be able to allocate the required amount of memory to suffice for the
dentry and inode caches.  This results in crashes like

Hence only implement arch_reserved_kernel_pages() for CONFIG_FA_DUMP
configurations.  The amount reserved will be reduced while calculating the
large caches and will avoid crashes like the below on large systems such
as 32 TB systems.

Dentry cache hash table entries: 536870912 (order: 16, 4294967296 bytes)
vmalloc: allocation failure, allocated 4097114112 of 17179934720 bytes
swapper/0: page allocation failure: order:0, mode:0x2080020(GFP_ATOMIC)
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.6-master+ #3
Call Trace:
[c00000000108fb10] [c0000000007fac88] dump_stack+0xb0/0xf0 (unreliable)
[c00000000108fb50] [c000000000235264] warn_alloc_failed+0x114/0x160
[c00000000108fbf0] [c000000000281484] __vmalloc_node_range+0x304/0x340
[c00000000108fca0] [c00000000028152c] __vmalloc+0x6c/0x90
[c00000000108fd40] [c000000000aecfb0]
alloc_large_system_hash+0x1b8/0x2c0
[c00000000108fe00] [c000000000af7240] inode_init+0x94/0xe4
[c00000000108fe80] [c000000000af6fec] vfs_caches_init+0x8c/0x13c
[c00000000108ff00] [c000000000ac4014] start_kernel+0x50c/0x578
[c00000000108ff90] [c000000000008c6c] start_here_common+0x20/0xa8

Link: http://lkml.kernel.org/r/1472476010-4709-4-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Suggested-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memblock.c: expose total reserved memory

The total reserved memory in a system is accounted but not available for
use use outside mm/memblock.c. By exposing the total reserved memory,
systems can better calculate the size of large hashes.

Link: http://lkml.kernel.org/r/1472476010-4709-3-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Suggested-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: introduce arch_reserved_kernel_pages()

Currently arch specific code can reserve memory blocks but
alloc_large_system_hash() may not take it into consideration when sizing
the hashes.  This can lead to bigger hash than required and lead to no
available memory for other purposes.  This is specifically true for
systems with CONFIG_DEFERRED_STRUCT_PAGE_INIT enabled.

One approach to solve this problem would be to walk through the memblock
regions and calculate the available memory and base the size of hash
system on the available memory.

The other approach would be to depend on the architecture to provide the
number of pages that are reserved.  This change provides hooks to allow
the architecture to provide the required info.

Link: http://lkml.kernel.org/r/1472476010-4709-2-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Suggested-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: use zonelist name instead of using hardcoded index

Use the existing enums instead of hardcoded index when looking at the
zonelist. This makes it more readable. No functionality change by this
patch.

Link: http://lkml.kernel.org/r/1472227078-24852-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

oom, oom_reaper: allow to reap mm shared by the kthreads

oom reaper was skipped for an mm which is shared with the kernel thread
(aka use_mm()).  The primary concern was that such a kthread might want to
read from the userspace memory and see zero page as a result of the oom
reaper action.  This is no longer a problem after "mm: make sure that
kthreads will not refault oom reaped memory" because any attempt to fault
in when the MMF_UNSTABLE is set will result in SIGBUS and so the target
user should see an error.  This means that we can finally allow oom reaper
also to tasks which share their mm with kthreads.

Link: http://lkml.kernel.org/r/1472119394-11342-10-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: make sure that kthreads will not refault oom reaped memory

There are only few use_mm() users in the kernel right now.  Most of them
write to the target memory but vhost driver relies on
copy_from_user/get_user from a kernel thread context.  This makes it
impossible to reap the memory of an oom victim which shares the mm with
the vhost kernel thread because it could see a zero page unexpectedly and
theoretically make an incorrect decision visible outside of the killed
task context.

To quote Michael S. Tsirkin:
: Getting an error from __get_user and friends is handled gracefully.
: Getting zero instead of a real value will cause userspace
: memory corruption.

The vhost kernel thread is bound to an open fd of the vhost device which
is not tight to the mm owner life cycle in general.  The device fd can be
inherited or passed over to another process which means that we really
have to be careful about unexpected memory corruption because unlike for
normal oom victims the result will be visible outside of the oom victim
context.

Make sure that no kthread context (users of use_mm) can ever see corrupted
data because of the oom reaper and hook into the page fault path by
checking MMF_UNSTABLE mm flag.  __oom_reap_task_mm will set the flag
before it starts unmapping the address space while the flag is checked
after the page fault has been handled.  If the flag is set then SIGBUS is
triggered so any g-u-p user will get a error code.

Regular tasks do not need this protection because all which share the mm
are killed when the mm is reaped and so the corruption will not outlive
them.

This patch shouldn't have any visible effect at this moment because the
OOM killer doesn't invoke oom reaper for tasks with mm shared with
kthreads yet.

Link: http://lkml.kernel.org/r/1472119394-11342-9-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, oom: enforce exit_oom_victim on current task

There are no users of exit_oom_victim on !current task anymore so enforce
the API to always work on the current.

Link: http://lkml.kernel.org/r/1472119394-11342-8-git-send-email-mhocko@kernel.org
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

oom, suspend: fix oom_killer_disable vs. pm suspend properly

74070542099c ("oom, suspend: fix oom_reaper vs.  oom_killer_disable race")
has workaround an existing race between oom_killer_disable and oom_reaper
by adding another round of try_to_freeze_tasks after the oom killer was
disabled.  This was the easiest thing to do for a late 4.7 fix.  Let's fix
it properly now.

After "oom: keep mm of the killed task available" we no longer have to
call exit_oom_victim from the oom reaper because we have stable mm
available and hide the oom_reaped mm by MMF_OOM_SKIP flag.  So let's
remove exit_oom_victim and the race described in the above commit doesn't
exist anymore if.

Unfortunately this alone is not sufficient for the oom_killer_disable
usecase because now we do not have any reliable way to reach
exit_oom_victim (the victim might get stuck on a way to exit for an
unbounded amount of time).  OOM killer can cope with that by checking mm
flags and move on to another victim but we cannot do the same for
oom_killer_disable as we would lose the guarantee of no further
interference of the victim with the rest of the system.  What we can do
instead is to cap the maximum time the oom_killer_disable waits for
victims.  The only current user of this function (pm suspend) already has
a concept of timeout for back off so we can reuse the same value there.

Let's drop set_freezable for the oom_reaper kthread because it is no
longer needed as the reaper doesn't wake or thaw any processes.

Link: http://lkml.kernel.org/r/1472119394-11342-7-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, oom: get rid of signal_struct::oom_victims

After "oom: keep mm of the killed task available" we can safely detect an
oom victim by checking task->signal->oom_mm so we do not need the
signal_struct counter anymore so let's get rid of it.

This alone wouldn't be sufficient for nommu archs because exit_oom_victim
doesn't hide the process from the oom killer anymore. We can, however,
mark the mm with a MMF flag in __mmput. We can reuse MMF_OOM_REAPED and
rename it to a more generic MMF_OOM_SKIP.

Link: http://lkml.kernel.org/r/1472119394-11342-6-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel, oom: fix potential pgd_lock deadlock from __mmdrop

Lockdep complains that __mmdrop is not safe from the softirq context:

[   63.860469] =================================
[   63.861326] [ INFO: inconsistent lock state ]
[   63.862677] 4.6.0-oomfortification2-00011-geeb3eadeab96-dirty #949 Tainted: G        W
[   63.864072] ---------------------------------
[   63.864072] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[   63.864072] swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
[   63.864072]  (pgd_lock){+.?...}, at: [<ffffffff81048762>] pgd_free+0x19/0x6b
[   63.864072] {SOFTIRQ-ON-W} state was registered at:
[   63.864072]   [<ffffffff81097da2>] __lock_acquire+0xa06/0x196e
[   63.864072]   [<ffffffff810994d8>] lock_acquire+0x139/0x1e1
[   63.864072]   [<ffffffff81625cd2>] _raw_spin_lock+0x32/0x41
[   63.864072]   [<ffffffff8104594d>] __change_page_attr_set_clr+0x2a5/0xacd
[   63.864072]   [<ffffffff810462e4>] change_page_attr_set_clr+0x16f/0x32c
[   63.864072]   [<ffffffff81046544>] set_memory_nx+0x37/0x3a
[   63.864072]   [<ffffffff81041b2c>] free_init_pages+0x9e/0xc7
[   63.864072]   [<ffffffff81d49105>] alternative_instructions+0xa2/0xb3
[   63.864072]   [<ffffffff81d4a763>] check_bugs+0xe/0x2d
[   63.864072]   [<ffffffff81d3eed0>] start_kernel+0x3ce/0x3ea
[   63.864072]   [<ffffffff81d3e2f1>] x86_64_start_reservations+0x2a/0x2c
[   63.864072]   [<ffffffff81d3e46d>] x86_64_start_kernel+0x17a/0x18d
[   63.864072] irq event stamp: 105916
[   63.864072] hardirqs last  enabled at (105916): [<ffffffff8112f5ba>] free_hot_cold_page+0x37e/0x390
[   63.864072] hardirqs last disabled at (105915): [<ffffffff8112f4fd>] free_hot_cold_page+0x2c1/0x390
[   63.864072] softirqs last  enabled at (105878): [<ffffffff81055724>] _local_bh_enable+0x42/0x44
[   63.864072] softirqs last disabled at (105879): [<ffffffff81055a6d>] irq_exit+0x6f/0xd1
[   63.864072]
[   63.864072] other info that might help us debug this:
[   63.864072]  Possible unsafe locking scenario:
[   63.864072]
[   63.864072]        CPU0
[   63.864072]        ----
[   63.864072]   lock(pgd_lock);
[   63.864072]   <Interrupt>
[   63.864072]     lock(pgd_lock);
[   63.864072]
[   63.864072]  *** DEADLOCK ***
[   63.864072]
[   63.864072] 1 lock held by swapper/1/0:
[   63.864072]  #0:  (rcu_callback){......}, at: [<ffffffff810b44f2>] rcu_process_callbacks+0x390/0x800
[   63.864072]
[   63.864072] stack backtrace:
[   63.864072] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G        W       4.6.0-oomfortification2-00011-geeb3eadeab96-dirty #949
[   63.864072] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[   63.864072]  0000000000000000 ffff88000fb03c38 ffffffff81312df8 ffffffff8257a0d0
[   63.864072]  ffff8800069f8000 ffff88000fb03c70 ffffffff81125bc5 0000000000000004
[   63.864072]  ffff8800069f8888 ffff8800069f8000 ffffffff8109603a 0000000000000004
[   63.864072] Call Trace:
[   63.864072]  <IRQ>  [<ffffffff81312df8>] dump_stack+0x67/0x90
[   63.864072]  [<ffffffff81125bc5>] print_usage_bug.part.25+0x259/0x268
[   63.864072]  [<ffffffff8109603a>] ? print_shortest_lock_dependencies+0x180/0x180
[   63.864072]  [<ffffffff81096d33>] mark_lock+0x381/0x567
[   63.864072]  [<ffffffff81097d2f>] __lock_acquire+0x993/0x196e
[   63.864072]  [<ffffffff81048762>] ? pgd_free+0x19/0x6b
[   63.864072]  [<ffffffff8117b8ae>] ? discard_slab+0x42/0x44
[   63.864072]  [<ffffffff8117e00d>] ? __slab_free+0x3e6/0x429
[   63.864072]  [<ffffffff810994d8>] lock_acquire+0x139/0x1e1
[   63.864072]  [<ffffffff810994d8>] ? lock_acquire+0x139/0x1e1
[   63.864072]  [<ffffffff81048762>] ? pgd_free+0x19/0x6b
[   63.864072]  [<ffffffff81625cd2>] _raw_spin_lock+0x32/0x41
[   63.864072]  [<ffffffff81048762>] ? pgd_free+0x19/0x6b
[   63.864072]  [<ffffffff81048762>] pgd_free+0x19/0x6b
[   63.864072]  [<ffffffff8104d018>] __mmdrop+0x25/0xb9
[   63.864072]  [<ffffffff8104d29d>] __put_task_struct+0x103/0x11e
[   63.864072]  [<ffffffff810526a0>] delayed_put_task_struct+0x157/0x15e
[   63.864072]  [<ffffffff810b47c2>] rcu_process_callbacks+0x660/0x800
[   63.864072]  [<ffffffff81052549>] ? will_become_orphaned_pgrp+0xae/0xae
[   63.864072]  [<ffffffff8162921c>] __do_softirq+0x1ec/0x4d5
[   63.864072]  [<ffffffff81055a6d>] irq_exit+0x6f/0xd1
[   63.864072]  [<ffffffff81628d7b>] smp_apic_timer_interrupt+0x42/0x4d
[   63.864072]  [<ffffffff8162732e>] apic_timer_interrupt+0x8e/0xa0
[   63.864072]  <EOI>  [<ffffffff81021657>] ? default_idle+0x6b/0x16e
[   63.864072]  [<ffffffff81021ed2>] arch_cpu_idle+0xf/0x11
[   63.864072]  [<ffffffff8108e59b>] default_idle_call+0x32/0x34
[   63.864072]  [<ffffffff8108e7a9>] cpu_startup_entry+0x20c/0x399
[   63.864072]  [<ffffffff81034600>] start_secondary+0xfe/0x101

