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 C4764C6FD1D for ; Mon, 27 Mar 2023 20:40:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230344AbjC0Ukn (ORCPT ); Mon, 27 Mar 2023 16:40:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229456AbjC0Ukk (ORCPT ); Mon, 27 Mar 2023 16:40:40 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4485F1719; Mon, 27 Mar 2023 13:40:39 -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 DE16C1FE22; Mon, 27 Mar 2023 20:40:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1679949637; 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=IgIrKz0UNBCn4PDiHW0xzrI6MTRBYSXxkJu/zMHUvKg=; b=aTyTas8xnndKQ+7rRpt7+uxegjLQTBesNPvbKnCfTN5qLbE6ycmNqY7poDyjI3gNMFpEEc q9Tr3ZJm7OP//76yYW4qy6Urq56r/oM+X/rPvVywvwdlCrSja9e+wB0YDmj0DVFfr2QMqj TEEofls4ExVM5wz3WIr2NkNvgkrZNJI= 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 C06BA13482; Mon, 27 Mar 2023 20:40:37 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id PIgTLEX/IWSFNAAAMHmgww (envelope-from ); Mon, 27 Mar 2023 20:40:37 +0000 Date: Mon, 27 Mar 2023 22:40:37 +0200 From: Michal Hocko To: Florian Schmidt Cc: Michal =?iso-8859-1?Q?Koutn=FD?= , Johannes Weiner , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC] memcg v1: provide read access to memory.pressure_level Message-ID: References: <20230322142525.162469-1-flosch@nutanix.com> <20230324150350.fu7itbqqvtjmyf3s@blackpad> <6f4420d0-2f86-7294-01e1-6806ef7e4686@nutanix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <6f4420d0-2f86-7294-01e1-6806ef7e4686@nutanix.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 27-03-23 14:59:37, Florian Schmidt wrote: > Hi Michal, > > On 24/03/2023 15:03, Michal Koutný wrote: > > On Wed, Mar 22, 2023 at 02:25:25PM +0000, Florian Schmidt wrote: [...] > > > (b) would you be interested to take this patch, or is it too niche a fix > > > for a legacy subsystem? > > > > I'd rather not extend this "unique way" with additionally unique dummy > > helpers. > > I understand that this is all code that has no modern user any more, which > is why I tried to keep the fix as self-contained as possible. > Another option would be to have a special handler in cgroup_file_mode(), but > that feels a lot klunkier to me, and leaks a v1-specific behaviour into the > shared cgroup code. Yes, this is effectivelly a deprecated interface but I do agree that we shouldn't really make life of users more complicated than necessary. If the simplest solution to address this is to provide an empty callback then be it. I am not sure but I do not think there are other cgroup interfaces to warrant a more generic solution. -- Michal Hocko SUSE Labs