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 8B6141B7E6E; Fri, 29 Mar 2024 12:50:35 +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=1711716635; cv=none; b=RCqV0zNfVp9b4XAe0mDIeY5plwLFGHt+L8Cl4p677YnGHQ2yZKEOF41tpShBEIoM0misGju5yYNIuX0lX+vK8umBzw8MhewkETylFkLXfzmRgkimrjbecUaz1tlpFgXqYFAnmPxzIdyuBD3jXSjODr4Gmqz/uBqmMp3lCk6wdUI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711716635; c=relaxed/simple; bh=xs7/v+Mzn5X7V0ApC3oJ6aQLmUE0xXQdx/iuOdrouHQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=p9dAx9sSIa6FRc3L1vX6+rZFZcKdKGpA7lA67ot+RCxpV5gqxwVpcZQ4KOvQIs/L4Gjim3hbZoBq6R91j+RVqUwWIwgCCB+J3fwcZDyNCoNJtG7frsEkeJwZPw05BroTmEgd2w+lNxElmBEDypIByAdiASXR0o14J3l6bklgWeI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=glPlO2rn; 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="glPlO2rn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A289C43390; Fri, 29 Mar 2024 12:50:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711716635; bh=xs7/v+Mzn5X7V0ApC3oJ6aQLmUE0xXQdx/iuOdrouHQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=glPlO2rnPGGhDrRhuBEWZXQRETpQAZrpoAZAXzP4zgXH4UfkXNhpYH/Nf/xgApkY5 eZwi69s5kq9/Z6wTHyLG6Yoeb9DSm6cMLHVBfaRlXa3/HIntgfVwstETrKwd5GPv2t HIhmw88ME0aXs3CWDLE7vp1cmVe2QwEYZQRcIV1utBuW2kc65qO7ldaspz2wRqWiKF rT7jiY1paihfe0yW/qB8ryQC/IgQ8lIVNatl1m6Qqz8njKJqCKouIx8EiXPxmgnQNE trvaa1AIkeflcLPY/ePzwewnuczfxx1kdl5/UJKncnOCHHGiwVYe89QPcg0dtkNnM9 mJDMPEF6gwCnQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Dai Ngo , Jeff Layton , Trond Myklebust , Sasha Levin , chuck.lever@oracle.com, anna@kernel.org, linux-nfs@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 13/23] SUNRPC: increase size of rpc_wait_queue.qlen from unsigned short to unsigned int Date: Fri, 29 Mar 2024 08:49:46 -0400 Message-ID: <20240329125009.3093845-13-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240329125009.3093845-1-sashal@kernel.org> References: <20240329125009.3093845-1-sashal@kernel.org> 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 5.4.273 Content-Transfer-Encoding: 8bit From: Dai Ngo [ Upstream commit 2c35f43b5a4b9cdfaa6fdd946f5a212615dac8eb ] When the NFS client is under extreme load the rpc_wait_queue.qlen counter can be overflowed. Here is an instant of the backlog queue overflow in a real world environment shown by drgn helper: rpc_task_stats(rpc_clnt): ------------------------- rpc_clnt: 0xffff92b65d2bae00 rpc_xprt: 0xffff9275db64f000 Queue: sending[64887] pending[524] backlog[30441] binding[0] XMIT task: 0xffff925c6b1d8e98 WRITE: 750654 __dta_call_status_580: 65463 __dta_call_transmit_status_579: 1 call_reserveresult: 685189 nfs_client_init_is_complete: 1 COMMIT: 584 call_reserveresult: 573 __dta_call_status_580: 11 ACCESS: 1 __dta_call_status_580: 1 GETATTR: 10 __dta_call_status_580: 4 call_reserveresult: 6 751249 tasks for server 111.222.333.444 Total tasks: 751249 count_rpc_wait_queues(xprt): ---------------------------- **** rpc_xprt: 0xffff9275db64f000 num_reqs: 65511 wait_queue: xprt_binding[0] cnt: 0 wait_queue: xprt_binding[1] cnt: 0 wait_queue: xprt_binding[2] cnt: 0 wait_queue: xprt_binding[3] cnt: 0 rpc_wait_queue[xprt_binding].qlen: 0 maxpriority: 0 wait_queue: xprt_sending[0] cnt: 0 wait_queue: xprt_sending[1] cnt: 64887 wait_queue: xprt_sending[2] cnt: 0 wait_queue: xprt_sending[3] cnt: 0 rpc_wait_queue[xprt_sending].qlen: 64887 maxpriority: 3 wait_queue: xprt_pending[0] cnt: 524 wait_queue: xprt_pending[1] cnt: 0 wait_queue: xprt_pending[2] cnt: 0 wait_queue: xprt_pending[3] cnt: 0 rpc_wait_queue[xprt_pending].qlen: 524 maxpriority: 0 wait_queue: xprt_backlog[0] cnt: 0 wait_queue: xprt_backlog[1] cnt: 685801 wait_queue: xprt_backlog[2] cnt: 0 wait_queue: xprt_backlog[3] cnt: 0 rpc_wait_queue[xprt_backlog].qlen: 30441 maxpriority: 3 [task cnt mismatch] There is no effect on operations when this overflow occurs. However it causes confusion when trying to diagnose the performance problem. Signed-off-by: Dai Ngo Reviewed-by: Jeff Layton Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- include/linux/sunrpc/sched.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h index 5c37fabdec103..61de83be9cc27 100644 --- a/include/linux/sunrpc/sched.h +++ b/include/linux/sunrpc/sched.h @@ -196,7 +196,7 @@ struct rpc_wait_queue { unsigned char maxpriority; /* maximum priority (0 if queue is not a priority queue) */ unsigned char priority; /* current priority */ unsigned char nr; /* # tasks remaining for cookie */ - unsigned short qlen; /* total # tasks waiting in queue */ + unsigned int qlen; /* total # tasks waiting in queue */ struct rpc_timer timer_list; #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS) const char * name; -- 2.43.0