1. 16 Jan, 2016 40 commits
    • Minchan Kim's avatar
      mm: define MADV_FREE for some arches · ef58978f
      Minchan Kim authored
      Most architectures use asm-generic, but alpha, mips, parisc, xtensa need
      their own definitions.
      
      This patch defines MADV_FREE for them so it should fix build break for
      their architectures.
      
      Maybe, I should split and feed pieces to arch maintainers but included
      here for mmotm convenience.
      
      [gang.chen.5i5j@gmail.com: let MADV_FREE have same value for all architectures]
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Acked-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
      Cc: Wu Fengguang <fengguang.wu@intel.com>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
      Cc: Shaohua Li <shli@kernel.org>
      Cc: <yalin.wang2010@gmail.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Chen Gang <gang.chen.5i5j@gmail.com>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: Darrick J. Wong <darrick.wong@oracle.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Jason Evans <je@fb.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Kirill A. Shutemov <kirill@shutemov.name>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Roland Dreier <roland@kernel.org>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: Shaohua Li <shli@kernel.org>
      Cc: Will Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarChen Gang <gang.chen.5i5j@gmail.com>
      Acked-by: default avatarHugh Dickins <hughd@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ef58978f
    • Minchan Kim's avatar
      mm: support madvise(MADV_FREE) · 854e9ed0
      Minchan Kim authored
      Linux doesn't have an ability to free pages lazy while other OS already
      have been supported that named by madvise(MADV_FREE).
      
      The gain is clear that kernel can discard freed pages rather than
      swapping out or OOM if memory pressure happens.
      
      Without memory pressure, freed pages would be reused by userspace
      without another additional overhead(ex, page fault + allocation +
      zeroing).
      
      Jason Evans said:
      
      : Facebook has been using MAP_UNINITIALIZED
      : (https://lkml.org/lkml/2012/1/18/308) in some of its applications for
      : several years, but there are operational costs to maintaining this
      : out-of-tree in our kernel and in jemalloc, and we are anxious to retire it
      : in favor of MADV_FREE.  When we first enabled MAP_UNINITIALIZED it
      : increased throughput for much of our workload by ~5%, and although the
      : benefit has decreased using newer hardware and kernels, there is still
      : enough benefit that we cannot reasonably retire it without a replacement.
      :
      : Aside from Facebook operations, there are numerous broadly used
      : applications that would benefit from MADV_FREE.  The ones that immediately
      : come to mind are redis, varnish, and MariaDB.  I don't have much insight
      : into Android internals and development process, but I would hope to see
      : MADV_FREE support eventually end up there as well to benefit applications
      : linked with the integrated jemalloc.
      :
      : jemalloc will use MADV_FREE once it becomes available in the Linux kernel.
      : In fact, jemalloc already uses MADV_FREE or equivalent everywhere it's
      : available: *BSD, OS X, Windows, and Solaris -- every platform except Linux
      : (and AIX, but I'm not sure it even compiles on AIX).  The lack of
      : MADV_FREE on Linux forced me down a long series of increasingly
      : sophisticated heuristics for madvise() volume reduction, and even so this
      : remains a common performance issue for people using jemalloc on Linux.
      : Please integrate MADV_FREE; many people will benefit substantially.
      
      How it works:
      
      When madvise syscall is called, VM clears dirty bit of ptes of the
      range.  If memory pressure happens, VM checks dirty bit of page table
      and if it found still "clean", it means it's a "lazyfree pages" so VM
      could discard the page instead of swapping out.  Once there was store
      operation for the page before VM peek a page to reclaim, dirty bit is
      set so VM can swap out the page instead of discarding.
      
      One thing we should notice is that basically, MADV_FREE relies on dirty
      bit in page table entry to decide whether VM allows to discard the page
      or not.  IOW, if page table entry includes marked dirty bit, VM
      shouldn't discard the page.
      
      However, as a example, if swap-in by read fault happens, page table
      entry doesn't have dirty bit so MADV_FREE could discard the page
      wrongly.
      
