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 69E0B2ECE8D for ; Thu, 24 Jul 2025 19:31:14 +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=1753385474; cv=none; b=pJa3wBfPIZz6MCWNUm4kZbxF7PiTkdCPiz0hqiFNL8CkOjZR3xfZIlRxyLHRKYjuY6O5LR6ZG6ZVI//PrfqWsdt0Z+Y8MhLMEg9uTP5cFxrE08eXFKQvpMUWIaOAJYkGF5SBoModkdavSSxfGijkFboQvRLm7mWjV21QAv7jgeg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753385474; c=relaxed/simple; bh=3JlBlNu9YSycTI9u/dIkyiyMNt1HFdi72gm6pZEMSWs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HAme2K7DpiT1aPmrl1OIf49JTDr4LxAX7aUIfJ13CTkcgWVO2L54ebwqXoIf10cHWQTQHk3tmLyRB7hW7dnPolxlo7pHGkg9MvOkuQ5EyoQMpEgRSwQkERz4wDRcASmzAjCUd1zuw/MZ6lzC+LI8Z26J6R26MUGvWzyC0Y1Xu88= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WDDP9VXc; 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="WDDP9VXc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B88F7C4CEED; Thu, 24 Jul 2025 19:31:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753385474; bh=3JlBlNu9YSycTI9u/dIkyiyMNt1HFdi72gm6pZEMSWs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WDDP9VXcb5AkfWKL06GQn6al78aIc08lOjgARylIUwnzCQr33t3KfZl1zlvR6w54t mDoKWirjf1AC1AWOI1bNOrVGc3ujQl8XNN9fiNvQTuQ4tXlQsgAqzvEU+qN6J0RIai FPUqDC/tfGwlloDC+CXVThdkaCISzk64bJntYaybaeh1XCdNsT/WIUai23K6GSc7aq 8mRI7Njp2LkyENfwN6bQAzQc6xdYXX874OPAK4VaeG5Qz4IJRCuUlCdq3hciPWXRgM Ki3trgNiN7BPsQEE9Y8x4+mT2piWHLDz56AAjE9WEE8XWRFSJ8Y3E/ZDQU0ZY6pykX FSaG2FYaWlQ2g== From: Mike Snitzer To: Chuck Lever , Jeff Layton , Trond Myklebust , Anna Schumaker Cc: linux-nfs@vger.kernel.org Subject: [PATCH v5 07/13] nfs/localio: avoid bouncing LOCALIO if nfs_client_is_local() Date: Thu, 24 Jul 2025 15:30:56 -0400 Message-ID: <20250724193102.65111-8-snitzer@kernel.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20250724193102.65111-1-snitzer@kernel.org> References: <20250724193102.65111-1-snitzer@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Mike Snitzer Previously nfs_local_probe() was made to disable and then attempt to re-enable LOCALIO (via LOCALIO protocol handshake) if/when it was called and LOCALIO already enabled. Vague memory for _why_ this was the case is that this was useful if/when a local NFS server were to be restarted with a local NFS client connected to it. But as it happens this causes an absurd amount of LOCALIO flapping which has a side-effect of too much IO being needlessly sent to NFSD (using RPC over the loopback network interface). This is the definition of "serious performance loss" (that negates the point of having LOCALIO). So remove this mis-optimization for re-enabling LOCALIO if/when an NFS server is restarted (which is an extremely rare thing to do). Will revisit testing that scenario again but in the meantime this patch restores the full benefit of LOCALIO. Signed-off-by: Mike Snitzer Reviewed-by: Jeff Layton Reviewed-by: NeilBrown --- fs/nfs/localio.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c index 510d0a16cfe9..ecfe22a105ea 100644 --- a/fs/nfs/localio.c +++ b/fs/nfs/localio.c @@ -180,10 +180,8 @@ static void nfs_local_probe(struct nfs_client *clp) return; } - if (nfs_client_is_local(clp)) { - /* If already enabled, disable and re-enable */ - nfs_localio_disable_client(clp); - } + if (nfs_client_is_local(clp)) + return; if (!nfs_uuid_begin(&clp->cl_uuid)) return; @@ -244,7 +242,8 @@ __nfs_local_open_fh(struct nfs_client *clp, const struct cred *cred, case -ENOMEM: case -ENXIO: case -ENOENT: - /* Revalidate localio, will disable if unsupported */ + /* Revalidate localio */ + nfs_localio_disable_client(clp); nfs_local_probe(clp); } } -- 2.44.0