More over a79e53d85683 ("x86/mm: Fix pgd_lock deadlock") was explicit
about pgd_lock not to be called from the irq context. This means that
__mmdrop called from free_signal_struct has to be postponed to a user
context. We already have a similar mechanism for mmput_async so we
can use it here as well. This is safe because mm_count is pinned by
mm_users.

This fixes bug introduced by "oom: keep mm of the killed task available"

Link: http://lkml.kernel.org/r/1472119394-11342-5-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

oom: keep mm of the killed task available

oom_reap_task has to call exit_oom_victim in order to make sure that the
oom vicim will not block the oom killer for ever.  This is, however,
opening new problems (e.g oom_killer_disable exclusion - see 74070542099c
("oom, suspend: fix oom_reaper vs.  oom_killer_disable race")).
exit_oom_victim should be only called from the victim's context ideally.

One way to achieve this would be to rely on per mm_struct flags. We
already have MMF_OOM_REAPED to hide a task from the oom killer since
"mm, oom: hide mm which is shared with kthread or global init". The
problem is that the exit path:
do_exit
  exit_mm
    tsk->mm = NULL;
    mmput
      __mmput
    exit_oom_victim

doesn't guarantee that exit_oom_victim will get called in a bounded amount
of time.  At least exit_aio depends on IO which might get blocked due to
lack of memory and who knows what else is lurking there.

This patch takes a different approach.  We remember tsk->mm into the
signal_struct and bind it to the signal struct life time for all oom
victims.  __oom_reap_task_mm as well as oom_scan_process_thread do not
have to rely on find_lock_task_mm anymore and they will have a reliable
reference to the mm struct.  As a result all the oom specific
communication inside the OOM killer can be done via tsk->signal->oom_mm.

Increasing the signal_struct for something as unlikely as the oom killer
is far from ideal but this approach will make the code much more
reasonable and long term we even might want to move task->mm into the
signal_struct anyway.  In the next step we might want to make the oom
killer exclusion and access to memory reserves completely independent
which would be also nice.

Link: http://lkml.kernel.org/r/1472119394-11342-4-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm,oom_reaper: do not attempt to reap a task twice

"mm, oom_reaper: do not attempt to reap a task twice" tried to give the
OOM reaper one more chance to retry using MMF_OOM_NOT_REAPABLE flag.  But
the usefulness of the flag is rather limited and actually never shown in
practice.  If the flag is set, it means that the holder of mm->mmap_sem
cannot call up_write() due to presumably being blocked at unkillable wait
waiting for other thread's memory allocation.  But since one of threads
sharing that mm will queue that mm immediately via task_will_free_mem()
shortcut (otherwise, oom_badness() will select the same mm again due to
oom_score_adj value unchanged), retrying MMF_OOM_NOT_REAPABLE mm is
unlikely helpful.

Let's always set MMF_OOM_REAPED.

Link: http://lkml.kernel.org/r/1472119394-11342-3-git-send-email-mhocko@kernel.org
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm,oom_reaper: reduce find_lock_task_mm() usage

Patch series "fortify oom killer even more", v2.

This patch (of 9):

__oom_reap_task() can be simplified a bit if it receives a valid mm from
oom_reap_task() which also uses that mm when __oom_reap_task() failed.  We
can drop one find_lock_task_mm() call and also make the __oom_reap_task()
code flow easier to follow.  Moreover, this will make later patch in the
series easier to review.  Pinning mm's mm_count for longer time is not
really harmful because this will not pin much memory.

This patch doesn't introduce any functional change.

Link: http://lkml.kernel.org/r/1472119394-11342-2-git-send-email-mhocko@kernel.org
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm-swap-add-swap_cluster_list-checkpatch-fixes

WARNING: Missing a blank line after declarations
#91: FILE: mm/swapfile.c:285:
+ unsigned int tail = cluster_next(&list->tail);
+ cluster_set_next(&ci[tail], idx);

WARNING: line over 80 characters
#261: FILE: mm/swapfile.c:2347:
+ cluster_list_add_tail(&p->free_clusters, cluster_info, idx);

total: 0 errors, 2 warnings, 222 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
mechanically convert to the typical style using --fix or --fix-inplace.

./patches/mm-swap-add-swap_cluster_list.patch has style problems, please review.

NOTE: If any of the errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.

Please run checkpatch prior to sending patches

Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, swap: add swap_cluster_list

This is a code clean up patch without functionality changes. The
swap_cluster_list data structure and its operations are introduced to
provide some better encapsulation for the free cluster and discard cluster
list operations. This avoid some code duplication, improved the code
readability, and reduced the total line number.

Link: http://lkml.kernel.org/r/1472067356-16004-1-git-send-email-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: unrig VMA cache hit ratio

Current code doesn't count first FIND operation after VMA cache flush
(which happen surprisingly often) artificially increasing cache hit ratio.

On my regular setup the difference is:

Before After
==========================================================

* boot, login into KDE

vmacache_find_calls 446216 vmacache_find_calls 492741
vmacache_find_hits 277596 vmacache_find_hits 276096

~62.2% ~56.0%

* rebuild kernel (no changes to code, usual config)

vmacache_find_calls 1943007 vmacache_find_calls 2083718
vmacache_find_hits 1246123 vmacache_find_hits 1244146

~64.1% ~59.7%

* rebuild kernel (full rebuild, usual config)

vmacache_find_calls 32163155 vmacache_find_calls 33677183
vmacache_find_hits 27889956 vmacache_find_hits 27877591

~88.2% ~84.3%

Total: ~4% cache hit ratio.

If someone is counting _relative_ cache _miss_ ratio, misreporting is much
higher.

Link: http://lkml.kernel.org/r/20160822225009.GA3934@p183.telecom.by
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: pagewalk: fix the comment for test_walk

Modify the comment describing struct mm_walk->test_walk()s behaviour to
match the comment on walk_page_test() and the behaviour of
walk_page_vma().

Fixes: fafaa4264eba4 ("pagewalk: improve vma handling")
Link: http://lkml.kernel.org/r/1471622518-21980-1-git-send-email-james.morse@arm.com
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

do_generic_file_read(): fail immediately if killed

If a fatal signal has been received, fail immediately instead of trying to
read more data.

If wait_on_page_locked_killable() was interrupted then this page is most
likely is not PageUptodate() and in this case do_generic_file_read() will
fail after lock_page_killable().

See also commit ebded02788b5 ("mm: filemap: avoid unnecessary calls to
lock_page when waiting for IO to complete during a read")

[oleg@redhat.com: changelog addition]
Link: http://lkml.kernel.org/r/63068e8e-8bee-b208-8441-a3c39a9d9eb6@sandisk.com
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_owner: don't define fields on struct page_ext by hard-coding

There is a memory waste problem if we define field on struct page_ext by
hard-coding.  Entry size of struct page_ext includes the size of those
fields even if it is disabled at runtime.  Now, extra memory request at
runtime is possible so page_owner don't need to define it's own fields by
hard-coding.

This patch removes hard-coded define and uses extra memory for storing
page_owner information in page_owner.  Most of code are just mechanical
changes.

Link: http://lkml.kernel.org/r/1471315879-32294-7-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_ext: support extra space allocation by page_ext user

Until now, if some page_ext users want to use it's own field on page_ext,
it should be defined in struct page_ext by hard-coding.  It has a problem
that wastes memory in following situation.

struct page_ext {
#ifdef CONFIG_A
int a;
#endif
#ifdef CONFIG_B
int b;
#endif
};

Assume that kernel is built with both CONFIG_A and CONFIG_B.  Even if we
enable feature A and doesn't enable feature B at runtime, each entry of
struct page_ext takes two int rather than one int.  It's undesirable
result so this patch tries to fix it.

To solve above problem, this patch implements to support extra space
allocation at runtime.  When need() callback returns true, it's extra
memory requirement is summed to entry size of page_ext.  Also, offset for
each user's extra memory space is returned.  With this offset, user can
use this extra space and there is no need to define needed field on
page_ext by hard-coding.

