[RFC] [PATCH] bio-set patch on latest bk source tree

From: Dave Olien
Date: Mon Jan 31 2005 - 20:12:27 EST


Hi, Jens,

I sent you a patch for review about a week ago. Here is that same
patch, applied to the latest bk kernel. Thanks in advance for the review

Dave Olien


===== drivers/md/dm.c 1.61 vs edited =====
--- 1.61/drivers/md/dm.c 2005-01-25 13:50:21 -08:00
+++ edited/drivers/md/dm.c 2005-01-31 11:37:27 -08:00
@@ -96,10 +96,16 @@ struct mapped_device {
static kmem_cache_t *_io_cache;
static kmem_cache_t *_tio_cache;

+static struct bio_set *dm_set;
+
static int __init local_init(void)
{
int r;

+ dm_set = bioset_create(512, 512, 1);
+ if (!dm_set)
+ return -ENOMEM;
+
/* allocate a slab for the dm_ios */
_io_cache = kmem_cache_create("dm_io",
sizeof(struct dm_io), 0, 0, NULL, NULL);
@@ -133,6 +139,8 @@ static void local_exit(void)
kmem_cache_destroy(_tio_cache);
kmem_cache_destroy(_io_cache);

+ bioset_free(dm_set);
+
if (unregister_blkdev(_major, _name) < 0)
DMERR("devfs_unregister_blkdev failed");

@@ -393,7 +401,7 @@ static struct bio *split_bvec(struct bio
struct bio *clone;
struct bio_vec *bv = bio->bi_io_vec + idx;

- clone = bio_alloc(GFP_NOIO, 1);
+ clone = bio_alloc_bs(GFP_NOIO, 1, dm_set);
*clone->bi_io_vec = *bv;

clone->bi_sector = sector;
===== drivers/md/dm-io.c 1.4 vs edited =====
--- 1.4/drivers/md/dm-io.c 2005-01-25 13:50:21 -08:00
+++ edited/drivers/md/dm-io.c 2005-01-31 11:45:42 -08:00
@@ -12,191 +12,7 @@
#include <linux/sched.h>
#include <linux/slab.h>

