(2014/12/16 8:03), akpm@xxxxxxxxxxxxxxxxxxxx wrote:
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Subject: mm/page_alloc.c:__alloc_pages_nodemask(): don't alter arg gfp_mask __alloc_pages_nodemask() strips __GFP_IO when retrying the page allocation. But it does this by altering the function-wide variable gfp_mask. This will cause subsequent allocation attempts to inadvertently use the modified gfp_mask. Cc: Ming Lei <ming.lei@xxxxxxxxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff -puN mm/page_alloc.c~mm-page_allocc-__alloc_pages_nodemask-dont-alter-arg-gfp_mask mm/page_alloc.c --- a/mm/page_alloc.c~mm-page_allocc-__alloc_pages_nodemask-dont-alter-arg-gfp_mask +++ a/mm/page_alloc.c @@ -2918,8 +2918,9 @@ retry_cpuset: * can deadlock because I/O on the device might not * complete. */ - gfp_mask = memalloc_noio_flags(gfp_mask); - page = __alloc_pages_slowpath(gfp_mask, order,
+ gfp_t mask = memalloc_noio_flags(gfp_mask); + + page = __alloc_pages_slowpath(mask, order, zonelist, high_zoneidx, nodemask, preferred_zone, classzone_idx, migratetype); }
After allocating page, trace_mm_page_alloc(page, order, gfp_mask, migratetype) is called. But mask is not passed to it. So trace_mm_page_alloc traces wrong gfp_mask. Thanks, Yasuaki Ishimatsu
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