This patch only implements an infrastructure.  Following patch will use it
for page_owner which is only user having it's own fields on page_ext.

Link: http://lkml.kernel.org/r/1471315879-32294-6-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_ext: rename offset to index

Here, 'offset' means entry index in page_ext array. Following patch will
use 'offset' for field offset in each entry so rename current 'offset' to
prevent confusion.

Link: http://lkml.kernel.org/r/1471315879-32294-5-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_owner: move page_owner specific function to page_owner.c

There is no reason that page_owner specific function resides on vmstat.c.

Link: http://lkml.kernel.org/r/1471315879-32294-4-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/debug_pagealloc.c: don't allocate page_ext if we don't use guard page

What debug_pagealloc does is just mapping/unmapping page table.
Basically, it doesn't need additional memory space to memorize something.
But, with guard page feature, it requires additional memory to distinguish
if the page is for guard or not. Guard page is only used when
debug_guardpage_minorder is non-zero so this patch removes additional
memory allocation (page_ext) if debug_guardpage_minorder is zero.

It saves memory if we just use debug_pagealloc and not guard page.

Link: http://lkml.kernel.org/r/1471315879-32294-3-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/debug_pagealloc.c: clean-up guard page handling code

Patch series "Reduce memory waste by page extension user".

This patchset tries to reduce memory waste by page extension user.

First case is architecture supported debug_pagealloc.  It doesn't requires
additional memory if guard page isn't used.  8 bytes per page will be
saved in this case.

Second case is related to page owner feature.  Until now, if page_ext
users want to use it's own fields on page_ext, fields should be defined in
struct page_ext by hard-coding.  It has a following problem.

struct page_ext {
#ifdef CONFIG_A
int a;
#endif
#ifdef CONFIG_B
int b;
#endif
};

Assume that kernel is built with both CONFIG_A and CONFIG_B.  Even if we
enable feature A and doesn't enable feature B at runtime, each entry of
struct page_ext takes two int rather than one int.  It's undesirable waste
so this patch tries to reduce it.  By this patchset, we can save 20 bytes
per page dedicated for page owner feature in some configurations.

This patch (of 6):

We can make code clean by moving decision condition for set_page_guard()
into set_page_guard() itself.  It will help code readability.  There is no
functional change.

Link: http://lkml.kernel.org/r/1471315879-32294-2-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, vmscan: get rid of throttle_vm_writeout

throttle_vm_writeout() was introduced back in 2005 to fix OOMs caused by
excessive pageout activity during the reclaim.  Too many pages could be
put under writeback therefore LRUs would be full of unreclaimable pages
until the IO completes and in turn the OOM killer could be invoked.

There have been some important changes introduced since then in the
reclaim path though.  Writers are throttled by balance_dirty_pages when
initiating the buffered IO and later during the memory pressure, the
direct reclaim is throttled by wait_iff_congested if the node is
considered congested by dirty pages on LRUs and the underlying bdi is
congested by the queued IO.  The kswapd is throttled as well if it
encounters pages marked for immediate reclaim or under writeback which
signals that that there are too many pages under writeback already.
Finally should_reclaim_retry does congestion_wait if the reclaim cannot
make any progress and there are too many dirty/writeback pages.

Another important aspect is that we do not issue any IO from the direct
reclaim context anymore.  In a heavy parallel load this could queue a lot
of IO which would be very scattered and thus unefficient which would just
make the problem worse.

This three mechanisms should throttle and keep the amount of IO in a
steady state even under heavy IO and memory pressure so yet another
throttling point doesn't really seem helpful.  Quite contrary, Mikulas
Patocka has reported that swap backed by dm-crypt doesn't work properly
because the swapout IO cannot make sufficient progress as the writeout
path depends on dm_crypt worker which has to allocate memory to perform
the encryption.  In order to guarantee a forward progress it relies on the
mempool allocator.  mempool_alloc(), however, prefers to use the
underlying (usually page) allocator before it grabs objects from the pool.
Such an allocation can dive into the memory reclaim and consequently to
throttle_vm_writeout.  If there are too many dirty or pages under
writeback it will get throttled even though it is in fact a flusher to
clear pending pages.

[  345.352536] kworker/u4:0    D ffff88003df7f438 10488     6      2 0x00000000
[  345.352536] Workqueue: kcryptd kcryptd_crypt [dm_crypt]
[  345.352536]  ffff88003df7f438 ffff88003e5d0380 ffff88003e5d0380 ffff88003e5d8e80
[  345.352536]  ffff88003dfb3240 ffff88003df73240 ffff88003df80000 ffff88003df7f470
[  345.352536]  ffff88003e5d0380 ffff88003e5d0380 ffff88003df7f828 ffff88003df7f450
[  345.352536] Call Trace:
[  345.352536]  [<ffffffff818d466c>] schedule+0x3c/0x90
[  345.352536]  [<ffffffff818d96a8>] schedule_timeout+0x1d8/0x360
[  345.352536]  [<ffffffff81135e40>] ? detach_if_pending+0x1c0/0x1c0
[  345.352536]  [<ffffffff811407c3>] ? ktime_get+0xb3/0x150
[  345.352536]  [<ffffffff811958cf>] ? __delayacct_blkio_start+0x1f/0x30
[  345.352536]  [<ffffffff818d39e4>] io_schedule_timeout+0xa4/0x110
[  345.352536]  [<ffffffff8121d886>] congestion_wait+0x86/0x1f0
[  345.352536]  [<ffffffff810fdf40>] ? prepare_to_wait_event+0xf0/0xf0
[  345.352536]  [<ffffffff812061d4>] throttle_vm_writeout+0x44/0xd0
[  345.352536]  [<ffffffff81211533>] shrink_zone_memcg+0x613/0x720
[  345.352536]  [<ffffffff81211720>] shrink_zone+0xe0/0x300
[  345.352536]  [<ffffffff81211aed>] do_try_to_free_pages+0x1ad/0x450
[  345.352536]  [<ffffffff81211e7f>] try_to_free_pages+0xef/0x300
[  345.352536]  [<ffffffff811fef19>] __alloc_pages_nodemask+0x879/0x1210
[  345.352536]  [<ffffffff810e8080>] ? sched_clock_cpu+0x90/0xc0
[  345.352536]  [<ffffffff8125a8d1>] alloc_pages_current+0xa1/0x1f0
[  345.352536]  [<ffffffff81265ef5>] ? new_slab+0x3f5/0x6a0
[  345.352536]  [<ffffffff81265dd7>] new_slab+0x2d7/0x6a0
[  345.352536]  [<ffffffff810e7f87>] ? sched_clock_local+0x17/0x80
[  345.352536]  [<ffffffff812678cb>] ___slab_alloc+0x3fb/0x5c0
[  345.352536]  [<ffffffff811f71bd>] ? mempool_alloc_slab+0x1d/0x30
[  345.352536]  [<ffffffff810e7f87>] ? sched_clock_local+0x17/0x80
[  345.352536]  [<ffffffff811f71bd>] ? mempool_alloc_slab+0x1d/0x30
[  345.352536]  [<ffffffff81267ae1>] __slab_alloc+0x51/0x90
[  345.352536]  [<ffffffff811f71bd>] ? mempool_alloc_slab+0x1d/0x30
[  345.352536]  [<ffffffff81267d9b>] kmem_cache_alloc+0x27b/0x310
[  345.352536]  [<ffffffff811f71bd>] mempool_alloc_slab+0x1d/0x30
[  345.352536]  [<ffffffff811f6f11>] mempool_alloc+0x91/0x230
[  345.352536]  [<ffffffff8141a02d>] bio_alloc_bioset+0xbd/0x260
[  345.352536]  [<ffffffffc02f1a54>] kcryptd_crypt+0x114/0x3b0 [dm_crypt]

Let's just drop throttle_vm_writeout altogether. It is not very much
helpful anymore.

I have tried to test a potential writeback IO runaway similar to the one
described in the original patch which has introduced that [1].  Small
virtual machine (512MB RAM, 4 CPUs, 2G of swap space and disk image on a
rather slow NFS in a sync mode on the host) with 8 parallel writers each
writing 1G worth of data.  As soon as the pagecache fills up and the
direct reclaim hits then I start anon memory consumer in a loop
(allocating 300M and exiting after populating it) in the background to
make the memory pressure even stronger as well as to disrupt the steady
state for the IO.  The direct reclaim is throttled because of the
congestion as well as kswapd hitting congestion_wait due to nr_immediate
but throttle_vm_writeout doesn't ever trigger the sleep throughout the
test.  Dirty+writeback are close to nr_dirty_threshold with some
fluctuations caused by the anon consumer.

[1] https://www2.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.9-rc1/2.6.9-rc1-mm3/broken-out/vm-pageout-throttling.patch
Link: http://lkml.kernel.org/r/1471171473-21418-1-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: NeilBrown <neilb@suse.com>
Cc: Ondrej Kozina <okozina@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: fix set pageblock migratetype in deferred struct page init

On x86_64 MAX_ORDER_NR_PAGES is usually 4M, and a pageblock is usually 2M,
so we only set one pageblock's migratetype in deferred_free_range() if pfn
is aligned to MAX_ORDER_NR_PAGES. That means it causes uninitialized
migratetype blocks, you can see from "cat /proc/pagetypeinfo", almost half
blocks are Unmovable.

Also we missed freeing the last block in deferred_init_memmap(), it causes
memory leak.

