Messages in this thread | | | Date | Tue, 11 Oct 2011 12:54:19 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH -v2 -mm] add extra free kbytes tunable |
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On Tue, 11 Oct 2011 15:32:11 -0400 Satoru Moriya <satoru.moriya@hds.com> wrote:
> On 10/10/2011 06:37 PM, Andrew Morton wrote: > > On Fri, 7 Oct 2011 20:08:19 -0700 (PDT) David Rientjes > > <rientjes@google.com> wrote: > > > >> On Thu, 1 Sep 2011, Rik van Riel wrote: > > > > The page allocator already tries harder if the caller has > > rt_task(current). Why is this inadequate? Can we extend this idea > > further to fix whatever-the-problem-is? > > Actually page allocator decreases min watermark to 3/4 * min watermark > for rt-task. But in our case some applications create a lot of > processes and if all of them are rt-task, the amount of watermark > bonus(1/4 * min watermark) is not enough. > > If we can tune the amount of bonus, it may be fine. But that is > almost all same as extra free kbytes.
This situation is detectable at runtime. If realtime tasks are being stalled in the page allocator then start to increase the free-page reserves. A little control system.
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