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 D8EFDC7EE2D for ; Wed, 24 May 2023 12:30:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231203AbjEXMap (ORCPT ); Wed, 24 May 2023 08:30:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229457AbjEXMan (ORCPT ); Wed, 24 May 2023 08:30:43 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC67D99 for ; Wed, 24 May 2023 05:30:41 -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-out1.suse.de (Postfix) with ESMTPS id 75A0722207; Wed, 24 May 2023 12:30:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1684931440; 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=6dtqj2Y7bITU/eAH7KTmViAOMma17b5fIdPwVyyaIEw=; b=dMxcxuAcAL3GRLFP6ZIzOmFZboR+KmnvzQ4xXKlv6stzCbf54wDAvfK64d1QJJBHAMiHtn MvaUbiIE8ATHXYNrfIWwHWdf4gQYcctqAhWrPDJt6PAkkBJPv+Lg3cG3Pq+WX6lqWp7f7e ud8FaC872BYkAtxNOmhJXuZAKjTHseI= 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 559D813425; Wed, 24 May 2023 12:30:40 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id pGDLEnADbmT2aAAAMHmgww (envelope-from ); Wed, 24 May 2023 12:30:40 +0000 Date: Wed, 24 May 2023 14:30:39 +0200 From: Michal Hocko To: David Hildenbrand Cc: "Huang, Ying" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Arjan Van De Ven , Andrew Morton , Mel Gorman , Vlastimil Babka , Johannes Weiner , Dave Hansen , Pavel Tatashin , Matthew Wilcox Subject: Re: [RFC 0/6] mm: improve page allocator scalability via splitting zones Message-ID: References: <20230511065607.37407-1-ying.huang@intel.com> <87r0rm8die.fsf@yhuang6-desk2.ccr.corp.intel.com> <87jzx87h1d.fsf@yhuang6-desk2.ccr.corp.intel.com> <3d77ca46-6256-7996-b0f5-67c414d2a8dc@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3d77ca46-6256-7996-b0f5-67c414d2a8dc@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Sorry for late reply, conferencing last 2 weeks and now catching up] On Tue 16-05-23 12:30:21, David Hildenbrand wrote: [...] > > And auto-tuning doesn't sound easy. Do you have some idea of how to do > > that? > > If we could avoid instantiating more zones and rather improve existing > mechanisms (PCP), that would be much more preferred IMHO. I'm sure it's not > easy, but that shouldn't stop us from trying ;) Absolutely agreed. Increasing the zone number sounds like a hack to me TBH. It seems like an easier way but it allows more subtle problems later on. E.g. hard to predict per-zone memory consumption and memory reclaim disbalances. -- Michal Hocko SUSE Labs