Fixes: ac5d2539b238 ("mm: meminit: reduce number of times pageblocks are set during struct page init")
Link: http://lkml.kernel.org/r/57A3260F.4050709@huawei.com
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mem-hotplug: fix node spanned pages when we have a movable node

342332e6a925e9e ("mm/page_alloc.c: introduce kernelcore=mirror option")
rewrote the calculation of node spanned pages.  But when we have a movable
node, the size of node spanned pages is double added.  That's because we
have an empty normal zone, the present pages is zero, but its spanned
pages is not zero.

e.g.
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x0000000000001000-0x0000000000ffffff]
[    0.000000]   DMA32    [mem 0x0000000001000000-0x00000000ffffffff]
[    0.000000]   Normal   [mem 0x0000000100000000-0x0000007c7fffffff]
[    0.000000] Movable zone start for each node
[    0.000000]   Node 1: 0x0000001080000000
[    0.000000]   Node 2: 0x0000002080000000
[    0.000000]   Node 3: 0x0000003080000000
[    0.000000]   Node 4: 0x0000003c80000000
[    0.000000]   Node 5: 0x0000004c80000000
[    0.000000]   Node 6: 0x0000005c80000000
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000000001000-0x000000000009ffff]
[    0.000000]   node   0: [mem 0x0000000000100000-0x000000007552afff]
[    0.000000]   node   0: [mem 0x000000007bd46000-0x000000007bd46fff]
[    0.000000]   node   0: [mem 0x000000007bdcd000-0x000000007bffffff]
[    0.000000]   node   0: [mem 0x0000000100000000-0x000000107fffffff]
[    0.000000]   node   1: [mem 0x0000001080000000-0x000000207fffffff]
[    0.000000]   node   2: [mem 0x0000002080000000-0x000000307fffffff]
[    0.000000]   node   3: [mem 0x0000003080000000-0x0000003c7fffffff]
[    0.000000]   node   4: [mem 0x0000003c80000000-0x0000004c7fffffff]
[    0.000000]   node   5: [mem 0x0000004c80000000-0x0000005c7fffffff]
[    0.000000]   node   6: [mem 0x0000005c80000000-0x0000006c7fffffff]
[    0.000000]   node   7: [mem 0x0000006c80000000-0x0000007c7fffffff]

node1:
[  760.227767] Normal, start=0x1080000, present=0x0, spanned=0x1000000
[  760.234024] Movable, start=0x1080000, present=0x1000000, spanned=0x1000000
[  760.240883] pgdat, start=0x1080000, present=0x1000000, spanned=0x2000000

After apply this patch, the problem is fixed.
node1:
[  289.770922] Normal, start=0x0, present=0x0, spanned=0x0
[  289.776153] Movable, start=0x1080000, present=0x1000000, spanned=0x1000000
[  289.783019] pgdat, start=0x1080000, present=0x1000000, spanned=0x1000000

Link: http://lkml.kernel.org/r/57A325E8.6070100@huawei.com
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, vmscan: make compaction_ready() more accurate and readable

The compaction_ready() is used during direct reclaim for costly order
allocations to skip reclaim for zones where compaction should be attempted
instead.  It's combining the standard compaction_suitable() check with its
own watermark check based on high watermark with extra gap, and the result
is confusing at best.

This patch attempts to better structure and document the checks involved.
First, compaction_suitable() can determine that the allocation should
either succeed already, or that compaction doesn't have enough free pages
to proceed.  The third possibility is that compaction has enough free
pages, but we still decide to reclaim first - unless we are already above
the high watermark with gap.  This does not mean that the reclaim will
actually reach this watermark during single attempt, this is rather an
over-reclaim protection.  So document the code as such.  The check for
compaction_deferred() is removed completely, as it in fact had no proper
role here.

The result after this patch is mainly a less confusing code.  We also skip
some over-reclaim in cases where the allocation should already succed.

Link: http://lkml.kernel.org/r/20160810091226.6709-12-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm-compaction-require-only-min-watermarks-for-non-costly-orders-fix orders-fix

Clarify why __isolate_free_page() does a order-0 watermark check with
apparent (1UL << order) gap, per Joonsoo.

Link: http://lkml.kernel.org/r/7ae4baec-4eca-e70b-2a69-94bea4fb19fa@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: require only min watermarks for non-costly orders

The __compaction_suitable() function checks the low watermark plus a
compact_gap() gap to decide if there's enough free memory to perform
compaction.  Then __isolate_free_page uses low watermark check to decide
if particular free page can be isolated.  In the latter case, using low
watermark is needlessly pessimistic, as the free page isolations are only
temporary.  For __compaction_suitable() the higher watermark makes sense
for high-order allocations where more freepages increase the chance of
success, and we can typically fail with some order-0 fallback when the
system is struggling to reach that watermark.  But for low-order
allocation, forming the page should not be that hard.  So using low
watermark here might just prevent compaction from even trying, and
eventually lead to OOM killer even if we are above min watermarks.

So after this patch, we use min watermark for non-costly orders in
__compaction_suitable(), and for all orders in __isolate_free_page().

Link: http://lkml.kernel.org/r/20160810091226.6709-11-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: use proper alloc_flags in __compaction_suitable()

The __compaction_suitable() function checks the low watermark plus a
compact_gap() gap to decide if there's enough free memory to perform
compaction. This check uses direct compactor's alloc_flags, but that's
wrong, since these flags are not applicable for freepage isolation.

For example, alloc_flags may indicate access to memory reserves, making
compaction proceed, and then fail watermark check during the isolation.

A similar problem exists for ALLOC_CMA, which may be part of alloc_flags,
but not during freepage isolation. In this case however it makes sense to
use ALLOC_CMA both in __compaction_suitable() and __isolate_free_page(),
since there's actually nothing preventing the freepage scanner to isolate
from CMA pageblocks, with the assumption that a page that could be
migrated once by compaction can be migrated also later by CMA allocation.
Thus we should count pages in CMA pageblocks when considering compaction
suitability and when isolating freepages.

To sum up, this patch should remove some false positives from
__compaction_suitable(), and allow compaction to proceed when free pages
required for compaction reside in the CMA pageblocks.

Link: http://lkml.kernel.org/r/20160810091226.6709-10-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm-compaction-create-compact_gap-wrapper-fix

Clarify the comment of compact_gap() wrt COMPACT_CLUSTER_MAX, per Joonsoo.

Link: http://lkml.kernel.org/r/7b6aed1f-fdf8-2063-9ff4-bbe4de712d37@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: create compact_gap wrapper

Compaction uses a watermark gap of (2UL << order) pages at various places
and it's not immediately obvious why. Abstract it through a compact_gap()
wrapper to create a single place with a thorough explanation.

Link: http://lkml.kernel.org/r/20160810091226.6709-9-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: use correct watermark when checking compaction success

The __compact_finished() function uses low watermark in a check that has
to pass if the direct compaction is to finish and allocation should
succeed.  This is too pessimistic, as the allocation will typically use
min watermark.  It may happen that during compaction, we drop below the
low watermark (due to parallel activity), but still form the target
high-order page.  By checking against low watermark, we might needlessly
continue compaction.

Similarly, __compaction_suitable() uses low watermark in a check whether
allocation can succeed without compaction.  Again, this is unnecessarily
pessimistic.

After this patch, these check will use direct compactor's alloc_flags to
determine the watermark, which is effectively the min watermark.

Link: http://lkml.kernel.org/r/20160810091226.6709-8-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm-compaction-add-the-ultimate-direct-compaction-priority-fix

Use the MIN_COMPACT_PRIORITY alias instead of COMPACT_PRIO_SYNC_FULL to
disable heuristics "because this would be easier to follow and it would be
easier for future changes", per Michal.

Link: http://lkml.kernel.org/r/d443b884-87e7-1c93-8684-3a3a35759fb1@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: add the ultimate direct compaction priority

During reclaim/compaction loop, it's desirable to get a final answer from
unsuccessful compaction so we can either fail the allocation or invoke the
OOM killer. However, heuristics such as deferred compaction or pageblock
skip bits can cause compaction to skip parts or whole zones and lead to
premature OOM's, failures or excessive reclaim/compaction retries.

To remedy this, we introduce a new direct compaction priority called
COMPACT_PRIO_SYNC_FULL, which instructs direct compaction to:

- ignore deferred compaction status for a zone
- ignore pageblock skip hints
- ignore cached scanner positions and scan the whole zone

The new priority should get eventually picked up by should_compact_retry()
and this should improve success rates for costly allocations using
__GFP_REPEAT, such as hugetlbfs allocations, and reduce some corner-case
OOM's for non-costly allocations.

Link: http://lkml.kernel.org/r/20160810091226.6709-6-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: don't recheck watermarks after COMPACT_SUCCESS

Joonsoo has reminded me that in a later patch changing watermark checks
throughout compaction I forgot to update checks in
try_to_compact_pages() and compactd_do_work().  Closer inspection
however shows that they are redundant now in the success case, because
compact_zone() now reliably reports this with COMPACT_SUCCESS.  So
effectively the checks just repeat (a subset) of checks that have just
passed.  So instead of checking watermarks again, just test the return
value.

Note it's also possible that compaction would declare failure e.g.
because its find_suitable_fallback() is more strict than simple
watermark check, and then the watermark check we are removing would
then still succeed.  After this patch this is not possible and it's
arguably better, because for long-term fragmentation avoidance we
should rather try a different zone than allocate with the unsuitable
fallback.  If compaction of all zones fail and the allocation is
important enough, it will retry and succeed anyway.

Also remove the stray "bool success" variable from kcompactd_do_work().

Link: http://lkml.kernel.org/r/20160810091226.6709-5-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: rename COMPACT_PARTIAL to COMPACT_SUCCESS

COMPACT_PARTIAL has historically meant that compaction returned after
doing some work without fully compacting a zone.  It however didn't
distinguish if compaction terminated because it succeeded in creating the
requested high-order page.  This has changed recently and now we only
return COMPACT_PARTIAL when compaction thinks it succeeded, or the
high-order watermark check in compaction_suitable() passes and no
compaction needs to be done.

So at this point we can make the return value clearer by renaming it to
COMPACT_SUCCESS.  The next patch will remove some redundant tests for
success where compaction just returned COMPACT_SUCCESS.

Link: http://lkml.kernel.org/r/20160810091226.6709-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: cleanup unused functions

Since kswapd compaction moved to kcompactd, compact_pgdat() is not called
anymore, so we remove it. The only caller of __compact_pgdat() is
compact_node(), so we merge them and remove code that was only reachable
from kswapd.

Link: http://lkml.kernel.org/r/20160810091226.6709-3-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm-compaction-make-whole_zone-flag-ignore-cached-scanner-positions-checkpatch-fixes

fix typo in comment

Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, compaction: make whole_zone flag ignore cached scanner positions

Patch series "make direct compaction more deterministic")

This is mostly a followup to Michal's oom detection rework, which
highlighted the need for direct compaction to provide better feedback in
reclaim/compaction loop, so that it can reliably recognize when compaction
cannot make further progress, and allocation should invoke OOM killer or
fail.  We've discussed this at LSF/MM [1] where I proposed expanding the
async/sync migration mode used in compaction to more general "priorities".
This patchset adds one new priority that just overrides all the
heuristics and makes compaction fully scan all zones.  I don't currently
think that we need more fine-grained priorities, but we'll see.  Other
than that there's some smaller fixes and cleanups, mainly related to the
THP-specific hacks.

I've tested this with stress-highalloc in GFP_KERNEL order-4 and THP-like
order-9 scenarios.  There's some improvement for compaction stats for the
order-4, which is likely due to the better watermarks handling.  In the
previous version I reported mostly noise wrt compaction stats, and
decreased direct reclaim - now the reclaim is without difference.  I
believe this is due to the less aggressive compaction priority increase in
patch 6.

