Messages in this thread | | | Date | Wed, 20 Jul 2011 14:44:21 +0900 | Subject | Re: [PATCH]vmscan: fix a livelock in kswapd | From | Minchan Kim <> |
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On Tue, Jul 19, 2011 at 4:09 PM, Shaohua Li <shaohua.li@intel.com> 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@intel.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
-- Kind regards, Minchan Kim
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