On Tue 11-08-20 18:28:23, Charan Teja Reddy wrote: [...] > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index e4896e6..839039f 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1304,6 +1304,11 @@ static void free_pcppages_bulk(struct zone *zone, int count, > struct page *page, *tmp; > LIST_HEAD(head); > > + /* > + * Ensure proper count is passed which otherwise would stuck in the > + * below while (list_empty(list)) loop. > + */ > + count = min(pcp->count, count); > while (count) { > struct list_head *list; How does this prevent the race actually? Don't we need something like the following instead? diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e028b87ce294..45bcc7ba37c4 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1317,9 +1317,16 @@ static void free_pcppages_bulk(struct zone *zone, int count, * lists */ do { + bool looped = false; + batch_free++; - if (++migratetype == MIGRATE_PCPTYPES) + if (++migratetype == MIGRATE_PCPTYPES) { + if (looped) + goto free; + migratetype = 0; + looped = true; + } list = &pcp->lists[migratetype]; } while (list_empty(list)); @@ -1352,6 +1359,7 @@ static void free_pcppages_bulk(struct zone *zone, int count, } while (--count && --batch_free && !list_empty(list)); } +free: spin_lock(&zone->lock); isolated_pageblocks = has_isolate_pageblock(zone); -- Michal Hocko SUSE Labs