Messages in this thread | | | Date | Fri, 11 Dec 2009 10:12:57 +0900 | Subject | Re: [RFC mm][PATCH 5/5] counting lowmem rss per mm | From | Minchan Kim <> |
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On Thu, Dec 10, 2009 at 5:01 PM, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > Some case of OOM-Kill is caused by memory shortage in lowmem area. For example, > NORMAL_ZONE is exhausted on x86-32/HIGHMEM kernel. > > Now, oom-killer doesn't have no lowmem usage information of processes and > selects victim processes based on global memory usage information. > In bad case, this can cause chains of kills of innocent processes without > progress, oom-serial-killer. > > For making oom-killer lowmem aware, this patch adds counters for accounting > lowmem usage per process. (patches for oom-killer is not included in this.) > > Adding counter is easy but one of concern is the cost for new counter. > > Following is the test result of micro-benchmark of parallel page faults. > Bigger page fault number indicates better scalability. > (measured under USE_SPLIT_PTLOCKS environemt) > [Before lowmem counter] > Performance counter stats for './multi-fault 2' (5 runs): > > 46997471 page-faults ( +- 0.720% ) > 1004100076 cache-references ( +- 0.734% ) > 180959964 cache-misses ( +- 0.374% ) > 29263437363580464 bus-cycles ( +- 0.002% ) > > 60.003315683 seconds time elapsed ( +- 0.004% ) > > 3.85 miss/faults > [After lowmem counter] > Performance counter stats for './multi-fault 2' (5 runs): > > 45976947 page-faults ( +- 0.405% ) > 992296954 cache-references ( +- 0.860% ) > 183961537 cache-misses ( +- 0.473% ) > 29261902069414016 bus-cycles ( +- 0.002% ) > > 60.001403261 seconds time elapsed ( +- 0.000% ) > > 4.0 miss/faults. > > Then, small cost is added. But I think this is within reasonable > range. > > If you have good idea for improve this number, it's welcome. > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
-- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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