Messages in this thread | | | Date | Thu, 18 Nov 2010 08:37:02 -0500 | From | Christoph Hellwig <> | Subject | Re: [PATCH 3/3] mlock: avoid dirtying pages and triggering writeback |
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On Thu, Nov 18, 2010 at 10:11:43AM +1100, Dave Chinner wrote: > Hence I think that avoiding ->page_mkwrite callouts is likely to > break some filesystems in subtle, undetected ways. IMO, regardless > of what is done, it would be really good to start by writing a new > regression test to exercise and encode the expected the mlock > behaviour so we can detect regressions later on....
I think it would help if we could drink a bit of the test driven design coolaid here. Michel, can you write some testcases where pages on a shared mapping are mlocked, then dirtied and then munlocked, and then written out using msync/fsync. Anything that fails this test on btrfs/ext4/gfs/xfs/etc obviously doesn't work.
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