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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C013EC0218A for ; Thu, 30 Jan 2025 18:16:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 24CBC2802AD; Thu, 30 Jan 2025 13:16:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1FC382802AA; Thu, 30 Jan 2025 13:16:22 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0C3D02802AD; Thu, 30 Jan 2025 13:16:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id E22C72802AA for ; Thu, 30 Jan 2025 13:16:21 -0500 (EST) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 6DC7CC045F for ; Thu, 30 Jan 2025 18:16:13 +0000 (UTC) X-FDA: 83064922626.29.3ABB9CC Received: from mail-qt1-f175.google.com (mail-qt1-f175.google.com [209.85.160.175]) by imf15.hostedemail.com (Postfix) with ESMTP id C8A16A005A for ; Thu, 30 Jan 2025 18:15:50 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b="t//qTByF"; spf=pass (imf15.hostedemail.com: domain of mclapinski@google.com designates 209.85.160.175 as permitted sender) smtp.mailfrom=mclapinski@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1738260950; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=NEOd77SjPb3m7UT+5pRuzEhuc6qBHIUpHw9saacVwdQ=; b=Rh6zs4P+/xdAvGcyh7IZv6TSPzCuE+CdlSLgdArdf1QGo64wZrv6KdSxHwkgZIbQVBRIh+ Kljf0PU+G2FVjjCj54zRJSyoiYRuzArP6pcla42rvstPc6SQAUtwHHrL+eGsqw+OiC5S19 18cgqrKSNypK6sW2X5W9UCc98oiFKxw= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b="t//qTByF"; spf=pass (imf15.hostedemail.com: domain of mclapinski@google.com designates 209.85.160.175 as permitted sender) smtp.mailfrom=mclapinski@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1738260950; a=rsa-sha256; cv=none; b=Nl1hr0xvONE5EbM/l8kzKEitI/0sl3jytzehOKtKwG7sNVl2D/3zmV7kVVJXu3amSEljCu qRhOPbTwj7HoYbNKkEsHNkK0YvZnYlphH0R4sZB6vBpkpDbx8aFE4B0/AXhDC/t295+En5 7Tuskv5yq9RE8Z2D9LdbYyBc8Au1XDQ= Received: by mail-qt1-f175.google.com with SMTP id d75a77b69052e-4679b5c66d0so4761cf.1 for ; Thu, 30 Jan 2025 10:15:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1738260950; x=1738865750; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=NEOd77SjPb3m7UT+5pRuzEhuc6qBHIUpHw9saacVwdQ=; b=t//qTByFdfeB8VZa5tPaBB56Br+IPdsw/3IhwrARJuPTgQR1tkJagualoM8hNF241P ugIke2ikfV9FylVFvlVNRYCH11Le1wrFSGt4mmPoOds4r0sLCPqzTuYLpgXMb3vRn+D4 prnofsQ/HyXKACr1I6NVdMKBwRnhz2cCU71BMVyVSPwJwXVR7vS/MEmvQ0q3NrLy+5Ug LKK1oAzTyEryllkYChuQj41+3nZqNhjl1D2AuPdh6IDE1KH/kBaD6g9rN8ln5uTRYcP7 5oDGWIUBiXRpd97hnWd3Srj+NtmpnBRGSTce5YNRxrI4xovDbE9UaPOh55lisaVtXgvG 1bvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738260950; x=1738865750; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=NEOd77SjPb3m7UT+5pRuzEhuc6qBHIUpHw9saacVwdQ=; b=rwxtczEVdj4xRt1PAvZKCnr9HYh0v/0nYrAQdMhQvyo0WLkstpcW4HuyY8tu4mhzuL 4ETCBu5/ZyPloggqEHBCmJioGyf8Dd2iJ0Ab+NgwuPq3G6/o5r9VAS+c08ryrwKcRCLT 9UumEbje2amjIZg8z/ULgvceHP8ORzab9+FVnti+ndHcjCTggSuMhEvRbaxni9F6daeU KZv1M/1FJCMhYIUrg7wq1hWPO1MpFeTq9TAt9nFiXM+oNSnwdrIfDfx+r0+UN7T+Kvei JVpk0hONxH3nEkJDqxrrpk6h4dXNm8Za3PQOaywAyk6vX3P1H3u/vPPRVpuE7YYIrNxr 70aw== X-Forwarded-Encrypted: i=1; AJvYcCX/SL8IcKOazNUvnbkO0t8krCflC/2TpjFqyBHnC8G0KrPlX5gom2tMr88azAOrhD9iOSVSnliy9Q==@kvack.org X-Gm-Message-State: AOJu0YwSRs2tq3HhdOrxCkMimnl8MI9iGCvD5oUXt4yj1v83nRj7uXSE 5/HzgJce7xU+FDj1dzTEnuO1yZ9jwaHOkWJFtjIC928vqXCQoqAYFHfsgYc8fiD52kSNNg5dodP B4573nEGRKYoCpPbR2wxVcJNc32pqa56RhEjtGH7jl2SrDIu9OI4S X-Gm-Gg: ASbGnctH9YJ2+tYswYxZs/hVW12zYhXHPO1ZapzI/MpiS9iSPnHQUKdqd4Xu10yNm9C wFO2+4I81kpVQTL3SRzG3VkkaWSyNjlWs5c/f2/NvHcKCTIoqWroLr+zZ88hOUgcA5n23qP22ia 9q30+nscquMuXsptNfaPoIbKyW X-Google-Smtp-Source: AGHT+IFp3IJsIIJ2xzyXdmC4xIiXCDX+fRic3ZlvOOA8Nre+b/VfyACkHHml3EuDasdckZPGmgEzAI0EypULH8+K6l8= X-Received: by 2002:a05:622a:3cb:b0:466:861a:f633 with SMTP id d75a77b69052e-46fdf5b7ce6mr3849541cf.5.1738260949710; Thu, 30 Jan 2025 10:15:49 -0800 (PST) MIME-Version: 1.0 References: <20250127215020.4023545-1-mclapinski@google.com> <20250127215020.4023545-3-mclapinski@google.com> <20250127171857.34c71d3a6f0cde1953b02a58@linux-foundation.org> In-Reply-To: From: =?UTF-8?B?TWljaGHFgiBDxYJhcGnFhHNraQ==?