-#define BIO_POOL_SIZE 256
-
-
-/*-----------------------------------------------------------------
- * Bio set, move this to bio.c
- *---------------------------------------------------------------*/
-#define BV_NAME_SIZE 16
-struct biovec_pool {
- int nr_vecs;
- char name[BV_NAME_SIZE];
- kmem_cache_t *slab;
- mempool_t *pool;
- atomic_t allocated; /* FIXME: debug */
-};
-
-#define BIOVEC_NR_POOLS 6
-struct bio_set {
- char name[BV_NAME_SIZE];
- kmem_cache_t *bio_slab;
- mempool_t *bio_pool;
- struct biovec_pool pools[BIOVEC_NR_POOLS];
-};
-
-static void bio_set_exit(struct bio_set *bs)
-{
- unsigned i;
- struct biovec_pool *bp;
-
- if (bs->bio_pool)
- mempool_destroy(bs->bio_pool);
-
- if (bs->bio_slab)
- kmem_cache_destroy(bs->bio_slab);
-
- for (i = 0; i < BIOVEC_NR_POOLS; i++) {
- bp = bs->pools + i;
- if (bp->pool)
- mempool_destroy(bp->pool);
-
- if (bp->slab)
- kmem_cache_destroy(bp->slab);
- }
-}
-
-static void mk_name(char *str, size_t len, const char *prefix, unsigned count)
-{
- snprintf(str, len, "%s-%u", prefix, count);
-}
-
-static int bio_set_init(struct bio_set *bs, const char *slab_prefix,
- unsigned pool_entries, unsigned scale)
-{
- /* FIXME: this must match bvec_index(), why not go the
- * whole hog and have a pool per power of 2 ? */
- static unsigned _vec_lengths[BIOVEC_NR_POOLS] = {
- 1, 4, 16, 64, 128, BIO_MAX_PAGES
- };
-
-
- unsigned i, size;
- struct biovec_pool *bp;
-
- /* zero the bs so we can tear down properly on error */
- memset(bs, 0, sizeof(*bs));
-
- /*
- * Set up the bio pool.
- */
- snprintf(bs->name, sizeof(bs->name), "%s-bio", slab_prefix);
-
- bs->bio_slab = kmem_cache_create(bs->name, sizeof(struct bio), 0,
- SLAB_HWCACHE_ALIGN, NULL, NULL);
- if (!bs->bio_slab) {
- DMWARN("can't init bio slab");
- goto bad;
- }
-
- bs->bio_pool = mempool_create(pool_entries, mempool_alloc_slab,
- mempool_free_slab, bs->bio_slab);
- if (!bs->bio_pool) {
- DMWARN("can't init bio pool");
- goto bad;
- }
-
- /*
- * Set up the biovec pools.
- */
- for (i = 0; i < BIOVEC_NR_POOLS; i++) {
- bp = bs->pools + i;
- bp->nr_vecs = _vec_lengths[i];
- atomic_set(&bp->allocated, 1); /* FIXME: debug */
-
-
- size = bp->nr_vecs * sizeof(struct bio_vec);
-
- mk_name(bp->name, sizeof(bp->name), slab_prefix, i);
- bp->slab = kmem_cache_create(bp->name, size, 0,
- SLAB_HWCACHE_ALIGN, NULL, NULL);
- if (!bp->slab) {
- DMWARN("can't init biovec slab cache");
- goto bad;
- }
-
- if (i >= scale)
- pool_entries >>= 1;
-
- bp->pool = mempool_create(pool_entries, mempool_alloc_slab,
- mempool_free_slab, bp->slab);
- if (!bp->pool) {
- DMWARN("can't init biovec mempool");
- goto bad;
- }
- }
-
- return 0;
-
- bad:
- bio_set_exit(bs);
- return -ENOMEM;
-}
-
-/* FIXME: blech */
-static inline unsigned bvec_index(unsigned nr)
-{
- switch (nr) {
- case 1: return 0;
- case 2 ... 4: return 1;
- case 5 ... 16: return 2;
- case 17 ... 64: return 3;
- case 65 ... 128:return 4;
- case 129 ... BIO_MAX_PAGES: return 5;
- }
-
- BUG();
- return 0;
-}
-
-static unsigned _bio_count = 0;
-struct bio *bio_set_alloc(struct bio_set *bs, int gfp_mask, int nr_iovecs)
-{
- struct biovec_pool *bp;
- struct bio_vec *bv = NULL;
- unsigned long idx;
- struct bio *bio;
-
- bio = mempool_alloc(bs->bio_pool, gfp_mask);
- if (unlikely(!bio))
- return NULL;
-
- bio_init(bio);
-
- if (likely(nr_iovecs)) {
- idx = bvec_index(nr_iovecs);
- bp = bs->pools + idx;
- bv = mempool_alloc(bp->pool, gfp_mask);
- if (!bv) {
- mempool_free(bio, bs->bio_pool);
- return NULL;
- }
-
- memset(bv, 0, bp->nr_vecs * sizeof(*bv));
- bio->bi_flags |= idx << BIO_POOL_OFFSET;
- bio->bi_max_vecs = bp->nr_vecs;
- atomic_inc(&bp->allocated);
- }
-
- bio->bi_io_vec = bv;
- return bio;
-}
-
-static void bio_set_free(struct bio_set *bs, struct bio *bio)
-{
- struct biovec_pool *bp = bs->pools + BIO_POOL_IDX(bio);
-
- if (atomic_dec_and_test(&bp->allocated))
- BUG();
-
- mempool_free(bio->bi_io_vec, bp->pool);
- mempool_free(bio, bs->bio_pool);
-}
-
-/*-----------------------------------------------------------------
- * dm-io proper
- *---------------------------------------------------------------*/
-static struct bio_set _bios;
+static struct bio_set *_bios;

/* FIXME: can we shrink this ? */
struct io {
@@ -240,7 +56,8 @@ static int resize_pool(unsigned int new_
/* free off the pool */
mempool_destroy(_io_pool);
_io_pool = NULL;
- bio_set_exit(&_bios);
+ /*bio_set_exit(&_bios); XXX */
+ bioset_free(_bios);

