From 7ff9345ffac56743b5001561bc2dc1e041b79149 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 11 Dec 2008 11:53:43 +0100 Subject: [PATCH] bio: only mempool back the largest bio_vec slab cache We only very rarely need the mempool backing, so it makes sense to get rid of all but one of the mempool in a bio_set. So keep the largest bio_vec count mempool so we can always honor the largest allocation, and "upgrade" callers that fail. Signed-off-by: Jens Axboe --- fs/bio.c | 129 +++++++++++++++++++++++++------------------- include/linux/bio.h | 3 +- 2 files changed, 76 insertions(+), 56 deletions(-) diff --git a/fs/bio.c b/fs/bio.c index df99c882b807..eb6b4683a265 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -58,7 +58,8 @@ unsigned int bvec_nr_vecs(unsigned short idx) return bvec_slabs[idx].nr_vecs; } -struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, struct bio_set *bs) +struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, + struct bio_set *bs) { struct bio_vec *bvl; @@ -67,60 +68,90 @@ struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, struct * If not, this is a bio_kmalloc() allocation and just do a * kzalloc() for the exact number of vecs right away. */ - if (bs) { - /* - * see comment near bvec_array define! - */ - switch (nr) { - case 1: - *idx = 0; - break; - case 2 ... 4: - *idx = 1; - break; - case 5 ... 16: - *idx = 2; - break; - case 17 ... 64: - *idx = 3; - break; - case 65 ... 128: - *idx = 4; - break; - case 129 ... BIO_MAX_PAGES: - *idx = 5; - break; - default: - return NULL; - } + if (!bs) + bvl = kzalloc(nr * sizeof(struct bio_vec), gfp_mask); + + /* + * see comment near bvec_array define! + */ + switch (nr) { + case 1: + *idx = 0; + break; + case 2 ... 4: + *idx = 1; + break; + case 5 ... 16: + *idx = 2; + break; + case 17 ... 64: + *idx = 3; + break; + case 65 ... 128: + *idx = 4; + break; + case 129 ... BIO_MAX_PAGES: + *idx = 5; + break; + default: + return NULL; + } + + /* + * idx now points to the pool we want to allocate from. only the + * 1-vec entry pool is mempool backed. + */ + if (*idx == BIOVEC_MAX_IDX) { +fallback: + bvl = mempool_alloc(bs->bvec_pool, gfp_mask); + } else { + struct biovec_slab *bvs = bvec_slabs + *idx; + gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO); /* - * idx now points to the pool we want to allocate from + * Make this allocation restricted and don't dump info on + * allocation failures, since we'll fallback to the mempool + * in case of failure. */ - bvl = mempool_alloc(bs->bvec_pools[*idx], gfp_mask); - if (bvl) - memset(bvl, 0, - bvec_nr_vecs(*idx) * sizeof(struct bio_vec)); - } else - bvl = kzalloc(nr * sizeof(struct bio_vec), gfp_mask); + __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; + + /* + * Try a slab allocation. If this fails and __GFP_WAIT + * is set, retry with the 1-entry mempool + */ + bvl = kmem_cache_alloc(bvs->slab, __gfp_mask); + if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) { + *idx = BIOVEC_MAX_IDX; + goto fallback; + } + } + + if (bvl) + memset(bvl, 0, bvec_nr_vecs(*idx) * sizeof(struct bio_vec)); return bvl; } -void bio_free(struct bio *bio, struct bio_set *bio_set) +void bio_free(struct bio *bio, struct bio_set *bs) { if (bio->bi_io_vec) { const int pool_idx = BIO_POOL_IDX(bio); BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS); - mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]); + if (pool_idx == BIOVEC_MAX_IDX) + mempool_free(bio->bi_io_vec, bs->bvec_pool); + else { + struct biovec_slab *bvs = bvec_slabs + pool_idx; + + kmem_cache_free(bvs->slab, bio->bi_io_vec); + } } if (bio_integrity(bio)) - bio_integrity_free(bio, bio_set); + bio_integrity_free(bio, bs); - mempool_free(bio, bio_set->bio_pool); + mempool_free(bio, bs->bio_pool); } /* @@ -1346,30 +1377,18 @@ EXPORT_SYMBOL(bio_sector_offset); */ static int biovec_create_pools(struct bio_set *bs, int pool_entries) { - int i; + struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX; - for (i = 0; i < BIOVEC_NR_POOLS; i++) { - struct biovec_slab *bp = bvec_slabs + i; - mempool_t **bvp = bs->bvec_pools + i; + bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab); + if (!bs->bvec_pool) + return -ENOMEM; - *bvp = mempool_create_slab_pool(pool_entries, bp->slab); - if (!*bvp) - return -ENOMEM; - } return 0; } static void biovec_free_pools(struct bio_set *bs) { - int i; - - for (i = 0; i < BIOVEC_NR_POOLS; i++) { - mempool_t *bvp = bs->bvec_pools[i]; - - if (bvp) - mempool_destroy(bvp); - } - + mempool_destroy(bs->bvec_pool); } void bioset_free(struct bio_set *bs) diff --git a/include/linux/bio.h b/include/linux/bio.h index 3ed714eb54d9..d76e4bf22f29 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -397,13 +397,14 @@ static inline void bio_set_completion_cpu(struct bio *bio, unsigned int cpu) */ #define BIO_POOL_SIZE 2 #define BIOVEC_NR_POOLS 6 +#define BIOVEC_MAX_IDX (BIOVEC_NR_POOLS - 1) struct bio_set { mempool_t *bio_pool; #if defined(CONFIG_BLK_DEV_INTEGRITY) mempool_t *bio_integrity_pool; #endif - mempool_t *bvec_pools[BIOVEC_NR_POOLS]; + mempool_t *bvec_pool; }; struct biovec_slab {