block: enable per-cpu bio caching for the fs bio set

PATCH In review Jens Axboe 2 participants 2 messages Sep 2, 2022 Block layer

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Jens Axboe

author maintainer

2022-09-02 16:42 UTC #0 lore raw

PATCH 1/1 block: enable per-cpu bio caching for the fs bio set

This is useful for polled IO on a file, or for polled IO with the io_uring passthrough mechanism. If bio allocations are done with REQ_POLLED for those cases, then initializing the bio set with BIOSET_PERCPU_CACHE enables the local per-cpu cache which eliminates allocations (and frees) of bio structs when possible.

Signed-off-by Jens Axboe <[email protected]>

---

block/bio.c +2 -1

index 3d3a2678fea2..d3154d8beed7 100644
@@ -1754,7 +1754,8 @@ static int __init init_bio(void)
 	cpuhp_setup_state_multi(CPUHP_BIO_DEAD, "block/bio:dead", NULL,
 					bio_cpu_dead);
 
-	if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS))
+	if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0,
+			BIOSET_NEED_BVECS | BIOSET_PERCPU_CACHE))
 		panic("bio: can't allocate bios\n");
 
 	if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE))

Signature · 1 line

Jens Axboe

Kanchan Joshi

Reviewed-by on v1 1/1

2022-09-02 18:58 UTC #1 lore raw

Quoted 7 lines · Jens Axboe

This is useful for polled IO on a file, or for polled IO with the io_uring passthrough mechanism. If bio allocations are done with REQ_POLLED for those cases, then initializing the bio set with BIOSET_PERCPU_CACHE enables the local per-cpu cache which eliminates allocations (and frees) of bio structs when possible.
Signed-off-by Jens Axboe <[email protected]>

Reviewed-by Kanchan Joshi <[email protected]>