diff options
| -rw-r--r-- | include/linux/mm.h | 6 | ||||
| -rw-r--r-- | include/linux/mmzone.h | 14 | ||||
| -rw-r--r-- | mm/page_alloc.c | 11 |
3 files changed, 23 insertions, 8 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 083cc0ba23848..4310f80ce956b 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1313,6 +1313,7 @@ extern void free_initmem(void); */ extern unsigned long free_reserved_area(void *start, void *end, int poison, char *s); + #ifdef CONFIG_HIGHMEM /* * Free a highmem page into the buddy system, adjusting totalhigh_pages @@ -1321,10 +1322,7 @@ extern unsigned long free_reserved_area(void *start, void *end, extern void free_highmem_page(struct page *page); #endif -static inline void adjust_managed_page_count(struct page *page, long count) -{ - totalram_pages += count; -} +extern void adjust_managed_page_count(struct page *page, long count); /* Free the reserved page into the buddy system, so it gets managed. */ static inline void __free_reserved_page(struct page *page) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index e511f9429f1e3..09d381b71fd8a 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -474,10 +474,16 @@ struct zone { * frequently read in proximity to zone->lock. It's good to * give them a chance of being in the same cacheline. * - * Write access to present_pages and managed_pages at runtime should - * be protected by lock_memory_hotplug()/unlock_memory_hotplug(). - * Any reader who can't tolerant drift of present_pages and - * managed_pages should hold memory hotplug lock to get a stable value. + * Write access to present_pages at runtime should be protected by + * lock_memory_hotplug()/unlock_memory_hotplug(). Any reader who can't + * tolerant drift of present_pages should hold memory hotplug lock to + * get a stable value. + * + * Read access to managed_pages should be safe because it's unsigned + * long. Write access to zone->managed_pages and totalram_pages are + * protected by managed_page_count_lock at runtime. Idealy only + * adjust_managed_page_count() should be used instead of directly + * touching zone->managed_pages and totalram_pages. */ unsigned long spanned_pages; unsigned long present_pages; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 22438eba00b63..93f292a60cb03 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -103,6 +103,9 @@ nodemask_t node_states[NR_NODE_STATES] __read_mostly = { }; EXPORT_SYMBOL(node_states); +/* Protect totalram_pages and zone->managed_pages */ +static DEFINE_SPINLOCK(managed_page_count_lock); + unsigned long totalram_pages __read_mostly; unsigned long totalreserve_pages __read_mostly; /* @@ -5206,6 +5209,14 @@ early_param("movablecore", cmdline_parse_movablecore); #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ +void adjust_managed_page_count(struct page *page, long count) +{ + spin_lock(&managed_page_count_lock); + page_zone(page)->managed_pages += count; + totalram_pages += count; + spin_unlock(&managed_page_count_lock); +} + unsigned long free_reserved_area(void *start, void *end, int poison, char *s) { void *pos; |