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alistair23-linux
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block: remove the 1 and 4 vec bvec_slabs entries 

All bios with up to 4 bvecs use the inline bvecs in the bio itself, so
don't bother to define bvec_slabs entries for them.  Also decruftify
the bvec_slabs definition and initialization while we're at it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
master
Christoph Hellwig 2021-02-02 18:19:23 +01:00 committed by Jens Axboe
parent f007a3d66c
commit de76fd8930
1 changed files with 16 additions and 37 deletions
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53
block/bio.c
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@ -25,23 +25,17 @@
#include "blk.h"
#include "blk-rq-qos.h"
struct biovec_slab {
static struct biovec_slab {
int nr_vecs;
char *name;
struct kmem_cache *slab;
} bvec_slabs[] __read_mostly = {
{ .nr_vecs = 16, .name = "biovec-16" },
{ .nr_vecs = 64, .name = "biovec-64" },
{ .nr_vecs = 128, .name = "biovec-128" },
{ .nr_vecs = BIO_MAX_PAGES, .name = "biovec-max" },
};
/*
* if you change this list, also change bvec_alloc or things will
* break badly! cannot be bigger than what you can fit into an
* unsigned short
*/
#define BV(x, n) { .nr_vecs = x, .name = "biovec-"#n }
static struct biovec_slab bvec_slabs[BVEC_POOL_NR] __read_mostly = {
BV(1, 1), BV(4, 4), BV(16, 16), BV(64, 64), BV(128, 128), BV(BIO_MAX_PAGES, max),
};
#undef BV
/*
* fs_bio_set is the bio_set containing bio and iovec memory pools used by
* IO code that does not need private memory pools.
@ -176,12 +170,7 @@ struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
* see comment near bvec_array define!
*/
switch (nr) {
case 1:
*idx = 0;
break;
case 2 ... 4:
*idx = 1;
break;
/* smaller bios use inline vecs */
case 5 ... 16:
*idx = 2;
break;
@ -1613,31 +1602,21 @@ int bioset_init_from_src(struct bio_set *bs, struct bio_set *src)
}
EXPORT_SYMBOL(bioset_init_from_src);
static void __init biovec_init_slabs(void)
static int __init init_bio(void)
{
int i;
for (i = 0; i < BVEC_POOL_NR; i++) {
int size;
struct biovec_slab *bvs = bvec_slabs + i;
if (bvs->nr_vecs <= BIO_INLINE_VECS) {
bvs->slab = NULL;
continue;
}
size = bvs->nr_vecs * sizeof(struct bio_vec);
bvs->slab = kmem_cache_create(bvs->name, size, 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
}
}
static int __init init_bio(void)
{
BUILD_BUG_ON(BIO_FLAG_LAST > BVEC_POOL_OFFSET);
bio_integrity_init();
biovec_init_slabs();
for (i = 0; i < ARRAY_SIZE(bvec_slabs); i++) {
struct biovec_slab *bvs = bvec_slabs + i;
bvs->slab = kmem_cache_create(bvs->name,
bvs->nr_vecs * sizeof(struct bio_vec), 0,
SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
}
if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS))
panic("bio: can't allocate bios\n");