Make @root exclusive in mem_cgroup_low; it is never considered low when
looked at directly and is not checked when traversing the tree.  In
effect, @root is handled identically to how root_mem_cgroup was
previously handled by mem_cgroup_low.

If @root is not excluded from the checks, a cgroup underneath @root will
never be considered low during targeted reclaim of @root, e.g.  due to
memory.current > memory.high, unless @root is misconfigured to have
memory.low > memory.high.

Excluding @root enables using memory.low to prioritize memory usage
between cgroups within a subtree of the hierarchy that is limited by
memory.high or memory.max, e.g.  when ROOT owns @root's controls but
delegates the @root directory to a USER so that USER can create and
administer children of @root.

For example, given cgroup A with children B and C:

    A
   / \
  B   C

and

  1. A/memory.current > A/memory.high
  2. A/B/memory.current < A/B/memory.low
  3. A/C/memory.current >= A/C/memory.low

As 'A' is high, i.e.  triggers reclaim from 'A', and 'B' is low, we
should reclaim from 'C' until 'A' is no longer high or until we can no
longer reclaim from 'C'.  If 'A', i.e.  @root, isn't excluded by
mem_cgroup_low when reclaming from 'A', then 'B' won't be considered low
and we will reclaim indiscriminately from both 'B' and 'C'.

Here is the test I used to confirm the bug and the patch.

20:00:55@sjchrist-vm ? ~ $ cat ~/.bin/memcg_low_test
#!/bin/bash

x62mb=$((62<<20))
x66mb=$((66<<20))
x94mb=$((94<<20))
x98mb=$((98<<20))

setup() {
    set -e

    if [[ -n $DEBUG ]]; then
        set -x
    fi

    trap teardown EXIT HUP INT TERM

    if [[ ! -e /mnt/1gb.swap ]]; then
        sudo fallocate -l 1G /mnt/1gb.swap > /dev/null
        sudo mkswap /mnt/1gb.swap > /dev/null
    fi
    if ! swapon --show=NAME | grep -q "/mnt/1gb.swap"; then
        sudo swapon /mnt/1gb.swap
    fi

    if [[ ! -e /cgroup/cgroup.controllers ]]; then
        sudo mount -t cgroup2 none /cgroup
    fi

    grep -q memory /cgroup/cgroup.controllers

    sudo sh -c "echo '+memory' > /cgroup/cgroup.subtree_control"

    sudo mkdir /cgroup/A && sudo chown $USER:$USER /cgroup/A
    sudo sh -c "echo '+memory' > /cgroup/A/cgroup.subtree_control"
    sudo sh -c "echo '96m' > /cgroup/A/memory.high"

    mkdir /cgroup/A/0
    mkdir /cgroup/A/1

    echo 64m > /cgroup/A/0/memory.low
}

teardown() {
    set +e

    trap - EXIT HUP INT TERM

    if [[ -z $1 ]]; then
        printf "\n"
        printf "%0.s*" {1..35}
        printf "\nFAILED!\n\n"
        tail /cgroup/A/**/memory.current
        printf "%0.s*" {1..35}
        printf "\n\n"
    fi

    ps | grep stress | tr -s ' ' | cut -f 2 -d ' ' | xargs -I % kill %

    sleep 2

    if [[ -e /cgroup/A/0 ]]; then
        rmdir /cgroup/A/0
    fi
    if [[ -e /cgroup/A/1 ]]; then
        rmdir /cgroup/A/1
    fi
    if [[ -e /cgroup/A ]]; then
        sudo rmdir /cgroup/A
    fi
}

stress_test() {
    sudo sh -c "echo $$ > /cgroup/A/$1/cgroup.procs"
    stress --vm 1 --vm-bytes 64M --vm-keep > /dev/null &

    sudo sh -c "echo $$ > /cgroup/A/$2/cgroup.procs"
    stress --vm 1 --vm-bytes 64M --vm-keep > /dev/null &

    sudo sh -c "echo $$ > /cgroup/cgroup.procs"

    sleep 1

    # A/0 should be consuming more memory than A/1
    [[ $(cat /cgroup/A/0/memory.current) -ge $(cat /cgroup/A/1/memory.current) ]]

    # A/0 should be consuming ~64mb
    [[ $(cat /cgroup/A/0/memory.current) -ge $x62mb ]] && [[ $(cat /cgroup/A/0/memory.current) -le $x66mb ]]

    # A should cumulatively be consuming ~96mb
    [[ $(cat /cgroup/A/memory.current) -ge $x94mb ]] && [[ $(cat /cgroup/A/memory.current) -le $x98mb ]]

    # Stop the stressors
    ps | grep stress | tr -s ' ' | cut -f 2 -d ' ' | xargs -I % kill %
}

teardown 1
setup

for ((i=1;i<=$1;i++)); do
    printf "ITERATION $i of $1 - stress_test 0 1"
    stress_test 0 1
    printf "\x1b[2K\r"

    printf "ITERATION $i of $1 - stress_test 1 0"
    stress_test 1 0
    printf "\x1b[2K\r"

    printf "ITERATION $i of $1 - PASSED\n"
done

teardown 1

echo PASSED!

