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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>