From: Peter Zijlstra <[email protected]> Instead of using comments in an attempt at getting the locking right, use proper assertions that actively warn you if you got it wrong.
Also add extra braces in a few sites to comply with coding-style. Signed-off-by: Peter Zijlstra <[email protected]> Signed-off-by: Pekka Enberg <[email protected]> [ported from ms, resolved conflict with commit 345c905d13a4 ("slub: Make cpu partial slab support configurable")] Signed-off-by: Dmitry Safonov <[email protected]> --- mm/slub.c | 40 ++++++++++++++++++++-------------------- 1 file changed, 20 insertions(+), 20 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 2f07a63..93068da 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -956,23 +956,22 @@ static void trace(struct kmem_cache *s, struct page *page, void *object, /* * Tracking of fully allocated slabs for debugging purposes. - * - * list_lock must be held. */ static void add_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page) { + lockdep_assert_held(&n->list_lock); + if (!(s->flags & SLAB_STORE_USER)) return; list_add(&page->lru, &n->full); } -/* - * list_lock must be held. - */ -static void remove_full(struct kmem_cache *s, struct page *page) +static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page) { + lockdep_assert_held(&n->list_lock); + if (!(s->flags & SLAB_STORE_USER)) return; @@ -1220,7 +1219,8 @@ static inline int check_object(struct kmem_cache *s, struct page *page, void *object, u8 val) { return 1; } static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page) {} -static inline void remove_full(struct kmem_cache *s, struct page *page) {} +static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, + struct page *page) {} static inline unsigned long kmem_cache_flags(unsigned long object_size, unsigned long flags, const char *name, void (*ctor)(void *)) @@ -1507,12 +1507,12 @@ static void discard_slab(struct kmem_cache *s, struct page *page) /* * Management of partially allocated slabs. - * - * list_lock must be held. */ static inline void add_partial(struct kmem_cache_node *n, struct page *page, int tail) { + lockdep_assert_held(&n->list_lock); + n->nr_partial++; if (tail == DEACTIVATE_TO_TAIL) list_add_tail(&page->lru, &n->partial); @@ -1520,12 +1520,11 @@ static inline void add_partial(struct kmem_cache_node *n, list_add(&page->lru, &n->partial); } -/* - * list_lock must be held. - */ static inline void remove_partial(struct kmem_cache_node *n, struct page *page) { + lockdep_assert_held(&n->list_lock); + list_del(&page->lru); n->nr_partial--; } @@ -1535,8 +1534,6 @@ static inline void remove_partial(struct kmem_cache_node *n, * return the pointer to the freelist. * * Returns a list of objects or NULL if it fails. - * - * Must hold list_lock since we modify the partial list. */ static inline void *acquire_slab(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page, @@ -1546,6 +1543,8 @@ static inline void *acquire_slab(struct kmem_cache *s, unsigned long counters; struct page new; + lockdep_assert_held(&n->list_lock); + /* * Zap the freelist and set the frozen bit. * The old freelist is the list of objects for the @@ -1893,7 +1892,7 @@ redo: else if (l == M_FULL) - remove_full(s, page); + remove_full(s, n, page); if (m == M_PARTIAL) { @@ -2559,7 +2558,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page, new.inuse--; if ((!new.inuse || !prior) && !was_frozen) { - if (!kmem_cache_debug(s) && !prior) + if (!kmem_cache_debug(s) && !prior) { /* * Slab was on no list before and will be partially empty @@ -2567,7 +2566,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page, */ new.frozen = 1; - else { /* Needs to be taken off a list */ + } else { /* Needs to be taken off a list */ n = get_node(s, page_to_nid(page)); /* @@ -2615,7 +2614,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page, * then add it. */ if (kmem_cache_debug(s) && unlikely(!prior)) { - remove_full(s, page); + remove_full(s, n, page); add_partial(n, page, DEACTIVATE_TO_TAIL); stat(s, FREE_ADD_PARTIAL); } @@ -2629,9 +2628,10 @@ slab_empty: */ remove_partial(n, page); stat(s, FREE_REMOVE_PARTIAL); - } else + } else { /* Slab must be on the full list */ - remove_full(s, page); + remove_full(s, n, page); + } spin_unlock_irqrestore(&n->list_lock, flags); stat(s, FREE_SLAB); -- 2.7.2 _______________________________________________ Devel mailing list [email protected] https://lists.openvz.org/mailman/listinfo/devel
