diff options
| -rw-r--r-- | include/linux/swap.h | 2 | ||||
| -rw-r--r-- | mm/compaction.c | 42 | ||||
| -rw-r--r-- | mm/vmscan.c | 43 |
3 files changed, 56 insertions, 31 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index 5e1e967c225f..596bc2f4d9b0 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -356,7 +356,7 @@ extern void lru_cache_add_inactive_or_unevictable(struct page *page, extern unsigned long zone_reclaimable_pages(struct zone *zone); extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order, gfp_t gfp_mask, nodemask_t *mask); -extern int __isolate_lru_page(struct page *page, isolate_mode_t mode); +extern int __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode); extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg, unsigned long nr_pages, gfp_t gfp_mask, diff --git a/mm/compaction.c b/mm/compaction.c index dbcfdfce1b82..50938e66083c 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -890,6 +890,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, if (!valid_page && IS_ALIGNED(low_pfn, pageblock_nr_pages)) { if (!cc->ignore_skip_hint && get_pageblock_skip(page)) { low_pfn = end_pfn; + page = NULL; goto isolate_abort; } valid_page = page; @@ -971,6 +972,21 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, if (!(cc->gfp_mask & __GFP_FS) && page_mapping(page)) goto isolate_fail; + /* + * Be careful not to clear PageLRU until after we're + * sure the page is not being freed elsewhere -- the + * page release code relies on it. + */ + if (unlikely(!get_page_unless_zero(page))) + goto isolate_fail; + + if (__isolate_lru_page_prepare(page, isolate_mode) != 0) + goto isolate_fail_put; + + /* Try isolate the page */ + if (!TestClearPageLRU(page)) + goto isolate_fail_put; + /* If we already hold the lock, we can skip some rechecking */ if (!locked) { locked = compact_lock_irqsave(&pgdat->lru_lock, @@ -983,10 +999,6 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, goto isolate_abort; } - /* Recheck PageLRU and PageCompound under lock */ - if (!PageLRU(page)) - goto isolate_fail; - /* * Page become compound since the non-locked check, * and it's on LRU. It can only be a THP so the order @@ -994,16 +1006,13 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, */ if (unlikely(PageCompound(page) && !cc->alloc_contig)) { low_pfn += compound_nr(page) - 1; - goto isolate_fail; + SetPageLRU(page); + goto isolate_fail_put; } } lruvec = mem_cgroup_page_lruvec(page, pgdat); - /* Try isolate the page */ - if (__isolate_lru_page(page, isolate_mode) != 0) - goto isolate_fail; - /* The whole page is taken off the LRU; skip the tail pages. */ if (PageCompound(page)) low_pfn += compound_nr(page) - 1; @@ -1032,6 +1041,15 @@ isolate_success: } continue; + +isolate_fail_put: + /* Avoid potential deadlock in freeing page under lru_lock */ + if (locked) { + spin_unlock_irqrestore(&pgdat->lru_lock, flags); + locked = false; + } + put_page(page); + isolate_fail: if (!skip_on_failure) continue; @@ -1068,9 +1086,15 @@ isolate_fail: if (unlikely(low_pfn > end_pfn)) low_pfn = end_pfn; + page = NULL; + isolate_abort: if (locked) spin_unlock_irqrestore(&pgdat->lru_lock, flags); + if (page) { + SetPageLRU(page); + put_page(page); + } /* * Updated the cached scanner pfn once the pageblock has been scanned diff --git a/mm/vmscan.c b/mm/vmscan.c index 54ab9cbb631a..cf99e66e7f33 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1539,7 +1539,7 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone, * * returns 0 on success, -ve errno on failure. */ -int __isolate_lru_page(struct page *page, isolate_mode_t mode) +int __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode) { int ret = -EBUSY; @@ -1591,22 +1591,9 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode) if ((mode & ISOLATE_UNMAPPED) && page_mapped(page)) return ret; - if (likely(get_page_unless_zero(page))) { - /* - * Be careful not to clear PageLRU until after we're - * sure the page is not being freed elsewhere -- the - * page release code relies on it. - */ - if (TestClearPageLRU(page)) - ret = 0; - else - put_page(page); - } - - return ret; + return 0; } - /* * Update LRU sizes after isolating pages. The LRU size updates must * be complete before mem_cgroup_update_lru_size due to a sanity check. @@ -1686,20 +1673,34 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan, * only when the page is being freed somewhere else. */ scan += nr_pages; - switch (__isolate_lru_page(page, mode)) { + switch (__isolate_lru_page_prepare(page, mode)) { case 0: + /* + * Be careful not to clear PageLRU until after we're + * sure the page is not being freed elsewhere -- the + * page release code relies on it. + */ + if (unlikely(!get_page_unless_zero(page))) + goto busy; + + if (!TestClearPageLRU(page)) { + /* + * This page may in other isolation path, + * but we still hold lru_lock. + */ + put_page(page); + goto busy; + } + nr_taken += nr_pages; nr_zone_taken[page_zonenum(page)] += nr_pages; list_move(&page->lru, dst); break; - case -EBUSY: + default: +busy: /* else it is being freed elsewhere */ list_move(&page->lru, src); - continue; - - default: - BUG(); } } |