      For avoiding the problem, MADV_FREE did more checks with PageDirty and
      PageSwapCache.  It worked out because swapped-in page lives on swap
      cache and since it is evicted from the swap cache, the page has PG_dirty
      flag.  So both page flags check effectively prevent wrong discarding by
      MADV_FREE.
      
      However, a problem in above logic is that swapped-in page has PG_dirty
      still after they are removed from swap cache so VM cannot consider the
      page as freeable any more even if madvise_free is called in future.
      
      Look at below example for detail.
      
          ptr = malloc();
          memset(ptr);
          ..
          ..
          .. heavy memory pressure so all of pages are swapped out
          ..
          ..
          var = *ptr; -> a page swapped-in and could be removed from
                         swapcache. Then, page table doesn't mark
                         dirty bit and page descriptor includes PG_dirty
          ..
          ..
          madvise_free(ptr); -> It doesn't clear PG_dirty of the page.
          ..
          ..
          ..
          .. heavy memory pressure again.
          .. In this time, VM cannot discard the page because the page
          .. has *PG_dirty*
      
      To solve the problem, this patch clears PG_dirty if only the page is
      owned exclusively by current process when madvise is called because
      PG_dirty represents ptes's dirtiness in several processes so we could
      clear it only if we own it exclusively.
      
      Firstly, heavy users would be general allocators(ex, jemalloc, tcmalloc
      and hope glibc supports it) and jemalloc/tcmalloc already have supported
      the feature for other OS(ex, FreeBSD)
      
        barrios@blaptop:~/benchmark/ebizzy$ lscpu
        Architecture:          x86_64
        CPU op-mode(s):        32-bit, 64-bit
        Byte Order:            Little Endian
        CPU(s):                12
        On-line CPU(s) list:   0-11
        Thread(s) per core:    1
        Core(s) per socket:    1
        Socket(s):             12
        NUMA node(s):          1
        Vendor ID:             GenuineIntel
        CPU family:            6
        Model:                 2
        Stepping:              3
        CPU MHz:               3200.185
        BogoMIPS:              6400.53
        Virtualization:        VT-x
        Hypervisor vendor:     KVM
        Virtualization type:   full
        L1d cache:             32K
        L1i cache:             32K
        L2 cache:              4096K
        NUMA node0 CPU(s):     0-11
        ebizzy benchmark(./ebizzy -S 10 -n 512)
      
        Higher avg is better.
      
         vanilla-jemalloc             MADV_free-jemalloc
      
        1 thread
        records: 10                   records: 10
        avg:   2961.90                avg:  12069.70
        std:     71.96(2.43%)         std:    186.68(1.55%)
        max:   3070.00                max:  12385.00
        min:   2796.00                min:  11746.00
      
        2 thread
        records: 10                   records: 10
        avg:   5020.00                avg:  17827.00
        std:    264.87(5.28%)         std:    358.52(2.01%)
        max:   5244.00                max:  18760.00
        min:   4251.00                min:  17382.00
      
        4 thread
        records: 10                   records: 10
        avg:   8988.80                avg:  27930.80
        std:   1175.33(13.08%)        std:   3317.33(11.88%)
        max:   9508.00                max:  30879.00
        min:   5477.00                min:  21024.00
      
        8 thread
        records: 10                   records: 10
        avg:  13036.50                avg:  33739.40
        std:    170.67(1.31%)         std:   5146.22(15.25%)
        max:  13371.00                max:  40572.00
        min:  12785.00                min:  24088.00
      
        16 thread
        records: 10                   records: 10
        avg:  11092.40                avg:  31424.20
        std:    710.60(6.41%)         std:   3763.89(11.98%)
        max:  12446.00                max:  36635.00
        min:   9949.00                min:  25669.00
      
        32 thread
        records: 10                   records: 10
        avg:  11067.00                avg:  34495.80
        std:    971.06(8.77%)         std:   2721.36(7.89%)
        max:  12010.00                max:  38598.00
        min:   9002.00                min:  30636.00
      
      In summary, MADV_FREE is about much faster than MADV_DONTNEED.
      
