Messages in this thread | | | Date | Wed, 24 Jul 2013 20:46:42 +0800 | From | Hush Bensen <> | Subject | Re: [patch 0/3] mm: improve page aging fairness between zones/nodes |
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于 2013/7/24 19:18, Zlatko Calusic 写道: > On 22.07.2013 18:48, Zlatko Calusic wrote: >> On 19.07.2013 22:55, Johannes Weiner wrote: >>> The way the page allocator interacts with kswapd creates aging >>> imbalances, where the amount of time a userspace page gets in memory >>> under reclaim pressure is dependent on which zone, which node the >>> allocator took the page frame from. >>> >>> #1 fixes missed kswapd wakeups on NUMA systems, which lead to some >>> nodes falling behind for a full reclaim cycle relative to the other >>> nodes in the system >>> >>> #3 fixes an interaction where kswapd and a continuous stream of page >>> allocations keep the preferred zone of a task between the high and >>> low watermark (allocations succeed + kswapd does not go to sleep) >>> indefinitely, completely underutilizing the lower zones and >>> thrashing on the preferred zone >>> >>> These patches are the aging fairness part of the thrash-detection >>> based file LRU balancing. Andrea recommended to submit them >>> separately as they are bugfixes in their own right. >>> >> >> I have the patch applied and under testing. So far, so good. It looks >> like it could finally fix the bug that I was chasing few months ago >> (nicely described in your bullet #3). But, few more days of testing will >> be needed before I can reach a quality verdict. >> > > Well, only 2 days later it's already obvious that the patch is > perfect! :) > > In the attached image, in the left column are the graphs covering last > day and a half. It can be observed that zones are really balanced, and > that aging is practically perfect. Graphs on the right column cover > last 10 day period, and the left side of the upper graph shows how it > would look with the stock kernel after about 20 day uptime (although > only a few days is enough to reach such imbalance). File pages in the > Normal zone are extinct species (red) and the zone is choke full of > anon pages (blue). Having seen a lot of this graphs, I'm certain that > it won't happen anymore with your patch applied. The balance is > restored! Thank you for your work. Feel free to add: > > Tested-by: Zlatko Calusic <zcalusic@bitsync.net>
Thanks for your testing Zlatko, could you tell me which benchmark or workload you are using? Btw, which tool is used to draw these nice pictures? ;-)
> > Regards,
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