From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0B2841FB4 for ; Fri, 3 Feb 2023 10:22:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C83BC433D2; Fri, 3 Feb 2023 10:22:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675419724; bh=ptS80CaKmAaxnVgO5uFtYCDNS250QnOe4rrGaZZzuYE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AF9MkOYUlx66ovC/y9VqkrcfCiB8IrwORDj0fVAF8BoNYU1q4mhKkWPuL6yeQ3i/p lH5kIdVzRAb9fDWFMDZMksryfo/p9H+T+JjXjmY26DClFnNUylF9ad7JcoyDeqnD6Z iptk2MGI0JSzSIgmk951+4Hsz3HL/dRDDXXfKGbI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pavel Begunkov , Jens Axboe , Sasha Levin Subject: [PATCH 6.1 16/28] block: fix hctx checks for batch allocation Date: Fri, 3 Feb 2023 11:13:04 +0100 Message-Id: <20230203101010.657044513@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230203101009.946745030@linuxfoundation.org> References: <20230203101009.946745030@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Pavel Begunkov [ Upstream commit 7746564793978fe2f43b18a302b22dca0ad3a0e8 ] When there are no read queues read requests will be assigned a default queue on allocation. However, blk_mq_get_cached_request() is not prepared for that and will fail all attempts to grab read requests from the cache. Worst case it doubles the number of requests allocated, roughly half of which will be returned by blk_mq_free_plug_rqs(). It only affects batched allocations and so is io_uring specific. For reference, QD8 t/io_uring benchmark improves by 20-35%. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/80d4511011d7d4751b4cf6375c4e38f237d935e3.1673955390.git.asml.silence@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-mq.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 63abbe342b28..83fbc7c54617 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2858,6 +2858,7 @@ static inline struct request *blk_mq_get_cached_request(struct request_queue *q, struct blk_plug *plug, struct bio **bio, unsigned int nsegs) { struct request *rq; + enum hctx_type type, hctx_type; if (!plug) return NULL; @@ -2870,7 +2871,10 @@ static inline struct request *blk_mq_get_cached_request(struct request_queue *q, return NULL; } - if (blk_mq_get_hctx_type((*bio)->bi_opf) != rq->mq_hctx->type) + type = blk_mq_get_hctx_type((*bio)->bi_opf); + hctx_type = rq->mq_hctx->type; + if (type != hctx_type && + !(type == HCTX_TYPE_READ && hctx_type == HCTX_TYPE_DEFAULT)) return NULL; if (op_is_flush(rq->cmd_flags) != op_is_flush((*bio)->bi_opf)) return NULL; -- 2.39.0