diff options
| author | Huang Ying <ying.huang@intel.com> | 2017-05-03 14:54:39 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-03 15:52:10 -0700 |
| commit | 2872bb2d0a4952ffb721e703555cb73d40b2c2f0 (patch) | |
| tree | 6f7936193bf981d5aff8f1af8b723dd0c0dabb2b /mm/swapfile.c | |
| parent | 0ef017d117d79eb765cb490a8d7e323752a13f4a (diff) | |
| download | lwn-2872bb2d0a4952ffb721e703555cb73d40b2c2f0.tar.gz lwn-2872bb2d0a4952ffb721e703555cb73d40b2c2f0.zip | |
mm, swap: avoid lock swap_avail_lock when held cluster lock
Cluster lock is used to protect the swap_cluster_info and corresponding
elements in swap_info_struct->swap_map[]. But it is found that now in
scan_swap_map_slots(), swap_avail_lock may be acquired when cluster lock
is held. This does no good except making the locking more complex and
improving the potential locking contention, because the
swap_info_struct->lock is used to protect the data structure operated in
the code already. Fix this via moving the corresponding operations in
scan_swap_map_slots() out of cluster lock.
Link: http://lkml.kernel.org/r/20170317064635.12792-3-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swapfile.c')
| -rw-r--r-- | mm/swapfile.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index 42fd620dcf4c..53b5881ee0d6 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -672,6 +672,9 @@ checks: else goto done; } + si->swap_map[offset] = usage; + inc_cluster_info_page(si, si->cluster_info, offset); + unlock_cluster(ci); if (offset == si->lowest_bit) si->lowest_bit++; @@ -685,9 +688,6 @@ checks: plist_del(&si->avail_list, &swap_avail_head); spin_unlock(&swap_avail_lock); } - si->swap_map[offset] = usage; - inc_cluster_info_page(si, si->cluster_info, offset); - unlock_cluster(ci); si->cluster_next = offset + 1; slots[n_ret++] = swp_entry(si->type, offset); |