diff options
| author | Huang Ying <ying.huang@intel.com> | 2017-02-22 15:45:46 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-22 16:41:30 -0800 |
| commit | ba81f83842549871cbd7226fc11530dc464500bb (patch) | |
| tree | 1722a6591e970b93efbbf51c39b6dd09f7832d6a /mm/swap_slots.c | |
| parent | 039939a65059852242c823ece685579370bc574f (diff) | |
| download | linux-ba81f83842549871cbd7226fc11530dc464500bb.tar.gz | |
mm/swap: skip readahead only when swap slot cache is enabled
Because during swap off, a swap entry may have swap_map[] == SWAP_HAS_CACHE (for example, just allocated). If we return NULL in __read_swap_cache_async(), the swap off will abort. So when swap slot cache is disabled, (for swap off), we will wait for page to be put into swap cache in such race condition. This should not be a problem for swap slot cache, because swap slot cache should be drained after clearing swap_slot_cache_enabled. [ying.huang@intel.com: fix memory leak in __read_swap_cache_async()] Link: http://lkml.kernel.org/r/874lzt6znd.fsf@yhuang-dev.intel.com Link: http://lkml.kernel.org/r/5e2c5f6abe8e6eb0797408897b1bba80938e9b9d.1484082593.git.tim.c.chen@linux.intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Cc: Aaron Lu <aaron.lu@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> escreveu: Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Shaohua Li <shli@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swap_slots.c')
| -rw-r--r-- | mm/swap_slots.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/swap_slots.c b/mm/swap_slots.c index ebf4f1cbac04..9b5bc86f96ad 100644 --- a/mm/swap_slots.c +++ b/mm/swap_slots.c @@ -36,7 +36,7 @@ static DEFINE_PER_CPU(struct swap_slots_cache, swp_slots); static bool swap_slot_cache_active; -static bool swap_slot_cache_enabled; +bool swap_slot_cache_enabled; static bool swap_slot_cache_initialized; DEFINE_MUTEX(swap_slots_cache_mutex); /* Serialize swap slots cache enable/disable operations */ |