17 Oct, 2013

1 commit

• aa9bca05a   mm/zswap: bugfix: memory leak when re-swapon ... Browse Code »

  zswap_tree is not freed when swapoff, and it got re-kmalloced in swapon,
  so a memory leak occurs.

  Free the memory of zswap_tree in zswap_frontswap_invalidate_area().

  Signed-off-by: Weijie Yang
  Reviewed-by: Bob Liu
  Cc: Minchan Kim
  Reviewed-by: Minchan Kim
  Cc:
  From: Weijie Yang
  Subject: mm/zswap: bugfix: memory leak when invalidate and reclaim occur concurrently

  Consider the following scenario:
  thread 0: reclaim entry x (get refcount, but not call zswap_get_swap_cache_page)
  thread 1: call zswap_frontswap_invalidate_page to invalidate entry x.
  finished, entry x and its zbud is not freed as its refcount != 0
  now, the swap_map[x] = 0
  thread 0: now call zswap_get_swap_cache_page
  swapcache_prepare return -ENOENT because entry x is not used any more
  zswap_get_swap_cache_page return ZSWAP_SWAPCACHE_NOMEM
  zswap_writeback_entry do nothing except put refcount
  Now, the memory of zswap_entry x and its zpage leak.

  Modify:
  - check the refcount in fail path, free memory if it is not referenced.

  - use ZSWAP_SWAPCACHE_FAIL instead of ZSWAP_SWAPCACHE_NOMEM as the fail path
  can be not only caused by nomem but also by invalidate.

  [akpm@linux-foundation.org: coding-style fixes]
  Signed-off-by: Weijie Yang
  Reviewed-by: Bob Liu
  Cc: Minchan Kim
  Cc:
  Acked-by: Seth Jennings

  Signed-off-by: Andrew Morton
  Signed-off-by: Linus Torvalds

  Weijie Yang

  2013-10-17 12:35:52 +0800  

12 Sep, 2013

2 commits

• 0bd42136f   mm/zswap: use postorder iteration when destroying rbtree ... Browse Code »

  Signed-off-by: Cody P Schafer
  Reviewed-by: Seth Jennings
  Cc: David Woodhouse
  Cc: Rik van Riel
  Cc: Michel Lespinasse
  Signed-off-by: Andrew Morton
  Signed-off-by: Linus Torvalds

  Cody P Schafer

  2013-09-12 06:59:21 +0800  
• 822518dc5   mm/zswap.c: get swapper address_space by using macro ... Browse Code »

  There is a proper macro to get the corresponding swapper address space
  from a swap entry. Instead of directly accessing "swapper_spaces" array,
  use the "swap_address_space" macro.

  Signed-off-by: Sunghan Suh
  Reviewed-by: Bob Liu
  Reviewed-by: Wanpeng Li
  Acked-by: Seth Jennings
  Signed-off-by: Andrew Morton
  Signed-off-by: Linus Torvalds

  Sunghan Suh

  2013-09-12 06:57:08 +0800  

11 Jul, 2013

1 commit

• 2b2811178   zswap: add to mm/ ... Browse Code »

  zswap is a thin backend for frontswap that takes pages that are in the
  process of being swapped out and attempts to compress them and store
  them in a RAM-based memory pool. This can result in a significant I/O
  reduction on the swap device and, in the case where decompressing from
  RAM is faster than reading from the swap device, can also improve
  workload performance.

  It also has support for evicting swap pages that are currently
  compressed in zswap to the swap device on an LRU(ish) basis. This
  functionality makes zswap a true cache in that, once the cache is full,
  the oldest pages can be moved out of zswap to the swap device so newer
  pages can be compressed and stored in zswap.

  This patch adds the zswap driver to mm/

  Signed-off-by: Seth Jennings
  Acked-by: Rik van Riel
  Cc: Greg Kroah-Hartman
  Cc: Nitin Gupta
  Cc: Minchan Kim
  Cc: Konrad Rzeszutek Wilk
  Cc: Dan Magenheimer
  Cc: Robert Jennings
  Cc: Jenifer Hopper
  Cc: Mel Gorman
  Cc: Johannes Weiner
  Cc: Larry Woodman
  Cc: Benjamin Herrenschmidt
  Cc: Dave Hansen
  Cc: Joe Perches
  Cc: Joonsoo Kim
  Cc: Cody P Schafer
  Cc: Hugh Dickens
  Cc: Paul Mackerras
  Cc: Fengguang Wu
  Signed-off-by: Andrew Morton
  Signed-off-by: Linus Torvalds

  Seth Jennings

  2013-07-11 09:11:34 +0800