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 1838FC61DA4 for ; Mon, 13 Mar 2023 16:26:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230001AbjCMQ03 (ORCPT ); Mon, 13 Mar 2023 12:26:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231132AbjCMQ0Y (ORCPT ); Mon, 13 Mar 2023 12:26:24 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 284D077E2E for ; Mon, 13 Mar 2023 09:26:21 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id CDFF31FE0E; Mon, 13 Mar 2023 16:26:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1678724779; h=from:from:reply-to: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; bh=BSRdEVYjIp3MPfK6d1mb8MjcriEK9DC473gzAVaXYC4=; b=NXt0ygQ5dQYT2n0avtfdCcn1HyyFiIaVgfT4u/L6yNULFuYxnVZc/P/+QoR4pI0XQ7EOkJ BqlpCMlbDZtUIDLGqVym7G0Tu7oFuz4zdJ06rDtuitNO8lyIGwA5tqaYWNvOHrpAbxg1a4 sL+TleXLvIyU5YtBAJbUhA5bMRB0e80= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1678724779; h=from:from:reply-to: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; bh=BSRdEVYjIp3MPfK6d1mb8MjcriEK9DC473gzAVaXYC4=; b=/ViIEdP1QPQw63BYLqTLgjilMHEV49DDb7/K8iE2xQL6A7TxdzbTmTD8zFU4k7LDiX85W/ gA1mT8ajCadaIADA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id B136F13517; Mon, 13 Mar 2023 16:26:19 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id xEq+KatOD2QIDwAAMHmgww (envelope-from ); Mon, 13 Mar 2023 16:26:19 +0000 Message-ID: Date: Mon, 13 Mar 2023 17:26:19 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH] mm/slub: fix help comment of SLUB_DEBUG[_ON] Content-Language: en-US To: Hyeonggon Yoo <42.hyeyoo@gmail.com>, Vernon Yang Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20230222232058.66971-1-vernon2gm@gmail.com> From: Vlastimil Babka In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Yeah we could say that /sys/kernel/slab will exist but will not provide e.g. cache validation. >> 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 > 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? >> >> config PAGE_OWNER >> bool "Track page owner" >> -- >> 2.34.1 >> >>