From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f194.google.com (mail-pf1-f194.google.com [209.85.210.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3C9D24E1CA; Fri, 1 Nov 2024 07:17:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.194 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730445441; cv=none; b=CcIM5JcdFPSMgVcwiYXr04mnE46REErPpQ3xd6xAv8rDRYM9gipnAVYMr6vLv5bW7j3upOE/9pasN3HujHv1Mr+1STZv5E+DEvzfTPb0n3InNKRns0EijzuWk11DNRobB8E9tzmSRWdjcU3TGuIWEfrdDVTt54sYrbgVbi7UdvE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730445441; c=relaxed/simple; bh=R87Oj6EwN9I1UmpVHQXJ6UwyrWlYwJB6czR7sLZDWLM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=ZQucR+apUSUhHQM8rpV7ScqwgOfNikfg4uO31Sxe3ydj+ARLC2xTXMsMrNDfGSC5OxWD6jVWV6DeVcDY5ZZXG9B9QYj/XHRmxUd3Z1Hi11HufPY6YLTxMtl/kFPO3GRCPzCHMAOAToV7QMVI1JEpvqDE2Iv4YBLDS+TXw9Vk8a8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=fICwDs9S; arc=none smtp.client-ip=209.85.210.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="fICwDs9S" Received: by mail-pf1-f194.google.com with SMTP id d2e1a72fcca58-720aa3dbda5so1249883b3a.1; Fri, 01 Nov 2024 00:17:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1730445437; x=1731050237; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=7zePBKOg1NOjIX6qGBpn66Tx/Y9R4RC4MGQIIOmHAXU=; b=fICwDs9SQCMCx+QJ+FXijaaYjv1pWWt9hZS8Xn25Z19PUs+Q8R0qanaDIZBcmrJ348 9iPVfUf35GpiluWmfNpeNIJ+HtE3fCy6G/YKGk+GfY/cRQjkhSPkTlm5r4SywD1S1PGt l0lq0qqjpbKNaM2woLr677Fe2xB7nmK+HYNZiVIwmSMxKbftP7wePRMeoyNE0Mqo9mIN k6y97Z8x7kt9cXFIuHnJ49b33/S0z0i3q41WrrafpkZMUPDfluEZu3gJ+dvxqnLL9V8d ygnFWznGLku+k/M2jM4VEI23hVD3xlhShhdF2i+rtbNcGhMkqv5JtEDOGR8PO+E+J2e5 KHUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730445437; x=1731050237; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=7zePBKOg1NOjIX6qGBpn66Tx/Y9R4RC4MGQIIOmHAXU=; b=WDgzGtlr51Bj1uFPqrALqvax7LCDzmPLgiPJjLWZmMhxQHzBiS9/bdMge6h/ERvXDh V/RDxqhITtTSLeheBu9zhSxHu434xQrzAu8an+m63oLTqSFqdVZQLKJPJB2NxAHdI4gs fYtw0ms+rGirj0nyHkGO/WFNboDyzGBQ4v1bACDW/7mtNypjPjQSkaUt4UM6PbYz1RXE jQDraIIBr42CkTzIqWyZ+0XWYeK1HuRDXt/NtatKgjo6TFS93bQksu/WFbXERH+4zhrh 7x6PGe6sAEq6uMYHpeWq0o29v6pekMaJg5s7ae6jDsZgNYtH0YfJS2+ggh5oEqdIeZ1j b8SA== X-Forwarded-Encrypted: i=1; AJvYcCU3ieICrJ5+qY9nq60dfnIjWjMwaAsWs1s9wcvXQiZdWGQUtJIsrIqNKYclvp/nAfPJKLGR16mM0rk+dOz+@vger.kernel.org, AJvYcCXSm/TgXgcMlr9AxVK7giRhwFct7T49PCCbAqAsZHFFHcMJNXRp4+6EKbDXRFAblY1YDUWw1ddDJa/hGi9v@vger.kernel.org X-Gm-Message-State: AOJu0Yw1v4+Ja4doYaGuhSbyMtDDnMLFTYEP8Z4iBo8U7601rWab06d7 dPWhjISgTcCbS7CmFlbBtxXhvg/6GijbG8+NMS5Lg4Q+BKskELzf X-Google-Smtp-Source: AGHT+IGbmekDEKQHy5m+gSdvzXWtzFsxIOVGg3WesPOFxjOBIk0/TiwjMbUOR8Zt+gDbBd6mHoSliw== X-Received: by 2002:a05:6a00:b93:b0:71e:589a:7e3e with SMTP id d2e1a72fcca58-720ab39e77fmr12493848b3a.3.1730445437354; Fri, 01 Nov 2024 00:17:17 -0700 (PDT) Received: from localhost.localdomain ([43.154.34.99]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-720bc1ba244sm2228025b3a.19.2024.11.01.00.17.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 01 Nov 2024 00:17:17 -0700 (PDT) From: Jim Zhao To: akpm@linux-foundation.org Cc: jimzhao.ai@gmail.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, willy@infradead.org Subject: Re: [PATCH] mm/page-writeback: Raise wb_thresh to prevent write blocking with strictlimit Date: Fri, 1 Nov 2024 15:17:13 +0800 Message-Id: <20241101071713.4085752-1-jimzhao.ai@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20241025170222.0ced663e778935946ea1c9fa@linux-foundation.org> References: <20241025170222.0ced663e778935946ea1c9fa@linux-foundation.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit > On Thu, 24 Oct 2024 15:29:19 +0800 Jim Zhao wrote: > > > > > 2. FUSE with Unstable Network Backends and Occasional Writes > > > > Not easy to reproduce, but when it occurs in this scenario, > > > > it causes the write thread to experience more pauses and longer durations. > > > > > Thanks, but it's still unclear how this impacts our users. How lenghty > > > are these pauses? > > > > The length is related to device writeback bandwidth. > > Under normal bandwidth, each pause may last around 4ms in several times as shown in the trace above(5 times). > > In extreme cases, fuse with unstable network backends, > > if pauses occur frequently and bandwidth is low, each pause can exceed 10ms, the total duration of pauses can accumulate to second. > > Thanks. I'll assume that the userspace impact isn't serious to warrant > a backport into -stable kernel. > > If you disagree with this, please let me know and send along additional > changelog text which helps others understand why we think our users > will significantly benefit from this change. It’s acceptable not to backport this to earlier kernels. After additional testing, under normal conditions, the impact on userspace is limited, with blocking times generally in the millisecond range. However, I recommend including this patch in the next kernel version. In cases of low writeback bandwidth and high writeback delay, blocking times can significantly increase. This patch helps eliminate unnecessary blocks in those scenarios. Thanks.