Messages in this thread | | | Subject | Re: [RFC PATCH 2/2] mm: Batch page_check_references in shrink_page_list sharing the same i_mmap_mutex | From | Tim Chen <> | Date | Tue, 04 Sep 2012 15:54:19 -0700 |
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On Tue, 2012-09-04 at 08:21 -0700, Tim Chen wrote: > On Tue, 2012-08-21 at 17:48 -0700, Tim Chen wrote: > > > > > Thanks to Matthew's suggestions on improving the patch. Here's the > > updated version. It seems to be sane when I booted my machine up. I > > will put it through more testing when I get a chance. > > > > Tim > > > > Matthew, > > The new patch seems to be causing some of the workloads with mmaped file > read to seg fault. Will need to dig further to find out why. > > Tim >
Okay, the problem seems to be the code below. It is too restrictive and causes some cases where the mutex needs to be taken in try_to_unmap_file to be missed.
> > +int needs_page_mmap_mutex(struct page *page) > > +{ > > + return page->mapping && page_mapped(page) && page_rmapping(page) && > > + !PageKsm(page) && !PageAnon(page); > > +} > > +
Changing the check to the following fixes the problem:
@@ -873,8 +873,7 @@ static int page_referenced_file(struct page *page,
int needs_page_mmap_mutex(struct page *page) { - return page->mapping && page_mapped(page) && page_rmapping(page) && - !PageKsm(page) && !PageAnon(page); + return page->mapping && !PageKsm(page) && !PageAnon(page); }
I'll do more testing and generate a second version of the patch set with the fixes.
Tim
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