From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 ABB5D46D544; Tue, 21 Jul 2026 18:06:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657171; cv=none; b=qqm2vR+yI43tbjFD9NrGcCETQfQ2eQZ4EtdIT3e1y2VpKwDeKawo6LhWx5EauGOU1Vi/pVgwOC6Gn9EggHiVBPTGD9Dq2BH3dbOAWt1tZbGCG+OUDpcaW8pilRuk4uAN+8K7vDsLGVg/9v8Bd1bp25x45fbCBr6r+GtP0ayvVKk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657171; c=relaxed/simple; bh=K8a2QidDBkpdv/mEQ9xwXQD5lP/g/5YxBlg/RO7xWzU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mndqyKlDObJcovuA2F4hrXNTGv204tUXYgWg4oJuZK6+gMomouV5xR0wuk9a0aSTTFOiXpdt1tGbjrjFEPcN4bZxC6jeGK3NQfPGB6PhhlkgmqOkApKryUUSSc8xIaqpgipAx/N8N2bSiT68lFcr2cObbVZLDAKunOsMurkvUWM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HTqGFrd0; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="HTqGFrd0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1F4F11F000E9; Tue, 21 Jul 2026 18:06:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784657170; bh=gjd5z52T6bViJWcWk7teCrpExuhldN4BAlqfEzU7ssM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HTqGFrd0duTtvB4k5gHoDHJQSabvwzSVhHLq5/Ivrbeg07bzkzyNj6IeQN7i/jhXe YgHyiqAy+d1JeQRSXjwFPway2ueZ5FAgnrUP3m1fNoIBad2wuE0ncnhYdSfPTuj4Tg 3Wqz/4DnOKARPU6lepM3fMvGYa4RncArUnvn46VI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chuck Lever , Trond Myklebust , Sasha Levin Subject: [PATCH 6.18 0665/1611] xprtrdma: Avoid 250 ms delay on backlog wakeup Date: Tue, 21 Jul 2026 17:13:01 +0200 Message-ID: <20260721152530.340961708@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chuck Lever [ Upstream commit 100142093e22b3f7741ac88e94878bb3694e306f ] 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 Signed-off-by: Trond Myklebust Stable-dep-of: e786233d2e0b ("xprtrdma: Decouple req recycling from RPC completion") Signed-off-by: Sasha Levin --- 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 9a8ce5df83cad9..ca079439f9cceb 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