Messages in this thread | | | Date | Mon, 19 Mar 2012 08:37:13 +0100 | From | Johannes Weiner <> | Subject | Re: [PATCH] mm: use global_dirty_limit in throttle_vm_writeout() |
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On Fri, Mar 02, 2012 at 02:14:51PM +0800, Fengguang Wu wrote: > 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>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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