On Fri, 30 Nov 2018 14:58:12 -0500 Josef Bacik <josef@xxxxxxxxxxxxxx> 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.
