From d8f429e1669b9709f5b669aac9d734dbe0640891 Mon Sep 17 00:00:00 2001 From: Junichi Nomura Date: Fri, 3 Oct 2014 17:27:12 -0400 Subject: [PATCH] block: add bioset_create_nobvec() Users of bio_clone_fast() do not want bios with their own bvecs. Allocating a bvec mempool as part of the bioset intended for such users is a waste of memory. bioset_create_nobvec() creates a bioset that doesn't have the bvec mempool. Signed-off-by: Jun'ichi Nomura Signed-off-by: Mike Snitzer Signed-off-by: Jens Axboe --- block/bio.c | 61 ++++++++++++++++++++++++++++++++------------- include/linux/bio.h | 1 + 2 files changed, 45 insertions(+), 17 deletions(-) diff --git a/block/bio.c b/block/bio.c index 3e6331d25d90..3e6e1986a5b2 100644 --- a/block/bio.c +++ b/block/bio.c @@ -428,6 +428,9 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) front_pad = 0; inline_vecs = nr_iovecs; } else { + /* should not use nobvec bioset for nr_iovecs > 0 */ + if (WARN_ON_ONCE(!bs->bvec_pool && nr_iovecs > 0)) + return NULL; /* * generic_make_request() converts recursion to iteration; this * means if we're running beneath it, any bios we allocate and @@ -1900,20 +1903,9 @@ void bioset_free(struct bio_set *bs) } EXPORT_SYMBOL(bioset_free); -/** - * bioset_create - Create a bio_set - * @pool_size: Number of bio and bio_vecs to cache in the mempool - * @front_pad: Number of bytes to allocate in front of the returned bio - * - * Description: - * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller - * to ask for a number of bytes to be allocated in front of the bio. - * Front pad allocation is useful for embedding the bio inside - * another structure, to avoid allocating extra data to go with the bio. - * Note that the bio must be embedded at the END of that structure always, - * or things will break badly. - */ -struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad) +static struct bio_set *__bioset_create(unsigned int pool_size, + unsigned int front_pad, + bool create_bvec_pool) { unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); struct bio_set *bs; @@ -1938,9 +1930,11 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad) if (!bs->bio_pool) goto bad; - bs->bvec_pool = biovec_create_pool(pool_size); - if (!bs->bvec_pool) - goto bad; + if (create_bvec_pool) { + bs->bvec_pool = biovec_create_pool(pool_size); + if (!bs->bvec_pool) + goto bad; + } bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0); if (!bs->rescue_workqueue) @@ -1951,8 +1945,41 @@ bad: bioset_free(bs); return NULL; } + +/** + * bioset_create - Create a bio_set + * @pool_size: Number of bio and bio_vecs to cache in the mempool + * @front_pad: Number of bytes to allocate in front of the returned bio + * + * Description: + * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller + * to ask for a number of bytes to be allocated in front of the bio. + * Front pad allocation is useful for embedding the bio inside + * another structure, to avoid allocating extra data to go with the bio. + * Note that the bio must be embedded at the END of that structure always, + * or things will break badly. + */ +struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad) +{ + return __bioset_create(pool_size, front_pad, true); +} EXPORT_SYMBOL(bioset_create); +/** + * bioset_create_nobvec - Create a bio_set without bio_vec mempool + * @pool_size: Number of bio to cache in the mempool + * @front_pad: Number of bytes to allocate in front of the returned bio + * + * Description: + * Same functionality as bioset_create() except that mempool is not + * created for bio_vecs. Saving some memory for bio_clone_fast() users. + */ +struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_pad) +{ + return __bioset_create(pool_size, front_pad, false); +} +EXPORT_SYMBOL(bioset_create_nobvec); + #ifdef CONFIG_BLK_CGROUP /** * bio_associate_current - associate a bio with %current diff --git a/include/linux/bio.h b/include/linux/bio.h index ce6b75964b71..7347f486ceca 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -378,6 +378,7 @@ static inline struct bio *bio_next_split(struct bio *bio, int sectors, } extern struct bio_set *bioset_create(unsigned int, unsigned int); +extern struct bio_set *bioset_create_nobvec(unsigned int, unsigned int); extern void bioset_free(struct bio_set *); extern mempool_t *biovec_create_pool(int pool_entries);