On Tue, 26 Mar 2019 at 01:31, Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> wrote:
>
>
> Ok, thanks.
>
> Trying one last time before putting together a debugging patch to see
> exactly what PFNs are triggering as I still have not reproduced this on a
> local machine. This is another replacement that is based on the assumption
> that it's the free_pfn at the end of the zone that is triggering the
> warning and it happens to be the case the end of a zone is aligned. Sorry
> for the frustration with this and for persisting.
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index f171a83707ce..b4930bf93c8a 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -242,6 +242,7 @@ __reset_isolation_pfn(struct zone *zone, unsigned long pfn, bool check_source,
> bool check_target)
> {
> struct page *page = pfn_to_online_page(pfn);
> + struct page *block_page;
> struct page *end_page;
> unsigned long block_pfn;
>
> @@ -267,20 +268,26 @@ __reset_isolation_pfn(struct zone *zone, unsigned long pfn, bool check_source,
> get_pageblock_migratetype(page) != MIGRATE_MOVABLE)
> return false;
>
> + /* Ensure the start of the pageblock or zone is online and valid */
> + block_pfn = pageblock_start_pfn(pfn);
> + block_page = pfn_to_online_page(max(block_pfn, zone->zone_start_pfn));
> + if (block_page) {
> + page = block_page;
> + pfn = block_pfn;
> + }
> +
> + /* Ensure the end of the pageblock or zone is online and valid */
> + block_pfn += pageblock_nr_pages;
> + block_pfn = min(block_pfn, zone_end_pfn(zone) - 1);
> + end_page = pfn_to_online_page(block_pfn);
> + if (!end_page)
> + return false;
> +
> /*
> * Only clear the hint if a sample indicates there is either a
> * free page or an LRU page in the block. One or other condition
> * is necessary for the block to be a migration source/target.
> */
> - block_pfn = pageblock_start_pfn(pfn);
> - pfn = max(block_pfn, zone->zone_start_pfn);
> - page = pfn_to_page(pfn);
> - if (zone != page_zone(page))
> - return false;
> - pfn = block_pfn + pageblock_nr_pages;
> - pfn = min(pfn, zone_end_pfn(zone));
> - end_page = pfn_to_page(pfn);
> -
> do {
> if (pfn_valid_within(pfn)) {
> if (check_source && PageLRU(page)) {
> @@ -309,7 +316,7 @@ __reset_isolation_pfn(struct zone *zone, unsigned long pfn, bool check_source,
> static void __reset_isolation_suitable(struct zone *zone)
> {
> unsigned long migrate_pfn = zone->zone_start_pfn;
> - unsigned long free_pfn = zone_end_pfn(zone);
> + unsigned long free_pfn = zone_end_pfn(zone) - 1;
> unsigned long reset_migrate = free_pfn;
> unsigned long reset_free = migrate_pfn;
> bool source_set = false;
>
>
>
> --
> Mel Gorman
> SUSE Labs
I do not want to hurry, but it looks like this patch has fixed the problem.
I will watch for a day.
But the system has already experienced a night without a hang (kernel panic).
--
Best Regards,
Mike Gavrilov.
