On Tue, Jul 19, 2011 at 03:09:27PM +0800, Shaohua Li wrote: > I'm running a workload which triggers a lot of swap in a machine with 4 nodes. > After I kill the workload, I found a kswapd livelock. Sometimes kswapd3 or > kswapd2 are keeping running and I can't access filesystem, but most memory is > free. This looks like a regression since commit 08951e545918c159. > Node 2 and 3 have only ZONE_NORMAL, but balance_pgdat() will return 0 for > classzone_idx. The reason is end_zone in balance_pgdat() is 0 by default, if > all zones have watermark ok, end_zone will keep 0. > Later sleeping_prematurely() always returns true. Because this is an order 3 > wakeup, and if classzone_idx is 0, both balanced_pages and present_pages > in pgdat_balanced() are 0. > We add a special case here. If a zone has no page, we think it's balanced. This > fixes the livelock. > > Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx> > Acked-by: Mel Gorman <mgorman@xxxxxxx> It's also needed for 3.0 and 2.6.39-stable I believe. -- Mel Gorman SUSE Labs -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>