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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64B2AC46CA0 for ; Thu, 30 Nov 2023 21:46:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376985AbjK3Vq3 (ORCPT ); Thu, 30 Nov 2023 16:46:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376954AbjK3Vq1 (ORCPT ); Thu, 30 Nov 2023 16:46:27 -0500 Received: from mail-oi1-x235.google.com (mail-oi1-x235.google.com [IPv6:2607:f8b0:4864:20::235]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEA1110D9; Thu, 30 Nov 2023 13:46:33 -0800 (PST) Received: by mail-oi1-x235.google.com with SMTP id 5614622812f47-3b2ec9a79bdso902849b6e.3; Thu, 30 Nov 2023 13:46:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701380793; x=1701985593; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=E7kw1SluTyHuS8yhLQtATJ7V+RH9z5AGm8JV2/YS9U8=; b=OcfX/OUDOeuukd4WpimK/PFzkflmOaTZlpC/bymlQ4NQ/w942I9yYdmcpFHrcvc1tl bxmDDKwY++cCd0Da+nwa7+OPXY5+haqoNLeDVmffMnTnrm6uwdDYY8vfBROmcra/ylcm ZJsvSum0j3jAwXq8dahFV/pTHMFkgqU3bjoFEAtmA179tnaVHc6dFTJ/qviVAihf5iD1 Wj+InDKMuq5D5Z0obopCjMhkNhTvbAv69VQ4UlAcVgQujeN16lTWOttg23dxaq9/eHxo 9Q7Y2/FvxcL2JmrXh47cRvUsezdbXtOoe5q4DGRBcOh4aZFTSXPVNeCChz8L/URlFDoF acqQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701380793; x=1701985593; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=E7kw1SluTyHuS8yhLQtATJ7V+RH9z5AGm8JV2/YS9U8=; b=gtQztwrjsrdlZzSoATF6dhUfTOiW3f7BJp8sAuLp1OZe5IAgTvt6fdFmjmXhzGQrNE KVhN6jlD3YdEV9PGiAKt+jQHoVS5v8x4mQut+taWBmJNLY+hF32P9nYHJQqRFw0psaCk YTV8GF5mDb4f07bu+tScd3A3wXO5s/Gv5oVFD5W7MbeDqwNqk6WhELbYoHIGxsPJfDGy PkY6Tn0pGaZkzfykyWcVHa8wgA7gX6nWs4+WooCCJipCTZlw6EqqIdrODvCXJQoJ9jra phZb330j/LCl153+ZqltgXBT6zYhEuAhvlBnXAhYLeYmV7UbbOSE9Y8/TtznN3T7o4A7 LZ1g== X-Gm-Message-State: AOJu0YyCJ1AJ4K0wDrpUrbNh9LaTuWyD2WGQranQJaI7y/jvcL/RCXfQ UucwMWA8frLueGkTpnnHggU= X-Google-Smtp-Source: AGHT+IFt3eeK3wvzcN/i7Gz7UOv+pTeHBd5sEJ2IHfzZ+nl1IKWIB2GxU4N1giT2RlMwQ3Enzjbcjw== X-Received: by 2002:aca:f17:0:b0:3b8:79a8:cc7b with SMTP id 23-20020aca0f17000000b003b879a8cc7bmr948016oip.16.1701380793258; Thu, 30 Nov 2023 13:46:33 -0800 (PST) Received: from dschatzberg-fedora-PF3DHTBV ([2620:10d:c091:500::7:5fb0]) by smtp.gmail.com with ESMTPSA id vy13-20020a05620a490d00b0077da601f06csm865412qkn.10.2023.11.30.13.46.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Nov 2023 13:46:32 -0800 (PST) Date: Thu, 30 Nov 2023 16:46:30 -0500 From: Dan Schatzberg To: Andrew Morton Cc: Johannes Weiner , Roman Gushchin , Yosry Ahmed , Huan Yang , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Shakeel Butt , Muchun Song , David Hildenbrand , Matthew Wilcox , Huang Ying , Kefeng Wang , Peter Xu , "Vishal Moola (Oracle)" , Yue Zhao , Hugh Dickins Subject: Re: [PATCH 1/1] mm: add swapiness= arg to memory.reclaim Message-ID: References: <20231130153658.527556-1-schatzberg.dan@gmail.com> <20231130153658.527556-2-schatzberg.dan@gmail.com> <20231130133340.36140526608289898acb3ac5@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231130133340.36140526608289898acb3ac5@linux-foundation.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 30, 2023 at 01:33:40PM -0800, Andrew Morton wrote: > On Thu, 30 Nov 2023 07:36:54 -0800 Dan Schatzberg wrote: > > > Allow proactive reclaimers to submit an additional swappiness= > > argument to memory.reclaim. This overrides the global or per-memcg > > swappiness setting for that reclaim attempt. > > > > For example: > > > > echo "2M swappiness=0" > /sys/fs/cgroup/memory.reclaim > > > > will perform reclaim on the rootcg with a swappiness setting of 0 (no > > swap) regardless of the vm.swappiness sysctl setting. > > > > Signed-off-by: Dan Schatzberg > > --- > > include/linux/swap.h | 3 ++- > > mm/memcontrol.c | 55 +++++++++++++++++++++++++++++++++++--------- > > mm/vmscan.c | 13 +++++++++-- > > Documentation/admin-guide/cgroup-v2.rst is feeling unloved! Oops - total oversight on my part. I'll add docs in a V2 if we can come to consensus on this interface change in general. > > Please check whether this interface change can lead to > non-backward-compatible userspace. If someone's script does the above > echo command, will it break on older kernels? If so, does it matter? Older kernels will return -EINVAL with such a command - that seems appropriate, indicating that the argument is not supported.