1. 16 Jan, 2016 40 commits
    • Dan Williams's avatar
      dax: re-enable dax pmd mappings · c046c321
      Dan Williams authored
      
      
      Now that the get_user_pages() path knows how to handle dax-pmd mappings,
      remove the protections that disabled dax-pmd support.
      
      Tests available from github.com/pmem/ndctl:
      
          make TESTS="lib/test-dax.sh lib/test-mmap.sh" check
      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>
      c046c321
    • Dan Williams's avatar
      dax: provide diagnostics for pmd mapping failures · cbb38e41
      Dan Williams authored
      
      
      There is a wide gamut of conditions that can trigger the dax pmd path to
      fallback to pte mappings.  Ideally we'd have a syscall interface to
      determine mapping characteristics after the fact.  In the meantime
      provide debug messages.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Suggested-by: default avatarMatthew 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>
      cbb38e41
    • Dan Williams's avatar
      mm, x86: get_user_pages() for dax mappings · 3565fce3
      Dan Williams authored
      
      
      A dax mapping establishes a pte with _PAGE_DEVMAP set when the driver
      has established a devm_memremap_pages() mapping, i.e.  when the pfn_t
      return from ->direct_access() has PFN_DEV and PFN_MAP set.  Later, when
      encountering _PAGE_DEVMAP during a page table walk we lookup and pin a
      struct dev_pagemap instance to keep the result of pfn_to_page() valid
      until put_page().
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Tested-by: default avatarLogan Gunthorpe <logang@deltatee.com>
      Cc: Dave Hansen <dave@sr71.net>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3565fce3
    • Dan Williams's avatar
      mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd · 5c7fb56e
      Dan Williams authored
      
      
      A dax-huge-page mapping while it uses some thp helpers is ultimately not
      a transparent huge page.  The distinction is especially important in the
      get_user_pages() path.  pmd_devmap() is used to distinguish dax-pmds
      from pmd_huge() and pmd_trans_huge() which have slightly different
      semantics.
      
      Explicitly mark the pmd_trans_huge() helpers that dax needs by adding
      pmd_devmap() checks.
      
      [kirill.shutemov@linux.intel.com: fix regression in handling mlocked pages in  __split_huge_pmd()]
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: Dave Hansen <dave@sr71.net>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Matthew Wilcox <willy@linux.intel.com>
      Signed-off-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>
      5c7fb56e
    • Dan Williams's avatar
      mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gup · 5c2c2587
      Dan Williams authored
      
      
      get_dev_page() enables paths like get_user_pages() to pin a dynamically
      mapped pfn-range (devm_memremap_pages()) while the resulting struct page
      objects are in use.  Unlike get_page() it may fail if the device is, or
      is in the process of being, disabled.  While the initial lookup of the
      range may be an expensive list walk, the result is cached to speed up
      subsequent lookups which are likely to be in the same mapped range.
      
      devm_memremap_pages() now requires a reference counter to be specified
      at init time.  For pmem this means moving request_queue allocation into
      pmem_alloc() so the existing queue usage counter can track "device
      pages".
      
      ZONE_DEVICE pages always have an elevated count and will never be on an
      lru reclaim list.  That space in 'struct page' can be redirected for
      other uses, but for safety introduce a poison value that will always
      trip __list_add() to assert.  This allows half of the struct list_head
      storage to be reclaimed with some assurance to back up the assumption
      that the page count never goes to zero and a list_add() is never
      attempted.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Tested-by: default avatarLogan Gunthorpe <logang@deltatee.com>
      Cc: Dave Hansen <dave@sr71.net>
      Cc: Matthew Wilcox <willy@linux.intel.com>
      Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5c2c2587
    • Dan Williams's avatar
      libnvdimm, pmem: move request_queue allocation earlier in probe · 468ded03
      Dan Williams authored
      
      
      Before the dynamically allocated struct pages from devm_memremap_pages()
      can be put to use outside the driver, we need a mechanism to track
      whether they are still in use at teardown.  Towards that goal reorder
      the initialization sequence to allow the 'q_usage_counter' from the
      request_queue to be used by the devm_memremap_pages() implementation (in
      subsequent patches).
      Signed-off-by: default avatarDan Williams <dan.j.williams@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>
      468ded03
    • Dan Williams's avatar
      mm, dax: convert vmf_insert_pfn_pmd() to pfn_t · f25748e3
      Dan Williams authored
      
      
      Similar to the conversion of vm_insert_mixed() use pfn_t in the
      vmf_insert_pfn_pmd() to tag the resulting pte with _PAGE_DEVICE when the
      pfn is backed by a devm_memremap_pages() mapping.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: Dave Hansen <dave@sr71.net>
      Cc: Matthew Wilcox <willy@linux.intel.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f25748e3
    • Dan Williams's avatar
      mm, dax, gpu: convert vm_insert_mixed to pfn_t · 01c8f1c4
      Dan Williams authored
      
      
      Convert the raw unsigned long 'pfn' argument to pfn_t for the purpose of
      evaluating the PFN_MAP and PFN_DEV flags.  When both are set it triggers
      _PAGE_DEVMAP to be set in the resulting pte.
      