      This patch (of 12):
      
      Add core MADV_FREE implementation.
      
      [akpm@linux-foundation.org: small cleanups]
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Acked-by: default avatarMichal Hocko <mhocko@suse.com>
      Acked-by: default avatarHugh Dickins <hughd@google.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Jason Evans <je@fb.com>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
      Cc: Shaohua Li <shli@kernel.org>
      Cc: <yalin.wang2010@gmail.com>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
      Cc: "Shaohua Li" <shli@kernel.org>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Chen Gang <gang.chen.5i5j@gmail.com>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: Darrick J. Wong <darrick.wong@oracle.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Roland Dreier <roland@kernel.org>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: Shaohua Li <shli@kernel.org>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Wu Fengguang <fengguang.wu@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      854e9ed0
    • Jerome Marchand's avatar
      zram: don't call idr_remove() from zram_remove() · 17ec4cd9
      Jerome Marchand authored
      The use of idr_remove() is forbidden in the callback functions of
      idr_for_each().  It is therefore unsafe to call idr_remove in
      zram_remove().
      
      This patch moves the call to idr_remove() from zram_remove() to
      hot_remove_store().  In the detroy_devices() path, idrs are removed by
      idr_destroy().  This solves an use-after-free detected by KASan.
      
      [akpm@linux-foundation.org: fix coding stype, per Sergey]
      Signed-off-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Acked-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: <stable@vger.kernel.org>	[4.2+]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      17ec4cd9
    • Vladimir Davydov's avatar
      mm: add page_check_address_transhuge() helper · 8749cfea
      Vladimir Davydov authored
      page_referenced_one() and page_idle_clear_pte_refs_one() duplicate the
      code for looking up pte of a (possibly transhuge) page.  Move this code
      to a new helper function, page_check_address_transhuge(), and make the
      above mentioned functions use it.
      
      This is just a cleanup, no functional changes are intended.
      Signed-off-by: default avatarVladimir Davydov <vdavydov@virtuozzo.com>
      Reviewed-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8749cfea
    • Kirill A. Shutemov's avatar
      thp: increase split_huge_page() success rate · d9654322
      Kirill A. Shutemov authored
      During freeze_page(), we remove the page from rmap.  It munlocks the
      page if it was mlocked.  clear_page_mlock() uses thelru cache, which
      temporary pins the page.
      
      Let's drain the lru cache before checking page's count vs.  mapcount.
      The change makes mlocked page split on first attempt, if it was not
      pinned by somebody else.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d9654322
    • Kirill A. Shutemov's avatar
      thp: add debugfs handle to split all huge pages · 49071d43
      Kirill A. Shutemov authored
      Writing 1 into 'split_huge_pages' will try to find and split all huge
      pages in the system.  This is useful for debuging.
      
      [akpm@linux-foundation.org: fix printk text, per Vlastimil]
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      49071d43
    • Kirill A. Shutemov's avatar
      mm: prepare page_referenced() and page_idle to new THP refcounting · b20ce5e0
      Kirill A. Shutemov authored
      Both page_referenced() and page_idle_clear_pte_refs_one() assume that
      THP can only be mapped with PMD, so there's no reason to look on PTEs
      for PageTransHuge() pages.  That's no true anymore: THP can be mapped
      with PTEs too.
      
      The patch removes PageTransHuge() test from the functions and opencode
      page table check.
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Vladimir Davydov <vdavydov@parallels.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Minchan Kim <minchan@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b20ce5e0
    • Kirill A. Shutemov's avatar
      thp: allow mlocked THP again · e90309c9
      Kirill A. Shutemov authored
      Before THP refcounting rework, THP was not allowed to cross VMA
      boundary.  So, if we have THP and we split it, PG_mlocked can be safely
      transferred to small pages.
      
