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From: Jens Axboe <axboe@kernel.dk>
To: io-uring@vger.kernel.org
Cc: linux-block@vger.kernel.org, hch@infradead.org,
	Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 1/6] bio: optimize initialization of a bio
Date: Thu, 12 Aug 2021 09:41:44 -0600	[thread overview]
Message-ID: <20210812154149.1061502-2-axboe@kernel.dk> (raw)
In-Reply-To: <20210812154149.1061502-1-axboe@kernel.dk>

The memset() used is measurably slower in targeted benchmarks, wasting
about 1% of the total runtime, or 50% of the (later) hot path cached
bio alloc. Get rid of it and fill in the bio manually.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 block/bio.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index 1fab762e079b..9bf98b877aba 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -246,7 +246,34 @@ static void bio_free(struct bio *bio)
 void bio_init(struct bio *bio, struct bio_vec *table,
 	      unsigned short max_vecs)
 {
-	memset(bio, 0, sizeof(*bio));
+	bio->bi_next = NULL;
+	bio->bi_bdev = NULL;
+	bio->bi_opf = 0;
+	bio->bi_flags = 0;
+	bio->bi_ioprio = 0;
+	bio->bi_write_hint = 0;
+	bio->bi_status = 0;
+	bio->bi_iter.bi_sector = 0;
+	bio->bi_iter.bi_size = 0;
+	bio->bi_iter.bi_idx = 0;
+	bio->bi_iter.bi_bvec_done = 0;
+	bio->bi_end_io = NULL;
+	bio->bi_private = NULL;
+#ifdef CONFIG_BLK_CGROUP
+	bio->bi_blkg = NULL;
+	bio->bi_issue.value = 0;
+#ifdef CONFIG_BLK_CGROUP_IOCOST
+	bio->bi_iocost_cost = 0;
+#endif
+#endif
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+	bio->bi_crypt_context = NULL;
+#endif
+#ifdef CONFIG_BLK_DEV_INTEGRITY
+	bio->bi_integrity = NULL;
+#endif
+	bio->bi_vcnt = 0;
+
 	atomic_set(&bio->__bi_remaining, 1);
 	atomic_set(&bio->__bi_cnt, 1);
 
-- 
2.32.0


  reply	other threads:[~2021-08-12 15:41 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-12 15:41 [PATCHSET v5 0/6] Enable bio recycling for polled IO Jens Axboe
2021-08-12 15:41 ` Jens Axboe [this message]
2021-08-12 16:16   ` [PATCH 1/6] bio: optimize initialization of a bio Christoph Hellwig
2021-08-12 15:41 ` [PATCH 2/6] fs: add kiocb alloc cache flag Jens Axboe
2021-08-12 16:20   ` Christoph Hellwig
2021-08-12 15:41 ` [PATCH 3/6] bio: add allocation cache abstraction Jens Axboe
2021-08-12 16:32   ` Christoph Hellwig
2021-08-12 16:39     ` Jens Axboe
2021-08-12 15:41 ` [PATCH 4/6] block: clear BIO_PERCPU_CACHE flag if polling isn't supported Jens Axboe
2021-08-12 16:33   ` Christoph Hellwig
2021-08-12 17:31   ` Keith Busch
2021-08-12 17:41     ` Jens Axboe
2021-08-13 20:17       ` Keith Busch
2021-08-13 20:19         ` Jens Axboe
2021-08-13 20:31           ` Keith Busch
2021-08-13 20:33             ` Jens Axboe
2021-08-12 15:41 ` [PATCH 5/6] io_uring: enable use of bio alloc cache Jens Axboe
2021-08-12 16:39   ` Christoph Hellwig
2021-08-12 16:46     ` Jens Axboe
2021-08-12 15:41 ` [PATCH 6/6] block: use the percpu bio cache in __blkdev_direct_IO Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2021-08-11 19:35 [PATCHSET v4 0/6] Enable bio recycling for polled IO Jens Axboe
2021-08-11 19:35 ` [PATCH 1/6] bio: optimize initialization of a bio Jens Axboe
2021-08-12  6:51   ` Christoph Hellwig
2021-08-12 15:29     ` Jens Axboe

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