PM / Hibernate / Memory hotplug: Always use for_each_populated_zone() (98e73dc5) · Commits · 戴 / test

Use for_each_populated_zone() instead of for_each_zone() in hibernation code. This fixes a bug on s390, where we allow both config options HIBERNATION and MEMORY_HOTPLUG, so that we also have a ZONE_MOVABLE here. We only allow hibernation if no memory hotplug operation was performed, so in fact both features can only be used exclusively, but this way we don't need 2 differently configured (distribution) kernels. If we have an unpopulated ZONE_MOVABLE, we allow hibernation but run into a BUG_ON() in memory_bm_test/set/clear_bit() because hibernation code iterates through all zones, not only the populated zones, in several places. For example, swsusp_free() does for_each_zone() and then checks for pfn_valid(), which is true even if the zone is not populated, resulting in a BUG_ON() later because the pfn cannot be found in the memory bitmap. Replacing all occurences of for_each_zone() in hibernation code with for_each_populated_zone() would fix this issue. [rjw: Rebased on top of linux-next hibernation patches.] Signed-off-by:

Gerald Schaefer <gerald.schaefer@de.ibm.com> Acked-by:

KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by:

Rafael J. Wysocki <rjw@sisk.pl>

kernel/power/snapshot.c

+6 −6

Original line number	Diff line number	Diff line
		@@ -853,7 +853,7 @@ static unsigned int count_highmem_pages(void)
		struct zone *zone;
		unsigned int n = 0;

		for_each_zone(zone) {
		for_each_populated_zone(zone) {
		unsigned long pfn, max_zone_pfn;

		if (!is_highmem(zone))
		@@ -916,7 +916,7 @@ static unsigned int count_data_pages(void)
		unsigned long pfn, max_zone_pfn;
		unsigned int n = 0;

		for_each_zone(zone) {
		for_each_populated_zone(zone) {
		if (is_highmem(zone))
		continue;

		@@ -1010,7 +1010,7 @@ copy_data_pages(struct memory_bitmap copy_bm, struct memory_bitmap orig_bm)
		struct zone *zone;
		unsigned long pfn;

		for_each_zone(zone) {
		for_each_populated_zone(zone) {
		unsigned long max_zone_pfn;

		mark_free_pages(zone);
		@@ -1065,7 +1065,7 @@ void swsusp_free(void)
		struct zone *zone;
		unsigned long pfn, max_zone_pfn;

		for_each_zone(zone) {
		for_each_populated_zone(zone) {
		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
		if (pfn_valid(pfn)) {
		@@ -1397,7 +1397,7 @@ static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
		struct zone *zone;
		unsigned int free = alloc_normal;

		for_each_zone(zone)
		for_each_populated_zone(zone)
		if (!is_highmem(zone))
		free += zone_page_state(zone, NR_FREE_PAGES);

		@@ -1688,7 +1688,7 @@ static int mark_unsafe_pages(struct memory_bitmap *bm)
		unsigned long pfn, max_zone_pfn;

		/* Clear page flags */
		for_each_zone(zone) {
		for_each_populated_zone(zone) {
		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
		if (pfn_valid(pfn))

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