1. 28 Oct, 2006 2 commits
    • Martin Bligh's avatar
      [PATCH] vmscan: Fix temp_priority race · 3bb1a852
      Martin Bligh authored
      The temp_priority field in zone is racy, as we can walk through a reclaim
      path, and just before we copy it into prev_priority, it can be overwritten
      (say with DEF_PRIORITY) by another reclaimer.
      
      The same bug is contained in both try_to_free_pages and balance_pgdat, but
      it is fixed slightly differently.  In balance_pgdat, we keep a separate
      priority record per zone in a local array.  In try_to_free_pages there is
      no need to do this, as the priority level is the same for all zones that we
      reclaim from.
      
      Impact of this bug is that temp_priority is copied into prev_priority, and
      setting this artificially high causes reclaimers to set distress
      artificially low.  They then fail to reclaim mapped pages, when they are,
      in fact, under severe memory pressure (their priority may be as low as 0).
      This causes the OOM killer to fire incorrectly.
      
      From: Andrew Morton <akpm@osdl.org>
      
      __zone_reclaim() isn't modifying zone->prev_priority.  But zone->prev_priority
      is used in the decision whether or not to bring mapped pages onto the inactive
      list.  Hence there's a risk here that __zone_reclaim() will fail because
      zone->prev_priority ir large (ie: low urgency) and lots of mapped pages end up
      stuck on the active list.
      
      Fix that up by decreasing (ie making more urgent) zone->prev_priority as
      __zone_reclaim() scans the zone's pages.
      
      This bug perhaps explains why ZONE_RECLAIM_PRIORITY was created.  It should be
      possible to remove that now, and to just start out at DEF_PRIORITY?
      
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Christoph Lameter <clameter@engr.sgi.com>
      Cc: <stable@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      3bb1a852
    • Nick Piggin's avatar
      [PATCH] mm: clean up pagecache allocation · 2ae88149
      Nick Piggin authored
      - Consolidate page_cache_alloc
      
      - Fix splice: only the pagecache pages and filesystem data need to use
        mapping_gfp_mask.
      
      - Fix grab_cache_page_nowait: same as splice, also honour NUMA placement.
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Cc: Jens Axboe <jens.axboe@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      2ae88149
  2. 27 Oct, 2006 11 commits
  3. 26 Oct, 2006 23 commits
  4. 25 Oct, 2006 4 commits