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 514A51CAB98; Wed, 5 Jun 2024 12:04:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717589097; cv=none; b=egvZ2bWaU5lcU4RGeq3W5GmYB3sisLxsvJRHracbJ8qc80POQulXfkLDb1sVl1ezwhrTp/9JTkUdj7BiPwPQ6c7yzWU8Q9yplsfshSSY13zj//5izH+YD5J4WdNoTATIzc5mv8R4Xglxjd3HU/t538QRjqzsilgChoMQT6qG7l0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717589097; c=relaxed/simple; bh=Lmhh63CniRz7dCHgOoa4jJKSV5NqmaSY2UWwpsyRO/A=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Iu7sACbwemOSovHKeE3IvCrM1ccoEAHOivucMGsQRdxujDLVXyKdoz8pzTDiJZv0XyPs3gAB+o99r75QBtcTNLtwJzGzSMZeLLn8OY7fRjlwN6YcUAV6Y5eFAeZTDRETopq/sdxdqRNtYMMEQPi2sgeZ21mtQh0aViBWib6UhRM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P0lCkUmj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="P0lCkUmj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EC0BC3277B; Wed, 5 Jun 2024 12:04:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717589096; bh=Lmhh63CniRz7dCHgOoa4jJKSV5NqmaSY2UWwpsyRO/A=; h=From:To:Cc:Subject:Date:From; b=P0lCkUmjbvMsZkviWDnsFdlkiu9GDL7kb/FDCZEvtcNdunnVq/cWPlAae1GNLt5vY 0BbGaZhZ3XQsyhOjia+BdwmyCKUsyqkj4lnffTRkXJwKnZkiz2d/KzC2vJlYQK+iye GqknQMgW34XbRcMP8W4TsrgG8O+OUHS9A9QMQWHUzFaeN5HZ24Ui+7jT5DG8xu0qeo yBT3IcNhEOldoW1KXRZQEvShrRvyPre/YoSrA/RPR01prTu85dSRZUI1CILuIBLnvB r4wduJKS36W3z9MsK5ha4WiRgLwWYvQo1b8wlpMxNuowUZbHRq6/ouUuRo2QZ2cbfr mfUQHmCaQL82w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nilay Shroff , Christoph Hellwig , Keith Busch , Sasha Levin , sagi@grimberg.me, linux-nvme@lists.infradead.org Subject: [PATCH AUTOSEL 6.1 01/14] nvme-multipath: find NUMA path only for online numa-node Date: Wed, 5 Jun 2024 08:04:34 -0400 Message-ID: <20240605120455.2967445-1-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.1.92 Content-Transfer-Encoding: 8bit From: Nilay Shroff [ Upstream commit d3a043733f25d743f3aa617c7f82dbcb5ee2211a ] In current native multipath design when a shared namespace is created, we loop through each possible numa-node, calculate the NUMA distance of that node from each nvme controller and then cache the optimal IO path for future reference while sending IO. The issue with this design is that we may refer to the NUMA distance table for an offline node which may not be populated at the time and so we may inadvertently end up finding and caching a non-optimal path for IO. Then latter when the corresponding numa-node becomes online and hence the NUMA distance table entry for that node is created, ideally we should re-calculate the multipath node distance for the newly added node however that doesn't happen unless we rescan/reset the controller. So essentially, we may keep using non-optimal IO path for a node which is made online after namespace is created. This patch helps fix this issue ensuring that when a shared namespace is created, we calculate the multipath node distance for each online numa-node instead of each possible numa-node. Then latter when a node becomes online and we receive any IO on that newly added node, we would calculate the multipath node distance for newly added node but this time NUMA distance table would have been already populated for newly added node. Hence we would be able to correctly calculate the multipath node distance and choose the optimal path for the IO. Signed-off-by: Nilay Shroff Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch Signed-off-by: Sasha Levin --- drivers/nvme/host/multipath.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index f96d330d39641..ead42a81cb352 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -558,7 +558,7 @@ static void nvme_mpath_set_live(struct nvme_ns *ns) int node, srcu_idx; srcu_idx = srcu_read_lock(&head->srcu); - for_each_node(node) + for_each_online_node(node) __nvme_find_path(head, node); srcu_read_unlock(&head->srcu, srcu_idx); } -- 2.43.0