      With new THP refcounting and naive approach to mlocking we can end up
      with this scenario:
       1. we have a mlocked THP, which belong to one VM_LOCKED VMA.
       2. the process does munlock() on the *part* of the THP:
            - the VMA is split into two, one of them VM_LOCKED;
            - huge PMD split into PTE table;
            - THP is still mlocked;
       3. split_huge_page():
            - it transfers PG_mlocked to *all* small pages regrardless if it
      	blong to any VM_LOCKED VMA.
      
      We probably could munlock() all small pages on split_huge_page(), but I
      think we have accounting issue already on step two.
      
      Instead of forbidding mlocked pages altogether, we just avoid mlocking
      PTE-mapped THPs and munlock THPs on split_huge_pmd().
      
      This means PTE-mapped THPs will be on normal lru lists and will be split
      under memory pressure by vmscan.  After the split vmscan will detect
      unevictable small pages and mlock them.
      
      With this approach we shouldn't hit situation like described above.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Jerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e90309c9
    • Kirill A. Shutemov's avatar
      thp: update documentation · a46e6376
      Kirill A. Shutemov authored
      The patch updates Documentation/vm/transhuge.txt to reflect changes in
      THP design.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a46e6376
    • Kirill A. Shutemov's avatar
      mm: re-enable THP · 61f5d698
      Kirill A. Shutemov authored
      All parts of THP with new refcounting are now in place.  We can now
      allow to enable THP.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      61f5d698
    • Kirill A. Shutemov's avatar
      thp: introduce deferred_split_huge_page() · 9a982250
      Kirill A. Shutemov authored
      Currently we don't split huge page on partial unmap.  It's not an ideal
      situation.  It can lead to memory overhead.
      
      Furtunately, we can detect partial unmap on page_remove_rmap().  But we
      cannot call split_huge_page() from there due to locking context.
      
      It's also counterproductive to do directly from munmap() codepath: in
      many cases we will hit this from exit(2) and splitting the huge page
      just to free it up in small pages is not what we really want.
      
      The patch introduce deferred_split_huge_page() which put the huge page
      into queue for splitting.  The splitting itself will happen when we get
      memory pressure via shrinker interface.  The page will be dropped from
      list on freeing through compound page destructor.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9a982250
    • Kirill A. Shutemov's avatar
      migrate_pages: try to split pages on queuing · 248db92d
      Kirill A. Shutemov authored
      We are not able to migrate THPs.  It means it's not enough to split only
      PMD on migration -- we need to split compound page under it too.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      248db92d
    • Kirill A. Shutemov's avatar
      thp: reintroduce split_huge_page() · e9b61f19
      Kirill A. Shutemov authored
      This patch adds implementation of split_huge_page() for new
      refcountings.
      
      Unlike previous implementation, new split_huge_page() can fail if
      somebody holds GUP pin on the page.  It also means that pin on page
      would prevent it from bening split under you.  It makes situation in
      many places much cleaner.
      
      The basic scheme of split_huge_page():
      
        - Check that sum of mapcounts of all subpage is equal to page_count()
          plus one (caller pin). Foll off with -EBUSY. This way we can avoid
          useless PMD-splits.
      
        - Freeze the page counters by splitting all PMD and setup migration
          PTEs.
      
        - Re-check sum of mapcounts against page_count(). Page's counts are
          stable now. -EBUSY if page is pinned.
      
        - Split compound page.
      
        - Unfreeze the page by removing migration entries.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e9b61f19
    • Naoya Horiguchi's avatar
      mm: hwpoison: adjust for new thp refcounting · 4e41a30c
      Naoya Horiguchi authored
      Some mm-related BUG_ON()s could trigger from hwpoison code due to recent
      changes in thp refcounting rule.  This patch fixes them up.
      
      In the new refcounting, we no longer use tail->_mapcount to keep tail's
      refcount, and thereby we can simplify get/put_hwpoison_page().
      
