From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A85BAC55178 for ; Tue, 27 Oct 2020 00:43:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 734EC21707 for ; Tue, 27 Oct 2020 00:43:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603759415; bh=A13ztRz3hfVCYuX8QCRdP7ucVEpzD5vonq4BkI9VVFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xBzweibzETADg6+G7ZR5CWSosz3aLpvKQR40B9lcAoHstoHyU6pogCCeqCIpYSMYr T9K9TQX5dTfke1QFdM8bo3Qll6kdfYt9VTvsOs2+CEiyNMVd0QgNNz47AfKvuPBjuG 1jqdt5nYoPcbOf0f1HTQWVXEmT30Zadf3NUHjNzY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2409114AbgJ0Anb (ORCPT ); Mon, 26 Oct 2020 20:43:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:50524 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2409179AbgJZXuo (ORCPT ); Mon, 26 Oct 2020 19:50:44 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8674720B1F; Mon, 26 Oct 2020 23:50:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603756243; bh=A13ztRz3hfVCYuX8QCRdP7ucVEpzD5vonq4BkI9VVFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J18EjqDLQz2OP4nPD0tKEOjQrDiPsHiVj1NBqjT5Vok1OqFtqlAwDsIWRjSq1mZEf jR432yvjdiAupVUpfHDAkSsvCqZ+tp5rRc9QNhtK+b4FsMhg8GTL1gz+mDRVJaW1xd sSX/371j/WbxcgFGFHMz4xLA9jhOo+97VwuEqJ7k= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Chuck Lever , Anna Schumaker , Sasha Levin , linux-nfs@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.9 079/147] SUNRPC: Mitigate cond_resched() in xprt_transmit() Date: Mon, 26 Oct 2020 19:47:57 -0400 Message-Id: <20201026234905.1022767-79-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201026234905.1022767-1-sashal@kernel.org> References: <20201026234905.1022767-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Chuck Lever [ Upstream commit 6f9f17287e78e5049931af2037b15b26d134a32a ] The original purpose of this expensive call is to prevent a long queue of requests from blocking other work. The cond_resched() call is unnecessary after just a single send operation. For longer queues, instead of invoking the kernel scheduler, simply release the transport send lock and return to the RPC scheduler. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin --- net/sunrpc/xprt.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 5a8e47bbfb9f4..13fbc2dd4196a 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1520,10 +1520,13 @@ xprt_transmit(struct rpc_task *task) { struct rpc_rqst *next, *req = task->tk_rqstp; struct rpc_xprt *xprt = req->rq_xprt; - int status; + int counter, status; spin_lock(&xprt->queue_lock); + counter = 0; while (!list_empty(&xprt->xmit_queue)) { + if (++counter == 20) + break; next = list_first_entry(&xprt->xmit_queue, struct rpc_rqst, rq_xmit); xprt_pin_rqst(next); @@ -1531,7 +1534,6 @@ xprt_transmit(struct rpc_task *task) status = xprt_request_transmit(next, task); if (status == -EBADMSG && next != req) status = 0; - cond_resched(); spin_lock(&xprt->queue_lock); xprt_unpin_rqst(next); if (status == 0) { -- 2.25.1