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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E2FAC4332F for ; Wed, 13 Oct 2021 10:48:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3BCCE60FDA for ; Wed, 13 Oct 2021 10:48:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3BCCE60FDA Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id D5DFD6B006C; Wed, 13 Oct 2021 06:48:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D0ED26B0071; Wed, 13 Oct 2021 06:48:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BD6AC6B0072; Wed, 13 Oct 2021 06:48:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0119.hostedemail.com [216.40.44.119]) by kanga.kvack.org (Postfix) with ESMTP id AF52E6B006C for ; Wed, 13 Oct 2021 06:48:36 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 3554D30C9C for ; Wed, 13 Oct 2021 10:48:36 +0000 (UTC) X-FDA: 78691090632.11.CE0BF47 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf16.hostedemail.com (Postfix) with ESMTP id D1A7AF00008E for ; Wed, 13 Oct 2021 10:48:35 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 91FCF201DE; Wed, 13 Oct 2021 10:48:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1634122114; 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=8YRMS+abbsrYOuV5GYRPb1+QeE3+N7GArz59RZJi/OQ=; b=pygTJETpdVLPWOhYiGShptN+MbO168JrEU4eehy7MbOch+ApCosRTWXNkdUIUsFRyv/LsM DdEx/aFWln8sX9RWvGTYt8eYurciD9oO1B0sm+dMfWiXNUH+vspjtdG/IkaEWJxJob5fYM f5IYh3wxEYOW7PZeJJdGjjQPBGwN5t4= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 5596DA3B81; Wed, 13 Oct 2021 10:48:34 +0000 (UTC) Date: Wed, 13 Oct 2021 12:48:33 +0200 From: Michal Hocko To: "Aneesh Kumar K.V" Cc: linux-mm@kvack.org, akpm@linux-foundation.org, Ben Widawsky , Dave Hansen , Feng Tang , Andrea Arcangeli , Mel Gorman , Mike Kravetz , Randy Dunlap , Vlastimil Babka , Andi Kleen , Dan Williams , Huang Ying , linux-api@vger.kernel.org Subject: Re: [RFC PATCH] mm/mempolicy: add MPOL_PREFERRED_STRICT memory policy Message-ID: References: <20211013094539.962357-1-aneesh.kumar@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: D1A7AF00008E X-Stat-Signature: yqaoguds8eh149omscfka9hwd4obg5jb Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=pygTJETp; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf16.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com X-HE-Tag: 1634122115-580405 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed 13-10-21 12:42:34, Michal Hocko wrote: > [Cc linux-api] > > On Wed 13-10-21 15:15:39, Aneesh Kumar K.V wrote: > > This mempolicy mode can be used with either the set_mempolicy(2) > > or mbind(2) interfaces. Like the MPOL_PREFERRED interface, it > > allows an application to set a preference node from which the kernel > > will fulfill memory allocation requests. Unlike the MPOL_PREFERRED mode, > > it takes a set of nodes. The nodes in the nodemask are used as fallback > > allocation nodes if memory is not available on the preferred node. > > Unlike MPOL_PREFERRED_MANY, it will not fall back memory allocations > > to all nodes in the system. Like the MPOL_BIND interface, it works over a > > set of nodes and will cause a SIGSEGV or invoke the OOM killer if > > memory is not available on those preferred nodes. > > > > This patch helps applications to hint a memory allocation preference node > > and fallback to _only_ a set of nodes if the memory is not available > > on the preferred node. Fallback allocation is attempted from the node which is > > nearest to the preferred node. > > > > This new memory policy helps applications to have explicit control on slow > > memory allocation and avoids default fallback to slow memory NUMA nodes. > > The difference with MPOL_BIND is the ability to specify a preferred node > > which is the first node in the nodemask argument passed. I am sorry but I do not understand the semantic diffrence from MPOL_BIND. Could you be more specific please? -- Michal Hocko SUSE Labs