      And another change is that tail's refcount is not transferred to the raw
      page during thp split (more precisely, in new rule we don't take
      refcount on tail page any more.) So when we need thp split, we have to
      transfer the refcount properly to the 4kB soft-offlined page before
      migration.
      
      thp split code goes into core code only when precheck
      (total_mapcount(head) == page_count(head) - 1) passes to avoid useless
      split, where we assume that one refcount is held by the caller of thp
      split and the others are taken via mapping.  To meet this assumption,
      this patch moves thp split part in soft_offline_page() after
      get_any_page().
      
      [akpm@linux-foundation.org: remove unneeded #define, per Kirill]
      Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Acked-by: default avatarKirill A.  Shutemov <kirill.shutemov@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4e41a30c
    • Naoya Horiguchi's avatar
      mm: soft-offline: check return value in second __get_any_page() call · d96b339f
      Naoya Horiguchi authored
      I saw the following BUG_ON triggered in a testcase where a process calls
      madvise(MADV_SOFT_OFFLINE) on thps, along with a background process that
      calls migratepages command repeatedly (doing ping-pong among different
      NUMA nodes) for the first process:
      
         Soft offlining page 0x60000 at 0x700000600000
         __get_any_page: 0x60000 free buddy page
         page:ffffea0001800000 count:0 mapcount:-127 mapping:          (null) index:0x1
         flags: 0x1fffc0000000000()
         page dumped because: VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0)
         ------------[ cut here ]------------
         kernel BUG at /src/linux-dev/include/linux/mm.h:342!
         invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
         Modules linked in: cfg80211 rfkill crc32c_intel serio_raw virtio_balloon i2c_piix4 virtio_blk virtio_net ata_generic pata_acpi
         CPU: 3 PID: 3035 Comm: test_alloc_gene Tainted: G           O    4.4.0-rc8-v4.4-rc8-160107-1501-00000-rc8+ #74
         Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
         task: ffff88007c63d5c0 ti: ffff88007c210000 task.ti: ffff88007c210000
         RIP: 0010:[<ffffffff8118998c>]  [<ffffffff8118998c>] put_page+0x5c/0x60
         RSP: 0018:ffff88007c213e00  EFLAGS: 00010246
         Call Trace:
           put_hwpoison_page+0x4e/0x80
           soft_offline_page+0x501/0x520
           SyS_madvise+0x6bc/0x6f0
           entry_SYSCALL_64_fastpath+0x12/0x6a
         Code: 8b fc ff ff 5b 5d c3 48 89 df e8 b0 fa ff ff 48 89 df 31 f6 e8 c6 7d ff ff 5b 5d c3 48 c7 c6 08 54 a2 81 48 89 df e8 a4 c5 01 00 <0f> 0b 66 90 66 66 66 66 90 55 48 89 e5 41 55 41 54 53 48 8b 47
         RIP  [<ffffffff8118998c>] put_page+0x5c/0x60
          RSP <ffff88007c213e00>
      
      The root cause resides in get_any_page() which retries to get a refcount
      of the page to be soft-offlined.  This function calls
      put_hwpoison_page(), expecting that the target page is putback to LRU
      list.  But it can be also freed to buddy.  So the second check need to
      care about such case.
      
      Fixes: af8fae7c ("mm/memory-failure.c: clean up soft_offline_page()")
      Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Jerome Marchand <jmarchan@redhat.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: <stable@vger.kernel.org>	[3.9+]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d96b339f
    • Kirill A. Shutemov's avatar
      thp, mm: split_huge_page(): caller need to lock page · 4d2fa965
      Kirill A. Shutemov authored
      We're going to use migration entries instead of compound_lock() to
      stabilize page refcounts.  Setup and remove migration entries require
      page to be locked.
      
      Some of split_huge_page() callers already have the page locked.  Let's
      require everybody to lock the page before calling split_huge_page().
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4d2fa965
    • Kirill A. Shutemov's avatar
      thp: add option to setup migration entries during PMD split · ba988280
      Kirill A. Shutemov authored
      We are going to use migration PTE entries to stabilize page counts.  If
      the page is mapped with PMDs we need to split the PMD and setup
      migration entries.  It's reasonable to combine these operations to avoid
      double-scanning over the page table.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ba988280
    • Kirill A. Shutemov's avatar
      thp: implement split_huge_pmd() · eef1b3ba
      Kirill A. Shutemov authored
      Original split_huge_page() combined two operations: splitting PMDs into
      tables of PTEs and splitting underlying compound page.  This patch
      implements split_huge_pmd() which split given PMD without splitting
      other PMDs this page mapped with or underlying compound page.
      
