From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f199.google.com (mail-io0-f199.google.com [209.85.223.199]) by kanga.kvack.org (Postfix) with ESMTP id 229A36B0012 for ; Fri, 23 Mar 2018 20:54:37 -0400 (EDT) Received: by mail-io0-f199.google.com with SMTP id d187so11764194iog.6 for ; Fri, 23 Mar 2018 17:54:37 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id m7sor266830iog.59.2018.03.23.17.54.36 for (Google Transport Security); Fri, 23 Mar 2018 17:54:36 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20180323174447.55F35636@viggo.jf.intel.com> From: Linus Torvalds Date: Fri, 23 Mar 2018 17:54:35 -0700 Message-ID: Subject: Re: [PATCH 00/11] Use global pages with PTI Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: Linux Kernel Mailing List , linux-mm , Andrea Arcangeli , Andrew Lutomirski , Kees Cook , Hugh Dickins , =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= , the arch/x86 maintainers , namit@vmware.com On Fri, Mar 23, 2018 at 5:46 PM, Linus Torvalds wrote: > > It is, of course, possible that I misunderstood what you actually > benchmarked. But I assume the above benchmark numbers are with the > whole "don't even do global entries if you have PCID". Oh, I went back and read your description, and realized that I _had_ misunderstood what you did. I thought you didn't bother with global pages at all when you had PCID. But that's not what you meant. You always do global for the actual user-mapped kernel pages, but when you don't have PCID you do *all* kernel test as global, whether shared or not. So I entirely misread what the latest change was. Linus