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=-5.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 8B44CC47E49 for ; Wed, 23 Oct 2019 15:56:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6114121929 for ; Wed, 23 Oct 2019 15:56:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="gzPtJc9U" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406971AbfJWP4r (ORCPT ); Wed, 23 Oct 2019 11:56:47 -0400 Received: from mail-qt1-f193.google.com ([209.85.160.193]:36676 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406962AbfJWP4q (ORCPT ); Wed, 23 Oct 2019 11:56:46 -0400 Received: by mail-qt1-f193.google.com with SMTP id d17so18401366qto.3 for ; Wed, 23 Oct 2019 08:56:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=qCDfb7NBt3k96Z3LHT9+wyaPinygdsUVG4eMjwQIig0=; b=gzPtJc9UG7/c3nCw1QDLmDFrPZ2p/5hVgwAWj5fxU7jOZw+4M6LELBbAGYk+6wbln3 f8ief24ppj67ptUxcdk4CzpF1yUiOP/2cRcPsqUBcFvNqdvDdfh1GrdDRfcdT6jSga8O lCUDrd5RQn/iYeUN5F8eMCJalFsQlOXYkpMo6RwW+lAx6M9sN67Bw/rIRZs76wUfN5ST 3CmZcNDi0/pmB0JWE+/PHNP2bwbar9mrnhDdr4HqOzD/LbibMVqfVF5SBw424VYUqiAQ ZP48m8ZlTKx6J90KvpquV6g52d05IyK6VPpkmJ5aUaOaY30+/V/qPLq6e17IUoCMFz2f +SgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=qCDfb7NBt3k96Z3LHT9+wyaPinygdsUVG4eMjwQIig0=; b=hRs/1N2WkLNgE14Hi8A7W5dVee9aqaPKHPZ48YOqDe7ab/vsnfEw6Twwjf6VE4zRfy F7z07/hO4JQx92CLO04NWmvjrDH7p2sGLkyZg2o7G9fgfia21Vl1joEBkUwWZ5g3l/4O H9EzO32hkYQIyrEze/+DP6GIRsDl0OEgtZ3VhfByCMKyh7Dxl+hzADMxor2mwJVEKeHY REXMNHVKX2peYFsv39C5c5F6QzpvVhAXTh51acGu8w229E4ve0msGEn2iEbOHYHkjvo9 QXc3n1EMbVrsuZTxaJTkEc9YZBCV8uGCQ0Zr89mN2pXEhIiGLp69cQvTpN1VSWYEkbGZ WBnw== X-Gm-Message-State: APjAAAUcbVeMQUbuqqFqCHzM0yo7BNgMxN8MQlteV5qsowtbZsYNU2d/ 5mtashu72ZNN3O1FI8EC4BGfLg== X-Google-Smtp-Source: APXvYqx0acPfaJc7aDp/xUAu/oImOejs62QLL76QQZnIiy0PFClGHYdtIYajkheNs7/YVZ6DSkKAsQ== X-Received: by 2002:ac8:4506:: with SMTP id q6mr10062633qtn.277.1571846205200; Wed, 23 Oct 2019 08:56:45 -0700 (PDT) Received: from localhost ([2620:10d:c091:500::2:c4de]) by smtp.gmail.com with ESMTPSA id p7sm12637822qkc.21.2019.10.23.08.56.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Oct 2019 08:56:44 -0700 (PDT) Date: Wed, 23 Oct 2019 11:56:43 -0400 From: Johannes Weiner To: Michal Hocko Cc: Andrew Morton , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 4/8] mm: vmscan: naming fixes: global_reclaim() and sane_reclaim() Message-ID: <20191023155643.GB366316@cmpxchg.org> References: <20191022144803.302233-1-hannes@cmpxchg.org> <20191022144803.302233-5-hannes@cmpxchg.org> <20191023141436.GE17610@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191023141436.GE17610@dhcp22.suse.cz> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 23, 2019 at 04:14:36PM +0200, Michal Hocko wrote: > On Tue 22-10-19 10:47:59, Johannes Weiner wrote: > > Seven years after introducing the global_reclaim() function, I still > > have to double take when reading a callsite. I don't know how others > > do it, this is a terrible name. > > I somehow never had problem with that but ... > > > > Invert the meaning and rename it to cgroup_reclaim(). > > > > [ After all, "global reclaim" is just regular reclaim invoked from the > > page allocator. It's reclaim on behalf of a cgroup limit that is a > > special case of reclaim, and should be explicit - not the reverse. ] > > ... this is a valid point. > > > sane_reclaim() isn't very descriptive either: it tests whether we can > > use the regular writeback throttling - available during regular page > > reclaim or cgroup2 limit reclaim - or need to use the broken > > wait_on_page_writeback() method. Use "writeback_throttling_sane()". > > I do have a stronger opinion on this one. sane_reclaim is really a > terrible name. As you say the only thing this should really tell is > whether writeback throttling is available so I would rather go with > has_writeback_throttling() or writeba_throttling_{eabled,available} > If you insist on having sane in the name then I won't object but it just > raises a question whether we have some levels of throttling with a > different level of sanity. I mean, cgroup1 *does* have a method to not OOM due to pages under writeback: wait_on_page_writeback() on each wb page on the LRU. It's terrible, but it's a form of writeback throttling. That's what the sane vs insane distinction is about, I guess: we do in fact have throttling implementations with different levels of sanity. > > Signed-off-by: Johannes Weiner > > Acked-by: Michal Hocko Thanks!