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 ED3BFC74A44 for ; Tue, 14 Mar 2023 06:33:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229796AbjCNGdo (ORCPT ); Tue, 14 Mar 2023 02:33:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229475AbjCNGdl (ORCPT ); Tue, 14 Mar 2023 02:33:41 -0400 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C27F59ED2 for ; Mon, 13 Mar 2023 23:33:39 -0700 (PDT) Received: by mail-pj1-x102a.google.com with SMTP id h11-20020a17090a2ecb00b00237c740335cso14108518pjs.3 for ; Mon, 13 Mar 2023 23:33:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1678775619; 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=eWhc5GI6KxiqzBSNgylF0hu+tPDYSfgvHUxc/4hzpYk=; b=WZMLxYnO9qDcaaIsZ5nrDoWGNVvWDi3HDW/6rytnUzEHGwOP61EefD91KkRmH8LiZL vaIfbkwNIhj9vqgZdW5mnSWASh28uh632JY8/rbJDkDPup7CjGt3WsX5vnoJx2CyAVaO g9nzjuMgF3DEixBOT0/F0vLNz9JwSOWDwSpGZKdu6t7A7e+r0w7mbuTj1wt52q9KXSra iulVHi9lX+Mb8lEcM3vbFvszIMPfjcrQrq7CuKiz/YYnGszlD4eMSX17nHpmw57uJgTC 40azU5JuwbT50om1OiQVnIhb/+hDxK2QnZ0x930YzPViFewwhrNvyj6jZct4SxNPIsI0 l3eQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678775619; 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=eWhc5GI6KxiqzBSNgylF0hu+tPDYSfgvHUxc/4hzpYk=; b=GaBcZ4dHFOPz5UMVY86aIzdCVrVGRNn80c3cSz46qxrjRMo2ww2Xkk1d1QMLgbGKeq EIkGt1qIpPK9g7uu6nMtP76+3a3UqUQZf+zNhVb6MFUqwpj5v2HS+4ALTdUzcveh8yzE 9tYCNwtu011lHXXyOV+aRftdHN5ZuN5H1pEEKiG/5RCbMixybpb//f9Mag++/3kRe2j9 826//ScNCMw09/WHdCB2G2v+mJGZqDa3hs728nBWth6wW3Xqr3+ylhwXCBOp8lgj2/LR v0cNAfWPvz3aMdQtntMWttuQWUwQNRhjhUwMnymQsO6sPy5Ig1ZGHDginR1qRZaWG+sQ Swzg== X-Gm-Message-State: AO0yUKW6UjEfxSRYX+xqaiGTxxhm0E+hkCGEAWVYlBD/1Xb1K9fm45RV KFOP/VdsMNdh0oImWcrC7bo4681OR4rHag== X-Google-Smtp-Source: AK7set9KQw3OEZASJWg5oP+D7flBYwBxNKRCMplbGTp8Mq535lr4GErZimI1rD4DC7SpEYRme2T4eA== X-Received: by 2002:a17:90a:498b:b0:236:84a:8d9d with SMTP id d11-20020a17090a498b00b00236084a8d9dmr38144469pjh.39.1678775619182; Mon, 13 Mar 2023 23:33:39 -0700 (PDT) Received: from vernon-pc ([49.67.2.142]) by smtp.gmail.com with ESMTPSA id kj11-20020a17090306cb00b00198ac2769aesm893531plb.135.2023.03.13.23.33.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Mar 2023 23:33:38 -0700 (PDT) Date: Tue, 14 Mar 2023 14:33:34 +0800 From: Vernon Yang To: Vlastimil Babka Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/slub: fix help comment of SLUB_DEBUG[_ON] Message-ID: References: <20230222232058.66971-1-vernon2gm@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 13, 2023 at 05:26:19PM +0100, Vlastimil Babka wrote: > On 2/23/23 02:03, Hyeonggon Yoo wrote: > > On Thu, Feb 23, 2023 at 07:20:58AM +0800, Vernon Yang wrote: > >> Since commit 081248de0a02 ("kset: move /sys/slab to /sys/kernel/slab"), > >> the SYSFS path of slab was modified, so fix up the help comment of > >> SLUB_DEBUG to use the correct one. > >> > >> And now the "slub_debug" parameter on boot that is support for more > >> fine grained debug control, so fix up help comment of SLUB_DEBUG_ON > >> for "no support" to "support". > >> > >> Signed-off-by: Vernon Yang > >> --- > >> mm/Kconfig.debug | 12 ++++++------ > >> 1 file changed, 6 insertions(+), 6 deletions(-) > >> > >> diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > >> index fca699ad1fb0..732043bf56c6 100644 > >> --- a/mm/Kconfig.debug > >> +++ b/mm/Kconfig.debug > >> @@ -61,8 +61,8 @@ config SLUB_DEBUG > >> help > >> SLUB has extensive debug support features. Disabling these can > >> result in significant savings in code size. This also disables > >> - SLUB sysfs support. /sys/slab will not exist and there will be > >> - no support for cache validation etc. > >> + SLUB sysfs support. /sys/kernel/slab will not exist and there > >> + will be no support for cache validation etc. > > > > After commit ab4d5ed5eeda ("slub: Enable sysfs support for !CONFIG_SLUB_DEBUG"), > > "Disabling SLUB_DEBUG also disables SLUB sysfs support" is not true anymore. Yes, You are right. Thanks. > > Yeah we could say that /sys/kernel/slab will exist but will not provide e.g. > cache validation. OK. > > >> config SLUB_DEBUG_ON > >> bool "SLUB debugging on by default" > >> @@ -73,10 +73,10 @@ config SLUB_DEBUG_ON > >> Boot with debugging on by default. SLUB boots by default with > >> the runtime debug capabilities switched off. Enabling this is > >> equivalent to specifying the "slub_debug" parameter on boot. > >> - There is no support for more fine grained debug control like > >> - possible with slub_debug=xxx. SLUB debugging may be switched > >> - off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying > >> - "slub_debug=-". > >> + There is support for more fine grained debug control like > >> + possible with slub_debug=xxx, details in Documentation/mm/slub.rst. > >> + SLUB debugging may be switched off in a kernel built with > >> + CONFIG_SLUB_DEBUG_ON by specifying "slub_debug=-". > > > > I think this is a misunderstanding. SLUB_DEBUG_ON is equivalent to Yeah, This is a misunderstanding. I remove this. > > passing boot parameter slub_debug=FUPZ, and what the help text says is that > > > > "You can enable slub debugging by default using this config option but > > there is no support for fine-grained control like what slub_debug > > boot parameter provides." > > > > IOW SLUB_DEBUG_ON cannot be used to have same effect as passing > > something like slub_debug=F. > > Agree with both comments. Vernon, will you send an updated patch? Ok, I'll be sending a new patch shortly. > > >> > >> config PAGE_OWNER > >> bool "Track page owner" > >> -- > >> 2.34.1 > >> > >> >