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| author | Fengguang Wu <fengguang.wu@intel.com> | 2012-03-21 16:34:09 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-21 17:54:58 -0700 |
| commit | 47a133339c332f9f8e155c70f5da401aded69948 (patch) | |
| tree | 94f8fb512ebe8e29d0a3f11a04b04004afd4ab59 /mm/page-writeback.c | |
| parent | 1010bb1b80edb0713415dfe1f97114d320f58c4f (diff) | |
| download | lwn-47a133339c332f9f8e155c70f5da401aded69948.tar.gz lwn-47a133339c332f9f8e155c70f5da401aded69948.zip | |
mm: use global_dirty_limit in throttle_vm_writeout()
When starting a memory hog task, a desktop box w/o swap is found to go
unresponsive for a long time. It's solely caused by lots of congestion
waits in throttle_vm_writeout():
gnome-system-mo-4201 553.073384: congestion_wait: throttle_vm_writeout+0x70/0x7f shrink_mem_cgroup_zone+0x48f/0x4a1
gnome-system-mo-4201 553.073386: writeback_congestion_wait: usec_timeout=100000 usec_delayed=100000
gtali-4237 553.080377: congestion_wait: throttle_vm_writeout+0x70/0x7f shrink_mem_cgroup_zone+0x48f/0x4a1
gtali-4237 553.080378: writeback_congestion_wait: usec_timeout=100000 usec_delayed=100000
Xorg-3483 553.103375: congestion_wait: throttle_vm_writeout+0x70/0x7f shrink_mem_cgroup_zone+0x48f/0x4a1
Xorg-3483 553.103377: writeback_congestion_wait: usec_timeout=100000 usec_delayed=100000
The root cause is, the dirty threshold is knocked down a lot by the memory
hog task. Fixed by using global_dirty_limit which decreases gradually on
such events and can guarantee we stay above (the also decreasing) nr_dirty
in the progress of following down to the new dirty threshold.
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ying Han <yinghan@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page-writeback.c')
| -rw-r--r-- | mm/page-writeback.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 363ba7082ef5..3fc261705b1e 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -1472,6 +1472,7 @@ void throttle_vm_writeout(gfp_t gfp_mask) for ( ; ; ) { global_dirty_limits(&background_thresh, &dirty_thresh); + dirty_thresh = hard_dirty_limit(dirty_thresh); /* * Boost the allowable dirty threshold a bit for page |