      Without tail page refcounting, implementation of split_huge_pmd() is
      pretty straight-forward.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      eef1b3ba
    • Kirill A. Shutemov's avatar
      mm, numa: skip PTE-mapped THP on numa fault · e81c4802
      Kirill A. Shutemov authored
      We're going to have THP mapped with PTEs.  It will confuse
      numabalancing.  Let's skip them for now.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e81c4802
    • Kirill A. Shutemov's avatar
      mm: differentiate page_mapped() from page_mapcount() for compound pages · e1534ae9
      Kirill A. Shutemov authored
      Let's define page_mapped() to be true for compound pages if any
      sub-pages of the compound page is mapped (with PMD or PTE).
      
      On other hand page_mapcount() return mapcount for this particular small
      page.
      
      This will make cases like page_get_anon_vma() behave correctly once we
      allow huge pages to be mapped with PTE.
      
      Most users outside core-mm should use page_mapcount() instead of
      page_mapped().
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e1534ae9
    • Kirill A. Shutemov's avatar
      mm: rework mapcount accounting to enable 4k mapping of THPs · 53f9263b
      Kirill A. Shutemov authored
      We're going to allow mapping of individual 4k pages of THP compound.  It
      means we need to track mapcount on per small page basis.
      
      Straight-forward approach is to use ->_mapcount in all subpages to track
      how many time this subpage is mapped with PMDs or PTEs combined.  But
      this is rather expensive: mapping or unmapping of a THP page with PMD
      would require HPAGE_PMD_NR atomic operations instead of single we have
      now.
      
      The idea is to store separately how many times the page was mapped as
      whole -- compound_mapcount.  This frees up ->_mapcount in subpages to
      track PTE mapcount.
      
      We use the same approach as with compound page destructor and compound
      order to store compound_mapcount: use space in first tail page,
      ->mapping this time.
      
      Any time we map/unmap whole compound page (THP or hugetlb) -- we
      increment/decrement compound_mapcount.  When we map part of compound
      page with PTE we operate on ->_mapcount of the subpage.
      
      page_mapcount() counts both: PTE and PMD mappings of the page.
      
      Basically, we have mapcount for a subpage spread over two counters.  It
      makes tricky to detect when last mapcount for a page goes away.
      
      We introduced PageDoubleMap() for this.  When we split THP PMD for the
      first time and there's other PMD mapping left we offset up ->_mapcount
      in all subpages by one and set PG_double_map on the compound page.
      These additional references go away with last compound_mapcount.
      
      This approach provides a way to detect when last mapcount goes away on
      per small page basis without introducing new overhead for most common
      cases.
      
      [akpm@linux-foundation.org: fix typo in comment]
      [mhocko@suse.com: ignore partial THP when moving task]
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Jerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      53f9263b
    • Kirill A. Shutemov's avatar
      mm, thp: remove infrastructure for handling splitting PMDs · 4b471e88
      Kirill A. Shutemov authored
      With new refcounting we don't need to mark PMDs splitting.  Let's drop
      code to handle this.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4b471e88
    • Kirill A. Shutemov's avatar
      x86, thp: remove infrastructure for handling splitting PMDs · 1f19617d
      Kirill A. Shutemov authored
      With new refcounting we don't need to mark PMDs splitting.  Let's drop
      code to handle this.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1f19617d
    • Kirill A. Shutemov's avatar
      tile, thp: remove infrastructure for handling splitting PMDs · 702b63ca
      Kirill A. Shutemov authored
      With new refcounting we don't need to mark PMDs splitting.  Let's drop
      code to handle this.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Jerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      702b63ca
    • Kirill A. Shutemov's avatar
      sparc, thp: remove infrastructure for handling splitting PMDs · 99f1bc01
      Kirill A. Shutemov authored
      With new refcounting we don't need to mark PMDs splitting.  Let's drop
      code to handle this.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Jerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      99f1bc01
    • Kirill A. Shutemov's avatar
      s390, thp: remove infrastructure for handling splitting PMDs · fecffad2
      Kirill A. Shutemov authored
      With new refcounting we don't need to mark PMDs splitting.  Let's drop
      code to handle this.
      