"before" is a mmotm tree prior to 4.7 release plus the first part of the
series that was sent and merged separately

                                    before        after
order-4:

Compaction stalls                    27216       30759
Compaction success                   19598       25475
Compaction failures                   7617        5283
Page migrate success                370510      464919
Page migrate failure                 25712       27987
Compaction pages isolated           849601     1041581
Compaction migrate scanned       143146541   101084990
Compaction free scanned          208355124   144863510
Compaction cost                       1403        1210

order-9:

Compaction stalls                     7311        7401
Compaction success                    1634        1683
Compaction failures                   5677        5718
Page migrate success                194657      183988
Page migrate failure                  4753        4170
Compaction pages isolated           498790      456130
Compaction migrate scanned          565371      524174
Compaction free scanned            4230296     4250744
Compaction cost                        215         203

[1] https://lwn.net/Articles/684611/

This patch (of 11):

A recent patch has added whole_zone flag that compaction sets when
scanning starts from the zone boundary, in order to report that zone has
been fully scanned in one attempt.  For allocations that want to try
really hard or cannot fail, we will want to introduce a mode where
scanning whole zone is guaranteed regardless of the cached positions.

This patch reuses the whole_zone flag in a way that if it's already passed
true to compaction, the cached scanner positions are ignored.  Employing
this flag during reclaim/compaction loop will be done in the next patch.
This patch however converts compaction invoked from userspace via procfs
to use this flag.  Before this patch, the cached positions were first
reset to zone boundaries and then read back from struct zone, so there was
a window where a parallel compaction could replace the reset values,
making the manual compaction less effective.  Using the flag instead of
performing reset is more robust.

Link: http://lkml.kernel.org/r/20160810091226.6709-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/oom_kill.c: fix task_will_free_mem() comment

Attempt to demystify the task_will_free_mem() loop.

Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: memcontrol: add sanity checks for memcg->id.ref on get/put

Link: http://lkml.kernel.org/r/1c5ddb1c171dbdfc3262252769d6138a29b35b70.1470219853.git.vdavydov@virtuozzo.com
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

bitops.h: move out get_count_order[_long]() from __KERNEL__ scope

move out get_count_order[_long]() definitions from scope limited by macro
__KERNEL__

it not only make both functions available in wider region regardless of
whether __KERNEL__ is defined but also keep original region for
get_count_order() before the recent commit c513b4cd2fe9
("mm-vmalloc-fix-align-value-calculation-error-v2-fix-fix")

Link: http://lkml.kernel.org/r/57B2C4CE.80303@zoho.com
Signed-off-by: zijun_hu <zijun_hu@htc.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm-vmalloc-fix-align-value-calculation-error-v2-fix-fix

move get_count_order[_long] definitions to pick up fls_long()

Cc: zijun_hu <zijun_hu@htc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm-vmalloc-fix-align-value-calculation-error-v2-fix

locate get_count_order_long() next to get_count_order()

Cc: zijun_hu <zijun_hu@htc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm-vmalloc-fix-align-value-calculation-error-v2

i provide another patch called v2 based on your suggestion as shown below
it have following correction against original patch v1
1) use name get_count_order_long() instead of get_order_long()
2) return -1 if @l == 0 to consist with get_order_long()
3) cast type to int before returning from get_count_order_long()
4) move up function parameter checking for __get_vm_area_node()
5) more commit message is offered to make issue and approach clear
any comments about new patch is welcome

Link: http://lkml.kernel.org/r/57AABC8B.1040409@zoho.com
Signed-off-by: zijun_hu <zijun_hu@htc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm-vmalloc-fix-align-value-calculation-error-fix

s/get_order_long()/get_count_order_long()/ to match get_count_order()

Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: zijun_hu <zijun_hu@htc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/vmalloc.c: fix align value calculation error

It causes double align requirement for __get_vm_area_node() if parameter
size is power of 2 and VM_IOREMAP is set in parameter flags, for example
size=0x10000 -> fls_long(0x10000)=17 -> align=0x20000

get_count_order_long() is implemented and used instead of fls_long() for
fixing the bug, for example
size=0x10000 -> get_count_order_long(0x10000)=16 -> align=0x10000

Link: http://lkml.kernel.org/r/fc045ecf-20fa-0722-b3ac-9a6140488fad@zoho.com
Signed-off-by: zijun_hu <zijun_hu@htc.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/zsmalloc: add per-class compact trace event

add per-class compact trace event to get number of migrated objects
and number of freed pages.

trace log is like below:

            bash-3863  [001] ....   141.791366: zs_compact_start: pool zram0
            bash-3863  [001] ....   141.791372: zs_compact: class 254: 0 objects migrated, 0 pages freed
            bash-3863  [001] ....   141.791375: zs_compact: class 202: 0 objects migrated, 0 pages freed
            bash-3863  [001] ....   141.791385: zs_compact: class 190: 1 objects migrated, 3 pages freed
            bash-3863  [001] ....   141.791393: zs_compact: class 168: 2 objects migrated, 2 pages freed
            bash-3863  [001] ....   141.791396: zs_compact: class 151: 0 objects migrated, 0 pages freed
            bash-3863  [001] ....   141.791407: zs_compact: class 144: 5 objects migrated, 4 pages freed
            bash-3863  [001] ....   141.791427: zs_compact: class 126: 8 objects migrated, 8 pages freed
            bash-3863  [001] ....   141.791433: zs_compact: class 111: 1 objects migrated, 4 pages freed
            bash-3863  [001] ....   141.791459: zs_compact: class 107: 18 objects migrated, 12 pages freed
            bash-3863  [001] ....   141.791487: zs_compact: class 100: 18 objects migrated, 16 pages freed
            bash-3863  [001] ....   141.791509: zs_compact: class  94: 18 objects migrated, 9 pages freed
            bash-3863  [001] ....   141.791560: zs_compact: class  91: 44 objects migrated, 24 pages freed
            bash-3863  [001] ....   141.791605: zs_compact: class  83: 35 objects migrated, 20 pages freed
            bash-3863  [001] ....   141.791616: zs_compact: class  76: 8 objects migrated, 4 pages freed
            bash-3863  [001] ....   141.791644: zs_compact: class  74: 21 objects migrated, 9 pages freed
            bash-3863  [001] ....   141.791665: zs_compact: class  71: 18 objects migrated, 10 pages freed
            bash-3863  [001] ....   141.791736: zs_compact: class  67: 0 objects migrated, 0 pages freed
            bash-3863  [001] ....   141.791763: zs_compact: class  66: 22 objects migrated, 8 pages freed
            bash-3863  [001] ....   141.791820: zs_compact: class  62: 18 objects migrated, 6 pages freed
            bash-3863  [001] ....   141.791826: zs_compact: class  58: 1 objects migrated, 4 pages freed
            bash-3863  [001] ....   141.791829: zs_compact: class  57: 0 objects migrated, 0 pages freed
            bash-3863  [001] ....   141.791834: zs_compact: class  54: 2 objects migrated, 2 pages freed
...
            bash-3863  [001] ....   141.791952: zs_compact: class   4: 0 objects migrated, 0 pages freed
            bash-3863  [001] ....   141.791964: zs_compact: class   3: 14 objects migrated, 1 pages freed
            bash-3863  [001] ....   141.791966: zs_compact: class   2: 0 objects migrated, 0 pages freed
            bash-3863  [001] ....   141.791968: zs_compact: class   1: 0 objects migrated, 0 pages freed
            bash-3863  [001] ....   141.791971: zs_compact: class   0: 0 objects migrated, 0 pages freed
            bash-3863  [001] ....   141.791973: zs_compact_end: pool zram0: 155 pages compacted

Also this patch changes trace_zsmalloc_compact_start[end] to
trace_zs_compact_start[end] to keep function naming consistent with others
in zsmalloc.

Link: http://lkml.kernel.org/r/1467882338-4300-8-git-send-email-opensource.ganesh@gmail.com
Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/zsmalloc: add trace events for zs_compact

Currently zsmalloc is widely used in android device.  Sometimes, we want
to see how frequently zs_compact is triggered or how may pages freed by
zs_compact(), or which zsmalloc pool is compacted.

We have backported the zs_compact() to our product(kernel 3.18).  It is
usefull for a longtime running device.  But there is not a convenient
way to get the detailed information of zs_comapct() which is usefull
for performance optimization.  Information about how much time
zs_compact used, which pool is compacted, how many page freed, etc.
With these information, we will know what is going on in zs_comapct.
And draw the relation between free mem and zs_comapct.

Most of the time, user can get the brief information from
trace_mm_shrink_slab_[start | end], but in some senario, they do not use
zsmalloc shrinker, but trigger compaction manually.  So add some trace
events in zs_compact is convenient.  Also we can add some zsmalloc
specific information(pool name, total compact pages, etc) in zsmalloc
trace.

This patch add two trace events for zs_compact(), below the trace log:
-----------------------------
root@land:/ # cat /d/tracing/trace
         kswapd0-125   [007] ...1   174.176979: zsmalloc_compact_start: pool zram0
         kswapd0-125   [007] ...1   174.181967: zsmalloc_compact_end: pool zram0: 608 pages compacted(total 1794)
         kswapd0-125   [000] ...1   184.134475: zsmalloc_compact_start: pool zram0
         kswapd0-125   [000] ...1   184.135010: zsmalloc_compact_end: pool zram0: 62 pages compacted(total 1856)
         kswapd0-125   [003] ...1   226.927221: zsmalloc_compact_start: pool zram0
         kswapd0-125   [003] ...1   226.928575: zsmalloc_compact_end: pool zram0: 250 pages compacted(total 2106)
-----------------------------

Link: http://lkml.kernel.org/r/1465289804-4913-1-git-send-email-opensource.ganesh@gmail.com
Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: oom: deduplicate victim selection code for memcg and global oom

When selecting an oom victim, we use the same heuristic for both memory
cgroup and global oom.  The only difference is the scope of tasks to
select the victim from.  So we could just export an iterator over all
memcg tasks and keep all oom related logic in oom_kill.c, but instead we
duplicate pieces of it in memcontrol.c reusing some initially private
functions of oom_kill.c in order to not duplicate all of it.  That looks
ugly and error prone, because any modification of select_bad_process
should also be propagated to mem_cgroup_out_of_memory.

Let's rework this as follows: keep all oom heuristic related code private
to oom_kill.c and make oom_kill.c use exported memcg functions when it's
really necessary (like in case of iterating over memcg tasks).

