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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A33F3C54EE9 for ; Tue, 20 Sep 2022 18:06:38 +0000 (UTC) Received: from localhost ([::1]:33096 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oahdl-0000eo-9o for qemu-devel@archiver.kernel.org; Tue, 20 Sep 2022 14:06:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46702) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oadbT-0000Nm-9G; Tue, 20 Sep 2022 09:47:59 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:45312 helo=fanzine2.igalia.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oadbQ-00074b-PD; Tue, 20 Sep 2022 09:47:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Type:MIME-Version:Message-ID:Date:References: In-Reply-To:Subject:Cc:To:From:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=zlNk8lkhcRTuX4rM3DLuKUUmF2qx5vs7ySqTzOLzqoE=; b=WPNct+E+JMAQ9ejSFShNKUSkMR Gk4JdLEYOh7bBlZqOtgOd4BIlu7jenWMBqNJuC4f67IxaumiytdOmkYc+sXFeSi8uR67OlqcdW2qY fR3Hapq374BdKEi1j0gDL49318eyTz6PlYLOHIInk+AT5zgEMh/hQ3rKvYOmrdggGsBlnogrHccRF Q09HZQ1XZhKGnAXbsRo+1MNi/g9ySePQ5IaNFdkZCD9FEDmsuhGfuN2dBeczYj2w7q+p2xCXSvFI9 SnvTE4w2pLdWrKeWh5x59aWIkwbRfJqiDIp9fGfKi4C7IUTqA7m2+9pHD1eJCjxZPMHRGtFCbha0p 7DqDcjLw==; Received: from maestria.local.igalia.com ([192.168.10.14] helo=mail.igalia.com) by fanzine2.igalia.com with esmtps (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1oad9O-00DZpZ-Nz; Tue, 20 Sep 2022 15:18:58 +0200 Received: from gate.service.igalia.com ([192.168.21.52]) by mail.igalia.com with esmtp (Exim) id 1oad9L-00F35w-7S; Tue, 20 Sep 2022 15:18:58 +0200 Received: from berto by gate.service.igalia.com with local (Exim 4.94.2) (envelope-from ) id 1oad9K-000rAJ-Kr; Tue, 20 Sep 2022 13:18:54 +0000 From: Alberto Garcia To: wangliangzz@126.com, qemu-devel@nongnu.org, qemu-block@nongnu.org, wangliangzz@126.com Cc: pbonzini@redhat.com, stefanha@redhat.com, silbe@linux.vnet.ibm.com, Wang Liang Subject: Re: [PATCH] ratelimit: restrict the delay time to a non-negative value In-Reply-To: <20220920123350.205391-1-wangliangzz@126.com> References: <20220920123350.205391-1-wangliangzz@126.com> Date: Tue, 20 Sep 2022 13:18:54 +0000 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=178.60.130.6; envelope-from=berto@igalia.com; helo=fanzine2.igalia.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue 20 Sep 2022 08:33:50 PM +08, wangliangzz@126.com wrote: > From: Wang Liang > > The delay time should never be a negative value. > > - return limit->slice_end_time - now; > + return MAX(limit->slice_end_time - now, 0); How can this be negative? slice_end_time is guaranteed to be larger than now: if (limit->slice_end_time < now) { /* Previous, possibly extended, time slice finished; reset the * accounting. */ limit->slice_start_time = now; limit->slice_end_time = now + limit->slice_ns; limit->dispatched = 0; } Berto