From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 C8096330D4C for ; Wed, 2 Sep 2026 20:06:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788379581; cv=none; b=FkkzUm/Zv8Hlgb2KclorRFMID4MCsgsfobi0HvHHCkEuS+dJ6h6rmM843F5XMSsV859WrmMzlXZAnXRoMGJTCo5Jw20Z1C9rO7StP53BdiBd6aG/iGtGgiS0sCodBspiP2JSmFKuHQCLH0ChhwWR+z4AHkhaHCD0j2UJYn5LfJM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788379581; c=relaxed/simple; bh=KyigujruG9PSQ4X/h7TyBYjnfhYpTml3X/Nidvemv3c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=R3+6uwlP56xDb56ampZzbhtvxgvmpolzenKb5V1e5KetfMas4H9s0hddrvhgagHSxU4ICSMYQS1pi5p1a9XYo5KotgXZMHgw+jO9TzXbyd4XOQUxh+Mds/2tKfYC6czpHsOjTVC1U2ak2YUYcCXP3/aobOWd11MukMb5H0HgBCc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=I4BUHvhH; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="I4BUHvhH" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1788379578; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=aOzuicW09ymDk9cexEa+3/Sews5a9NJ263znpzR+848=; b=I4BUHvhHPIaWu/wSZc/fhDXANyhHX5vz7M0m9IQh+B6VjxOyyQ9JGTI6ndlJdxX6PjQUEh sfTMUCc/UI4bCny7v6O5waNVFqlfiOZ+tOdIG9rq93/sWT8sWwU8DxYxpuCtI3aPVOfWSK WnvxW9oYy/1v5jRaw1lHtoRIFy5c1/A= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-28-72-yttTKMveSGAZMlApg2A-1; Wed, 02 Sep 2026 16:06:17 -0400 X-MC-Unique: 72-yttTKMveSGAZMlApg2A-1 X-Mimecast-MFC-AGG-ID: 72-yttTKMveSGAZMlApg2A_1788379568 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E64BF1955D99; Wed, 2 Sep 2026 20:06:07 +0000 (UTC) Received: from jtaubepe-thinkpadx1carbongen12.ibmlowe.csb (unknown [10.17.16.153]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id A8FE51955F02; Wed, 2 Sep 2026 20:06:04 +0000 (UTC) From: Jesse Taube To: linux-nvme@lists.infradead.org Cc: linux-scsi@vger.kernel.org, Jonathan Corbet , Shuah Khan , Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Justin Tee , Naresh Gottumukkala , Paul Ely , Chaitanya Kulkarni , "James E.J. Bottomley" , "Martin K. Petersen" , Nilesh Javali , GR-QLogic-Storage-Upstream@marvell.com, Hannes Reinecke , Jesse Taube , "Gustavo A. R. Silva" , John Meneghini , Bryan Gurney , Chris Leech , "Ewan D . Milne" , shinichiro.kawasaki@wdc.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Subject: [PATCH v2 4/7] nvme-multipath: round-robin support for marginal paths Date: Wed, 2 Sep 2026 16:05:44 -0400 Message-ID: <20260902200547.184734-5-jtaubepe@redhat.com> In-Reply-To: <20260902200547.184734-1-jtaubepe@redhat.com> References: <20260902200547.184734-1-jtaubepe@redhat.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Exclude marginal paths from round-robin io policy. In the case where all paths are marginal and no optimized or non-optimized path is found, we fall back and perform round-robin on the marginal paths. Signed-off-by: Jesse Taube --- V10 -> V1: - New commit V1 -> V2: - Rewrite --- drivers/nvme/host/multipath.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-) diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index f28797deab68..738e3c742b74 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -392,22 +392,29 @@ static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head) int node = numa_node_id(); struct nvme_ns *old = srcu_dereference(head->current_path[node], &head->srcu); + bool need_marginal; if (unlikely(!old)) return __nvme_find_path(head, node); if (list_is_singular(&head->list)) { - if (nvme_path_is_disabled(old)) - return NULL; - return old; + if (nvme_path_is_usable(old)) + return old; + return NULL; } + need_marginal = nvme_all_paths_marginal(head); + for (ns = nvme_next_ns(head, old); ns && ns != old; ns = nvme_next_ns(head, ns)) { if (nvme_path_is_disabled(ns)) continue; + /* Skip marginal paths unless we need to use them */ + if (!need_marginal && nvme_ctrl_is_marginal(ns->ctrl)) + continue; + if (ns->ana_state == NVME_ANA_OPTIMIZED) { found = ns; goto out; @@ -419,12 +426,23 @@ static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head) /* * The loop above skips the current path for round-robin semantics. * Fall back to the current path if either: - * - no other optimized path found and current is optimized, + * - no other optimized path found and current is, + * optimized and not marginal. + * - no other non-marginal path found and current is, + * optimized and marginal. * - no other usable path found and current is usable. */ - if (!nvme_path_is_disabled(old) && - (old->ana_state == NVME_ANA_OPTIMIZED || - (!found && old->ana_state == NVME_ANA_NONOPTIMIZED))) + /* no other usable path found and current is usable. */ + if (nvme_path_is_usable(old) && !found) + return old; + /* + * - no other optimized path found and current is, + * optimized and not marginal. + * - no other non-marginal path found and current is, + * optimized and marginal. + */ + if (nvme_path_is_usable(old) && old->ana_state == NVME_ANA_OPTIMIZED && + (!nvme_ctrl_is_marginal(old->ctrl) || need_marginal)) return old; if (!found) -- 2.55.0