} else {
/* resize the pool */
@@ -253,10 +70,11 @@ static int resize_pool(unsigned int new_
if (!_io_pool)
return -ENOMEM;

- r = bio_set_init(&_bios, "dm-io", 512, 1);
- if (r) {
+ _bios = bioset_create(512, 512, 1);
+ if (!_bios) {
mempool_destroy(_io_pool);
_io_pool = NULL;
+ return -ENOMEM;
}
}

@@ -280,6 +98,7 @@ void dm_io_put(unsigned int num_pages)
* We need to keep track of which region a bio is doing io for.
* In order to save a memory allocation we store this the last
* bvec which we know is unused (blech).
+ * XXX This is ugly and can OOPS with some configs... find another way.
*---------------------------------------------------------------*/
static inline void bio_set_region(struct bio *bio, unsigned region)
{
@@ -315,21 +134,6 @@ static void dec_count(struct io *io, uns
}
}

-/* FIXME Move this to bio.h? */
-static void zero_fill_bio(struct bio *bio)
-{
- unsigned long flags;
- struct bio_vec *bv;
- int i;
-
- bio_for_each_segment(bv, bio, i) {
- char *data = bvec_kmap_irq(bv, &flags);
- memset(data, 0, bv->bv_len);
- flush_dcache_page(bv->bv_page);
- bvec_kunmap_irq(data, &flags);
- }
-}
-
static int endio(struct bio *bio, unsigned int done, int error)
{
struct io *io = (struct io *) bio->bi_private;
@@ -347,12 +151,6 @@ static int endio(struct bio *bio, unsign
return 0;
}

-static void bio_dtr(struct bio *bio)
-{
- _bio_count--;
- bio_set_free(&_bios, bio);
-}
-
/*-----------------------------------------------------------------
* These little objects provide an abstraction for getting a new
* destination page for io.
@@ -461,13 +259,12 @@ static void do_region(int rw, unsigned i
* bvec for bio_get/set_region().
*/
num_bvecs = (remaining / (PAGE_SIZE >> 9)) + 2;
- _bio_count++;
- bio = bio_set_alloc(&_bios, GFP_NOIO, num_bvecs);
+ bio = bio_alloc_bs(GFP_NOIO, num_bvecs, _bios);
bio->bi_sector = where->sector + (where->count - remaining);
bio->bi_bdev = where->bdev;
bio->bi_end_io = endio;
bio->bi_private = io;
- bio->bi_destructor = bio_dtr;
+ /* bio->bi_destructor = bio_dtr; XXX */
bio_set_region(bio, region);

/*
===== drivers/md/dm-zero.c 1.3 vs edited =====
--- 1.3/drivers/md/dm-zero.c 2004-06-17 23:53:43 -07:00
+++ edited/drivers/md/dm-zero.c 2005-01-31 11:37:27 -08:00
@@ -24,23 +24,6 @@ static int zero_ctr(struct dm_target *ti
}

/*
- * Fills the bio pages with zeros
- */
-static void zero_fill_bio(struct bio *bio)
-{
- unsigned long flags;
- struct bio_vec *bv;
- int i;
-
- bio_for_each_segment(bv, bio, i) {
- char *data = bvec_kmap_irq(bv, &flags);
- memset(data, 0, bv->bv_len);
- flush_dcache_page(bv->bv_page);
- bvec_kunmap_irq(data, &flags);
- }
-}
-
-/*
* Return zeros only on reads
*/
static int zero_map(struct dm_target *ti, struct bio *bio,
===== fs/bio.c 1.73 vs edited =====
--- 1.73/fs/bio.c 2005-01-20 21:02:13 -08:00
+++ edited/fs/bio.c 2005-01-31 14:50:37 -08:00
@@ -28,7 +28,6 @@

#define BIO_POOL_SIZE 256

-static mempool_t *bio_pool;
static kmem_cache_t *bio_slab;

