1. 16 Jan, 2016 40 commits
    • Dan Williams's avatar
      mm: skip memory block registration for ZONE_DEVICE · 260ae3f7
      Dan Williams authored
      
      
      Prevent userspace from trying and failing to online ZONE_DEVICE pages
      which are meant to never be onlined.
      
      For example on platforms with a udev rule like the following:
      
        SUBSYSTEM=="memory", ACTION=="add", ATTR{state}=="offline", ATTR{state}="online"
      
      ...will generate futile attempts to online the ZONE_DEVICE sections.
      Example kernel messages:
      
          Built 1 zonelists in Node order, mobility grouping on.  Total pages: 1004747
          Policy zone: Normal
          online_pages [mem 0x248000000-0x24fffffff] failed
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      260ae3f7
    • Dan Williams's avatar
      mm, dax, pmem: introduce pfn_t · 34c0fd54
      Dan Williams authored
      
      
      For the purpose of communicating the optional presence of a 'struct
      page' for the pfn returned from ->direct_access(), introduce a type that
      encapsulates a page-frame-number plus flags.  These flags contain the
      historical "page_link" encoding for a scatterlist entry, but can also
      denote "device memory".  Where "device memory" is a set of pfns that are
      not part of the kernel's linear mapping by default, but are accessed via
      the same memory controller as ram.
      
      The motivation for this new type is large capacity persistent memory
      that needs struct page entries in the 'memmap' to support 3rd party DMA
      (i.e.  O_DIRECT I/O with a persistent memory source/target).  However,
      we also need it in support of maintaining a list of mapped inodes which
      need to be unmapped at driver teardown or freeze_bdev() time.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Dave Hansen <dave@sr71.net>
      Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      34c0fd54
    • Dan Williams's avatar
      kvm: rename pfn_t to kvm_pfn_t · ba049e93
      Dan Williams authored
      To date, we have implemented two I/O usage models for persistent memory,
      PMEM (a persistent "ram disk") and DAX (mmap persistent memory into
      userspace).  This series adds a third, DAX-GUP, that allows DAX mappings
      to be the target of direct-i/o.  It allows userspace to coordinate
      DMA/RDMA from/to persistent memory.
      
      The implementation leverages the ZONE_DEVICE mm-zone that went into
      4.3-rc1 (also discussed at kernel summit) to flag pages that are owned
      and dynamically mapped by a device driver.  The pmem driver, after
      mapping a persistent memory range into the system memmap via
      devm_memremap_pages(), arranges for DAX to distinguish pfn-only versus
      page-backed pmem-pfns via flags in the new pfn_t type.
      
      The DAX code, upon seeing a PFN_DEV+PFN_MAP flagged pfn, flags the
      resulting pte(s) inserted into the process page tables with a new
      _PAGE_DEVMAP flag.  Later, when get_user_pages() is walking ptes it keys
      off _PAGE_DEVMAP to pin the device hosting the page range active.
      Finally, get_page() and put_page() are modified to take references
      against the device driver established page mapping.
      
      Finally, this need for "struct page" for persistent memory requires
      memory capacity to store the memmap array.  Given the memmap array for a
      large pool of persistent may exhaust available DRAM introduce a
      mechanism to allocate the memmap from persistent memory.  The new
      "struct vmem_altmap *" parameter to devm_memremap_pages() enables
      arch_add_memory() to use reserved pmem capacity rather than the page
      allocator.
      
      This patch (of 18):
      
      The core has developed a need for a "pfn_t" type [1].  Move the existing
      pfn_t in KVM to kvm_pfn_t [2].
      
      [1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002199.html
      [2]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002218.html
      
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Acked-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ba049e93
    • Dan Williams's avatar
      um: kill pfn_t · 16da3068
      Dan Williams authored
      The core has developed a need for a "pfn_t" type [1].  Convert the usage
      of pfn_t by usermode-linux to an unsigned long, and update pfn_to_phys()
      to drop its expectation of a typed pfn.
      
      [1]: https://lists.01.org/pipermail/linux-nvdimm/2015-September/002199.html
      
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Jeff Dike <jdike@addtoit.com>
      Cc: Richard Weinberger <richard@nod.at>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      16da3068
    • Toshi Kani's avatar
      dax: Split pmd map when fallback on COW · 59bf4fb9
      Toshi Kani authored
      
      
      An infinite loop of PMD faults was observed when attempted to mlock() a
      private read-only PMD mmap'd range of a DAX file.
      
