On Thu, Dec 9, 2010 at 12:16 AM, Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > Kswapd tries to rebalance zones persistently until their high > watermarks are restored. > > If the amount of unreclaimable pages in a zone makes this impossible > for reclaim, though, kswapd will end up in a busy loop without a > chance of reaching its goal. > > This behaviour was observed on a virtual machine with a tiny > Normal-zone that filled up with unreclaimable slab objects. > > This patch makes kswapd skip rebalancing on such 'hopeless' zones and > leaves them to direct reclaim. > > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx> I like this. It makes code more readable as well as solving the problem. Just nitpick/off-topic. Doesn't we really consider NR_SLAB_RECLAIMABLE in zone_reclaimable_pages? We already consider it when we calculate size of free pages in some places(__vm_enough_memory, minimum_image_size) but it is hard to make sure we can really reclaim. But I it would be mitigated by Nick's per-zone slab shrinker. Maybe be another patch. -- Kind regards, Minchan Kim -- 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>