20:11:26@sjchrist-vm ? ~ $ memcg_low_test 10

Link: http://lkml.kernel.org/r/1496434412-21005-1-git-send-email-sean.j.christopherson@intel.comSigned-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

PR_SET_THP_DISABLE has a rather subtle semantic.  It doesn't affect any
existing mapping because it only updated mm->def_flags which is a
template for new mappings.

The mappings created after prctl(PR_SET_THP_DISABLE) have VM_NOHUGEPAGE
flag set.  This can be quite surprising for all those applications which
do not do prctl(); fork() & exec() and want to control their own THP
behavior.

Another usecase when the immediate semantic of the prctl might be useful
is a combination of pre- and post-copy migration of containers with
CRIU.  In this case CRIU populates a part of a memory region with data
that was saved during the pre-copy stage.  Afterwards, the region is
registered with userfaultfd and CRIU expects to get page faults for the
parts of the region that were not yet populated.  However, khugepaged
collapses the pages and the expected page faults do not occur.

In more general case, the prctl(PR_SET_THP_DISABLE) could be used as a
temporary mechanism for enabling/disabling THP process wide.

Implementation wise, a new MMF_DISABLE_THP flag is added.  This flag is
tested when decision whether to use huge pages is taken either during
page fault of at the time of THP collapse.

It should be noted, that the new implementation makes PR_SET_THP_DISABLE
master override to any per-VMA setting, which was not the case
previously.

Fixes: a0715cc2 ("mm, thp: add VM_INIT_DEF_MASK and PRCTL_THP_DISABLE")
Link: http://lkml.kernel.org/r/1496415802-30944-1-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

By default, vmpressure events are not pass-through, i.e.  they propagate
up through the memcg hierarchy until an event notifier is found for any
threshold level.

This presents a difficulty when a thread waiting on a read(2) for a
vmpressure event cannot distinguish between local memory pressure and
memory pressure in a descendant memcg, especially when that thread may
not control the memcg hierarchy.

Consider a user-controlled child memcg with a smaller limit than a
top-level memcg controlled by the "Activity Manager" specified in
Documentation/cgroup-v1/memory.txt.  It may register for memory pressure
notification for descendant memcgs to make a policy decision: oom kill a
low priority job, increase the limit, decrease other limits, etc.  If it
registers for memory pressure notification on the top-level memcg, it
currently cannot distinguish between memory pressure in its own memcg or
a descendant memcg, which is user-controlled.

Conversely, if a user registers for memory pressure notification on
their own descendant memcg, the Activity Manager does not receive any
pressure notification for that child memcg hierarchy.  Vmpressure events
are not received for ancestor memcgs if the memcg experiencing pressure
have notifiers registered, perhaps outside the knowledge of the thread
waiting on read(2) at the top level.

Both of these are consequences of vmpressure notification not being
pass-through.

This implements a pass-through behavior for vmpressure events.  When
writing to control.event_control, vmpressure event handlers may
optionally specify a mode.  There are two new modes:

 - "hierarchy": always propagate memory pressure events up the hierarchy
   regardless if descendant memcgs have their own notifiers registered,
   and

 - "local": only receive notifications when the memcg for which the
   event is registered experiences memory pressure.

Of course, processes may register for one notification of "low,local",
for example, and another for "low".

If no mode is specified, the current behavior is maintained for
backwards compatibility.

See the change to Documentation/cgroup-v1/memory.txt for full
specification.

[dan.carpenter@oracle.com: free the same pointer we allocated]
  Link: http://lkml.kernel.org/r/20170613191820.GA20003@elgon.mountain
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705311421320.8946@chino.kir.corp.google.comSigned-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Anton Vorontsov <anton@enomsg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Factoring duplicate code into a function.

Link: http://lkml.kernel.org/r/1496305019-5493-10-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dequeue_hwpoisoned_huge_page() is no longer used, so let's remove it.

Link: http://lkml.kernel.org/r/1496305019-5493-9-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently me_huge_page() relies on dequeue_hwpoisoned_huge_page() to
keep the error hugepage away from the system, which is OK but not good
enough because the hugepage still has a refcount and unpoison doesn't
work on the error hugepage (PageHWPoison flags are cleared but pages are
still leaked.) And there's "wasting health subpages" issue too.  This
patch reworks on me_huge_page() to solve these issues.

