Merge "mm: prevent double decrease of nr_reserved_highatomic" into msm-4.9 (339af29f) · Commits · e / devices / android_kernel_fairphone_FP3

mm/page_alloc.c

+18 −6

Original line number	Diff line number	Diff line
		@@ -2085,13 +2085,25 @@ static void unreserve_highatomic_pageblock(const struct alloc_context *ac)
		continue;

		/*
		* It should never happen but changes to locking could
		* inadvertently allow a per-cpu drain to add pages
		* to MIGRATE_HIGHATOMIC while unreserving so be safe
		* and watch for underflows.
		*/
		zone->nr_reserved_highatomic -= min(pageblock_nr_pages,
		* In page freeing path, migratetype change is racy so
		* we can counter several free pages in a pageblock
		* in this loop althoug we changed the pageblock type
		* from highatomic to ac->migratetype. So we should
		* adjust the count once.
		*/
		if (get_pageblock_migratetype(page) ==
		MIGRATE_HIGHATOMIC) {
		/*
		* It should never happen but changes to
		* locking could inadvertently allow a per-cpu
		* drain to add pages to MIGRATE_HIGHATOMIC
		* while unreserving so be safe and watch for
		* underflows.
		*/
		zone->nr_reserved_highatomic -= min(
		pageblock_nr_pages,
		zone->nr_reserved_highatomic);
		}

		/*
		* Convert to ac->migratetype and avoid the normal