= Date: Thu, 30 Jan 2025 19:15:38 +0100 X-Gm-Features: AWEUYZnKb3rdQYIrF52rDuhVSFHUBikcqJzeUKWyTV-PGmhKIVE_rm6uFpOUdG0 Message-ID: Subject: Re: [PATCH v3 2/2] mm/compaction: make proactive compaction high watermark configurable via sysctl To: Vlastimil Babka Cc: Andrew Morton , Pasha Tatashin , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: C8A16A005A X-Stat-Signature: sbrykekef6mixxir1mnpeei6zx4m3fm9 X-Rspam-User: X-HE-Tag: 1738260950-416051 X-HE-Meta: U2FsdGVkX18WD6tjOd8pwtl2dfJtEe2ZCjzyrLnvF7yRjtQPjV9Dk8rSG0pzCV0zw/r9hQSnBLxg4lVVxSlISx+eL5taMqEeiWclbNSbbH+2ulmUoitaaVs5h7a91zGnNAV4HzPp/T6zUvp0CZDouAUjkDLVqRy0Jr9cnDLguN2Y9JeOjSCWA0f5WN5y+qEZWE4iaONSOaBIDbb6V6NE9eb8JGVPFACtUDDEGQ/1oZYkhlXkAdOQ6Wm/7r0/6DtbYEQ6Fz9SAaNVE4ZQEKdlrpWXh8PvdnbouzEC39o3z82UpCqoBv/au5gMBGO3zu9Ywru6x695V+ZEcxIpCqrDKHFtHBVbIttGRmOhyjqWSFPZC5lH8G2VLZcOuSDs+QFzOsfl25b2JnY3pXHAD0eFwBOHysRCXow2Z9Y1HvBqL4i+UVWQJXPf4Tj5Z39WLY5ZhwhW9ED0nAU6MKazKZPoqfn9oQRNyX19tdH2Et8nuU5I6UwGHbAXOf3zjBcb8LMNMQSRnyaTYjp89d69/42NK8sz8MvADmTDqv9o1PMheXI5Z2RbdRCpipDMk45nWJuyWj7Jh7+mqosumh0elCMYSGd2Al0WdaJu/Ww1rawqdSwU0ID47BUTfU2JbQ0ss5ixpyISDlZgzSjKwWZPxPUMP9DPbDTn4cqXxY3fbN9dDB25ANWZNNAdmfX3iqsXKKftjqSxcOhbpFIaEwZKJUSMQZqvxzo7gSx3/NVrQO4Bhz7e5q6X3f1sblQn8CThraMZJ8RIbrtwwj5+tDQUPFrfZtglGMfjsc54LX2l1t8s4GUHRYagk9F1XvnqjjlGucQb1Gw75i7tat5j58fUhvHTM/x9VR1/QybVxhGtZAM38GsPpIW9F8ZtMyAwMrvuhH7dQ80kwisLu9lpaATBbis68NNOdBgxHGATXsM1Tx/0ocrh091V7efV1cW81HuWTAnIG5JYuOXmNI4YmfYTSML M0uWtpcQ qaE+ZDQoELntdRKtEfGuGXyRQbqTKVrUv5tKn8UmrrE6Id4X26HdF1lHbY56YykU/4UG1x+Ni7ppfifpVJGb4OLkOd5t6uP+A2IurirgHuIN4ujDV0SiY1tEJnfoSv5La5nyaN5TO1Om8jBXdOA361ZMNOEgCR8UTkhnic9T0pBkKB8y7dZA8T8MjgtdPa9SseO99vjIjCLPWivJafn7HEufTdtWg0OOXtTCoLKDk9S8g9ZE8OoJhzIIdLw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.150289, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jan 30, 2025 at 3:18=E2=80=AFPM Vlastimil Babka wr= ote: > > On 1/28/25 02:18, Andrew Morton wrote: > > On Mon, 27 Jan 2025 22:50:20 +0100 Michal Clapinski wrote: > > > >> Currently, the difference between the high and low watermarks for > >> proactive compaction is hardcoded to 10. This hardcoded difference is > >> too large for free page reporting to work well. > >> > >> Add a new sysctl, `compaction_proactiveness_leeway`, to control the > >> difference between the high and low watermarks. > >> > > > > Oh dear, yet another tunable. Is there any way in which we can > > acceptably improve the kernel without adding this? > > compaction_proactiveness between 0 and 90 works as usual, > thus up to low watermark of 10 and high watermark of 20 > > compaction_proactiveness between 90 and 100 additionally reduces leeway, > with value of 100 resulting of low =3D high =3D 0 > > or some similar scheme, as long as a value of 100 does low =3D high =3D 0 Yes, I was thinking about leeway =3D min(10, (100 - wmark_low) / 2); to be able to get small leeway (and therefore more stable memory usage on the host) without having to opt for very aggressive compaction goals. Both of those solutions have the disadvantage of introducing even bigger changes to the behavior of systems that were already set to compaction_proactiveness close to 100. Though I'm not sure how common changing this tunable at all is. > It's rather arbitrary but AFAIU does what Michal needs and higher > proactiveness means more aggressive compaction. > > Question is, would anyone else find it useful to have low_watermark of 0 = and > high watermark of 10? > >