For hugetlb file, recently we have truncating code so let's use it in
hugetlbfs specific ->error_remove_page().

For anonymous hugepage, it's helpful to dissolve the error page after
freeing it into free hugepage list.  Migration entry and PageHWPoison in
the head page prevent the access to it.

TODO: dissolve_free_huge_page() can fail but we don't considered it yet.
It's not critical (and at least no worse that now) because in such case
the error hugepage just stays in free hugepage list without being
dissolved.  By virtue of PageHWPoison in head page, it's never allocated
to processes.

[akpm@linux-foundation.org: fix unused var warnings]
Fixes: 23a003bf ("mm/madvise: pass return code of memory_failure() to userspace")
Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop
Link: http://lkml.kernel.org/r/1496305019-5493-8-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memory_failure() is a big function and hard to maintain.  Handling
hugetlb- and non-hugetlb- case in a single function is not good, so this
patch separates PageHuge() branch into a new function, which saves many
PageHuge() check.

Link: http://lkml.kernel.org/r/1496305019-5493-7-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Now we have code to rescue most of healthy pages from a hwpoisoned
hugepage.  So let's apply it to soft_offline_free_page too.

Link: http://lkml.kernel.org/r/1496305019-5493-6-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently hugepage migrated by soft-offline (i.e.  due to correctable
memory errors) is contained as a hugepage, which means many non-error
pages in it are unreusable, i.e.  wasted.

This patch solves this issue by dissolving source hugepages into buddy.
As done in previous patch, PageHWPoison is set only on a head page of
the error hugepage.  Then in dissoliving we move the PageHWPoison flag
to the raw error page so that all healthy subpages return back to buddy.

[arnd@arndb.de: fix warnings: replace some macros with inline functions]
  Link: http://lkml.kernel.org/r/20170609102544.2947326-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/1496305019-5493-5-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We'd like to narrow down the error region in memory error on hugetlb
pages.  However, currently we set PageHWPoison flags on all subpages in
the error hugepage and add # of subpages to num_hwpoison_pages, which
doesn't fit our purpose.

So this patch changes the behavior and we only set PageHWPoison on the
head page then increase num_hwpoison_pages only by 1.  This is a
preparation for narrow-down part which comes in later patches.

Link: http://lkml.kernel.org/r/1496305019-5493-4-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We avoid calling __mod_node_page_state(NR_FILE_PAGES) for hugetlb page
now, but it's not enough because later code doesn't handle hugetlb
properly.  Actually in our testing, WARN_ON_ONCE(PageDirty(page)) at the
end of this function fires for hugetlb, which makes no sense.  So we
should return immediately for hugetlb pages.

Link: http://lkml.kernel.org/r/1496305019-5493-3-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "mm: hwpoison: fixlet for hugetlb migration".

This patchset updates the hwpoison/hugetlb code to address 2 reported
issues.

One is madvise(MADV_HWPOISON) failure reported by Intel's lkp robot (see
http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop.) First
half was already fixed in mainline, and another half about hugetlb cases
are solved in this series.

Another issue is "narrow-down error affected region into a single 4kB
page instead of a whole hugetlb page" issue, which was tried by Anshuman
(http://lkml.kernel.org/r/20170420110627.12307-1-khandual@linux.vnet.ibm.com)
and I updated it to apply it more widely.

This patch (of 9):

We no longer use MIGRATE_ISOLATE to prevent reuse of hwpoison hugepages
as we did before.  So current dequeue_huge_page_node() doesn't work as
intended because it still uses is_migrate_isolate_page() for this check.
This patch fixes it with PageHWPoison flag.

Link: http://lkml.kernel.org/r/1496305019-5493-2-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

To install a buffer_head into the cpu's LRU queue, bh_lru_install()
would construct a new copy of the queue and then memcpy it over the real
queue.  But it's easily possible to do the update in-place, which is
faster and simpler.  Some work can also be skipped if the buffer_head
was already in the queue.

As a microbenchmark I timed how long it takes to run sb_getblk()
10,000,000 times alternating between BH_LRU_SIZE + 1 blocks.
Effectively, this benchmarks looking up buffer_heads that are in the
page cache but not in the LRU:

	Before this patch: 1.758s
	After this patch: 1.653s

This patch also removes about 350 bytes of compiled code (on x86_64),
partly due to removal of the memcpy() which was being inlined+unrolled.

Link: http://lkml.kernel.org/r/20161229193445.1913-1-ebiggers3@gmail.comSigned-off-by: Eric Biggers <ebiggers@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

is_first_page() is only called from the macro VM_BUG_ON_PAGE() which is
only compiled in as a runtime check when CONFIG_DEBUG_VM is set,
otherwise is checked at compile time and not actually compiled in.

