On 07/21/2014 05:54 PM, Michal Hocko wrote: > From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > > commit b738d764652dc5aab1c8939f637112981fce9e0e upstream > > shrink_inactive_list() used to wait 0.1s to avoid congestion when all > the pages that were isolated from the inactive list were dirty but not > under active writeback. That makes no real sense, and apparently causes > major interactivity issues under some loads since 3.11. > > The ostensible reason for it was to wait for kswapd to start writing > pages, but that seems questionable as well, since the congestion wait > code seems to trigger for kswapd itself as well. Also, the logic behind > delaying anything when we haven't actually started writeback is not > clear - it only delays actually starting that writeback. > > We'll still trigger the congestion waiting if > > (a) the process is kswapd, and we hit pages flagged for immediate > reclaim > > (b) the process is not kswapd, and the zone backing dev writeback is > actually congested. > > This probably needs to be revisited, but as it is this fixes a reported > regression. > > [mhocko@xxxxxxx: backport to 3.12 stable tree] Applied, thanks! -- js suse labs -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html