Messages in this thread Patch in this message | | | From | KOSAKI Motohiro <> | Subject | [PATCH] mm: stop kswapd's infinite loop at high order allocation | Date | Tue, 30 Dec 2008 19:55:47 +0900 (JST) |
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ok, wassim confirmed this patch works well.
== From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Subject: [PATCH] mm: kswapd stop infinite loop at high order allocation
Wassim Dagash reported following kswapd infinite loop problem.
kswapd runs in some infinite loop trying to swap until order 10 of zone highmem is OK, While zone higmem (as I understand) has nothing to do with contiguous memory (cause there is no 1-1 mapping) which means kswapd will continue to try to balance order 10 of zone highmem forever (or until someone release a very large chunk of highmem).
He proposed remove contenious checking on highmem at all. However hugepage on highmem need contenious highmem page.
To add infinite loop stopper is simple and good.
Reported-by: wassim dagash <wassim.dagash@gmail.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> --- mm/vmscan.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
Index: b/mm/vmscan.c =================================================================== --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1872,6 +1872,17 @@ out: try_to_freeze(); + /* + * When highmem is very fragmented, + * alloc_pages(GFP_KERNEL, very-high-order) can cause + * infinite loop because zone_watermark_ok(highmem) failed. + * However, alloc_pages(GFP_KERNEL..) indicate highmem memory + * continuousness isn't necessary. + * Therefore we don't want contenious check at 2nd loop. + */ + if (nr_reclaimed < SWAP_CLUSTER_MAX) + order = sc.order = 0; + goto loop_again; }
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