      __dax_pmd_fault() simply returns with VM_FAULT_FALLBACK when falling
      back to PTE on COW.  However, __handle_mm_fault() returns without
      falling back to handle_pte_fault() because a PMD map is present in this
      case.
      
      Change __dax_pmd_fault() to split the PMD map, if present, before
      returning with VM_FAULT_FALLBACK.
      Signed-off-by: default avatarToshi Kani <toshi.kani@hpe.com>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Matthew Wilcox <willy@linux.intel.com>
      Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      59bf4fb9
    • Ross Zwisler's avatar
      mm, dax: fix livelock, allow dax pmd mappings to become writeable · 01871e59
      Ross Zwisler authored
      
      
      Prior to this change DAX PMD mappings that were made read-only were
      never able to be made writable again.  This is because the code in
      insert_pfn_pmd() that calls pmd_mkdirty() and pmd_mkwrite() would skip
      these calls if the PMD already existed in the page table.
      
      Instead, if we are doing a write always mark the PMD entry as dirty and
      writeable.  Without this code we can get into a condition where we mark
      the PMD as read-only, and then on a subsequent write fault we get into
      an infinite loop of PMD faults where we try unsuccessfully to make the
      PMD writeable.
      Signed-off-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Reported-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Reported-by: default avatarToshi Kani <toshi.kani@hpe.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      01871e59
    • Dan Williams's avatar
      dax: fix lifetime of in-kernel dax mappings with dax_map_atomic() · b2e0d162
      Dan Williams authored
      
      
      The DAX implementation needs to protect new calls to ->direct_access()
      and usage of its return value against the driver for the underlying
      block device being disabled.  Use blk_queue_enter()/blk_queue_exit() to
      hold off blk_cleanup_queue() from proceeding, or otherwise fail new
      mapping requests if the request_queue is being torn down.
      
      This also introduces blk_dax_ctl to simplify the interface from fs/dax.c
      through dax_map_atomic() to bdev_direct_access().
      
      [willy@linux.intel.com: fix read() of a hole]
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Reviewed-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Cc: Jan Kara <jack@suse.com>
      Cc: Jens Axboe <axboe@fb.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
      Cc: Matthew Wilcox <willy@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b2e0d162
    • Dan Williams's avatar
      dax: guarantee page aligned results from bdev_direct_access() · fe683ada
      Dan Williams authored
      
      
      If a ->direct_access() implementation ever returns a map count less than
      PAGE_SIZE, catch the error in bdev_direct_access().  This simplifies
      error checking in upper layers.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Reported-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fe683ada
    • Dan Williams's avatar
      dax: increase granularity of dax_clear_blocks() operations · 0e749e54
      Dan Williams authored
      
      
      dax_clear_blocks is currently performing a cond_resched() after every
      PAGE_SIZE memset.  We need not check so frequently, for example md-raid
      only calls cond_resched() at stripe granularity.  Also, in preparation
      for introducing a dax_map_atomic() operation that temporarily pins a dax
      mapping move the call to cond_resched() to the outer loop.
      
      The worst case latency between calls to cond_resched() after this change
      is 500us the average latency is 133us.  This is up from a 10us max and
      4us average.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Reviewed-by: default avatarJan Kara <jack@suse.com>
      Reviewed-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0e749e54
    • Dan Williams's avatar
      pmem, dax: clean up clear_pmem() · 52db400f
      Dan Williams authored
      
      
      To date, we have implemented two I/O usage models for persistent memory,
      PMEM (a persistent "ram disk") and DAX (mmap persistent memory into
      userspace).  This series adds a third, DAX-GUP, that allows DAX mappings
      to be the target of direct-i/o.  It allows userspace to coordinate
      DMA/RDMA from/to persistent memory.
      
      The implementation leverages the ZONE_DEVICE mm-zone that went into
      4.3-rc1 (also discussed at kernel summit) to flag pages that are owned
      and dynamically mapped by a device driver.  The pmem driver, after
      mapping a persistent memory range into the system memmap via
      devm_memremap_pages(), arranges for DAX to distinguish pfn-only versus
      page-backed pmem-pfns via flags in the new pfn_t type.
      