#define BIOVEC_NR_POOLS 6
@@ -40,11 +39,10 @@ static kmem_cache_t *bio_slab;
#define BIO_SPLIT_ENTRIES 8
mempool_t *bio_split_pool;

-struct biovec_pool {
+struct biovec_slab {
int nr_vecs;
char *name;
kmem_cache_t *slab;
- mempool_t *pool;
};

/*
@@ -54,15 +52,32 @@ struct biovec_pool {
*/

#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) }
-static struct biovec_pool bvec_array[BIOVEC_NR_POOLS] = {
+static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] = {
BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES),
};
#undef BV

-static inline struct bio_vec *bvec_alloc(int gfp_mask, int nr, unsigned long *idx)
+/*
+ * bio_set is used to allow other portions of the IO system to
+ * allocate their own private memory pools for bio and iovec structures.
+ * These memory pools in turn all allocate from the bio_slab
+ * and the bvec_slabs[].
+ */
+struct bio_set {
+ mempool_t *bio_pool;
+ mempool_t *bvec_pools[BIOVEC_NR_POOLS];
+};
+
+/*
+ * fs_bio_set is the bio_set containing bio and iovec memory pools used by
+ * IO code that does not need private memory pools.
+ */
+static struct bio_set *fs_bio_set;
+
+static inline struct bio_vec *bvec_alloc_bs(int gfp_mask, int nr, unsigned long *idx, struct bio_set *bs)
{
- struct biovec_pool *bp;
struct bio_vec *bvl;
+ struct biovec_slab *bp;

/*
* see comment near bvec_array define!
@@ -80,26 +95,27 @@ static inline struct bio_vec *bvec_alloc
/*
* idx now points to the pool we want to allocate from
*/
- bp = bvec_array + *idx;

- bvl = mempool_alloc(bp->pool, gfp_mask);
+ bp = bvec_slabs + *idx;
+ bvl = mempool_alloc(bs->bvec_pools[*idx], gfp_mask);
if (bvl)
memset(bvl, 0, bp->nr_vecs * sizeof(struct bio_vec));
+
return bvl;
}

/*
- * default destructor for a bio allocated with bio_alloc()
+ * default destructor for a bio allocated with bio_alloc_bs()
*/
static void bio_destructor(struct bio *bio)
{
const int pool_idx = BIO_POOL_IDX(bio);
- struct biovec_pool *bp = bvec_array + pool_idx;
+ struct bio_set *bs = bio->bi_set;

BIO_BUG_ON(pool_idx >= BIOVEC_NR_POOLS);

- mempool_free(bio->bi_io_vec, bp->pool);
- mempool_free(bio, bio_pool);
+ mempool_free(bio->bi_io_vec, bs->bvec_pools[pool_idx]);
+ mempool_free(bio, bs->bio_pool);
}

inline void bio_init(struct bio *bio)
@@ -121,18 +137,21 @@ inline void bio_init(struct bio *bio)
}

/**
- * bio_alloc - allocate a bio for I/O
+ * bio_alloc_bs - allocate a bio for I/O
* @gfp_mask: the GFP_ mask given to the slab allocator
* @nr_iovecs: number of iovecs to pre-allocate
*
* Description:
- * bio_alloc will first try it's on mempool to satisfy the allocation.
+ * bio_alloc_bs will first try it's on mempool to satisfy the allocation.
* If %__GFP_WAIT is set then we will block on the internal pool waiting
* for a &struct bio to become free.
+ *
+ * allocate bio and iovecs from the memory pools specified by the
+ * bio_set structure.
**/
-struct bio *bio_alloc(int gfp_mask, int nr_iovecs)
+struct bio *bio_alloc_bs(int gfp_mask, int nr_iovecs, struct bio_set *bs)
{
- struct bio *bio = mempool_alloc(bio_pool, gfp_mask);
+ struct bio *bio = mempool_alloc(bs->bio_pool, gfp_mask);

if (likely(bio)) {
struct bio_vec *bvl = NULL;
@@ -141,22 +160,28 @@ struct bio *bio_alloc(int gfp_mask, int
if (likely(nr_iovecs)) {
unsigned long idx;

- bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx);
+ bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
if (unlikely(!bvl)) {
- mempool_free(bio, bio_pool);
+ mempool_free(bio, bs->bio_pool);
bio = NULL;
goto out;
}
bio->bi_flags |= idx << BIO_POOL_OFFSET;
- bio->bi_max_vecs = bvec_array[idx].nr_vecs;
+ bio->bi_max_vecs = bvec_slabs[idx].nr_vecs;
}
bio->bi_io_vec = bvl;
bio->bi_destructor = bio_destructor;
+ bio->bi_set = bs;
}
out:
return bio;
}

+struct bio *bio_alloc(int gfp_mask, int nr_iovecs)
+{
+ return bio_alloc_bs(gfp_mask, nr_iovecs, fs_bio_set);
+}
+
/**
* bio_put - release a reference to a bio
* @bio: bio to release reference to
@@ -233,7 +258,7 @@ inline void __bio_clone(struct bio *bio,
*/
struct bio *bio_clone(struct bio *bio, int gfp_mask)
{
- struct bio *b = bio_alloc(gfp_mask, bio->bi_max_vecs);
+ struct bio *b = bio_alloc_bs(gfp_mask, bio->bi_max_vecs, bio->bi_set);

if (b)
__bio_clone(b, bio);
@@ -904,11 +929,101 @@ static void bio_pair_free(void *bp, void
kfree(bp);
}

-static void __init biovec_init_pools(void)
+
+/*
+ * create memory pools for biovec's in a bio_set.
+ * use the global biovec slabs created for general use.
+ */
+static int biovec_create_pools(struct bio_set *bs, int pool_entries, int scale)
+{
+ int i;
+
+ for (i = 0; i < BIOVEC_NR_POOLS; i++) {
+ struct biovec_slab *bp = bvec_slabs + i;
+ mempool_t **bvp = bs->bvec_pools + i;
+
+ if (i >= scale)
+ pool_entries >>= 1;
+
+ *bvp = mempool_create(pool_entries, mempool_alloc_slab,
+ mempool_free_slab, bp->slab);
+ if (!*bvp)
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+static void biovec_free_pools(struct bio_set *bs)
{
- int i, size, megabytes, pool_entries = BIO_POOL_SIZE;
+ int i;
+
+ for (i = 0; i < BIOVEC_NR_POOLS; i++) {
+ mempool_t *bvp = bs->bvec_pools[i];
+
+ if (bvp)
+ mempool_destroy(bvp);
+ }
+
+}
+
+void bioset_free(struct bio_set *bs)
+{
+ if (!bs->bio_pool)
+ mempool_destroy(bs->bio_pool);
+
+ biovec_free_pools(bs);
+
+ kfree(bs);
+}
+
+struct bio_set *bioset_create(int bio_pool_size, int bvec_pool_size, int scale)
+{
+ struct bio_set *bs = kmalloc(sizeof(*bs), GFP_KERNEL);
+
+ if (!bs)
+ return NULL;
+
+ memset(bs, 0, sizeof(*bs));
+ bs->bio_pool = mempool_create(bio_pool_size, mempool_alloc_slab,
+ mempool_free_slab, bio_slab);
+
+ if (!bs->bio_pool)
+ goto bad;
+
+ if (biovec_create_pools(bs, bvec_pool_size, scale))
+ goto bad;
+
+ return bs;
+
+bad:
+ bioset_free(bs);
+ return NULL;
+}
+
+static void __init biovec_init_slabs(void)
+{
+ int i;
+
+ for (i = 0; i < BIOVEC_NR_POOLS; i++) {
+ int size;
+ struct biovec_slab *bvs = bvec_slabs + i;
+
+ size = bvs->nr_vecs * sizeof(struct bio_vec);
+ bvs->slab = kmem_cache_create(bvs->name, size, 0,
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+ }
+}
+
+static int __init init_bio(void)
+{
+ int megabytes, bvec_pool_entries;
int scale = BIOVEC_NR_POOLS;

+ bio_slab = kmem_cache_create("bio", sizeof(struct bio), 0,
+ SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
+
+ biovec_init_slabs();
+
megabytes = nr_free_pages() >> (20 - PAGE_SHIFT);

