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  1. Jul 26, 2007
  2. Jul 20, 2007
    • Paul Mundt's avatar
      mm: Remove slab destructors from kmem_cache_create(). · 20c2df83
      Paul Mundt authored
      
      
      Slab destructors were no longer supported after Christoph's
      c59def9f change. They've been
      BUGs for both slab and slub, and slob never supported them
      either.
      
      This rips out support for the dtor pointer from kmem_cache_create()
      completely and fixes up every single callsite in the kernel (there were
      about 224, not including the slab allocator definitions themselves,
      or the documentation references).
      
      Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
      20c2df83
  3. Jul 19, 2007
    • Nicholas Piggin's avatar
      mm: fault feedback #1 · d0217ac0
      Nicholas Piggin authored
      
      
      Change ->fault prototype.  We now return an int, which contains
      VM_FAULT_xxx code in the low byte, and FAULT_RET_xxx code in the next byte.
       FAULT_RET_ code tells the VM whether a page was found, whether it has been
      locked, and potentially other things.  This is not quite the way he wanted
      it yet, but that's changed in the next patch (which requires changes to
      arch code).
      
      This means we no longer set VM_CAN_INVALIDATE in the vma in order to say
      that a page is locked which requires filemap_nopage to go away (because we
      can no longer remain backward compatible without that flag), but we were
      going to do that anyway.
      
      struct fault_data is renamed to struct vm_fault as Linus asked. address
      is now a void __user * that we should firmly encourage drivers not to use
      without really good reason.
      
      The page is now returned via a page pointer in the vm_fault struct.
      
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d0217ac0
    • Nicholas Piggin's avatar
      mm: merge populate and nopage into fault (fixes nonlinear) · 54cb8821
      Nicholas Piggin authored
      
      
      Nonlinear mappings are (AFAIKS) simply a virtual memory concept that encodes
      the virtual address -> file offset differently from linear mappings.
      
      ->populate is a layering violation because the filesystem/pagecache code
      should need to know anything about the virtual memory mapping.  The hitch here
      is that the ->nopage handler didn't pass down enough information (ie.  pgoff).
       But it is more logical to pass pgoff rather than have the ->nopage function
      calculate it itself anyway (because that's a similar layering violation).
      
      Having the populate handler install the pte itself is likewise a nasty thing
      to be doing.
      
      This patch introduces a new fault handler that replaces ->nopage and
      ->populate and (later) ->nopfn.  Most of the old mechanism is still in place
      so there is a lot of duplication and nice cleanups that can be removed if
      everyone switches over.
      
      The rationale for doing this in the first place is that nonlinear mappings are
      subject to the pagefault vs invalidate/truncate race too, and it seemed stupid
      to duplicate the synchronisation logic rather than just consolidate the two.
      
      After this patch, MAP_NONBLOCK no longer sets up ptes for pages present in
      pagecache.  Seems like a fringe functionality anyway.
      
      NOPAGE_REFAULT is removed.  This should be implemented with ->fault, and no
      users have hit mainline yet.
      
      [akpm@linux-foundation.org: cleanup]
      [randy.dunlap@oracle.com: doc. fixes for readahead]
      [akpm@linux-foundation.org: build fix]
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarRandy Dunlap <randy.dunlap@oracle.com>
      Cc: Mark Fasheh <mark.fasheh@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      54cb8821
    • Nicholas Piggin's avatar
      mm: fix fault vs invalidate race for linear mappings · d00806b1
      Nicholas Piggin authored
      
      
      Fix the race between invalidate_inode_pages and do_no_page.
      
      Andrea Arcangeli identified a subtle race between invalidation of pages from
      pagecache with userspace mappings, and do_no_page.
      
      The issue is that invalidation has to shoot down all mappings to the page,
      before it can be discarded from the pagecache.  Between shooting down ptes to
      a particular page, and actually dropping the struct page from the pagecache,
      do_no_page from any process might fault on that page and establish a new
      mapping to the page just before it gets discarded from the pagecache.
      
      The most common case where such invalidation is used is in file truncation.
      This case was catered for by doing a sort of open-coded seqlock between the
      file's i_size, and its truncate_count.
      
      Truncation will decrease i_size, then increment truncate_count before
      unmapping userspace pages; do_no_page will read truncate_count, then find the
      page if it is within i_size, and then check truncate_count under the page
      table lock and back out and retry if it had subsequently been changed (ptl
      will serialise against unmapping, and ensure a potentially updated
      truncate_count is actually visible).
      
      Complexity and documentation issues aside, the locking protocol fails in the
      case where we would like to invalidate pagecache inside i_size.  do_no_page
      can come in anytime and filemap_nopage is not aware of the invalidation in
      progress (as it is when it is outside i_size).  The end result is that
      dangling (->mapping == NULL) pages that appear to be from a particular file
      may be mapped into userspace with nonsense data.  Valid mappings to the same
      place will see a different page.
      
      Andrea implemented two working fixes, one using a real seqlock, another using
      a page->flags bit.  He also proposed using the page lock in do_no_page, but
      that was initially considered too heavyweight.  However, it is not a global or
      per-file lock, and the page cacheline is modified in do_no_page to increment
      _count and _mapcount anyway, so a further modification should not be a large
      performance hit.  Scalability is not an issue.
      