Link: http://lkml.kernel.org/r/1470056933-7505-1-git-send-email-vdavydov@virtuozzo.com
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel/watchdog: use nmi registers snapshot in hardlockup handler

NMI handler doesn't call set_irq_regs(), it's set only by normal IRQ.
Thus get_irq_regs() returns NULL or stale registers snapshot with IP/SP
pointing to the code interrupted by IRQ which was interrupted by NMI.
NULL isn't a problem: in this case watchdog calls dump_stack() and
prints full stack trace including NMI. But if we're stuck in IRQ
handler then NMI watchlog will print stack trace without IRQ part at
all.

This patch uses registers snapshot passed into NMI handler as
arguments: these registers points exactly to the instruction
interrupted by NMI.

Fixes: 55537871ef66 ("kernel/watchdog.c: perform all-CPU backtrace in case of hard lockup")
Link: http://lkml.kernel.org/r/146771764784.86724.6006627197118544150.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: <stable@vger.kernel.org> [4.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

block: restore /proc/partitions to not display non-partitionable removable devices

We found with newer kernels we started seeing the cdrom device showing
up in /proc/partitions, but it was not there before.

Looking into this I found that commit d27769ec ("block: add
GENHD_FL_NO_PART_SCAN") introduces this change in behavior. It's not
clear to me from the commit's changelog if this change was intentional or
not. This comment still remains: /* Don't show non-partitionable
removeable devices or empty devices */ so I've decided to send a patch to
restore the behavior of not printing unpartitionable removable devices.

Signed-off-by: Josh Hunt <johunt@akamai.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/ocfs2/dlm: remove deprecated create_singlethread_workqueue()

The workqueue "dlm_worker" queues a single work item &dlm->dispatched_work
and thus it doesn't require execution ordering. Hence, alloc_workqueue
has been used to replace the deprecated create_singlethread_workqueue
instance.

The WQ_MEM_RECLAIM flag has been set to ensure forward progress under
memory pressure.

Since there are fixed number of work items, explicit concurrency
limit is unnecessary here.

Link: http://lkml.kernel.org/r/2b5ad8d6688effe1a9ddb2bc2082d26fbbe00302.1472590094.git.bhaktipriya96@gmail.com
Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/ocfs2/super: remove deprecated create_singlethread_workqueue()

The workqueue "ocfs2_wq" queues multiple work items viz
&osb->la_enable_wq, &journal->j_recovery_work, &os->os_orphan_scan_work,
&osb->osb_truncate_log_wq which require strict execution ordering. Hence,
an ordered dedicated workqueue has been used.

WQ_MEM_RECLAIM has been set to ensure forward progress under memory
pressure because the workqueue is being used on a memory reclaim path.

Link: http://lkml.kernel.org/r/66279de510a7f4cfc6e386d99b7e04b3f65fb11b.1472590094.git.bhaktipriya96@gmail.com
Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/ocfs2/cluster: remove deprecated create_singlethread_workqueue()

The workqueue "o2net_wq" queues multiple work items viz
&old_sc->sc_shutdown_work, &sc->sc_rx_work, &sc->sc_connect_work which
require strict execution ordering. Hence, an ordered dedicated workqueue
has been used.

WQ_MEM_RECLAIM has been set to ensure forward progress under memory
pressure.

Link: http://lkml.kernel.org/r/ddc12e5766c79ba26f8a00d98049107f8a1d4866.1472590094.git.bhaktipriya96@gmail.com
Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/ocfs2/dlmfs: remove deprecated create_singlethread_workqueue()

The workqueue "user_dlm_worker" queues a single work item &lockres->l_work
per user_lock_res instance and hence it doesn't require execution
ordering. Hence, alloc_workqueue has been used to replace the deprecated
create_singlethread_workqueue instance.

The WQ_MEM_RECLAIM flag has been set to ensure forward progress under
memory pressure.

Since there are fixed number of work items, explicit concurrency
limit is unnecessary here.

Link: http://lkml.kernel.org/r/9748136d3a3b18138ad1d6ba708367aa1fe9f98c.1472590094.git.bhaktipriya96@gmail.com
Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kbuild: simpler generation of assembly constants

gcc doesn't really look inside "asm" statements and more or less
directly emits it into assembly. So pretend "#define" is CPU
instruction.

C++ comment can't be used because sparc assembler doesn't understand it.

Link: http://lkml.kernel.org/r/20160713173646.GA1910@p183.telecom.by
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arm: arch/arm/include/asm/page.h needs personality.h

VM_DATA_DEFAULT_FLAGS uses READ_IMPLIES_EXEC, so page.h should include
personality.h to provide this.

This fixes no known bugs and can be safely ignored ;)

Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

MAINTAINERS: update email for VLYNQ bus entry

Link: http://lkml.kernel.org/r/1473218738-21836-1-git-send-email-f.fainelli@gmail.com
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: avoid endless recursion in dump_page()

dump_page() uses page_mapcount() to get mapcount of the page.
page_mapcount() has VM_BUG_ON_PAGE(PageSlab(page)) as mapcount doesn't
make sense for slab pages and the field in struct page used for other
information.

It leads to recursion if dump_page() called for slub page and DEBUG_VM
is enabled:

dump_page() -> page_mapcount() -> VM_BUG_ON_PAGE() -> dump_page -> ...

Let's avoid calling page_mapcount() for slab pages in dump_page().

Link: http://lkml.kernel.org/r/20160908082137.131076-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm, thp: fix leaking mapped pte in __collapse_huge_page_swapin()

Currently, khugepaged does not permit swapin if there are enough young
pages in a THP. The problem is when a THP does not have enough young
pages, khugepaged leaks mapped ptes.

This patch prohibits leaking mapped ptes.

Link: http://lkml.kernel.org/r/1472820276-7831-1-git-send-email-ebru.akagunduz@gmail.com
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Suggested-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

stackdepot: fix mempolicy use-after-free

This patch fixes the following:

    BUG: KASAN: use-after-free in alloc_pages_current+0x363/0x370 at addr ffff88010b48102c
    Read of size 2 by task trinity-c2/15425
    CPU: 0 PID: 15425 Comm: trinity-c2 Not tainted 4.8.0-rc2+ #140
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-proje
    ct.org 04/01/2014
     ffff88010b481040 ffff88010b557650 ffffffff81f08d11 ffff88011a40d380
     ffff88010b481028 ffff88010b557678 ffffffff815dac7c ffff88010b557708
     ffff88010b481028 ffff88011a40d380 ffff88010b5576f8 ffffffff815daf15
    Call Trace:
     [<ffffffff81f08d11>] dump_stack+0x65/0x84
     [<ffffffff815dac7c>] kasan_object_err+0x1c/0x70
     [<ffffffff815daf15>] kasan_report_error+0x1f5/0x4c0
     [<ffffffff815db2fe>] __asan_report_load2_noabort+0x3e/0x40
     [<ffffffff815cb903>] alloc_pages_current+0x363/0x370    <---- use-after-free
     [<ffffffff81fa9954>] depot_save_stack+0x3f4/0x490
     [<ffffffff815d9bb5>] save_stack+0xb5/0xd0
     [<ffffffff815da211>] kasan_slab_free+0x71/0xb0
     [<ffffffff815d6643>] kmem_cache_free+0xa3/0x290
     [<ffffffff815c8149>] __mpol_put+0x19/0x20               <---- free
     [<ffffffff81260635>] do_exit+0x1515/0x2b70
     [<ffffffff81261dc4>] do_group_exit+0xf4/0x2f0
     [<ffffffff81281c5d>] get_signal+0x53d/0x1120
     [<ffffffff8119e993>] do_signal+0x83/0x1e20
     [<ffffffff810027af>] exit_to_usermode_loop+0xaf/0x140
     [<ffffffff810051e4>] syscall_return_slowpath+0x144/0x170
     [<ffffffff83ae406f>] ret_from_fork+0x2f/0x40
    Read of size 2 by task trinity-c2/15425

The problem is that we may be calling alloc_pages() in a code path where
current->mempolicy has already been freed.

By passing __GFP_THISNODE we will always use default_mempolicy (which
cannot be freed).

Link: https://lkml.org/lkml/2016/7/29/277
Link: https://github.com/google/kasan/issues/35
Link: http://lkml.kernel.org/r/1471603265-31804-1-git-send-email-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_alloc.c: replace set_dma_reserve to set_memory_reserve

Expand the scope of the existing dma_reserve to accommodate other memory
reserves too. Accordingly rename variable dma_reserve to
nr_memory_reserve.

set_memory_reserve() also takes a new parameter that helps to identify if
the current value needs to be incremented.

Link: http://lkml.kernel.org/r/1470330729-6273-1-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Suggested-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/slab: improve performance of gathering slabinfo stats

On large systems, when some slab caches grow to millions of objects (and
many gigabytes), running 'cat /proc/slabinfo' can take up to 1-2 seconds.
During this time, interrupts are disabled while walking the slab lists
(slabs_full, slabs_partial, and slabs_free) for each node, and this
sometimes causes timeouts in other drivers (for instance, Infiniband).

This patch optimizes 'cat /proc/slabinfo' by maintaining a counter for
total number of allocated slabs per node, per cache.  This counter is
updated when a slab is created or destroyed.  This enables us to skip
traversing the slabs_full list while gathering slabinfo statistics, and
since slabs_full tends to be the biggest list when the cache is large, it
results in a dramatic performance improvement.  Getting slabinfo
statistics now only requires walking the slabs_free and slabs_partial
lists, and those lists are usually much smaller than slabs_full.  We
tested this after growing the dentry cache to 70GB, and the performance
improved from 2s to 5ms.

Link: http://lkml.kernel.org/r/1472517876-26814-1-git-send-email-aruna.ramakrishna@oracle.com
Signed-off-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

khugepaged: fix use-after-free in collapse_huge_page()

hugepage_vma_revalidate() tries to re-check if we still should try to
collapse small pages into huge one after the re-acquiring mmap_sem.

The problem Dmitry Vyukov reported[1] is that the vma found by
hugepage_vma_revalidate() can be suitable for huge pages, but not the same
vma we had before dropping mmap_sem. And dereferencing original vma can
lead to fun results..

Let's use vma hugepage_vma_revalidate() found instead of assuming it's the
same as what we had before the lock was dropped. [1]
http://lkml.kernel.org/r/CACT4Y+Z3gigBvhca9kRJFcjX0G70V_nRhbwKBU+yGoESBDKi9Q@mail.gmail.com

Link: http://lkml.kernel.org/r/20160907122559.GA6542@black.fi.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

MAINTAINERS: Maik has moved

Maik is no longer using the plusserver.de email, update with his
current email.