      pmdp_splitting_flush() is not needed too: on splitting PMD we will do
      pmdp_clear_flush() + set_pte_at().  pmdp_clear_flush() will do IPI as
      needed for fast_gup.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Jerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fecffad2
    • Kirill A. Shutemov's avatar
      powerpc, thp: remove infrastructure for handling splitting PMDs · 7aa9a23c
      Kirill A. Shutemov authored
      With new refcounting we don't need to mark PMDs splitting.  Let's drop
      code to handle this.
      
      pmdp_splitting_flush() is not needed too: on splitting PMD we will do
      pmdp_clear_flush() + set_pte_at().  pmdp_clear_flush() will do IPI as
      needed for fast_gup.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Reviewed-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Jerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7aa9a23c
    • Kirill A. Shutemov's avatar
      mips, thp: remove infrastructure for handling splitting PMDs · b2787370
      Kirill A. Shutemov authored
      With new refcounting we don't need to mark PMDs splitting.  Let's drop
      code to handle this.
      
      pmdp_splitting_flush() is not needed too: on splitting PMD we will do
      pmdp_clear_flush() + set_pte_at().  pmdp_clear_flush() will do IPI as
      needed for fast_gup.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Jerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b2787370
    • Kirill A. Shutemov's avatar
      arm, thp: remove infrastructure for handling splitting PMDs · 0ebd7446
      Kirill A. Shutemov authored
      With new refcounting we don't need to mark PMDs splitting.  Let's drop
      code to handle this.
      
      pmdp_splitting_flush() is not needed too: on splitting PMD we will do
      pmdp_clear_flush() + set_pte_at().  pmdp_clear_flush() will do IPI as
      needed for fast_gup.
      
      [arnd@arndb.de: fix unterminated ifdef in header file]
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Jerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0ebd7446
    • Kirill A. Shutemov's avatar
      arm64, thp: remove infrastructure for handling splitting PMDs · b7ed934a
      Kirill A. Shutemov authored
      With new refcounting we don't need to mark PMDs splitting.  Let's drop
      code to handle this.
      
      pmdp_splitting_flush() is not needed too: on splitting PMD we will do
      pmdp_clear_flush() + set_pte_at().  pmdp_clear_flush() will do IPI as
      needed for fast_gup.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Jerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b7ed934a
    • Kirill A. Shutemov's avatar
      mm, thp: remove compound_lock() · 3ac808fd
      Kirill A. Shutemov authored
      We are going to use migration entries to stabilize page counts.  It
      means we don't need compound_lock() for that.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3ac808fd
    • Kirill A. Shutemov's avatar
      ksm: prepare to new THP semantics · f765f540
      Kirill A. Shutemov authored
      We don't need special code to stabilize THP.  If you've got reference to
      any subpage of THP it will not be split under you.
      
      New split_huge_page() also accepts tail pages: no need in special code
      to get reference to head page.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f765f540
    • Kirill A. Shutemov's avatar
      futex, thp: remove special case for THP in get_futex_key · 14d27abd
      Kirill A. Shutemov authored
      With new THP refcounting, we don't need tricks to stabilize huge page.
      If we've got reference to tail page, it can't split under us.
      
      This patch effectively reverts a5b338f2 ("thp: update futex compound
      knowledge").
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Tested-by: default avatarArtem Savkov <artem.savkov@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      14d27abd
    • Kirill A. Shutemov's avatar
      mm: drop tail page refcounting · ddc58f27
      Kirill A. Shutemov authored
      Tail page refcounting is utterly complicated and painful to support.
      
