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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 483BCC00307 for ; Fri, 6 Sep 2019 17:33:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E620D206A1 for ; Fri, 6 Sep 2019 17:33:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="B5lMPpGH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E620D206A1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7E6426B0005; Fri, 6 Sep 2019 13:33:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7982B6B0006; Fri, 6 Sep 2019 13:33:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 685376B0007; Fri, 6 Sep 2019 13:33:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0056.hostedemail.com [216.40.44.56]) by kanga.kvack.org (Postfix) with ESMTP id 4857E6B0005 for ; Fri, 6 Sep 2019 13:33:56 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id D4330824CA3B for ; Fri, 6 Sep 2019 17:33:55 +0000 (UTC) X-FDA: 75905193630.21.range10_223049ba24b25 X-HE-Tag: range10_223049ba24b25 X-Filterd-Recvd-Size: 4106 Received: from mail-oi1-f193.google.com (mail-oi1-f193.google.com [209.85.167.193]) by imf30.hostedemail.com (Postfix) with ESMTP for ; Fri, 6 Sep 2019 17:33:54 +0000 (UTC) Received: by mail-oi1-f193.google.com with SMTP id h4so5587583oih.8 for ; Fri, 06 Sep 2019 10:33:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=qpDnR/GYJ/XrBLmzSIYUWPDpRlqXVwU8hq/PPEapHXQ=; b=B5lMPpGHxIofgZL10Pn92uDG8MnE3nHQtXDzubuDNUxCRt56k31Zr5/4pBbkv4ywfp k2B9yLhvs+CQZolGYvrtvi/f3xzxDtXhUuaaFUh5Dvv21CfjE/LNyLRZb+x7i5PmiS1D ZIUPTbM+K/3hH0G5jF0Ehvp/Yz/ZSAz34z7I9miMnRsfe9zcMJiYCJBadW8maOBNVufF LcFtXZOm1s1HhJLXNF5PKER+f1vQe8CZv1SdFAlPsTrPBHjyL4m5sSnEEtuWzr+dME/d yPglC9Vp78a/MAqamkHBU5HxSM1bZk6G1BF35zRlxhELkYuQGhMHkWrK/kqOJOKhXYXT WCAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=qpDnR/GYJ/XrBLmzSIYUWPDpRlqXVwU8hq/PPEapHXQ=; b=ArhvuVbRTI4EElWho6dhn37QfgrmrL4plGjl4O4bnLDVrJ1KXxDoTwRhyqnZmi6k1v shIgGKx8S09QDqMH1bM3XLIRNV1aG4dn1q4QYYjU6X/A3aOrMBrT+PwBMman13klhUtb GDSJMJ5X8zi10XflMRebowX79+77wlvSUjlj7JSA7zw91Z5yAfYJYmRR3f2S31PzuryC VL/uOWO4aXgbFgYCbxJn5fOv/sgHMlNUo8V/upNjn8ka3mq+ZWhwe3o/i0I7EF+4MrXX /1mSxM3Jjtxb74ic0k4f6m4E1fqwg/8uShc19lK1JE3Qmd/y4cdwp2IkCei+IdXWqi1d NV9Q== X-Gm-Message-State: APjAAAVQqPtwsevotwm/2cYkN+/oe6Rdth3D43PpR+EpaCVtKHSNaNxB zPl8tOkkFs1iY8mJE1jzl+xCKOkdfzdKhRNhOH9psA== X-Google-Smtp-Source: APXvYqxs26WaI4nMH81FCrmErnLZVB0v+f8/lt+3MTncxWG87yVQW0BSOxASyAFc+69JKSrfI3WlFVqe6CUueDct1rs= X-Received: by 2002:aca:5dc3:: with SMTP id r186mr7672240oib.73.1567791233988; Fri, 06 Sep 2019 10:33:53 -0700 (PDT) MIME-Version: 1.0 References: <20190906145213.32552.30160.stgit@localhost.localdomain> <20190906145327.32552.39455.stgit@localhost.localdomain> In-Reply-To: <20190906145327.32552.39455.stgit@localhost.localdomain> From: Dan Williams Date: Fri, 6 Sep 2019 10:33:42 -0700 Message-ID: Subject: Re: [PATCH v8 1/7] mm: Add per-cpu logic to page shuffling To: Alexander Duyck Cc: nitesh@redhat.com, KVM list , "Michael S. Tsirkin" , David Hildenbrand , Dave Hansen , Linux Kernel Mailing List , Matthew Wilcox , Michal Hocko , Linux MM , Andrew Morton , virtio-dev@lists.oasis-open.org, Oscar Salvador , yang.zhang.wz@gmail.com, Pankaj Gupta , Rik van Riel , Konrad Rzeszutek Wilk , lcapitulino@redhat.com, "Wang, Wei W" , Andrea Arcangeli , Paolo Bonzini , Alexander Duyck 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: On Fri, Sep 6, 2019 at 7:53 AM Alexander Duyck wrote: > > From: Alexander Duyck > > Change the logic used to generate randomness in the suffle path so that we > can avoid cache line bouncing. The previous logic was sharing the offset > and entropy word between all CPUs. As such this can result in cache line > bouncing and will ultimately hurt performance when enabled. > > To resolve this I have moved to a per-cpu logic for maintaining a unsigned > long containing some amount of bits, and an offset value for which bit we > can use for entropy with each call. > Reviewed-by: Dan Williams