      There are no functional changes to the gpu drivers as a result of this
      conversion.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: Dave Hansen <dave@sr71.net>
      Cc: David Airlie <airlied@linux.ie>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      01c8f1c4
    • Dan Williams's avatar
      x86, mm: introduce _PAGE_DEVMAP · 69660fd7
      Dan Williams authored
      
      
      _PAGE_DEVMAP is a hardware-unused pte bit that will later be used in the
      get_user_pages() path to identify pfns backed by the dynamic allocation
      established by devm_memremap_pages.  Upon seeing that bit the gup path
      will lookup and pin the allocation while the pages are in use.
      
      Since the _PAGE_DEVMAP bit is > 32 it must be cast to u64 instead of a
      pteval_t to allow pmd_flags() usage in the realmode boot code to build.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      69660fd7
    • Dan Williams's avatar
      frv: fix compiler warning from definition of __pmd() · 6d8113c7
      Dan Williams authored
      
      
      Take into account that the pmd_t type is a array inside a struct, so it
      needs two levels of brackets to initialize.  Otherwise, a usage of __pmd
      generates a warning:
      
        include/linux/mm.h:986:2: warning: missing braces around initializer [-Wmissing-braces]
      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>
      6d8113c7
    • Dan Williams's avatar
      hugetlb: fix compile error on tile · 888cdbc2
      Dan Williams authored
      
      
      Inlude asm/pgtable.h to get the definition for pud_t to fix:
      
        include/linux/hugetlb.h:203:29: error: unknown type name 'pud_t'
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: Liviu Dudau <liviu.dudau@arm.com>
      Cc: Sudeep Holla <sudeep.holla@arm.com>
      Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
      Cc: David Howells <dhowells@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      888cdbc2
    • Dan Williams's avatar
      avr32: convert to asm-generic/memory_model.h · 083fc214
      Dan Williams authored
      
      
      Switch avr32/include/asm/page.h to use the common defintions for
      pfn_to_page(), page_to_pfn(), and ARCH_PFN_OFFSET.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
      Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      083fc214
    • Dan Williams's avatar
      libnvdimm, pfn, pmem: allocate memmap array in persistent memory · d2c0f041
      Dan Williams authored
      
      
      Use the new vmem_altmap capability to enable the pmem driver to arrange
      for a struct page memmap to be established in persistent memory.
      
      [linux@roeck-us.net: mn10300: declare __pfn_to_phys() to fix build error]
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
      Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d2c0f041
    • Dan Williams's avatar
      x86, mm: introduce vmem_altmap to augment vmemmap_populate() · 4b94ffdc
      Dan Williams authored
      
      
      In support of providing struct page for large persistent memory
      capacities, use struct vmem_altmap to change the default policy for
      allocating memory for the memmap array.  The default vmemmap_populate()
      allocates page table storage area from the page allocator.  Given
      persistent memory capacities relative to DRAM it may not be feasible to
      store the memmap in 'System Memory'.  Instead vmem_altmap represents
      pre-allocated "device pages" to satisfy vmemmap_alloc_block_buf()
      requests.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Reported-by: default avatarkbuild test robot <lkp@intel.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4b94ffdc
    • Dan Williams's avatar
      mm: introduce find_dev_pagemap() · 9476df7d
      Dan Williams authored
      
      
      There are several scenarios where we need to retrieve and update
      metadata associated with a given devm_memremap_pages() mapping, and the
      only lookup key available is a pfn in the range:
      
      1/ We want to augment vmemmap_populate() (called via arch_add_memory())
         to allocate memmap storage from pre-allocated pages reserved by the
         device driver.  At vmemmap_alloc_block_buf() time it grabs device pages
         rather than page allocator pages.  This is in support of
         devm_memremap_pages() mappings where the memmap is too large to fit in
         main memory (i.e. large persistent memory devices).
      
      2/ Taking a reference against the mapping when inserting device pages
         into the address_space radix of a given inode.  This facilitates
         unmap_mapping_range() and truncate_inode_pages() operations when the
         driver is tearing down the mapping.
      
      3/ get_user_pages() operations on ZONE_DEVICE memory require taking a
         reference against the mapping so that the driver teardown path can
         revoke and drain usage of device pages.
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      Tested-by: default avatarLogan Gunthorpe <logang@deltatee.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Dave Chinner <david@fromorbit.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>
      9476df7d
    • 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.
      Final...
      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