      The DAX code, upon seeing a PFN_DEV+PFN_MAP flagged pfn, flags the
      resulting pte(s) inserted into the process page tables with a new
      _PAGE_DEVMAP flag.  Later, when get_user_pages() is walking ptes it keys
      off _PAGE_DEVMAP to pin the device hosting the page range active.
      Finally, get_page() and put_page() are modified to take references
      against the device driver established page mapping.
      
      Finally, this need for "struct page" for persistent memory requires
      memory capacity to store the memmap array.  Given the memmap array for a
      large pool of persistent may exhaust available DRAM introduce a
      mechanism to allocate the memmap from persistent memory.  The new
      "struct vmem_altmap *" parameter to devm_memremap_pages() enables
      arch_add_memory() to use reserved pmem capacity rather than the page
      allocator.
      
      This patch (of 25):
      
      Both __dax_pmd_fault, and clear_pmem() were taking special steps to
      clear memory a page at a time to take advantage of non-temporal
      clear_page() implementations.  However, x86_64 does not use non-temporal
      instructions for clear_page(), and arch_clear_pmem() was always
      incurring the cost of __arch_wb_cache_pmem().
      
      Clean up the assumption that doing clear_pmem() a page at a time is more
      performant.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Reported-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
      Reviewed-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
      Reviewed-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Christoffer Dall <christoffer.dall@linaro.org>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: David Airlie <airlied@linux.ie>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Jan Kara <jack@suse.com>
      Cc: Jeff Dike <jdike@addtoit.com>
      Cc: Jens Axboe <axboe@fb.com>
      Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Logan Gunthorpe <logang@deltatee.com>
      Cc: Matthew Wilcox <willy@linux.intel.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Richard Weinberger <richard@nod.at>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Toshi Kani <toshi.kani@hpe.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      52db400f
    • Kirill A. Shutemov's avatar
      thp: fix split_huge_page() after mremap() of THP · bd56086f
      Kirill A. Shutemov authored
      Sasha Levin has reported KASAN out-of-bounds bug[1].  It points to "if
      (!is_swap_pte(pte[i]))" in unfreeze_page_vma() as a problematic access.
      
      The cause is that split_huge_page() doesn't handle THP correctly if it's
      not allingned to PMD boundary.  It can happen after mremap().
      
      Test-case (not always triggers the bug):
      
      	#define _GNU_SOURCE
      	#include <stdio.h>
      	#include <stdlib.h>
      	#include <sys/mman.h>
      
      	#define MB (1024UL*1024)
      	#define SIZE (2*MB)
      	#define BASE ((void *)0x400000000000)
      
      	int main()
      	{
      		char *p;
      
      		p = mmap(BASE, SIZE, PROT_READ | PROT_WRITE,
      				MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE,
      				-1, 0);
      		if (p == MAP_FAILED)
      			perror("mmap"), exit(1);
      		p = mremap(BASE, SIZE, SIZE, MREMAP_FIXED | MREMAP_MAYMOVE,
      				BASE + SIZE + 8192);
      		if (p == MAP_FAILED)
      			perror("mremap"), exit(1);
      		system("echo 1 > /sys/kernel/debug/split_huge_pages");
      		return 0;
      	}
      
      The patch fixes freeze and unfreeze paths to handle page table boundary
      crossing.
      
      It also makes mapcount vs count check in split_huge_page_to_list()
      stricter:
       - after freeze we don't expect any subpage mapped as we remove them
         from rmap when setting up migration entries;
       - count must be 1, meaning only caller has reference to the page;
      
      [1] https://gist.github.com/sashalevin/c67fbea55e7c0576972a
      
      Signed-off-by: default avatarKirill A.  Shutemov <kirill.shutemov@linux.intel.com>
      Reported-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bd56086f
    • Minchan Kim's avatar
      mm/huge_memory.c: don't split THP page when MADV_FREE syscall is called · b8d3c4c3
      Minchan Kim authored
      
      
      We don't need to split THP page when MADV_FREE syscall is called if
      [start, len] is aligned with THP size.  The split could be done when VM
      decide to free it in reclaim path if memory pressure is heavy.  With
      that, we could avoid unnecessary THP split.
      
