On Mon, Jul 23, 2012 at 02:38:29PM +0100, Mel Gorman wrote: > commit a77ebd333cd810d7b680d544be88c875131c2bd3 upstream. > > Stable note: Not tracked in Bugzilla. A fix aimed at preserving page aging > information by reducing LRU list churning had the side-effect of > reducing THP allocation success rates. This was part of a series > to restore the success rates while preserving the reclaim fix. > > Commit [39deaf85: mm: compaction: make isolate_lru_page() filter-aware] > noted that compaction does not migrate dirty or writeback pages and > that is was meaningless to pick the page and re-add it to the LRU list. > > What was missed during review is that asynchronous migration moves > dirty pages if their ->migratepage callback is migrate_page() because > these can be moved without blocking. This potentially impacted > hugepage allocation success rates by a factor depending on how many > dirty pages are in the system. > > This patch partially reverts 39deaf85 to allow migration to isolate > dirty pages again. This increases how much compaction disrupts the > LRU but that is addressed later in the series. > > Signed-off-by: Mel Gorman <mgorman@xxxxxxx> > Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx> > Reviewed-by: Rik van Riel <riel@xxxxxxxxxx> > Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx> Note, the changelog here differs from what is in Linus's tree by a LOT. I took the version in Linus's tree instead. greg k-h -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>