On Tue 10-01-17 07:43:20, Brian Foster wrote: > On Tue, Jan 10, 2017 at 11:17:45AM +0100, Jan Kara wrote: > > Commit 99579ccec4e2 "xfs: skip dirty pages in ->releasepage()" started > > to skip dirty pages in xfs_vm_releasepage() which also has the effect > > that if a dirty page is truncated, it does not get freed by > > block_invalidatepage() and is lingering in LRU list waiting for reclaim. > > So a simple loop like: > > > > while true; do > > dd if=/dev/zero of=file bs=1M count=100 > > rm file > > done > > > > will keep using more and more memory until we hit low watermarks and > > start pagecache reclaim which will eventually reclaim also the truncate > > pages. Keeping these truncated (and thus never usable) pages in memory > > is just a waste of memory, is unnecessarily stressing page cache > > reclaim, and is also confusing users thinking they are running out of > > memory. > > > > So instead of just skipping dirty pages in xfs_vm_releasepage(), return > > to old behavior of skipping them only if they have delalloc or unwritten > > buffers and fix the spurious warnings by warning only if the page is > > clean. > > > > CC: Brian Foster <bfoster@xxxxxxxxxx> > > CC: Vlastimil Babka <vbabka@xxxxxxx> > > Reported-by: Petr Tůma <petr.tuma@xxxxxxxxxxxxxxx> > > Fixes: 99579ccec4e271c3d4d4e7c946058766812afdab > > Signed-off-by: Jan Kara <jack@xxxxxxx> > > --- > > Ugh, so this is closer to the alternative I was considering at the time > this was posted. Thanks for the fix. The code looks fine, I'd just like > to update the comment... OK, done. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
