Messages in this thread Patch in this message | | | Subject | [PATCH] hibernate / memory hotplug: always use for_each_populated_zone() | From | Gerald Schaefer <> | Date | Mon, 20 Jul 2009 17:25:51 +0200 |
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From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
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.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> --- kernel/power/snapshot.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
Index: linux-2.6-work/kernel/power/snapshot.c =================================================================== --- linux-2.6-work.orig/kernel/power/snapshot.c +++ linux-2.6-work/kernel/power/snapshot.c @@ -853,7 +853,7 @@ static unsigned int count_highmem_pages( 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(voi 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 *co struct zone *zone; unsigned long pfn; - for_each_zone(zone) { + for_each_populated_zone(zone) { unsigned long max_zone_pfn; mark_free_pages(zone); @@ -1046,7 +1046,7 @@ 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)) { @@ -1166,7 +1166,7 @@ static int enough_free_mem(unsigned int struct zone *zone; unsigned int free = 0, meta = 0; - for_each_zone(zone) { + for_each_populated_zone(zone) { meta += snapshot_additional_pages(zone); if (!is_highmem(zone)) free += zone_page_state(zone, NR_FREE_PAGES); @@ -1474,7 +1474,7 @@ static int mark_unsafe_pages(struct memo 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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