/*
@@ -928,38 +1043,13 @@ static void __init biovec_init_pools(voi
/*
* scale number of entries
*/
- pool_entries = megabytes * 2;
- if (pool_entries > 256)
- pool_entries = 256;
-
- for (i = 0; i < BIOVEC_NR_POOLS; i++) {
- struct biovec_pool *bp = bvec_array + i;
-
- size = bp->nr_vecs * sizeof(struct bio_vec);
-
- bp->slab = kmem_cache_create(bp->name, size, 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
-
- if (i >= scale)
- pool_entries >>= 1;
-
- bp->pool = mempool_create(pool_entries, mempool_alloc_slab,
- mempool_free_slab, bp->slab);
- if (!bp->pool)
- panic("biovec: can't init mempool\n");
- }
-}
-
-static int __init init_bio(void)
-{
- bio_slab = kmem_cache_create("bio", sizeof(struct bio), 0,
- SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
- bio_pool = mempool_create(BIO_POOL_SIZE, mempool_alloc_slab,
- mempool_free_slab, bio_slab);
- if (!bio_pool)
- panic("bio: can't create mempool\n");
-
- biovec_init_pools();
+ bvec_pool_entries = megabytes * 2;
+ if (bvec_pool_entries > 256)
+ bvec_pool_entries = 256;
+
+ fs_bio_set = bioset_create(BIO_POOL_SIZE, bvec_pool_entries, scale);
+ if (!fs_bio_set)
+ panic("bio: can't allocate bios\n");

bio_split_pool = mempool_create(BIO_SPLIT_ENTRIES,
bio_pair_alloc, bio_pair_free, NULL);
@@ -988,3 +1078,6 @@ EXPORT_SYMBOL(bio_split);
EXPORT_SYMBOL(bio_split_pool);
EXPORT_SYMBOL(bio_copy_user);
EXPORT_SYMBOL(bio_uncopy_user);
+EXPORT_SYMBOL(bioset_create);
+EXPORT_SYMBOL(bioset_free);
+EXPORT_SYMBOL(bio_alloc_bs);
===== include/linux/bio.h 1.43 vs edited =====
--- 1.43/include/linux/bio.h 2004-11-06 03:03:05 -08:00
+++ edited/include/linux/bio.h 2005-01-31 11:37:27 -08:00
@@ -59,6 +59,7 @@ struct bio_vec {
unsigned int bv_offset;
};

+struct bio_set;
struct bio;
typedef int (bio_end_io_t) (struct bio *, unsigned int, int);
typedef void (bio_destructor_t) (struct bio *);
@@ -109,6 +110,7 @@ struct bio {
void *bi_private;

bio_destructor_t *bi_destructor; /* destructor */
+ struct bio_set *bi_set; /* memory pools set */
};

/*
@@ -258,7 +260,11 @@ extern struct bio_pair *bio_split(struct
extern mempool_t *bio_split_pool;
extern void bio_pair_release(struct bio_pair *dbio);

+extern struct bio_set *bioset_create(int, int, int);
+extern void bioset_free(struct bio_set *);
+
extern struct bio *bio_alloc(int, int);
+extern struct bio *bio_alloc_bs(int, int, struct bio_set *);
extern void bio_put(struct bio *);

extern void bio_endio(struct bio *, unsigned int, int);
@@ -328,5 +334,19 @@ extern inline char *__bio_kmap_irq(struc
#define bio_kmap_irq(bio, flags) \
__bio_kmap_irq((bio), (bio)->bi_idx, (flags))
#define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags)
+
+extern inline void zero_fill_bio(struct bio *bio)
+{
+ unsigned long flags;
+ struct bio_vec *bv;
+ int i;
+
+ bio_for_each_segment(bv, bio, i) {
+ char *data = bvec_kmap_irq(bv, &flags);
+ memset(data, 0, bv->bv_len);
+ flush_dcache_page(bv->bv_page);
+ bvec_kunmap_irq(data, &flags);
+ }
+}

#endif /* __LINUX_BIO_H */
-
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