Messages in this thread | | | Date | Tue, 4 Dec 2018 14:50:34 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 4/4] mm: use the cached page for filemap_fault |
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On Fri, 30 Nov 2018 14:58:12 -0500 Josef Bacik <josef@toxicpanda.com> wrote:
> If we drop the mmap_sem we have to redo the vma lookup which requires > redoing the fault handler. Chances are we will just come back to the > same page, so save this page in our vmf->cached_page and reuse it in the > next loop through the fault handler. >
Is this really worthwhile? Rerunning the fault handler is rare (we hope) and a single pagecache lookup is fast.
Some performance testing results would be helpful here. It's practically obligatory when claiming a performance improvement.
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