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[80.39.165.8]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4505558e213sm13671647f8f.25.2026.05.06.07.15.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 May 2026 07:15:47 -0700 (PDT) From: Xose Vazquez Perez To: Cc: Xose Vazquez Perez , Aviv Coro , Bart Van Assche , Benjamin Marzinski , Brian Bunker , Caleb Sander , Chaitanya Kulkarni , Chris Leech , Christophe Varoqui , Christoph Hellwig , Clayton Skaggs , Constantine Gavrilov , Daniel Wagner , =?UTF-8?q?David=20Santamar=C3=ADa=20Rogado?= , "Dmitry V. Levin" , "Ewan D. Milne" , Hannes Reinecke , James Smart , Jens Axboe , John Meneghini , Jyoti Rani , Keith Busch , Li Xiaokeng , Marco Patalano , Martin Belanger , Martin George , Martin Wilck , Matthias Rudolph , Maurizio Lombardi , NetApp RDAC team , Nilay Shroff , Randy Jennings , Sagi Grimberg , Simon Schricker , Steven Schremmer , Thomas Song , Uday Shankar , Vasuki Manikarnike , Wayne Berthiaume , Zou Ming , BLOCK-ML , DM_DEVEL-ML , NVME-ML , SCSI-ML Subject: [PATCH RFC] nvme-multipath: optimize path selection in queue-depth policy Date: Wed, 6 May 2026 16:15:41 +0200 Message-ID: <20260506141544.125089-1-xose.vazquez@gmail.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Bot: notify Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Move the zero-depth check inside the optimized path case to enable early exit. It avoids redundant condition checks for non-optimized paths, and eliminates the per-iteration check at the end of the loop, improving the performance. Cc: Aviv Coro Cc: Bart Van Assche Cc: Benjamin Marzinski Cc: Brian Bunker Cc: Caleb Sander Cc: Chaitanya Kulkarni Cc: Chris Leech Cc: Christophe Varoqui Cc: Christoph Hellwig Cc: Clayton Skaggs Cc: Constantine Gavrilov Cc: Daniel Wagner Cc: David Santamaría Rogado Cc: Dmitry V. Levin Cc: Ewan D. Milne Cc: Ewan Milne Cc: Hannes Reinecke Cc: James Smart Cc: Jens Axboe Cc: John Meneghini Cc: Jyoti Rani Cc: Keith Busch Cc: Li Xiaokeng Cc: Marco Patalano Cc: Martin Belanger Cc: Martin George Cc: Martin Wilck Cc: Matthias Rudolph Cc: Maurizio Lombardi Cc: NetApp RDAC team Cc: Nilay Shroff Cc: Randy Jennings Cc: Sagi Grimberg Cc: Simon Schricker Cc: Steven Schremmer Cc: Thomas Song Cc: Uday Shankar Cc: Vasuki Manikarnike Cc: Wayne Berthiaume Cc: Zou Ming Cc: BLOCK-ML Cc: DM_DEVEL-ML Cc: NVME-ML Cc: SCSI-ML Signed-off-by: Xose Vazquez Perez --- Status: Compile-tested only. UNTESTED on real hardware. [I do not have access to this kind of hardware] Feedback and testing are highly welcome. --- drivers/nvme/host/multipath.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 263161cb8ac0..7d212f6e865d 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -409,6 +409,8 @@ static struct nvme_ns *nvme_queue_depth_path(struct nvme_ns_head *head) min_depth_opt = depth; best_opt = ns; } + if (min_depth_opt == 0) + goto out; break; case NVME_ANA_NONOPTIMIZED: if (depth < min_depth_nonopt) { @@ -419,11 +421,8 @@ static struct nvme_ns *nvme_queue_depth_path(struct nvme_ns_head *head) default: break; } - - if (min_depth_opt == 0) - return best_opt; } - +out: return best_opt ? best_opt : best_nonopt; } -- 2.54.0