From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E893C134BE; Tue, 14 Nov 2023 09:43:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="NNhnrtvL" Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CFB61194; Tue, 14 Nov 2023 01:43:17 -0800 (PST) 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-out1.suse.de (Postfix) with ESMTPS id E139721898; Tue, 14 Nov 2023 09:43:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1699954994; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=mgQsT0odT754L8z+3U8Ly6+wQgAtpd/CnwwQT/eWbGI=; b=NNhnrtvLg8PfB8mUbc7N/HdOLXsPh/5OQiu6/44DHFXkC0f2rDOShtPI6i8AmkRnyQkfkf f/FD25+V3Qbkqh+Rngko70mZD/q5bcV7E8Z+PLl24rZAadbP5r4k3qo3OaXj7tnRDRRtQU OSy2FoNjadPlXc0Mxlo3tWXRjXaEQfg= 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 A731313416; Tue, 14 Nov 2023 09:43:14 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id mqVVJzJBU2UgGAAAMHmgww (envelope-from ); Tue, 14 Nov 2023 09:43:14 +0000 Date: Tue, 14 Nov 2023 10:43:13 +0100 From: Michal Hocko To: Gregory Price Cc: "tj@kernel.org" , John Groves , Gregory Price , "linux-kernel@vger.kernel.org" , "linux-cxl@vger.kernel.org" , "linux-mm@kvack.org" , "cgroups@vger.kernel.org" , "linux-doc@vger.kernel.org" , "ying.huang@intel.com" , "akpm@linux-foundation.org" , "lizefan.x@bytedance.com" , "hannes@cmpxchg.org" , "corbet@lwn.net" , "roman.gushchin@linux.dev" , "shakeelb@google.com" , "muchun.song@linux.dev" , "jgroves@micron.com" Subject: Re: [RFC PATCH v4 0/3] memcg weighted interleave mempolicy control Message-ID: References: <20231109002517.106829-1-gregory.price@memverge.com> <0100018bb64636ef-9daaf0c0-813c-4209-94e4-96ba6854f554-000000@email.amazonses.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Authentication-Results: smtp-out1.suse.de; none X-Spam-Level: X-Spam-Score: -3.86 X-Spamd-Result: default: False [-3.86 / 50.00]; ARC_NA(0.00)[]; TO_DN_EQ_ADDR_SOME(0.00)[]; RCVD_TLS_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; TO_MATCH_ENVRCPT_ALL(0.00)[]; TAGGED_RCPT(0.00)[]; MIME_GOOD(-0.10)[text/plain]; RCVD_VIA_SMTP_AUTH(0.00)[]; CLAM_VIRUS_FAIL(0.00)[failed to scan and retransmits exceed]; BAYES_HAM(-1.76)[93.55%]; NEURAL_HAM_LONG(-3.00)[-1.000]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; NEURAL_HAM_SHORT(-1.00)[-1.000]; RCPT_COUNT_TWELVE(0.00)[18]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; MID_RHS_NOT_FQDN(0.50)[]; FREEMAIL_CC(0.00)[kernel.org,jagalactic.com,gmail.com,vger.kernel.org,kvack.org,intel.com,linux-foundation.org,bytedance.com,cmpxchg.org,lwn.net,linux.dev,google.com,micron.com]; RCVD_COUNT_TWO(0.00)[2]; SUSPICIOUS_RECIPS(1.50)[] On Fri 10-11-23 22:42:39, Gregory Price wrote: [...] > If I can ask, do you think it would be out of line to propose a major > refactor to mempolicy to enable external task's the ability to change a > running task's mempolicy *as well as* a cgroup-wide mempolicy component? No, I actually think this is a reasonable idea. pidfd_setmempolicy is a generally useful extension. The mempolicy code is heavily current task based and there might be some challenges but I believe this will a) improve the code base and b) allow more usecases. That being said, I still believe that a cgroup based interface is a much better choice over a global one. Cpusets seem to be a good fit as the controller does control memory placement wrt NUMA interfaces. -- Michal Hocko SUSE Labs