      For the feature, this patch changes pte dirtness marking logic of THP.
      Now, it marks every ptes of pages dirty unconditionally in splitting,
      which makes MADV_FREE void.  So, instead, this patch propagates pmd
      dirtiness to all pages via PG_dirty and restores pte dirtiness from
      PG_dirty.  With this, if pmd is clean(ie, MADV_FREEed) when split
      happens(e,g, shrink_page_list), all of pages are clean too so we could
      discard them.
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Kirill A. Shutemov <kirill@shutemov.name>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      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: 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: Daniel Micay <danielmicay@gmail.com>
      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: Jason Evans <je@fb.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Henderson <rth@twiddle.net>
      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>
      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>
      b8d3c4c3
    • Minchan Kim's avatar
      arch/arm64/include/asm/pgtable.h: add pmd_mkclean for THP · 05ee26d9
      Minchan Kim authored
      
      
      MADV_FREE needs pmd_dirty and pmd_mkclean for detecting recent overwrite
      of the contents since MADV_FREE syscall is called for THP page.
      
      This patch adds pmd_mkclean for THP page MADV_FREE support.
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      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: Chris Zankel <chris@zankel.net>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: Darrick J. Wong <darrick.wong@oracle.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      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: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Henderson <rth@twiddle.net>
      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>
      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>
      05ee26d9
    • Minchan Kim's avatar
      arch/arm/include/asm/pgtable-3level.h: add pmd_mkclean for THP · 44842045
      Minchan Kim authored
      
      
      MADV_FREE needs pmd_dirty and pmd_mkclean for detecting recent overwrite
      of the contents since MADV_FREE syscall is called for THP page.
      
      This patch adds pmd_mkclean for THP page MADV_FREE support.
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will.deacon@arm.com>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      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: Chen Gang <gang.chen.5i5j@gmail.com>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: Darrick J. Wong <darrick.wong@oracle.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      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: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Roland Dreier <roland@kernel.org>
      Cc: Shaohua Li <shli@kernel.org>
      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>
      44842045
    • Minchan Kim's avatar
      arch/powerpc/include/asm/pgtable-ppc64.h: add pmd_[dirty|mkclean] for THP · d5d6a443
      Minchan Kim authored
      
      
      MADV_FREE needs pmd_dirty and pmd_mkclean for detecting recent overwrite
      of the contents since MADV_FREE syscall is called for THP page.
      
      This patch adds pmd_dirty and pmd_mkclean for THP page MADV_FREE
      support.
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      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: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Chen Gang <gang.chen.5i5j@gmail.com>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: Darrick J. Wong <darrick.wong@oracle.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      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: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Henderson <rth@twiddle.net>
      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>
      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>
      d5d6a443
    • Minchan Kim's avatar
      arch/sparc/include/asm/pgtable_64.h: add pmd_[dirty|mkclean] for THP · 79cedb8f
      Minchan Kim authored
      
      
      MADV_FREE needs pmd_dirty and pmd_mkclean for detecting recent overwrite
      of the contents since MADV_FREE syscall is called for THP page.
      
      This patch adds pmd_dirty and pmd_mkclean for THP page MADV_FREE
      support.
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      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: Chris Zankel <chris@zankel.net>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: Darrick J. Wong <darrick.wong@oracle.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      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: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Henderson <rth@twiddle.net>
      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>
      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>
      79cedb8f
    • Minchan Kim's avatar
      arch/x86/include/asm/pgtable.h: add pmd_[dirty|mkclean] for THP · 590a471c
      Minchan Kim authored
      
      
      MADV_FREE needs pmd_dirty and pmd_mkclean for detecting recent overwrite
      of the contents since MADV_FREE syscall is called for THP page.
      
      This patch adds pmd_dirty and pmd_mkclean for THP page MADV_FREE
      support.
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      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: Chris Zankel <chris@zankel.net>
      Cc: Daniel Micay <danielmicay@gmail.com>
      Cc: Darrick J. Wong <darrick.wong@oracle.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      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: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Henderson <rth@twiddle.net>
      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>
      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>
      590a471c
    • Minchan Kim's avatar
      mm/ksm.c: mark stable page dirty · 337ed7eb
      Minchan Kim authored
      
      
      The MADV_FREE patchset changes page reclaim to simply free a clean
      anonymous page with no dirty ptes, instead of swapping it out; but KSM
      uses clean write-protected ptes to reference the stable ksm page.  So be
      sure to mark that page dirty, so it's never mistakenly discarded.
      
