diff options
| -rw-r--r-- | init/Kconfig | 11 | ||||
| -rw-r--r-- | mm/slub.c | 27 |
2 files changed, 32 insertions, 6 deletions
diff --git a/init/Kconfig b/init/Kconfig index 7d30240e5bfe..3b34a88cf34e 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1511,6 +1511,17 @@ config SLOB endchoice +config SLUB_CPU_PARTIAL + default y + depends on SLUB + bool "SLUB per cpu partial cache" + help + Per cpu partial caches accellerate objects allocation and freeing + that is local to a processor at the price of more indeterminism + in the latency of the free. On overflow these caches will be cleared + which requires the taking of locks that may cause latency spikes. + Typically one would choose no for a realtime system. + config MMAP_ALLOW_UNINITIALIZED bool "Allow mmapped anonymous memory to be uninitialized" depends on EXPERT && !MMU diff --git a/mm/slub.c b/mm/slub.c index 54cc4d544f3c..ef60536c5d69 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -122,6 +122,15 @@ static inline int kmem_cache_debug(struct kmem_cache *s) #endif } +static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s) +{ +#ifdef CONFIG_SLUB_CPU_PARTIAL + return !kmem_cache_debug(s); +#else + return false; +#endif +} + /* * Issues still to be resolved: * @@ -1572,7 +1581,8 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, put_cpu_partial(s, page, 0); stat(s, CPU_PARTIAL_NODE); } - if (kmem_cache_debug(s) || available > s->cpu_partial / 2) + if (!kmem_cache_has_cpu_partial(s) + || available > s->cpu_partial / 2) break; } @@ -1883,6 +1893,7 @@ redo: static void unfreeze_partials(struct kmem_cache *s, struct kmem_cache_cpu *c) { +#ifdef CONFIG_SLUB_CPU_PARTIAL struct kmem_cache_node *n = NULL, *n2 = NULL; struct page *page, *discard_page = NULL; @@ -1937,6 +1948,7 @@ static void unfreeze_partials(struct kmem_cache *s, discard_slab(s, page); stat(s, FREE_SLAB); } +#endif } /* @@ -1950,6 +1962,7 @@ static void unfreeze_partials(struct kmem_cache *s, */ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) { +#ifdef CONFIG_SLUB_CPU_PARTIAL struct page *oldpage; int pages; int pobjects; @@ -1989,6 +2002,7 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) page->next = oldpage; } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage); +#endif } static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c) @@ -2497,7 +2511,7 @@ 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_has_cpu_partial(s) && !prior) /* * Slab was on no list before and will be partially empty @@ -2552,8 +2566,9 @@ static void __slab_free(struct kmem_cache *s, struct page *page, * Objects left in the slab. If it was not on the partial list before * then add it. */ - if (kmem_cache_debug(s) && unlikely(!prior)) { - remove_full(s, page); + if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) { + if (kmem_cache_debug(s)) + remove_full(s, page); add_partial(n, page, DEACTIVATE_TO_TAIL); stat(s, FREE_ADD_PARTIAL); } @@ -3061,7 +3076,7 @@ static int kmem_cache_open(struct kmem_cache *s, unsigned long flags) * per node list when we run out of per cpu objects. We only fetch 50% * to keep some capacity around for frees. */ - if (kmem_cache_debug(s)) + if (!kmem_cache_has_cpu_partial(s)) s->cpu_partial = 0; else if (s->size >= PAGE_SIZE) s->cpu_partial = 2; @@ -4456,7 +4471,7 @@ static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf, err = strict_strtoul(buf, 10, &objects); if (err) return err; - if (objects && kmem_cache_debug(s)) + if (objects && !kmem_cache_has_cpu_partial(s)) return -EINVAL; s->cpu_partial = objects; |