diff mbox

[3/4] block: add bioset_nobvec_create()

Message ID 542E8EAB.5010603@ce.jp.nec.com (mailing list archive)
State Superseded, archived
Delegated to: Mike Snitzer
Headers show

Commit Message

Junichi Nomura Oct. 3, 2014, 11:55 a.m. UTC
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 <j-nomura@ce.jp.nec.com>
---
 block/bio.c         | 61 ++++++++++++++++++++++++++++++++++++++---------------
 include/linux/bio.h |  1 +
 2 files changed, 45 insertions(+), 17 deletions(-)

Comments

Mike Snitzer Oct. 3, 2014, 1:16 p.m. UTC | #1
On Fri, Oct 03 2014 at  7:55am -0400,
Junichi Nomura <j-nomura@ce.jp.nec.com> 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 <j-nomura@ce.jp.nec.com>
> ---
>  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 <snitzer@redhat.com>

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diff mbox

Patch

diff --git a/block/bio.c b/block/bio.c
index 3e6331d..98c5100 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,
+				       unsigned int 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, 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
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);