      [hughd@google.com: adjusted comments]
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Acked-by: default avatarHugh Dickins <hughd@google.com>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      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: Chris Zankel <chris@zankel.net>
      Cc: Daniel Micay <danielmicay@gmail.com>
      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: 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: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Henderson <rth@twiddle.net>
      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>
      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>
      337ed7eb
    • Minchan Kim's avatar
      mm: move lazily freed pages to inactive list · 10853a03
      Minchan Kim authored
      
      
      MADV_FREE is a hint that it's okay to discard pages if there is memory
      pressure and we use reclaimers(ie, kswapd and direct reclaim) to free
      them so there is no value keeping them in the active anonymous LRU so
      this patch moves them to inactive LRU list's head.
      
      This means that MADV_FREE-ed pages which were living on the inactive
      list are reclaimed first because they are more likely to be cold rather
      than recently active pages.
      
      An arguable issue for the approach would be whether we should put the
      page to the head or tail of the inactive list.  I chose head because the
      kernel cannot make sure it's really cold or warm for every MADV_FREE
      usecase but at least we know it's not *hot*, so landing of inactive head
      would be a comprimise for various usecases.
      
      This fixes suboptimal behavior of MADV_FREE when pages living on the
      active list will sit there for a long time even under memory pressure
      while the inactive list is reclaimed heavily.  This basically breaks the
      whole purpose of using MADV_FREE to help the system to free memory which
      is might not be used.
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Acked-by: default avatarHugh Dickins <hughd@google.com>
      Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Shaohua Li <shli@kernel.org>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
      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: Chris Zankel <chris@zankel.net>
      Cc: Daniel Micay <danielmicay@gmail.com>
      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: Jason Evans <je@fb.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Kirill A. Shutemov <kirill@shutemov.name>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Mika Penttil <mika.penttila@nextfour.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: 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>
      10853a03
    • Minchan Kim's avatar
      mm/madvise.c: free swp_entry in madvise_free · 64b42bc1
      Minchan Kim authored
      
      
      When I test below piece of code with 12 processes(ie, 512M * 12 = 6G
      consume) on my (3G ram + 12 cpu + 8G swap, the madvise_free is
      siginficat slower (ie, 2x times) than madvise_dontneed.
      
           loop = 5;
           mmap(512M);
           while (loop--) {
                   memset(512M);
                   madvise(MADV_FREE or MADV_DONTNEED);
           }
      
      The reason is lots of swapin.
      
      1) dontneed: 1,612 swapin
      2) madvfree: 879,585 swapin
      
      If we find hinted pages were already swapped out when syscall is called,
      it's pointless to keep the swapped-out pages in pte.  Instead, let's
      free the cold page because swapin is more expensive than (alloc page +
      zeroing).
      
      With this patch, it reduced swapin from 879,585 to 1,878 so elapsed time
      
      1) dontneed: 6.10user 233.50system 0:50.44elapsed
      2) madvfree: 6.03user 401.17system 1:30.67elapsed
      2) madvfree + below patch: 6.70user 339.14system 1:04.45elapsed
      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: "James E.J. Bottomley" <jejb@parisc-linux.org>
      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: Chris Zankel <chris@zankel.net>
      Cc: Daniel Micay <danielmicay@gmail.com>
      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: 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: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Richard Henderson <rth@twiddle.net>
      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>
      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>
      64b42bc1
    • Chen Gang's avatar
      arch/*/include/uapi/asm/mman.h: : let MADV_FREE have same value for all architectures · 21f55b01
      Chen Gang authored
      
      
      For uapi, need try to let all macros have same value, and MADV_FREE is
      added into main branch recently, so need redefine MADV_FREE for it.
      
      At present, '8' can be shared with all architectures, so redefine it to
      '8'.
      
      [sudipm.mukherjee@gmail.com: correct uniform value of MADV_FREE]
      Signed-off-by: default avatarChen Gang <gang.chen.5i5j@gmail.com>
      Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
      Acked-by: default avatarHugh Dickins <hughd@google.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Matt Turner <mattst88@gmail.com>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: Max Filippov <jcmvbkbc@gmail.com>
      Cc: Roland Dreier <roland@kernel.org>
      Cc: Darrick J. Wong <darrick.wong@oracle.com>
      Cc: David S. Miller <davem@davemloft.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: Daniel Micay <danielmicay@gmail.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: Mel Gorman <mgorman@suse.de>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Mika Penttil <mika.penttila@nextfour.com>
      Cc: Rik van Riel <riel@redhat.com>
      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 avatarSudip Mukherjee <sudip@vectorindia.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      21f55b01
    • 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