Fixes the following warning, found with Clang:

  mm/zsmalloc.c:472:12: warning: function 'is_first_page' is not needed and will not be emitted [-Wunneeded-internal-declaration]
  static int is_first_page(struct page *page)
           ^

Link: http://lkml.kernel.org/r/20170524053859.29059-1-nick.desaulniers@gmail.comSigned-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The NULL check at line 1226: if (!pgdat), implies that pointer pgdat
might be NULL.

rollback_node_hotadd() dereferences this pointer.  Add NULL check to
avoid a potential NULL pointer dereference.

Addresses-Coverity-ID: 1369133
Link: http://lkml.kernel.org/r/20170530212436.GA6195@embeddedgusSigned-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The purpose of the code that commit 62376251 ("revert 'mm: vmscan:
do not swap anon pages just because free+file is low'") reintroduces is
to prefer swapping anonymous memory rather than trashing the file lru.

If the anonymous inactive lru for the set of eligible zones is
considered low, however, or the length of the list for the given reclaim
priority does not allow for effective anonymous-only reclaiming, then
avoid forcing SCAN_ANON.  Forcing SCAN_ANON will end up thrashing the
small list and leave unreclaimed memory on the file lrus.

If the inactive list is insufficient, fallback to balanced reclaim so
the file lru doesn't remain untouched.

[akpm@linux-foundation.org: fix build]
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705011432220.137835@chino.kir.corp.google.comSigned-off-by: David Rientjes <rientjes@google.com>
Suggested-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The preferred strategy to define debugfs attributes is to use the
DEFINE_DEBUGFS_ATTRIBUTE() macro and to use debugfs_create_file_unsafe().

Link: http://lkml.kernel.org/r/20170528145948.32127-1-y.pronenko@gmail.comSigned-off-by: Yevgen Pronenko <y.pronenko@gmail.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Since commit 3bc48f96 ("mm, page_alloc: split smallest stolen page
in fallback") we pick the smallest (but sufficient) page of all that
have been stolen from a pageblock of different migratetype.  However,
there are cases when we decide not to steal the whole pageblock.

Practically in the current implementation it means that we are trying to
fallback for a MIGRATE_MOVABLE allocation of order X, go through the
freelists from MAX_ORDER-1 down to X, and find free page of order Y.  If
Y is less than pageblock_order / 2, we decide not to steal all pages
from the pageblock.  When Y > X, it means we are potentially splitting a
larger page than we need, as there might be other pages of order Z,
where X <= Z < Y.  Since Y is already too small to steal whole
pageblock, picking smallest available Z will result in the same decision
and we avoid splitting a higher-order page in a MIGRATE_UNMOVABLE or
MIGRATE_RECLAIMABLE pageblock.

This patch therefore changes the fallback algorithm so that in the
situation described above, we switch the fallback search strategy to go
from order X upwards to find the smallest suitable fallback.  In theory
there shouldn't be a downside of this change wrt fragmentation.

This has been tested with mmtests' stress-highalloc performing
GFP_KERNEL order-4 allocations, here is the relevant extfrag tracepoint
statistics:

                                                        4.12.0-rc2      4.12.0-rc2
                                                         1-kernel4       2-kernel4
  Page alloc extfrag event                                  25640976    69680977
  Extfrag fragmenting                                       25621086    69661364
  Extfrag fragmenting for unmovable                            74409       73204
  Extfrag fragmenting unmovable placed with movable            69003       67684
  Extfrag fragmenting unmovable placed with reclaim.            5406        5520
  Extfrag fragmenting for reclaimable                           6398        8467
  Extfrag fragmenting reclaimable placed with movable            869         884
  Extfrag fragmenting reclaimable placed with unmov.            5529        7583
  Extfrag fragmenting for movable                           25540279    69579693

Since we force movable allocations to steal the smallest available page
(which we then practially always split), we steal less per fallback, so
the number of fallbacks increases and steals potentially happen from
different pageblocks.  This is however not an issue for movable pages
that can be compacted.

Importantly, the "unmovable placed with movable" statistics is lower,
which is the result of less fragmentation in the unmovable pageblocks.
The effect on reclaimable allocation is a bit unclear.

Link: http://lkml.kernel.org/r/20170529093947.22618-1-vbabka@suse.czSigned-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

For fast flash disk, async IO could introduce overhead because of
context switch.  block-mq now supports IO poll, which improves
performance and latency a lot.  swapin is a good place to use this
technique, because the task is waiting for the swapin page to continue
execution.

