> @@ -2579,20 +2612,22 @@ struct page *buffered_rmqueue(struct zone *preferred_zone,
> struct list_head *list;
>
> local_irq_save(flags);
> - pcp = &this_cpu_ptr(zone->pageset)->pcp;
> - list = &pcp->lists[migratetype];
> - if (list_empty(list)) {
> - pcp->count += rmqueue_bulk(zone, 0,
> - pcp->batch, list,
> - migratetype, cold);
> - if (unlikely(list_empty(list)))
> - goto failed;
> - }
> + do {
> + pcp = &this_cpu_ptr(zone->pageset)->pcp;
> + list = &pcp->lists[migratetype];
> + if (list_empty(list)) {
> + pcp->count += rmqueue_bulk(zone, 0,
> + pcp->batch, list,
> + migratetype, cold);
> + if (unlikely(list_empty(list)))
> + goto failed;
> + }
>
> - if (cold)
> - page = list_last_entry(list, struct page, lru);
> - else
> - page = list_first_entry(list, struct page, lru);
> + if (cold)
> + page = list_last_entry(list, struct page, lru);
> + else
> + page = list_first_entry(list, struct page, lru);
> + } while (page && check_new_pcp(page));
This causes infinite loop when check_new_pcp() returns 1, because the bad
page is still in the list (I assume that a bad page never disappears).
The original kernel is free from this problem because we do retry after
list_del(). So moving the following 3 lines into this do-while block solves
the problem?
__dec_zone_state(zone, NR_ALLOC_BATCH);
list_del(&page->lru);
pcp->count--;
There seems no infinit loop issue in order > 0 block below, because bad pages
are deleted from free list in __rmqueue_smallest().
Thanks,
Naoya Horiguchi
>
> __dec_zone_state(zone, NR_ALLOC_BATCH);
> list_del(&page->lru);
> @@ -2605,14 +2640,16 @@ struct page *buffered_rmqueue(struct zone *preferred_zone,
> WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
> spin_lock_irqsave(&zone->lock, flags);
>
> - page = NULL;
> - if (alloc_flags & ALLOC_HARDER) {
> - page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
> - if (page)
> - trace_mm_page_alloc_zone_locked(page, order, migratetype);
> - }
> - if (!page)
> - page = __rmqueue(zone, order, migratetype);
> + do {
> + page = NULL;
> + if (alloc_flags & ALLOC_HARDER) {
> + page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
> + if (page)
> + trace_mm_page_alloc_zone_locked(page, order, migratetype);
> + }
> + if (!page)
> + page = __rmqueue(zone, order, migratetype);
> + } while (page && check_new_pages(page, order));
> spin_unlock(&zone->lock);
> if (!page)
> goto failed;
> @@ -2979,8 +3016,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
> page = buffered_rmqueue(ac->preferred_zoneref->zone, zone, order,
> gfp_mask, alloc_flags, ac->migratetype);
> if (page) {
> - if (prep_new_page(page, order, gfp_mask, alloc_flags))
> - goto try_this_zone;
> + prep_new_page(page, order, gfp_mask, alloc_flags);
>
> /*
> * If this is a high-order atomic allocation then check
> --
> 2.6.4
>
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