Link: http://lkml.kernel.org/r/1473007794-27960-1-git-send-email-sudipm.mukherjee@gmail.com
Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Cc: Maik Broemme <mbroemme@libmpq.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

ocfs2/dlm: fix race between convert and migration

Commit ac7cf246dfdb ("ocfs2/dlm: fix race between convert and recovery")
checks if lockres master has changed to identify whether new master has
finished recovery or not. This will introduce a race that right after old
master does umount ( means master will change), a new convert request
comes.

In this case, it will reset lockres state to DLM_RECOVERING and then retry
convert, and then fail with lockres->l_action being set to
OCFS2_AST_INVALID, which will cause inconsistent lock level between ocfs2
and dlm, and then finally BUG.

Since dlm recovery will clear lock->convert_pending in
dlm_move_lockres_to_recovery_list, we can use it to correctly identify the
race case between convert and recovery. So fix it.

Fixes: ac7cf246dfdb ("ocfs2/dlm: fix race between convert and recovery")
Link: http://lkml.kernel.org/r/57CE1569.8010704@huawei.com
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mem-hotplug: Don't clear the only node in new_node_page()

394e31d2c ("mem-hotplug: alloc new page from a nearest neighbor node when
mem-offline") introduced new_node_page() for memory hotplug.

In new_node_page(), the nid is cleared before calling
__alloc_pages_nodemask(). But if it is the only node of the system, and
the first round allocation fails, it will not be able to get memory from
an empty nodemask, and will trigger oom.

The patch checks whether it is the last node on the system, and if it is, then
don't clear the nid in the nodemask.

Fixes: 394e31d2ceb4 ("mem-hotplug: alloc new page from a nearest neighbor node when mem-offline")
Link: http://lkml.kernel.org/r/1473044391.4250.19.camel@TP420
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Reported-by: John Allen <jallen@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Merge tag 'ceph-for-4.8-rc6' of git://github.com/ceph/ceph-client

Pull ceph fix from Ilya Dryomov:
"A fix for a 4.7 performance regression, caused by a typo in an if
condition"

* tag 'ceph-for-4.8-rc6' of git://github.com/ceph/ceph-client:
ceph: do not modify fi->frag in need_reset_readdir()

Merge branch 'dmi-for-linus' of git://git./linux/kernel/git/jdelvare/staging

Pull dmi fix from Jean Delvare.

* 'dmi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
dmi-id: don't free dev structure after calling device_register

Merge tag 'armsoc-fixes' of git://git./linux/kernel/git/arm/arm-soc

Pull ARM SoC fixes from Olof Johansson:
"This is a slightly larger batch of fixes that we've been sitting on a
  few -rcs.  Most of them are simple oneliners, but there are two sets
  that are slightly larger and worth pointing out:

   - A set of patches to OMAP to deal with hwmod for RTC on am33xx
     (beaglebone SoC, among others).  It's the only clock that ever has
     a valid offset of 0, so a new flag needed introduction once this
     problem was discovered.

   - A collection of CCI fixes for performance counters discovered once
     people started using it on X-Gene CPUs"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (37 commits)
  arm-cci: pmu: Fix typo in event name
  Revert "ARM: tegra: fix erroneous address in dts"
  ARM: dts: imx6qdl: Fix SPDIF regression
  ARM: imx6: add missing BM_CLPCR_BYPASS_PMIC_READY setting for imx6sx
  ARM: dts: imx7d-sdb: fix ti,x-plate-ohms property name
  ARM: dts: kirkwood: Fix PCIe label on OpenRD
  ARM: kirkwood: ib62x0: fix size of u-boot environment partition
  bus: arm-ccn: make event groups reliable
  bus: arm-ccn: fix hrtimer registration
  bus: arm-ccn: fix PMU interrupt flags
  ARM: tegra: Correct polarity for Tegra114 PMIC interrupt
  MAINTAINERS: add tree entry for ARM/UniPhier architecture
  ARM: sun5i: Fix typo in trip point temperature
  MAINTAINERS: Switch to kernel.org account for Krzysztof Kozlowski
  ARM: imx6ul: populates platform device at .init_machine
  bus: arm-ccn: Add missing event attribute exclusions for host/guest
  bus: arm-ccn: Correct required arguments for XP PMU events
  bus: arm-ccn: Fix XP watchpoint settings bitmask
  bus: arm-ccn: Do not attempt to configure XPs for cycle counter
  bus: arm-ccn: Fix PMU handling of MN
  ...

dmi-id: don't free dev structure after calling device_register

dmi_dev is freed in error exit code but, according to the document
of device_register, it should never directly free device structure
after calling this function, even if it returned an error! Use
put_device() instead.

Signed-off-by: Allen Hung <allen_hung@dell.com>
Signed-off-by: Jean Delvare <jdelvare@suse.de>

Merge branch 'for-rc' of git://git./linux/kernel/git/rzhang/linux

Pull thermal fix from Zhang Rui:
"Only one patch this time, which fixes a crash in rcar_thermal driver.
From Dirk Behme"

* 'for-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
thermal: rcar_thermal: Fix priv->zone error handling

Merge tag 'sunxi-fixes-for-4.8' of https://git./linux/kernel/git/mripard/linux into fixes

Allwinner fixes for 4.8

A single patch fixing a typo in the temperature trip points in the A13
DTSI.

* tag 'sunxi-fixes-for-4.8' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux:
ARM: sun5i: Fix typo in trip point temperature

Signed-off-by: Olof Johansson <olof@lixom.net>

arm-cci: pmu: Fix typo in event name

For one of the CCI events exposed under sysfs, "snoop" was typo'd as
"snopp". Correct this such that users see the expected event name when
enumerating events via sysfs.

Cc: arm@kernel.org
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'imx-fixes-4.8-2' of git://git./linux/kernel/git/shawnguo/linux into fixes

i.MX fixes for 4.8, 2nd round:
- Fix misspelled "ti,x-plate-ohms" property name of touchscreen
   controller for imx7d-sdb DTS.
- Add missing BM_CLPCR_BYPASS_PMIC_READY setting for i.MX6SX to get
   suspend/resume work properly.
- Fix SPDIF regression on imx6qdl which caused by a clock update on
   spdif device node.

* tag 'imx-fixes-4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux:
  ARM: dts: imx6qdl: Fix SPDIF regression
  ARM: imx6: add missing BM_CLPCR_BYPASS_PMIC_READY setting for imx6sx
  ARM: dts: imx7d-sdb: fix ti,x-plate-ohms property name

Signed-off-by: Olof Johansson <olof@lixom.net>

Revert "ARM: tegra: fix erroneous address in dts"

This reverts commit b5c86b7496d74f6e454bcab5166efa023e1f0459.

This is no longer needed due to other changes going into 4.8 to rename
the unit addresses on a large number of device nodes. So it was picked up
for v4.8-rc1 in error.

Reported-by: Ralf Ramsauer <ralf@ramses-pyramidenbau.de>
Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'usercopy-v4.8-rc6-part2' of git://git./linux/kernel/git/kees/linux

Pull more hardened usercopyfixes from Kees Cook:

- force check_object_size() to be inline too

- move page-spanning check behind a CONFIG since it's triggering false
   positives

[ Changed the page-spanning config option to depend on EXPERT in the
  merge.  That way it still gets build testing, and you can enable it if
  you want to, but is never enabled for "normal" configurations ]

* tag 'usercopy-v4.8-rc6-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  usercopy: remove page-spanning test for now
  usercopy: force check_object_size() inline

usercopy: remove page-spanning test for now

A custom allocator without __GFP_COMP that copies to userspace has been
found in vmw_execbuf_process[1], so this disables the page-span checker
by placing it behind a CONFIG for future work where such things can be
tracked down later.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1373326

Reported-by: Vinson Lee <vlee@freedesktop.org>
Fixes: f5509cc18daa ("mm: Hardened usercopy")
Signed-off-by: Kees Cook <keescook@chromium.org>

usercopy: force check_object_size() inline

Just for good measure, make sure that check_object_size() is always
inlined too, as already done for copy_*_user() and __copy_*_user().

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Kees Cook <keescook@chromium.org>

Merge tag 'seccomp-v4.8-rc6' of git://git./linux/kernel/git/kees/linux

Pull seccomp fixes from Kees Cook:
"Fix UM seccomp vs ptrace, after reordering landed"

* tag 'seccomp-v4.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  seccomp: Remove 2-phase API documentation
  um/ptrace: Fix the syscall number update after a ptrace
  um/ptrace: Fix the syscall_trace_leave call

Merge tag 'usercopy-v4.8-rc6' of git://git./linux/kernel/git/kees/linux

Pull hardened usercopy fixes from Kees Cook:

- inline copy_*_user() for correct use of __builtin_const_p() for
   hardened usercopy and the recent compile-time checks.

- switch hardened usercopy to only check non-const size arguments to
   avoid meaningless checks on likely-sane const values.

- update lkdtm usercopy tests to compenstate for the const checking.

* tag 'usercopy-v4.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lkdtm: adjust usercopy tests to bypass const checks
  usercopy: fold builtin_const check into inline function
  x86/uaccess: force copy_*_user() to be inlined

seccomp: Remove 2-phase API documentation

Fixes: 8112c4f140fa ("seccomp: remove 2-phase API")
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

um/ptrace: Fix the syscall number update after a ptrace

Update the syscall number after each PTRACE_SETREGS on ORIG_*AX.

This is needed to get the potentially altered syscall number in the
seccomp filters after RET_TRACE.

This fix four seccomp_bpf tests:
> [ RUN      ] TRACE_syscall.skip_after_RET_TRACE
> seccomp_bpf.c:1560:TRACE_syscall.skip_after_RET_TRACE:Expected -1 (18446744073709551615) == syscall(39) (26)
> seccomp_bpf.c:1561:TRACE_syscall.skip_after_RET_TRACE:Expected 1 (1) == (*__errno_location ()) (22)
> [     FAIL ] TRACE_syscall.skip_after_RET_TRACE
> [ RUN      ] TRACE_syscall.kill_after_RET_TRACE
> TRACE_syscall.kill_after_RET_TRACE: Test exited normally instead of by signal (code: 1)
> [     FAIL ] TRACE_syscall.kill_after_RET_TRACE
> [ RUN      ] TRACE_syscall.skip_after_ptrace
> seccomp_bpf.c:1622:TRACE_syscall.skip_after_ptrace:Expected -1 (18446744073709551615) == syscall(39) (26)
> seccomp_bpf.c:1623:TRACE_syscall.skip_after_ptrace:Expected 1 (1) == (*__errno_location ()) (22)
> [     FAIL ] TRACE_syscall.skip_after_ptrace
> [ RUN      ] TRACE_syscall.kill_after_ptrace
> TRACE_syscall.kill_after_ptrace: Test exited normally instead of by signal (code: 1)
> [     FAIL ] TRACE_syscall.kill_after_ptrace

Fixes: 26703c636c1f ("um/ptrace: run seccomp after ptrace")
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: James Morris <jmorris@namei.org>
Cc: user-mode-linux-devel@lists.sourceforge.net
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

um/ptrace: Fix the syscall_trace_leave call

Keep the same semantic as before the commit 26703c636c1f: deallocate
audit context and fake a proper syscall exit.