In my virtual machine, directly read 4k data from a NVMe with iopoll is
about 60% better than that without poll.  With iopoll support in swapin
patch, my microbenchmark (a task does random memory write) is about
10%~25% faster.  CPU utilization increases a lot though, 2x and even 3x
CPU utilization.  This will depend on disk speed.

While iopoll in swapin isn't intended for all usage cases, it's a win
for latency sensistive workloads with high speed swap disk.  block layer
has knob to control poll in runtime.  If poll isn't enabled in block
layer, there should be no noticeable change in swapin.

I got a chance to run the same test in a NVMe with DRAM as the media.
In simple fio IO test, blkpoll boosts 50% performance in single thread
test and ~20% in 8 threads test.  So this is the base line.  In above
swap test, blkpoll boosts ~27% performance in single thread test.
blkpoll uses 2x CPU time though.

If we enable hybid polling, the performance gain has very slight drop
but CPU time is only 50% worse than that without blkpoll.  Also we can
adjust parameter of hybid poll, with it, the CPU time penality is
reduced further.  In 8 threads test, blkpoll doesn't help though.  The
performance is similar to that without blkpoll, but cpu utilization is
similar too.  There is lock contention in swap path.  The cpu time
spending on blkpoll isn't high.  So overall, blkpoll swapin isn't worse
than that without it.

The swapin readahead might read several pages in in the same time and
form a big IO request.  Since the IO will take longer time, it doesn't
make sense to do poll, so the patch only does iopoll for single page
swapin.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/070c3c3e40b711e7b1390002c991e86a-b5408f0@7511894063d3764ff01ea8111f5a004d7dd700ed078797c204a24e620ddb965cSigned-off-by: Shaohua Li <shli@fb.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull IPMI updates from Corey Minyard:
 "Some small fixes for IPMI, and one medium sized changed.

  The medium sized change is adding a platform device for IPMI entries
  in the DMI table. Otherwise there is no auto loading for IPMI devices
  if they are only in the DMI table"

* tag 'for-linus-4.13-v2' of git://github.com/cminyard/linux-ipmi:
  ipmi:ssif: Add missing unlock in error branch
  char: ipmi: constify bmc_dev_attr_group and bmc_device_type
  ipmi:ssif: Check dev before setting drvdata
  ipmi: Convert DMI handling over to a platform device
  ipmi: Create a platform device for a DMI-specified IPMI interface
  ipmi: use rcu lock around call to intf->handlers->sender()
  ipmi:ssif: Use i2c_adapter_id instead of adapter->nr
  ipmi: Use the proper default value for register size in ACPI
  ipmi_ssif: remove redundant null check on array client->adapter->name
  ipmi/watchdog: fix watchdog timeout set on reboot
  ipmi_ssif: unlock on allocation failure

Pull XFS updates from Darrick Wong:
 "Here are some changes for you for 4.13. For the most part it's fixes
  for bugs and deadlock problems, and preparation for online fsck in
  some future merge window.

   - Avoid quotacheck deadlocks

   - Fix transaction overflows when bunmapping fragmented files

   - Refactor directory readahead

   - Allow admin to configure if ASSERT is fatal

   - Improve transaction usage detail logging during overflows

   - Minor cleanups

   - Don't leak log items when the log shuts down

   - Remove double-underscore typedefs

   - Various preparation for online scrubbing

   - Introduce new error injection configuration sysfs knobs

   - Refactor dq_get_next to use extent map directly

   - Fix problems with iterating the page cache for unwritten data

   - Implement SEEK_{HOLE,DATA} via iomap

   - Refactor XFS to use iomap SEEK_HOLE and SEEK_DATA

   - Don't use MAXPATHLEN to check on-disk symlink target lengths"

* tag 'xfs-4.13-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (48 commits)
  xfs: don't crash on unexpected holes in dir/attr btrees
  xfs: rename MAXPATHLEN to XFS_SYMLINK_MAXLEN
  xfs: fix contiguous dquot chunk iteration livelock
  xfs: Switch to iomap for SEEK_HOLE / SEEK_DATA
  vfs: Add iomap_seek_hole and iomap_seek_data helpers
  vfs: Add page_cache_seek_hole_data helper
  xfs: remove a whitespace-only line from xfs_fs_get_nextdqblk
  xfs: rewrite xfs_dq_get_next_id using xfs_iext_lookup_extent
  xfs: Check for m_errortag initialization in xfs_errortag_test
  xfs: grab dquots without taking the ilock
  xfs: fix semicolon.cocci warnings
  xfs: Don't clear SGID when inheriting ACLs
  xfs: free cowblocks and retry on buffered write ENOSPC
  xfs: replace log_badcrc_factor knob with error injection tag
  xfs: convert drop_writes to use the errortag mechanism
  xfs: remove unneeded parameter from XFS_TEST_ERROR
  xfs: expose errortag knobs via sysfs
  xfs: make errortag a per-mountpoint structure
  xfs: free uncommitted transactions during log recovery
  xfs: don't allow bmap on rt files
  ...

