Commit f007a3d6 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: streamline bvec_alloc 



Avoid the pointless goto by trying the slab allocation first and falling
through to the mempool.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f2c3eb9b

block/bio.c

+10 −16
Original line number Diff line number Diff line
@@ -172,8 +172,6 @@ static inline gfp_t bvec_alloc_gfp(gfp_t gfp) 
struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,

			   mempool_t *pool)

{

	struct bio_vec *bvl;



	/*

	 * see comment near bvec_array define!

	 */
@@ -201,28 +199,24 @@ struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx, 
	}



	/*

	 * idx now points to the pool we want to allocate from. only the

	 * 1-vec entry pool is mempool backed.

	 * Try a slab allocation first for all smaller allocations.  If that

	 * fails and __GFP_DIRECT_RECLAIM is set retry with the mempool.

	 * The mempool is sized to handle up to BIO_MAX_PAGES entries.

	 */

	if (*idx == BVEC_POOL_MAX) {

fallback:

		bvl = mempool_alloc(pool, gfp_mask);

	} else {

	if (*idx < BVEC_POOL_MAX) {

		struct biovec_slab *bvs = bvec_slabs + *idx;

		struct bio_vec *bvl;



		/*

		 * Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM

		 * is set, retry with the 1-entry mempool

		 */

		bvl = kmem_cache_alloc(bvs->slab, bvec_alloc_gfp(gfp_mask));

		if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) {

			*idx = BVEC_POOL_MAX;

			goto fallback;

		if (likely(bvl) || !(gfp_mask & __GFP_DIRECT_RECLAIM)) {

			(*idx)++;

			return bvl;

		}

		*idx = BVEC_POOL_MAX;

	}



	(*idx)++;

	return bvl;

	return mempool_alloc(pool, gfp_mask);

}



void bio_uninit(struct bio *bio)