diff options
| -rw-r--r-- | include/linux/page-isolation.h | 4 | ||||
| -rw-r--r-- | mm/debug.c | 10 | ||||
| -rw-r--r-- | mm/page_alloc.c | 23 | ||||
| -rw-r--r-- | mm/page_isolation.c | 11 |
4 files changed, 31 insertions, 17 deletions
diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h index 148e65a9c606..572458016331 100644 --- a/include/linux/page-isolation.h +++ b/include/linux/page-isolation.h @@ -33,8 +33,8 @@ static inline bool is_migrate_isolate(int migratetype) #define MEMORY_OFFLINE 0x1 #define REPORT_FAILURE 0x2 -bool has_unmovable_pages(struct zone *zone, struct page *page, int migratetype, - int flags); +struct page *has_unmovable_pages(struct zone *zone, struct page *page, + int migratetype, int flags); void set_pageblock_migratetype(struct page *page, int migratetype); int move_freepages_block(struct zone *zone, struct page *page, int migratetype, int *num_movable); diff --git a/mm/debug.c b/mm/debug.c index 4a9ded0d3504..ecccd9f17801 100644 --- a/mm/debug.c +++ b/mm/debug.c @@ -46,6 +46,13 @@ void __dump_page(struct page *page, const char *reason) { struct address_space *mapping; bool page_poisoned = PagePoisoned(page); + /* + * Accessing the pageblock without the zone lock. It could change to + * "isolate" again in the meantime, but since we are just dumping the + * state for debugging, it should be fine to accept a bit of + * inaccuracy here due to racing. + */ + bool page_cma = is_migrate_cma_page(page); int mapcount; char *type = ""; @@ -92,7 +99,8 @@ void __dump_page(struct page *page, const char *reason) } BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1); - pr_warn("%sflags: %#lx(%pGp)\n", type, page->flags, &page->flags); + pr_warn("%sflags: %#lx(%pGp)%s\n", type, page->flags, &page->flags, + page_cma ? " CMA" : ""); hex_only: print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32, diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3aec60ddd6d6..2a1a816c7992 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8185,13 +8185,17 @@ void *__init alloc_large_system_hash(const char *tablename, * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable * check without lock_page also may miss some movable non-lru pages at * race condition. So you can't expect this function should be exact. + * + * Returns a page without holding a reference. If the caller wants to + * dereference that page (e.g., dumping), it has to make sure that that it + * cannot get removed (e.g., via memory unplug) concurrently. + * */ -bool has_unmovable_pages(struct zone *zone, struct page *page, int migratetype, - int flags) +struct page *has_unmovable_pages(struct zone *zone, struct page *page, + int migratetype, int flags) { unsigned long iter = 0; unsigned long pfn = page_to_pfn(page); - const char *reason = "unmovable page"; /* * TODO we could make this much more efficient by not checking every @@ -8208,9 +8212,8 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int migratetype, * so consider them movable here. */ if (is_migrate_cma(migratetype)) - return false; + return NULL; - reason = "CMA page"; goto unmovable; } @@ -8285,12 +8288,10 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int migratetype, */ goto unmovable; } - return false; + return NULL; unmovable: WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE); - if (flags & REPORT_FAILURE) - dump_page(pfn_to_page(pfn + iter), reason); - return true; + return pfn_to_page(pfn + iter); } #ifdef CONFIG_CONTIG_ALLOC @@ -8694,10 +8695,6 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) BUG_ON(!PageBuddy(page)); order = page_order(page); offlined_pages += 1 << order; -#ifdef CONFIG_DEBUG_VM - pr_info("remove from free list %lx %d %lx\n", - pfn, 1 << order, end_pfn); -#endif del_page_from_free_area(page, &zone->free_area[order]); pfn += (1 << order); } diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 1f8b9dfecbe8..e70586523ca3 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -17,6 +17,7 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_flags) { + struct page *unmovable = NULL; struct zone *zone; unsigned long flags; int ret = -EBUSY; @@ -37,7 +38,8 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_ * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself. * We just check MOVABLE pages. */ - if (!has_unmovable_pages(zone, page, migratetype, isol_flags)) { + unmovable = has_unmovable_pages(zone, page, migratetype, isol_flags); + if (!unmovable) { unsigned long nr_pages; int mt = get_pageblock_migratetype(page); @@ -54,6 +56,13 @@ out: spin_unlock_irqrestore(&zone->lock, flags); if (!ret) drain_all_pages(zone); + else if ((isol_flags & REPORT_FAILURE) && unmovable) + /* + * printk() with zone->lock held will guarantee to trigger a + * lockdep splat, so defer it here. + */ + dump_page(unmovable, "unmovable page"); + return ret; } |