Pull btrfs fix from David Sterba:
 "This fixes a user-visible bug introduced by the nowait-aio patches
  merged in this cycle"

* 'nowait-aio-btrfs-fixup' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: nowait aio: Correct assignment of pos

Pull copy*_iter fix from Al Viro.

[ Al used entirely the wrong return value. Oopsie. ]

* 'fix-uio' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fix brown paperbag bug in inlined copy_..._iter()

Pull HID updates from Jiri Kosina:

 - open/close tracking improvements from Dmitry Torokhov

 - battery support improvements in Wacom driver from Jason Gerecke

 - Win8 support fixes from Benjamin Tissories and Hans de Geode

 - misc fixes to Intel-ISH driver from Arnd Bergmann

 - support for quite a few new devices and small assorted fixes here and
   there

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid: (35 commits)
  HID: intel-ish-hid: Enable Gemini Lake ish driver
  HID: intel-ish-hid: Enable Cannon Lake ish driver
  HID: wacom: fix mistake in printk
  HID: multitouch: optimize the sticky fingers timer
  HID: multitouch: fix rare Win 8 cases when the touch up event gets missing
  HID: multitouch: use BIT macro
  HID: Add driver for Retrode2 joypad adapter
  HID: multitouch: Add support for Google Rose Touchpad
  HID: multitouch: Support PTP Stick and Touchpad device
  HID: core: don't use negative operands when shift
  HID: apple: Use country code to detect ISO keyboards
  HID: remove no longer used hid->open field
  greybus: hid: remove custom locking from gb_hid_open/close
  HID: usbhid: remove custom locking from usbhid_open/close
  HID: i2c-hid: remove custom locking from i2c_hid_open/close
  HID: serialize hid_hw_open and hid_hw_close
  HID: usbhid: do not rely on hid->open when deciding to do IO
  HID: hiddev: use hid_hw_power instead of usbhid_get/put_power
  HID: hiddev: use hid_hw_open/close instead of usbhid_open/close
  HID: asus: Add support for Zen AiO MD-5110 keyboard
  ...

Assigning pos for usage early messes up in append mode, where the pos is
re-assigned in generic_write_checks(). Assign pos later to get the
correct position to write from iocb->ki_pos.

Since check_can_nocow also uses the value of pos, we shift
generic_write_checks() before check_can_nocow(). Checks with IOCB_DIRECT
are present in generic_write_checks(), so checking for IOCB_NOWAIT is
enough.

Also, put locking sequence in the fast path.

This fixes a user visible bug, as reported:

"apparently breaks several shell related features on my system.
In zsh history stopped working, because no new entries are added
anymore.
I fist noticed the issue when I tried to build mplayer. It uses a shell
script to generate a help_mp.h file:
[...]

Here is a simple testcase:

 % echo "foo" >> test
 % echo "foo" >> test
 % cat test
 foo
 %
"

Fixes: edf064e7 ("btrfs: nowait aio support")
CC: Jens Axboe <axboe@kernel.dk>
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Link: https://lkml.kernel.org/r/20170704042306.GA274@x4Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

"copied nothing" == "return 0", not "return full size".

Fixes: aa28de27 "iov_iter/hardening: move object size checks to inlined part"
Spotted-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Merge branches 'for-4.13/multitouch', 'for-4.13/retrode', 'for-4.13/transport-open-close-consolidation', 'for-4.13/upstream' and 'for-4.13/wacom' into for-linus

Conflicts:
	drivers/hid/hid-core.c

Conflicts:
	drivers/hid/hid-core.c

Pull drm updates from Dave Airlie:
 "This is the main pull request for the drm, I think I've got one later
  driver pull for mediatek SoC driver, I'm undecided on if it needs to
  go to you yet.

