From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f47.google.com (mail-wm1-f47.google.com [209.85.128.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DD9B03F7861 for ; Wed, 6 May 2026 14:15:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778076952; cv=none; b=E5JDY3V3qiRWMTpItz5Lv6chBZk+6bczjQIBJFf8VInNl5+JxmsX5a3BclDMtr33xdkbmcGyHX7s0vmME8XZsSSlUzTVVXaXB41dz4BC6faOsNJ9YofCg185dZvGe+fOTQOW0BY+5791ZNLTRFrI8t3OJgTJPulcZz66gAg7uxE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778076952; c=relaxed/simple; bh=zZcagGFZAjrjlPTdskd9mqi0QrGre7yqU1eShhuplxw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=Exk8VdJQNfcGC326XnLy4o5RAn83LwzDUGfnUo0w9OhpLMOqxzKTYlwhA/BZ4As3Buh3JUPoJ3Y565g1oxogvWj1Mx2tPoH0nlL0Lm8uMYLgDoL3Fvwact7xeH2mnKi8xbRyWKFwrSKx3QZldeH/Sov0rU+bwcvI4zhSuoHwA3Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=BJ9XhKk0; arc=none smtp.client-ip=209.85.128.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BJ9XhKk0" Received: by mail-wm1-f47.google.com with SMTP id 5b1f17b1804b1-4832c8f9d87so11153825e9.3 for ; Wed, 06 May 2026 07:15:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778076949; x=1778681749; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=Io/N+hHnLMI/zVIF68lkuWkyC9l4bvcPQWSmOV0m6oQ=; b=BJ9XhKk0MrbDVLaIWxMT5d6zEFaVIIJWRlMtlXLgjDCsfaIL7Z8IJNXOxW5Z4ixUDa oF8it0AxhKV9+BapijXl4FQXvUb1AjQCz4aGwdIcJfbbYd+xmxOR7ACUq0nPR/T8RIrC Y6p6CA6k/j0YV8MzD1jdKNuS4u/D0gVtWsvYkOFhlX5+bEhRpdmLw0I7K/dVMHz02Yn2 6vlis2G9tkVNhGRhWqP4minQrJKfhb+LHGSEzUHOVpbEiADOpLEwGtcBKIaaFvcOZeiS +HKCx0aMP38thLUd7G4q/5pt536KRrUXhVHktVAMWaKu7I8KG88AYNoKhnwyQ+e6vod3 LOXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778076949; x=1778681749; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Io/N+hHnLMI/zVIF68lkuWkyC9l4bvcPQWSmOV0m6oQ=; b=m5VeteGeEmOL6T8RLGFgCnX0supnr/rfhmnZXDybjIsBrm86VttYOMC5mUlMYiTixb zmLRdX2VVsqN/2Nun4iVginkppIKU5kPPO48AfaoRzT7gKoCbdMqga2rf+ny8oDsvLPx SwcvknLJF3ZJLYAH51DgyFO4f2o+U4I9I8oZYv9mKEmWOjjT2l/2DCjCGVFlwdbvsapi zPPwubHVmpfWw5R0VGVo2d/DDQzGXsDQlB89Ww8Nt1NU3IAwn9nQHmbdYA2BQy6968rt Za5k4cPiPH08zgCuyMJQfwEcFsKMVGGMYUeiuav2e84RmEx4WeH4Q/5NMULkh08SC2uL pTIQ== X-Forwarded-Encrypted: i=1; AFNElJ++3aLda5Ww0G4P+ZKh0ZXdFzhLt/ec4PzKladqGWH8hJmetRsF1iptBQBfp4P3RpR997mf0QSn1WiTTg==@vger.kernel.org X-Gm-Message-State: AOJu0YyQVfsHpBiYunZDSul//16njlkZmb7ZPEWcUEiZBLiTcwZwEh2N iNbh9/fY211zxSMos1EgNvs8IskCbJ1KUQOmQo8GfYOD5lvuq3fytYM= X-Gm-Gg: AeBDievqE7KvdhguxBKCHA4nOhaPHYgz7DZmx+ylZYwgexD3EI+h/fEEqpyYSLXUpnX jQ4Ug/Rtebx2KddIqKzaZAygR8ONKBoATULkW74Ks+NpwuaXLhOc5jUhDk0GIOo5PLxVOduOK1o 74Lp4xRrRPzTYDPOaAjtjGiZ2AM0JRm4GgxYfOY3jQkc2F0ZSqeotaBl0HaFYqTIilvVWaRYkTj 9vnaxtwHvfzK3ndiMr1lRtG9YD0F1Pfl0izWGgGJi/rvnr8UBhhtMDPvdL/fMcPS9LhPaVc8mcq VmCTWXEPQ0bsp/cjgPJsohtn58BB5jea1Che/OoKNDefRz2ya3RzPQkwXfiKE5GLzHb1KlcqONx ARkN7zVjhZnW8+juZd+OV+YvH2p1SvsLr1DCdUP4S55lKesS17rIvUHXdjvbD6/zRpSB3X6cjyF R3/ytDWQhyNoWaKwP/QtmIlZl5Cd8mhBxmfVmozof9pdMcVJ93fipOXBd4RFEcUHtPofBVIv7X X-Received: by 2002:a05:600c:1f95:b0:486:fc61:541d with SMTP id 5b1f17b1804b1-48e51e124b9mr32527385e9.2.1778076948868; Wed, 06 May 2026 07:15:48 -0700 (PDT) Received: from localhost (8.red-80-39-165.dynamicip.rima-tde.net. [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-block@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