The patch titled
Subject: mm, page_alloc: move might_sleep_if check to the allocator slowpath
has been added to the -mm tree. Its filename is
mm-page_alloc-move-might_sleep_if-check-to-the-allocator-slowpath.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-move-might_sleep_if-check-to-the-allocator-slowpath.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-move-might_sleep_if-check-to-the-allocator-slowpath.patch
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------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: mm, page_alloc: move might_sleep_if check to the allocator slowpath
There is a debugging check for callers that specify __GFP_DIRECT_RECLAIM
from a context that cannot sleep. Triggering this is almost certainly a
bug but it's also overhead in the fast path. Move the check to the slow
path. It'll be harder to trigger as it'll only be checked when watermarks
are depleted but it'll also only be checked in a path that can sleep.
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN mm/page_alloc.c~mm-page_alloc-move-might_sleep_if-check-to-the-allocator-slowpath mm/page_alloc.c
--- a/mm/page_alloc.c~mm-page_alloc-move-might_sleep_if-check-to-the-allocator-slowpath
+++ a/mm/page_alloc.c
@@ -3202,6 +3202,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, u
return NULL;
}
+ might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
+
/*
* We also sanity check to catch abuse of atomic reserves being used by
* callers that are not in atomic context.
@@ -3395,8 +3397,6 @@ __alloc_pages_nodemask(gfp_t gfp_mask, u
lockdep_trace_alloc(gfp_mask);
- might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
-
if (should_fail_alloc_page(gfp_mask, order))
return NULL;
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
mm-page_alloc-only-check-pagecompound-for-high-order-pages.patch
mm-page_alloc-use-new-pageanonhead-helper-in-the-free-page-fast-path.patch
mm-page_alloc-reduce-branches-in-zone_statistics.patch
mm-page_alloc-inline-zone_statistics.patch
mm-page_alloc-inline-the-fast-path-of-the-zonelist-iterator.patch
mm-page_alloc-use-__dec_zone_state-for-order-0-page-allocation.patch
mm-page_alloc-avoid-unnecessary-zone-lookups-during-pageblock-operations.patch
mm-page_alloc-convert-alloc_flags-to-unsigned.patch
mm-page_alloc-convert-nr_fair_skipped-to-bool.patch
mm-page_alloc-remove-unnecessary-local-variable-in-get_page_from_freelist.patch
mm-page_alloc-remove-unnecessary-initialisation-in-get_page_from_freelist.patch
mm-page_alloc-remove-redundant-check-for-empty-zonelist.patch
mm-page_alloc-simplify-last-cpupid-reset.patch
mm-page_alloc-move-might_sleep_if-check-to-the-allocator-slowpath.patch
mm-page_alloc-move-__gfp_hardwall-modifications-out-of-the-fastpath.patch
mm-page_alloc-check-once-if-a-zone-has-isolated-pageblocks.patch
mm-page_alloc-shorten-the-page-allocator-fast-path.patch
mm-page_alloc-reduce-cost-of-fair-zone-allocation-policy-retry.patch
mm-page_alloc-shortcut-watermark-checks-for-order-0-pages.patch
mm-page_alloc-avoid-looking-up-the-first-zone-in-a-zonelist-twice.patch
mm-page_alloc-remove-field-from-alloc_context.patch
mm-page_alloc-check-multiple-page-fields-with-a-single-branch.patch
mm-page_alloc-remove-unnecessary-variable-from-free_pcppages_bulk.patch
mm-page_alloc-inline-pageblock-lookup-in-page-free-fast-paths.patch
mm-page_alloc-defer-debugging-checks-of-freed-pages-until-a-pcp-drain.patch
mm-page_alloc-defer-debugging-checks-of-pages-allocated-from-the-pcp.patch
--
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