  Otherwise summary below:

  Core drm:
   - Atomic add driver private objects
   - Deprecate preclose hook in modern drivers
   - MST bandwidth tracking
   - Use kvmalloc in more places
   - Add mode_valid hook for crtc/encoder/bridge
   - Reduce sync_file construction time
   - Documentation updates
   - New DRM synchronisation object support

  New drivers:
   - pl111 - pl111 CLCD display controller

  Panel:
   - Innolux P079ZCA panel driver
   - Add NL12880B20-05, NL192108AC18-02D, P320HVN03 panels
   - panel-samsung-s6e3ha2: Add s6e3hf2 panel support

  i915:
   - SKL+ watermark fixes
   - G4x/G33 reset improvements
   - DP AUX backlight improvements
   - Buffer based GuC/host communication
   - New getparam for (sub)slice infomation
   - Cannonlake and Coffeelake initial patches
   - Execbuf optimisations

  radeon/amdgpu:
   - Lots of Vega10 bug fixes
   - Preliminary raven support
   - KIQ support for compute rings
   - MEC queue management rework
   - DCE6 Audio support
   - SR-IOV improvements
   - Better radeon/amdgpu selection support

  nouveau:
   - HDMI stereoscopic support
   - Display code rework for >= GM20x GPUs

  msm:
   - GEM rework for fine-grained locking
   - Per-process pagetable work
   - HDMI fixes for Snapdragon 820.

  vc4:
   - Remove 256MB CMA limit from vc4
   - Add out-fence support
   - Add support for cygnus
   - Get/set tiling ioctls support
   - Add T-format tiling support for scanout

  zte:
   - add VGA support.

  etnaviv:
   - Thermal throttle support for newer GPUs
   - Restore userspace buffer cache performance
   - dma-buf sync fix

  stm:
   - add stm32f429 display support

  exynos:
   - Rework vblank handling
   - Fixup sw-trigger code

  sun4i:
   - V3s display engine support
   - HDMI support for older SoCs
   - Preliminary work on dual-pipeline SoCs.

  rcar-du:
   - VSP work

  imx-drm:
   - Remove counter load enable from PRE
   - Double read/write reduction flag support

  tegra:
   - Documentation for the host1x and drm driver.
   - Lots of staging ioctl fixes due to grate project work.

  omapdrm:
   - dma-buf fence support
   - TILER rotation fixes"

* tag 'drm-for-v4.13' of git://people.freedesktop.org/~airlied/linux: (1270 commits)
  drm: Remove unused drm_file parameter to drm_syncobj_replace_fence()
  drm/amd/powerplay: fix bug fail to remove sysfs when rmmod amdgpu.
  amdgpu: Set cik/si_support to 1 by default if radeon isn't built
  drm/amdgpu/gfx9: fix driver reload with KIQ
  drm/amdgpu/gfx8: fix driver reload with KIQ
  drm/amdgpu: Don't call amd_powerplay_destroy() if we don't have powerplay
  drm/ttm: Fix use-after-free in ttm_bo_clean_mm
  drm/amd/amdgpu: move get memory type function from early init to sw init
  drm/amdgpu/cgs: always set reference clock in mode_info
  drm/amdgpu: fix vblank_time when displays are off
  drm/amd/powerplay: power value format change for Vega10
  drm/amdgpu/gfx9: support the amdgpu.disable_cu option
  drm/amd/powerplay: change PPSMC_MSG_GetCurrPkgPwr for Vega10
  drm/amdgpu: Make amdgpu_cs_parser_init static (v2)
  drm/amdgpu/cs: fix a typo in a comment
  drm/amdgpu: Fix the exported always on CU bitmap
  drm/amdgpu/gfx9: gfx_v9_0_enable_gfx_static_mg_power_gating() can be static
  drm/amdgpu/psp: upper_32_bits/lower_32_bits for address setup
  drm/amd/powerplay/cz: print message if smc message fails
  drm/amdgpu: fix typo in amdgpu_debugfs_test_ib_init
  ...

Add xattrs to allow the user to get/set metadata in lieu of having pioctl()
available.  The following xattrs are now available:

 - "afs.cell"

   The name of the cell in which the vnode's volume resides.

 - "afs.fid"

   The volume ID, vnode ID and vnode uniquifier of the file as three hex
   numbers separated by colons.

 - "afs.volume"

   The name of the volume in which the vnode resides.

For example:

	# getfattr -d -m ".*" /mnt/scratch
	getfattr: Removing leading '/' from absolute path names
	# file: mnt/scratch
	afs.cell="mycell.myorg.org"
	afs.fid="10000b:1:1"
	afs.volume="scratch"
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The AFS_ACE_READ and AFS_ACE_WRITE permission bits should not
be used to make access decisions for the directory itself.  They
are meant to control access for the objects contained in that
directory.

Reading a directory is allowed if the AFS_ACE_LOOKUP bit is set.
This would cause an incorrect access denied error for a directory
with AFS_ACE_LOOKUP but not AFS_ACE_READ.

