From: Jens Axboe <axboe@kernel.dk>
To: linux-block@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 4/9] sbitmap: test bit before calling test_and_set_bit()
Date: Wed, 13 Oct 2021 10:54:11 -0600 [thread overview]
Message-ID: <20211013165416.985696-5-axboe@kernel.dk> (raw)
In-Reply-To: <20211013165416.985696-1-axboe@kernel.dk>
If we come across bits that are already set, then it's quicker to test
that first and gate the test_and_set_bit() operation on the result of
the bit test.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
lib/sbitmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index c6e2f1f2c4d2..11b244a8d00f 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -166,7 +166,7 @@ static int __sbitmap_get_word(unsigned long *word, unsigned long depth,
return -1;
}
- if (!test_and_set_bit_lock(nr, word))
+ if (!test_bit(nr, word) && !test_and_set_bit_lock(nr, word))
break;
hint = nr + 1;
--
2.33.0
next prev parent reply other threads:[~2021-10-13 16:54 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-13 16:54 [PATCHSET v2 0/9] Batched completions Jens Axboe
2021-10-13 16:54 ` [PATCH 1/9] block: define io_batch structure Jens Axboe
2021-10-14 5:45 ` Christoph Hellwig
2021-10-14 15:50 ` Jens Axboe
2021-10-14 16:06 ` Christoph Hellwig
2021-10-14 18:14 ` Jens Axboe
2021-10-13 16:54 ` [PATCH 2/9] block: add a struct io_batch argument to fops->iopoll() Jens Axboe
2021-10-13 16:54 ` [PATCH 3/9] sbitmap: add helper to clear a batch of tags Jens Axboe
2021-10-13 16:54 ` Jens Axboe [this message]
2021-10-14 7:20 ` [PATCH 4/9] sbitmap: test bit before calling test_and_set_bit() Hannes Reinecke
2021-10-14 13:01 ` Jens Axboe
2021-10-14 18:41 ` Bart Van Assche
2021-10-13 16:54 ` [PATCH 5/9] block: add support for blk_mq_end_request_batch() Jens Axboe
2021-10-14 7:32 ` Christoph Hellwig
2021-10-14 15:27 ` Jens Axboe
2021-10-13 16:54 ` [PATCH 6/9] nvme: add support for batched completion of polled IO Jens Axboe
2021-10-14 7:43 ` Christoph Hellwig
2021-10-14 15:30 ` Jens Axboe
2021-10-14 15:34 ` Jens Axboe
2021-10-14 16:07 ` Christoph Hellwig
2021-10-14 16:11 ` Jens Axboe
2021-10-13 16:54 ` [PATCH 7/9] block: assign batch completion handler in blk_poll() Jens Axboe
2021-10-14 7:48 ` Christoph Hellwig
2021-10-14 15:43 ` Jens Axboe
2021-10-13 16:54 ` [PATCH 8/9] io_uring: utilize the io_batch infrastructure for more efficient polled IO Jens Axboe
2021-10-14 8:03 ` Christoph Hellwig
2021-10-14 15:45 ` Jens Axboe
2021-10-14 16:08 ` Christoph Hellwig
2021-10-14 18:14 ` Jens Axboe
2021-10-16 4:29 ` Christoph Hellwig
2021-10-16 14:33 ` Jens Axboe
2021-10-13 16:54 ` [PATCH 9/9] nvme: wire up completion batching for the IRQ path Jens Axboe
2021-10-14 7:53 ` Christoph Hellwig
2021-10-14 15:49 ` Jens Axboe
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