From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id CAEC28E0001 for ; Tue, 22 Jan 2019 16:44:17 -0500 (EST) Received: by mail-pf1-f199.google.com with SMTP id s71so22363pfi.22 for ; Tue, 22 Jan 2019 13:44:17 -0800 (PST) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTPS id f5si11526028pfn.259.2019.01.22.13.44.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Jan 2019 13:44:16 -0800 (PST) From: Andi Kleen Subject: Re: [LSF/MM TOPIC] Page flags, can we free up space ? References: <20190122201744.GA3939@redhat.com> Date: Tue, 22 Jan 2019 13:44:15 -0800 In-Reply-To: <20190122201744.GA3939@redhat.com> (Jerome Glisse's message of "Tue, 22 Jan 2019 15:17:44 -0500") Message-ID: <87tvi074gg.fsf@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Jerome Glisse Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Jerome Glisse writes: > > Right now this is more a temptative ie i do not know if i will succeed, > in any case i can report on failure or success and discuss my finding to > get people opinions on the matter. I would just stop putting node/zone number into the flags. These could be all handled with a small perfect hash table, like the original x86_64 port did, which should be quite cheap to look up. Then there should be enough bits for everyone again. -Andi 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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 170DEC282C4 for ; Tue, 22 Jan 2019 21:44:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B47D7217D6 for ; Tue, 22 Jan 2019 21:44:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B47D7217D6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 206D18E0003; Tue, 22 Jan 2019 16:44:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1B5118E0001; Tue, 22 Jan 2019 16:44:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0A6288E0003; Tue, 22 Jan 2019 16:44:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id CAEC28E0001 for ; Tue, 22 Jan 2019 16:44:17 -0500 (EST) Received: by mail-pf1-f199.google.com with SMTP id s71so22363pfi.22 for ; Tue, 22 Jan 2019 13:44:17 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:from:to:cc :subject:references:date:in-reply-to:message-id:user-agent :mime-version; bh=WmCJIgU0U+rMXlSQge28ZABnQmUUFnt4rL6spZNid/o=; b=VVbxbD0jw9NlGTHXwYhLbLJd0eo772roFrBc6EAtN390nGYsWOI1MztmeMFpQmsxXR LLhwHDTUWYUhYvsOvI8RF/qXA8WJ0rsMl+kR/dKo78ahxsSqQQkWw0+lSgrfA1+ulo6I V+HRogfGwJyxgUeeIHKpHCQ49Yepmpye7BPsh5lj16D7xAD7Y2EajZ2w63diLzjk361i xtnfyejK5yxkM7B9MPjLlYcAURUBK6DD5BgIYVZUD7bkllCreCHgkhkXP2kBFdy1GOsh NSIWgeLsCP2ckNwJOObAS8b5tFts8H7mHY4a33InDpFCLD1beBMcWwVWDw1H9rc+j65h LMoQ== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of ak@linux.intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=ak@linux.intel.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Gm-Message-State: AJcUukdBqglmgbC6nstSdXrAAXaAZHlbZPfvUoYrx0mv3bpJepHlLmtz lk3oLMeN/QpqnAPsxK9WsJKh1IriSmVwuJiXBx53QT/WlEujnlRVcHMtYhIbBAGh0vMPvkDB3KB J0iTn7MYw2VM1IjVXZObsMIcGNSLY/W6B5kJHeYamw28HA9lapdiFzEK8DhaMdL+fiA== X-Received: by 2002:a62:3241:: with SMTP id y62mr35030342pfy.178.1548193457496; Tue, 22 Jan 2019 13:44:17 -0800 (PST) X-Google-Smtp-Source: ALg8bN5Di6cL8lTpNBK5npo6nuCiZnqQ/kSjGAAREXMFk1CQ6gg/WQNTFvKYO4GKeoAKymozCjs/ X-Received: by 2002:a62:3241:: with SMTP id y62mr35030308pfy.178.1548193456681; Tue, 22 Jan 2019 13:44:16 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1548193456; cv=none; d=google.com; s=arc-20160816; b=G3TceHQDbGa/GWxzOkKVW3wLGYI+FLtBwkgsUlUCjFbuKEyvSYFC6PFBiozbhi3G5P +vG/u+kqPhitnwMEvrslUEwgTLioy1UT/YcBfqt4UnFDjSxXE0gcTvo3EdUXn+tB+jFn 7nYNqGUGH4Jehpl+t4TGUBQ75P1/n15RjC5WUzXWxISPzKZj/svyHuX5OVkH1tM5Hj/J HysKObYO2po4iYWf7363TAyG6hFn+rlsjnUHMwd6O7p7c787mwti2/QdjKFD2e7yF/vR NUCC9SKbLXLiSiyuErLA8UrIALaA4Y8EO3RZnp4F/6+N+dIuBeYTi1r4egn3Y4r1D0Xs QwvQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:message-id:in-reply-to:date:references :subject:cc:to:from; bh=WmCJIgU0U+rMXlSQge28ZABnQmUUFnt4rL6spZNid/o=; b=YPBCcSxW7h3iGyIKM7rapSnZm1XUqihvXr7eAu50LEYYGnaZWkKsjKCILYbgYbSUqw lUPYmww/i6OmuRuE0O3BflhLNugbjiJ69mKCaKWZCwjemzKFvQDUstzkrzsjHLDRQEvJ 4tK3Bm5JMj8xt9f5Zo/FjCfLS23KbtaxuI8JPS8NOxH0fZT3k2kUbNoXG0deKIzc9CxD DDFQjL7DlEP+ySpKY0tGJEa/V0MgKHtdr6Dr4JQY+XnxSeWHh3b0kcOw9rbHa/QeuRPj aXX3kobnxsB4nBr6+hFravcTZ5SacK4aWv8JmXwSzxeQGmhZdc/Xku4l3KS3dDxbwebD UYHg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of ak@linux.intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=ak@linux.intel.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTPS id f5si11526028pfn.259.2019.01.22.13.44.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Jan 2019 13:44:16 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of ak@linux.intel.com designates 134.134.136.20 as permitted sender) client-ip=134.134.136.20; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of ak@linux.intel.com designates 134.134.136.20 as permitted sender) smtp.mailfrom=ak@linux.intel.com; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Jan 2019 13:44:15 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,508,1539673200"; d="scan'208";a="128046630" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.137]) by orsmga002.jf.intel.com with ESMTP; 22 Jan 2019 13:44:15 -0800 Received: by tassilo.localdomain (Postfix, from userid 1000) id B3876301202; Tue, 22 Jan 2019 13:44:15 -0800 (PST) From: Andi Kleen To: Jerome Glisse Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [LSF/MM TOPIC] Page flags, can we free up space ? References: <20190122201744.GA3939@redhat.com> Date: Tue, 22 Jan 2019 13:44:15 -0800 In-Reply-To: <20190122201744.GA3939@redhat.com> (Jerome Glisse's message of "Tue, 22 Jan 2019 15:17:44 -0500") Message-ID: <87tvi074gg.fsf@linux.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" 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: Message-ID: <20190122214415.iWizBunTWe7pg9VQwJ8u15R0TEnThblVlFyR7MxLUE0@z> Jerome Glisse writes: > > Right now this is more a temptative ie i do not know if i will succeed, > in any case i can report on failure or success and discuss my finding to > get people opinions on the matter. I would just stop putting node/zone number into the flags. These could be all handled with a small perfect hash table, like the original x86_64 port did, which should be quite cheap to look up. Then there should be enough bits for everyone again. -Andi