This fix a kernel panic triggered by the seccomp_bpf test:
> [ RUN ] global.ERRNO_valid
> BUG: failure at kernel/auditsc.c:1504/__audit_syscall_entry()!
> Kernel panic - not syncing: BUG!

Fixes: 26703c636c1f ("um/ptrace: run seccomp after ptrace")
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: James Morris <jmorris@namei.org>
Cc: user-mode-linux-devel@lists.sourceforge.net
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

Merge tag 'for-linus' of git://git./linux/kernel/git/dledford/rdma

Pull rdma fixes from Doug Ledford:
"This is the second pull request for the rdma subsystem.  Most of the
  patches are small and obvious.  I took two patches in that are larger
  than I wanted this late in the cycle.

  The first is the hfi1 patch that implements a work queue to test the
  QSFP read state.  I originally rejected the first patch for this
  (which would have place up to 20 seconds worth of udelays in their
  probe routine).  They then rewrote it the way I wanted (use delayed
  work tasks to wait asynchronously up to 20 seconds for the QSFP to
  come alive), so I can't really complain about the size of getting what
  I asked for :-/.

  The second is large because it switches the rcu locking in the debugfs
  code.  Since a locking change like this is done all at once, the size
  it what it is.  It resolves a litany of debug messages from the
  kernel, so I pulled it in for -rc.

  The rest are all typical -rc worthy patches I think.

  There will still be a third -rc pull request from the rdma subsystem
  this release.  I hope to have that one ready to go by the end of this
  week or early next.

  Summary:

   - a smattering of small fixes across the core, ipoib, i40iw, isert,
     cxgb4, and mlx4

   - a slightly larger group of fixes to each of mlx5 and hfi1"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma:
  IB/hfi1: Rework debugfs to use SRCU
  IB/hfi1: Make n_krcvqs be an unsigned long integer
  IB/hfi1: Add QSFP sanity pre-check
  IB/hfi1: Fix AHG KDETH Intr shift
  IB/hfi1: Fix SGE length for misaligned PIO copy
  IB/mlx5: Don't return errors from poll_cq
  IB/mlx5: Use TIR number based on selector
  IB/mlx5: Simplify code by removing return variable
  IB/mlx5: Return EINVAL when caller specifies too many SGEs
  IB/mlx4: Don't return errors from poll_cq
  Revert "IB/mlx4: Return EAGAIN for any error in mlx4_ib_poll_one"
  IB/ipoib: Fix memory corruption in ipoib cm mode connect flow
  IB/core: Fix use after free in send_leave function
  IB/cxgb4: Make _free_qp static to silence build warning
  IB/isert: Properly release resources on DEVICE_REMOVAL
  IB/hfi1: Fix the size parameter to find_first_bit
  IB/mlx5: Fix the size parameter to find_first_bit
  IB/hfi1: Clean up type used and casting
  i40iw: Receive notification events correctly
  i40iw: Update hw_iwarp_state

lkdtm: adjust usercopy tests to bypass const checks

The hardened usercopy is now consistently avoiding checks against const
sizes, since we really only want to perform runtime bounds checking
on lengths that weren't known at build time. To test the hardened usercopy
code, we must force the length arguments to be seen as non-const.

Signed-off-by: Kees Cook <keescook@chromium.org>

usercopy: fold builtin_const check into inline function

Instead of having each caller of check_object_size() need to remember to
check for a const size parameter, move the check into check_object_size()
itself. This actually matches the original implementation in PaX, though
this commit cleans up the now-redundant builtin_const() calls in the
various architectures.

Signed-off-by: Kees Cook <keescook@chromium.org>

x86/uaccess: force copy_*_user() to be inlined

As already done with __copy_*_user(), mark copy_*_user() as __always_inline.
Without this, the checks for things like __builtin_const_p() won't work
consistently in either hardened usercopy nor the recent adjustments for
detecting usercopy overflows at compile time.

The change in kernel text size is detectable, but very small:

text      data     bss     dec      hex     filename
12118735  5768608 14229504 32116847 1ea106f vmlinux.before
12120207  5768608 14229504 32118319 1ea162f vmlinux.after

Signed-off-by: Kees Cook <keescook@chromium.org>

Merge branch 'mailbox-devel' of git://git.linaro.org/landing-teams/working/fujitsu/integration

Pull mailbox fixes from Jassi Brar:
"Misc fixes for BCM mailbox driver

   - Fix build warnings by making static functions used within the file.
   - Check for potential NULL before dereferencing
   - Fix link error by defining HAS_DMA dependency"

* 'mailbox-devel' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
  fix:mailbox:bcm-pdc-mailbox:mark symbols static where possible
  mailbox: bcm-pdc: potential NULL dereference in pdc_shutdown()
  mailbox: Add HAS_DMA Kconfig dependency to BCM_PDC_MBOX

Merge tag 'scsi-fixes' of git://git./linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
"This is really three fixes, but the SES one comes in a bundle of three
  (making the replacement API available properly, using it and removing
  the non-working one).  The SES problem causes an oops on hpsa devices
  because they attach virtual disks to the host which aren't SAS
  attached (the replacement API ignores them).

  The other two fixes are fairly minor: the sense key one means we
  actually resolve a newly added sense key and the RDAC device
  blacklisting is needed to prevent us annoying the universal XPORT lun
  of various RDAC arrays"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: sas: remove is_sas_attached()
  scsi: ses: use scsi_is_sas_rphy instead of is_sas_attached
  scsi: sas: provide stub implementation for scsi_is_sas_rphy
  scsi: blacklist all RDAC devices for BLIST_NO_ULD_ATTACH
  scsi: fix upper bounds check of sense key in scsi_sense_key_string()

Merge tag 'regmap-fix-v4.8-rc5' of git://git./linux/kernel/git/broonie/regmap

Pull regmap fixes from Mark Brown:
"Several fixes here, the main one being the change from Lars-Peter
  which I'd been letting soak in -next since the merge window in case it
  uncovered further issues as it's a minimal fix rather than a change
  addressing the root cause of the problems (which would've been too
  invasive for -rc):

   - The biggest change is a fix from Lars-Peter to ensure that we don't
     create overlapping rbtree nodes which in turn avoids returning
     corrupt cache values to users, fixing some issues that were exposed
     by some recent optimisations with certain access patterns but had
     been present for a long time.

   - A fix from Elaine Zhang to stop us updating the cache if we get an
     I/O error when writing to the hardware.

   - A fix fromm Maarten ter Huurne to avoid uninitialized defaults in
     cases where we have non-readable registers but are initializing the
     cache by reading from the device"

* tag 'regmap-fix-v4.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: drop cache if the bus transfer error
  regmap: rbtree: Avoid overlapping nodes
  regmap: cache: Fix num_reg_defaults computation from reg_defaults_raw

Merge tag 'spi-fix-v4.8-rc5' of git://git./linux/kernel/git/broonie/spi

Pull spi fixes from Mark Brown:
"As well as the usual driver fixes there's a couple of non-trivial core
  fixes in here:

   - Fixes for issues reported by Julia Lawall in the changes that were
     sent last time to fix interaction between the bus lock and the
     locking done for the SPI thread.  I'd let this one cook for a while
     to make sure nothing else came up in testing.

   - A fix from Sien Wu for arithmetic overflows when calculating the
     timeout for larger transfers (espcially common with slow buses with
     flashes on them)"

* tag 'spi-fix-v4.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: Prevent unexpected SPI time out due to arithmetic overflow
  spi: pxa2xx-pci: fix ACPI-based enumeration of SPI devices
  MAINTAINERS: add myself as Samsung SPI maintainer
  spi: Drop io_mutex in error paths
  spi: sh-msiof: Avoid invalid clock generator parameters
  spi: img-spfi: Remove spi_master_put in img_spfi_remove()
  spi: mediatek: remove spi_master_put in mtk_spi_remove()
  spi: qup: Remove spi_master_put in spi_qup_remove()

Merge tag 'regulator-fix-v4.8-rc5' of git://git./linux/kernel/git/broonie/regulator

Pull regulator fixes from Mark Brown:
"Two things here, one an e-mail update for Krzysztof Kozlowski and the
  other a couple of fixes for issues with incorrectly described voltages
  in a couple of the Qualcomm regulator drivers that were breaking MMC
  on some platforms"

* tag 'regulator-fix-v4.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
  regulator: Change Krzysztof Kozlowski's email to kernel.org
  regulator: qcom_smd: Fix voltage ranges for pma8084 ftsmps and pldo
  regulator: qcom_smd: Fix voltage ranges for pm8x41

Merge tag 'pinctrl-v4.8-3' of git://git./linux/kernel/git/linusw/linux-pinctrl

Pull pin control fixes from Linus Walleij:
"Nothing special at all, just three SoC-specific driver fixes:

   - Fix routing problems in pistachio (Imagination) and sunxi
     (AllWinner)

   - Fix an interrupt problem in the Cherryview (Intel)"

* tag 'pinctrl-v4.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: sunxi: fix uart1 CTS/RTS pins at PG on A23/A33
  pinctrl: cherryview: Do not mask all interrupts in probe
  pinctrl: pistachio: fix mfio pll_lock pinmux

thermal: rcar_thermal: Fix priv->zone error handling

In case thermal_zone_xxx_register() returns an error, priv->zone
isn't NULL any more, but contains the error code.

This is passed to thermal_zone_device_unregister(), then. This checks
for priv->zone being NULL, but the error code is != NULL. So it works
with the error code as a pointer. Crashing immediately.

To fix this, reset priv->zone to NULL before entering
rcar_gen3_thermal_remove().

Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

Merge remote-tracking branches 'spi/fix/lock', 'spi/fix/maintainers', 'spi/fix/put', 'spi/fix/pxa2xx', 'spi/fix/sh-msiof' and 'spi/fix/timeout' into spi-linus

Merge remote-tracking branches 'regulator/fix/email' and 'regulator/fix/qcom-smd' into regulator-linus