mm: page_alloc: rearrange watermark checking in get_page_from_freelist (e085dbc5) · Commits · 戴 / test

Allocations that do not have to respect the watermarks are rare high-priority events. Reorder the code such that per-zone dirty limits and future checks important only to regular page allocations are ignored in these extraordinary situations. Signed-off-by:

Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Reviewed-by:

Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Paul Bolle <paul.bollee@gmail.com> Tested-by:

Zlatko Calusic <zcalusic@bitsync.net> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

+8 −8

Original line number	Diff line number	Diff line
		@@ -1889,12 +1889,17 @@ zonelist_scan:
		*/
		for_each_zone_zonelist_nodemask(zone, z, zonelist,
		high_zoneidx, nodemask) {
		unsigned long mark;

		if (IS_ENABLED(CONFIG_NUMA) && zlc_active &&
		!zlc_zone_worth_trying(zonelist, z, allowednodes))
		continue;
		if ((alloc_flags & ALLOC_CPUSET) &&
		!cpuset_zone_allowed_softwall(zone, gfp_mask))
		continue;
		BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
		if (alloc_flags & ALLOC_NO_WATERMARKS)
		goto try_this_zone;
		/*
		* When allocating a page cache page for writing, we
		* want to get it from a zone that is within its dirty
		@@ -1925,15 +1930,10 @@ zonelist_scan:
		(gfp_mask & __GFP_WRITE) && !zone_dirty_ok(zone))
		goto this_zone_full;

		BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
		if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
		unsigned long mark;
		int ret;

		mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
		if (zone_watermark_ok(zone, order, mark,
		classzone_idx, alloc_flags))
		goto try_this_zone;
		if (!zone_watermark_ok(zone, order, mark,
		classzone_idx, alloc_flags)) {
		int ret;

		if (IS_ENABLED(CONFIG_NUMA) &&
		!did_zlc_setup && nr_online_nodes > 1) {

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