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 120883B1EFC; Tue, 21 Jul 2026 20:41:07 +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=1784666468; cv=none; b=pCevG1Bw6nCk9BiZ5zkw2CKjQc+TbQPyRtqm8XuOAqccew0czdeg/cCvwjHXgCaN26GqHtxSrKhJj3ZnT++eq/ezDqODdsYboWrs0nkxGv6Lo6Wl9zaMJeIpJWSGajcH1Pz5pP0p9mFPNrz8S3iJ7TGjXVJOo8/6/gtihZWAg5o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784666468; c=relaxed/simple; bh=LJcyx3KfNnDKoAVBmlhkKyD9gB2AiAnkFFMcDq0NNmo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ONBOvFe8Dle+8lMTT5qf5Khn6JIMVC3LUwxfKehZXBktR+nv2krjmsd1pfo0qJ8UdvXi3+X5qsDfCm1nmkGe631lexjhxh0NVUGV3cpo7YSCkoqxJ2VYDQHUPc0fue+n5A4LoFrit7T9XZygndOtdhJlnnRwg3BBcV7tDghnsQs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zunu+UK9; 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="zunu+UK9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77D151F000E9; Tue, 21 Jul 2026 20:41:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784666467; bh=fSU4nb0ykQBv1UeFH3du6URqSLzNAK/9Ahqs5dbezCs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=zunu+UK9y9j2wv7++kPU8zJUxFAkOWTZGvBfACNrywu7coo8s/t7Y8Q/VYzdK8ZUm u2qmbYXMndaHP12jF4saTLv+s0567UzPJieYpp/U/Dw6zjgZZuBAN/RN/Qvf6DPvJJ Fp+ZiBiOwcDH9Sg/MNuhQuh2fMOLDOvxD0urOrlI= 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 6.6 0651/1266] xprtrdma: Avoid 250 ms delay on backlog wakeup Date: Tue, 21 Jul 2026 17:18:08 +0200 Message-ID: <20260721152456.423623807@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152441.786066624@linuxfoundation.org> References: <20260721152441.786066624@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 6.6-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 29b0562d62e759..b971776b55936c 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -511,7 +511,7 @@ 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