Messages in this thread | | | Date | Fri, 30 Dec 2016 09:11:17 +0000 | From | Mel Gorman <> | Subject | Re: [PATCH 0/7] vm, vmscan: enahance vmscan tracepoints |
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On Wed, Dec 28, 2016 at 04:30:25PM +0100, Michal Hocko wrote: > Hi, > while debugging [1] I've realized that there is some room for > improvements in the tracepoints set we offer currently. I had hard times > to make any conclusion from the existing ones. The resulting problem > turned out to be active list aging [2] and we are missing at least two > tracepoints to debug such a problem. > > Some existing tracepoints could export more information to see _why_ the > reclaim progress cannot be made not only _how much_ we could reclaim. > The later could be seen quite reasonably from the vmstat counters > already. It can be argued that we are showing too many implementation > details in those tracepoints but I consider them way too lowlevel > already to be usable by any kernel independent userspace. I would be > _really_ surprised if anything but debugging tools have used them. > > Any feedback is highly appreciated. >
There is some minor overhead introduced in some paths regardless of whether the tracepoints are active or not but I suspect it's negligible in the context of the overhead of reclaim in general so;
Acked-by: Mel Gorman <mgorman@suse.de>
-- Mel Gorman SUSE Labs
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