Messages in this thread | | | Date | Tue, 28 Jul 2009 17:00:54 -0700 | Subject | Re: [PATCH 1/1] pagemap clear_refs: modify to specify anon or mapped vma clearing | From | Moussa Ba <> |
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The patch makes the clear_refs more versatile in adding the option to select anonymous pages or file backed pages for clearing. This addition has a measurable impact on user space application performance as it decreases the number of pagewalks in scenarios where one is only interested in a specific type of page (anonymous or file mapped).
On Tue, Jul 28, 2009 at 4:52 PM, Andrew Morton<akpm@linux-foundation.org> wrote: > On Tue, 28 Jul 2009 15:52:05 -0700 > "Moussa A. Ba" <moussa.a.ba@gmail.com> wrote: > >> This patch adds anonymous and file backed filters to the clear_refs interface. >> echo 1 > /proc/PID/clear_refs resets the bits on all pages >> echo 2 > /proc/PID/clear_refs resets the bits on anonymous pages only >> echo 3 > /proc/PID/clear_refs resets the bits on file backed pages only >> Any other value is ignored > > The changelog is missing any rationale for making this change. > Originally we were told that it "makes the clear_refs proc interface a > bit more versatile", but that's a bit thin. > > How do we justify making this change to Linux? What value does it > have? Can you describe a usage scenario which would help people > understand the usefulness of the change? > > Thanks. > -- 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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