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 344A23ACEF3; Fri, 6 Mar 2026 21:56:34 +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=1772834194; cv=none; b=bGXySnqu4xRBfEO8B+zyX//2Y6O5QCSzL9FZCegRPkzxTxO8r8ps8qo765yyrOT08KW30M4+PZ73DkFphNP0iUQccwkDOtXu5uVw53HQUJzEX6bFMpN7Lb28tWSh8PJP1vsY2o+NgoM7PChFvF0qRYun+yF3BHvde4nmnVUSpsg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772834194; c=relaxed/simple; bh=JhNI3uLIe+HscvLElfDY7j7edv7/hA6m2Mcu+1L3lKA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=L2deCUmXGK9FPTtRzJD6Zwpf8yayBR+GSFU78xSrOKnPHFhqjvNYTkov983G2LLR1+a0U/Qv2h0dQpxIvPiEXnXpjlphVHQbqFnzb/2RjmIeNLprYHKQLYy6mUf+BJ9FpHeWVeFYCjaEgcqQRIfNOLB47kp+hGNbKgYXkqrgIBk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qGF/5rmE; 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="qGF/5rmE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B4B2C2BCB0; Fri, 6 Mar 2026 21:56:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772834194; bh=JhNI3uLIe+HscvLElfDY7j7edv7/hA6m2Mcu+1L3lKA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qGF/5rmEyf3+eozNE2UBLdDgOASoRpQW4MOKwlQ0dSSsyWPubkBZm+430XLnBiH2f Air20mm4EZEBJRBh5mKGsmdQA1Dvk6pyMvNqzzasou6PvHtc9TW70laeHcCyFKXSQy sHmbc5bOpMX4rNwS5hpdnSLhIA7VxqSSNKrACaa34LiIWg0avSSQcL9lvj6u3r27Le /qdgbgciPYYjMD32HvYJTkYHFqN7PXR6OB9Uw6JzNPPpEiwjJtkCDM8sUw33h03c/p bKxAXKrbyiiRK7gvmZap4DhFyJ5Zz8g/ZgjR83HpoBXcgN3rB3/2cfG9tpzgSl+jay WYNa7m/ttoOCg== From: Chuck Lever To: Anna Schumaker Cc: Trond Myklebust , , , Chuck Lever Subject: [PATCH v3 2/7] xprtrdma: Avoid 250 ms delay on backlog wakeup Date: Fri, 6 Mar 2026 16:56:23 -0500 Message-ID: <20260306215620.3668-11-cel@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260306215620.3668-9-cel@kernel.org> References: <20260306215620.3668-9-cel@kernel.org> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1253; i=chuck.lever@oracle.com; h=from:subject; bh=6pyUQpuVLSBToOuVdJ5zWkakk4/utGhpsQKz929K/qI=; b=owEBbQKS/ZANAwAKATNqszNvZn+XAcsmYgBpq02MlrcWStJfY0WLXFrjBf/nqK/fWjn5VyDsm /UrIZ0W1PWJAjMEAAEKAB0WIQQosuWwEobfJDzyPv4zarMzb2Z/lwUCaatNjAAKCRAzarMzb2Z/ l5LcEACWrybvHNXZfml/9QPwYv4hq5XNRb0Zk1t2/P33UZbtamI8jENqcU8ojDV8QzdRzVMINWJ Vob1vE1Nm1ai8cQzu33YYMXDoIYgjeiBLyoumLSxXJ+71xh2i1+Scv/7/0QouD6utxTudU0mB58 HiLBhu4WDJWlGjcwDJ+Ul548kZF3iM5lpyilOpH5SLS+Reu+Tf5TPIvLXS9FgD888u1qIPf4ot0 mO/7QA27XzlFkfhFv2DRoO4zwvgw5q75ANX4uzP5F9u4v2/V4mA59EhQU1+JQdSW724KEnTyTV5 /OXGdT1iFtItoD2kidl68QRLWjIuCE2ZoWadnB5Duq3cR4C1OUlYztca+q2R81yLkD1rGOMWjpm mkfXetlV4JwJn/WsOyDlVofEHjFonp+chmZrij7fns2PCtrqZCKCU0CZvaCwyUybJY/ARkmpFRR rexTxnvEXkb2gvPZMg2qvgxV++Z/SRFfvxFxDk0twtLpjOuWH5gP0vzkb2eemhtF5QQCDySF74I RvDiHZQwaPIkGHpc+TLK0Q9ZKxt1a5lKr4uW2EtbbNJOX31F5Qv8EraZ6XVecJ1IsyEXmbq4X4l NF9eWn6j+VfJHpfCj6C4RgxfqdyivHXg42i5aoWyDM6nLO5XrTpNVwNVkB7m/77lRckp2UDs/0n agVKPKbEReI3Pbg== X-Developer-Key: i=chuck.lever@oracle.com; a=openpgp; fpr=28B2E5B01286DF243CF23EFE336AB3336F667F97 Content-Transfer-Encoding: 8bit From: Chuck Lever Commit a721035477fb ("SUNRPC/xprt: async tasks mustn't block waiting for memory") changed xprt_rdma_alloc_slot() to set tk_status to -ENOMEM so that call_reserveresult() would sleep HZ/4 before retrying. That rationale applies to xprt_dynamic_alloc_slot(), where an immediate retry under memory pressure wastes CPU, but not to the RDMA backlog path: a task woken from the backlog has a slot waiting for it, so the 250 ms rpc_delay adds latency without benefit. This also aligns the code with the existing kernel-doc for xprt_rdma_alloc_slot(), which already documented %-EAGAIN. Fixes: a721035477fb ("SUNRPC/xprt: async tasks mustn't block waiting for memory") Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/transport.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index 9a8ce5df83ca..ca079439f9cc 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -510,7 +510,7 @@ xprt_rdma_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task) return; out_sleep: - task->tk_status = -ENOMEM; + task->tk_status = -EAGAIN; xprt_add_backlog(xprt, task); } -- 2.53.0