The patch titled
Subject: mm, page_alloc: remove redundant check for empty zonelist
has been removed from the -mm tree. Its filename was
mm-page_alloc-remove-redundant-check-for-empty-zonelist.patch
This patch was dropped because it was withdrawn
------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: mm, page_alloc: remove redundant check for empty zonelist
A check is made for an empty zonelist early in the page allocator fast
path but it's unnecessary. When get_page_from_freelist() is called, it'll
return NULL immediately. Removing the first check is slower for machines
with memoryless nodes but that is a corner case that can live with the
overhead.
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 | 11 -----------
1 file changed, 11 deletions(-)
diff -puN mm/page_alloc.c~mm-page_alloc-remove-redundant-check-for-empty-zonelist mm/page_alloc.c
--- a/mm/page_alloc.c~mm-page_alloc-remove-redundant-check-for-empty-zonelist
+++ a/mm/page_alloc.c
@@ -3373,14 +3373,6 @@ __alloc_pages_nodemask(gfp_t gfp_mask, u
if (should_fail_alloc_page(gfp_mask, order))
return NULL;
- /*
- * Check the zones suitable for the gfp_mask contain at least one
- * valid zone. It's possible to have an empty zonelist as a result
- * of __GFP_THISNODE and a memoryless node
- */
- if (unlikely(!zonelist->_zonerefs->zone))
- return NULL;
-
if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE)
alloc_flags |= ALLOC_CMA;
@@ -3393,8 +3385,6 @@ retry_cpuset:
/* The preferred zone is used for statistics later */
preferred_zoneref = first_zones_zonelist(ac.zonelist, ac.high_zoneidx,
ac.nodemask, &ac.preferred_zone);
- if (!ac.preferred_zone)
- goto out;
ac.classzone_idx = zonelist_zone_idx(preferred_zoneref);
/* First allocation attempt */
@@ -3417,7 +3407,6 @@ retry_cpuset:
trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);
-out:
/*
* When updating a task's mems_allowed, it is possible to race with
* parallel threads in such a way that an allocation can fail while
_
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-unnecessary-initialisation-from-__alloc_pages_nodemask.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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