From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: [PATCH 3/4] block: add bioset_nobvec_create() Date: Fri, 3 Oct 2014 09:16:05 -0400 Message-ID: <20141003131605.GA11977@redhat.com> References: <542E8CF9.6000609@ce.jp.nec.com> <542E8EAB.5010603@ce.jp.nec.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <542E8EAB.5010603@ce.jp.nec.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Junichi Nomura Cc: Jens Axboe , device-mapper development , Kent Overstreet List-Id: dm-devel.ids On Fri, Oct 03 2014 at 7:55am -0400, Junichi Nomura wrote: > Users of bio_clone_fast() do not need its own bvecs. > Allocating bvec mempool for such users is waste of memory. > > This variant allows them to create bioset without bvec mempool. > > Signed-off-by: Jun'ichi Nomura > --- > 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 3e6331d..98c5100 100644 > --- a/block/bio.c > +++ b/block/bio.c > @@ -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, > + unsigned int create_bvec_pool) > { > unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); > struct bio_set *bs; Any reason not to use bool for create_bvec_pool? > @@ -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, 1); > +} > EXPORT_SYMBOL(bioset_create); > > +/** > + * bioset_nobvec_create - 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_nobvec_create(unsigned int pool_size, unsigned int front_pad) > +{ > + return __bioset_create(pool_size, front_pad, 0); > +} > +EXPORT_SYMBOL(bioset_nobvec_create); > + > #ifdef CONFIG_BLK_CGROUP > /** > * bio_associate_current - associate a bio with %current And use true and false accordingly... > diff --git a/include/linux/bio.h b/include/linux/bio.h > index b39e500..7d7b2a7 100644 > --- a/include/linux/bio.h > +++ b/include/linux/bio.h > @@ -342,6 +342,7 @@ 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_nobvec_create(unsigned int, unsigned int); > extern void bioset_free(struct bio_set *); > extern mempool_t *biovec_create_pool(int pool_entries); Also, I prefer the function name: bioset_create_nobvec (to keep it in the "bioset_create" family). Otherwise, please feel free to add to v2: Acked-by: Mike Snitzer