diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index afdd406f618a..9e170d3c71e5 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -140,11 +140,17 @@ struct mem_cgroup { /* * We use the lower bit of the page->page_cgroup pointer as a bit spin - * lock. We need to ensure that page->page_cgroup is atleast two - * byte aligned (based on comments from Nick Piggin) + * lock. We need to ensure that page->page_cgroup is at least two + * byte aligned (based on comments from Nick Piggin). But since + * bit_spin_lock doesn't actually set that lock bit in a non-debug + * uniprocessor kernel, we should avoid setting it here too. */ #define PAGE_CGROUP_LOCK_BIT 0x0 -#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT) +#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) +#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT) +#else +#define PAGE_CGROUP_LOCK 0x0 +#endif /* * A page_cgroup page is associated with every page descriptor. The @@ -271,19 +277,10 @@ static inline int page_cgroup_locked(struct page *page) &page->page_cgroup); } -void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc) +static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc) { - int locked; - - /* - * While resetting the page_cgroup we might not hold the - * page_cgroup lock. free_hot_cold_page() is an example - * of such a scenario - */ - if (pc) - VM_BUG_ON(!page_cgroup_locked(page)); - locked = (page->page_cgroup & PAGE_CGROUP_LOCK); - page->page_cgroup = ((unsigned long)pc | locked); + VM_BUG_ON(!page_cgroup_locked(page)); + page->page_cgroup = ((unsigned long)pc | PAGE_CGROUP_LOCK); } struct page_cgroup *page_get_page_cgroup(struct page *page) |