The AFS_ACE_WRITE bit does not allow operations that modify the
directory.  For a directory with AFS_ACE_WRITE but neither
AFS_ACE_INSERT nor AFS_ACE_DELETE, this would result in trying
operations that would ultimately be denied by the server.
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The retry logic for netlink_attachskb() inside sys_mq_notify()
is nasty and vulnerable:

1) The sock refcnt is already released when retry is needed
2) The fd is controllable by user-space because we already
   release the file refcnt

so we when retry but the fd has been just closed by user-space
during this small window, we end up calling netlink_detachskb()
on the error path which releases the sock again, later when
the user-space closes this socket a use-after-free could be
triggered.

Setting 'sock' to NULL here should be sufficient to fix it.
Reported-by: GeneBlue <geneblue.mail@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull x86 fixes from Thomas Gleixner:
 "The x86 updates contain:

   - A fix for a longstanding PAT bug, where PAT was reported on CPUs
     that do not support it, which leads to wrong caching attributes and
     missing MTRR updates

   - Prevent overwriting of the e820 firmware table, which causes kexec
     kernels to lose the fake mptable which is stored there.

   - Cleanup of the UV/BAU code, removing unused code and making local
     functions static"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot/e820: Introduce the bootloader provided e820_table_firmware[] table
  x86/boot/e820: Rename the e820_table_firmware to e820_table_kexec
  x86/boot/e820: Avoid overwriting e820_table_firmware
  x86/mm/pat: Don't report PAT on CPUs that don't support it
  x86/platform/uv/BAU: Minor cleanup, make some local functions static

Pull timers fixlet from Thomas Gleixner:
 "Add Frederic Weisbecker as NOHZ/dyntick maintainer"

[ And an unmentioned and unrelated typo fix in the same commit? Hmm.. ]

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Add Frederic Weisbecker as nohz/dyntics maintainer

Pull smp/hotplug fix from Thomas Gleixner:
 "A single fix for a brown paperbag bug:

  The unparking of the initial percpu threads of an upcoming CPU happens
  right now on the idle task, but that's wrong as the unpark function
  might sleep. Move it to the control CPU."

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smp/hotplug: Move unparking of percpu threads to the control CPU

Pull scheduler fixes from Thomas Gleixner:
 "This scheduler update provides:

   - The (hopefully) final fix for the vtime accounting issues which
     were around for quite some time

   - Use types known to user space in UAPI headers to unbreak user space
     builds

   - Make load balancing respect the current scheduling domain again
     instead of evaluating unrelated CPUs"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/headers/uapi: Fix linux/sched/types.h userspace compilation errors
  sched/fair: Fix load_balance() affinity redo path
  sched/cputime: Accumulate vtime on top of nsec clocksource
  sched/cputime: Move the vtime task fields to their own struct
  sched/cputime: Rename vtime fields
  sched/cputime: Always set tsk->vtime_snap_whence after accounting vtime
  vtime, sched/cputime: Remove vtime_account_user()
  Revert "sched/cputime: Refactor the cputime_adjust() code"

Pull perf fixes from Thomas Gleixner:
 "A couple of fixes for perf and kprobes:

   - Add he missing exclude_kernel attribute for the precise_ip level so
     !CAP_SYS_ADMIN users get the proper results.

   - Warn instead of failing completely when perf has no unwind support
     for a particular architectiure built in.

   - Ensure that jprobes are at function entry and not at some random
     place"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kprobes: Ensure that jprobe probepoints are at function entry
  kprobes: Simplify register_jprobes()
  kprobes: Rename [arch_]function_offset_within_entry() to [arch_]kprobe_on_func_entry()
  perf unwind: Do not fail due to missing unwind support
  perf evsel: Set attr.exclude_kernel when probing max attr.precise_ip

Pull locking fixes from Thomas Gleixner:

 - Fix the EINTR logic in rwsem-spinlock to avoid double locking by a
   writer and a reader

 - Add a missing include to qspinlocks

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/qspinlock: Explicitly include asm/prefetch.h
  locking/rwsem-spinlock: Fix EINTR branch in __down_write_common()

Pull irq fixes from Thomas Gleixner:

 - A few fixes mopping up the fallout of the big irq overhaul

 - Move the interrupt resource management logic out of the spin locked,
   irq disabled region to avoid unnecessary restrictions of the resource
   callbacks

 - Preparation for reworking the per cpu irq request function.

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqdomain: Allow ACPI device nodes to be used as irqdomain identifiers
  genirq/debugfs: Remove redundant NULL pointer check
  genirq: Allow to pass the IRQF_TIMER flag with percpu irq request
  genirq/timings: Move free timings out of spinlocked region
  genirq: Move irq resource handling out of spinlocked region
  genirq: Add mutex to irq desc to serialize request/free_irq()
  genirq: Move bus locking into __setup_irq()
  genirq: Force inlining of __irq_startup_managed to prevent build failure
  genirq/debugfs: Fix build for !CONFIG_IRQ_DOMAIN