      It uses ->_mapcount on tail pages to store how many times this page is
      pinned.  get_page() bumps ->_mapcount on tail page in addition to
      ->_count on head.  This information is required by split_huge_page() to
      be able to distribute pins from head of compound page to tails during
      the split.
      
      We will need ->_mapcount to account PTE mappings of subpages of the
      compound page.  We eliminate need in current meaning of ->_mapcount in
      tail pages by forbidding split entirely if the page is pinned.
      
      The only user of tail page refcounting is THP which is marked BROKEN for
      now.
      
      Let's drop all this mess.  It makes get_page() and put_page() much
      simpler.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ddc58f27
    • Kirill A. Shutemov's avatar
      thp: drop all split_huge_page()-related code · ad0bed24
      Kirill A. Shutemov authored
      We will re-introduce new version with new refcounting later in patchset.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ad0bed24
    • Kirill A. Shutemov's avatar
      mm: temporarily mark THP broken · 56a17b88
      Kirill A. Shutemov authored
      Up to this point we tried to keep patchset bisectable, but next patches
      are going to change how core of THP refcounting work.
      
      It would be beneficial to split the change into several patches and make
      it more reviewable.  Unfortunately, I don't see how we can achieve that
      while keeping THP working.
      
      Let's hide THP under CONFIG_BROKEN for now and bring it back when new
      refcounting get established.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      56a17b88
    • Kirill A. Shutemov's avatar
      mm, vmstats: new THP splitting event · 122afea9
      Kirill A. Shutemov authored
      The patch replaces THP_SPLIT with tree events: THP_SPLIT_PAGE,
      THP_SPLIT_PAGE_FAILED and THP_SPLIT_PMD.  It reflects the fact that we
      are going to be able split PMD without the compound page and that
      split_huge_page() can fail.
      Signed-off-by: default avatarKirill A.  Shutemov <kirill.shutemov@linux.intel.com>
      Acked-by: default avatarChristoph Lameter <cl@linux.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      122afea9
    • Kirill A. Shutemov's avatar
      thp: rename split_huge_page_pmd() to split_huge_pmd() · 78ddc534
      Kirill A. Shutemov authored
      We are going to decouple splitting THP PMD from splitting underlying
      compound page.
      
      This patch renames split_huge_page_pmd*() functions to split_huge_pmd*()
      to reflect the fact that it doesn't imply page splitting, only PMD.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      78ddc534
    • Kirill A. Shutemov's avatar
      khugepaged: ignore pmd tables with THP mapped with ptes · b1caa957
      Kirill A. Shutemov authored
      Prepare khugepaged to see compound pages mapped with pte.  For now we
      won't collapse the pmd table with such pte.
      
      khugepaged is subject for future rework wrt new refcounting.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b1caa957
    • Kirill A. Shutemov's avatar
      thp, mlock: do not allow huge pages in mlocked area · 7479df6d
      Kirill A. Shutemov authored
      With new refcounting THP can belong to several VMAs.  This makes tricky
      to track THP pages, when they partially mlocked.  It can lead to leaking
      mlocked pages to non-VM_LOCKED vmas and other problems.
      
      With this patch we will split all pages on mlock and avoid
      fault-in/collapse new THP in VM_LOCKED vmas.
      
      I've tried alternative approach: do not mark THP pages mlocked and keep
      them on normal LRUs.  This way vmscan could try to split huge pages on
      memory pressure and free up subpages which doesn't belong to VM_LOCKED
      vmas.  But this is user-visible change: we screw up Mlocked accouting
      reported in meminfo, so I had to leave this approach aside.
      
      We can bring something better later, but this should be good enough for
      now.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Tested-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarJerome Marchand <jmarchan@redhat.com>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
      Cc: Steve Capper <steve.capper@linaro.org>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Michal Hocko <mhocko@suse.cz>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7479df6d