      This patch implements this latter approach.  ->nopage implementations return
      with the page locked if it is possible for their underlying file to be
      invalidated (in that case, they must set a special vm_flags bit to indicate
      so).  do_no_page only unlocks the page after setting up the mapping
      completely.  invalidation is excluded because it holds the page lock during
      invalidation of each page (and ensures that the page is not mapped while
      holding the lock).
      
      This also allows significant simplifications in do_no_page, because we have
      the page locked in the right place in the pagecache from the start.
      
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d00806b1
    • David Chinner's avatar
      [XFS] Fix inode size update before data write in xfs_setattr · c32676ee
      David Chinner authored
      
      
      When changing the file size by a truncate() call, we log the change in the
      inode size. However, we do not flush any outstanding data that might not
      have been written to disk, thereby violating the data/inode size update
      order. This can leave files full of NULLs on crash.
      
      Hence if we are truncating the file, flush any unwritten data that may lie
      between the curret on disk inode size and the new inode size that is being
      logged to ensure that ordering is preserved.
      
      SGI-PV: 966308
      SGI-Modid: xfs-linux-melb:xfs-kern:29174a
      
      Signed-off-by: default avatarDavid Chinner <dgc@sgi.com>
      Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarTim Shimmin <tes@sgi.com>
      c32676ee
    • David Chinner's avatar
      [XFS] Allow punching holes to free space when at ENOSPC · 91ebecc7
      David Chinner authored
      
      
      Make the free file space transaction able to dip into the reserved blocks
      to ensure that we can successfully free blocks when the filesystem is at
      ENOSPC.
      
      SGI-PV: 967788
      SGI-Modid: xfs-linux-melb:xfs-kern:29167a
      
      Signed-off-by: default avatarDavid Chinner <dgc@sgi.com>
      Signed-off-by: default avatarVlad Apostolov <vapo@sgi.com>
      Signed-off-by: default avatarTim Shimmin <tes@sgi.com>
      91ebecc7
    • David Chinner's avatar
      [XFS] Implement ->page_mkwrite in XFS. · 4f57dbc6
      David Chinner authored
      
      
      Hook XFS up to ->page_mkwrite to ensure that we know about mmap pages
      being written to. This allows use to do correct delayed allocation and
      ENOSPC checking as well as remap unwritten extents so that they get
      converted correctly during writeback. This is done via the generic
      block_page_mkwrite code.
      
      SGI-PV: 940392
      SGI-Modid: xfs-linux-melb:xfs-kern:29149a
      
      Signed-off-by: default avatarDavid Chinner <dgc@sgi.com>
      Signed-off-by: default avatarChristoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarTim Shimmin <tes@sgi.com>
      4f57dbc6
  4. Jul 17, 2007
    • Christoph Hellwig's avatar
      knfsd: exportfs: add exportfs.h header · a5694255
      Christoph Hellwig authored
      
      
      currently the export_operation structure and helpers related to it are in
      fs.h.  fs.h is already far too large and there are very few places needing the
      export bits, so split them off into a separate header.
      
      [akpm@linux-foundation.org: fix cifs build]
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarNeil Brown <neilb@suse.de>
      Cc: Steven French <sfrench@us.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a5694255
    • Rafael J. Wysocki's avatar
      Freezer: make kernel threads nonfreezable by default · 83144186
      Rafael J. Wysocki authored
      
      
      Currently, the freezer treats all tasks as freezable, except for the kernel
      threads that explicitly set the PF_NOFREEZE flag for themselves.  This
      approach is problematic, since it requires every kernel thread to either
      set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
      care for the freezing of tasks at all.
      
      It seems better to only require the kernel threads that want to or need to
      be frozen to use some freezer-related code and to remove any
      freezer-related code from the other (nonfreezable) kernel threads, which is
      done in this patch.
      
      The patch causes all kernel threads to be nonfreezable by default (ie.  to
      have PF_NOFREEZE set by default) and introduces the set_freezable()
      function that should be called by the freezable kernel threads in order to
      unset PF_NOFREEZE.  It also makes all of the currently freezable kernel
      threads call set_freezable(), so it shouldn't cause any (intentional)
      change of behaviour to appear.  Additionally, it updates documentation to
      describe the freezing of tasks more accurately.
      
      [akpm@linux-foundation.org: build fixes]
      Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
      Acked-by: default avatarNigel Cunningham <nigel@nigel.suspend2.net>
      Cc: Pavel Machek <pavel@ucw.cz>
      Cc: Oleg Nesterov <oleg@tv-sign.ru>
      Cc: Gautham R Shenoy <ego@in.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      83144186
    • Rusty Russell's avatar
      mm: clean up and kernelify shrinker registration · 8e1f936b
      Rusty Russell authored
      
      
      I can never remember what the function to register to receive VM pressure
      is called.  I have to trace down from __alloc_pages() to find it.
      
      It's called "set_shrinker()", and it needs Your Help.
      
      1) Don't hide struct shrinker.  It contains no magic.
      2) Don't allocate "struct shrinker".  It's not helpful.
      3) Call them "register_shrinker" and "unregister_shrinker".
      4) Call the function "shrink" not "shrinker".
      5) Reduce the 17 lines of waffly comments to 13, but document it properly.
      
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Cc: David Chinner <dgc@sgi.com>
      Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8e1f936b
  5. Jul 14, 2007
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