From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f72.google.com (mail-lf0-f72.google.com [209.85.215.72]) by kanga.kvack.org (Postfix) with ESMTP id 9A6996B0005 for ; Tue, 17 May 2016 08:04:01 -0400 (EDT) Received: by mail-lf0-f72.google.com with SMTP id m64so8131712lfd.1 for ; Tue, 17 May 2016 05:04:01 -0700 (PDT) Received: from mail-lb0-x242.google.com (mail-lb0-x242.google.com. [2a00:1450:4010:c04::242]) by mx.google.com with ESMTPS id kv18si2223041lbb.191.2016.05.17.05.04.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 May 2016 05:04:00 -0700 (PDT) Received: by mail-lb0-x242.google.com with SMTP id mx9so809564lbb.2 for ; Tue, 17 May 2016 05:04:00 -0700 (PDT) Date: Tue, 17 May 2016 15:03:57 +0300 From: "Kirill A. Shutemov" Subject: Re: [Bug 117731] New: Doing mprotect for PROT_NONE and then for PROT_READ|PROT_WRITE reduces CPU write B/W on buffer Message-ID: <20160517120357.GE9540@node.shutemov.name> References: <20160506150112.9b27324b4b2b141146b0ff25@linux-foundation.org> <20160516133543.GA9540@node.shutemov.name> <20160517113634.GD9540@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Ashish Srivastava Cc: Andrew Morton , bugzilla-daemon@bugzilla.kernel.org, Peter Feiner , linux-mm@kvack.org On Tue, May 17, 2016 at 05:17:23PM +0530, Ashish Srivastava wrote: > > Test-case for that would be helpful, as normal malloc()'ed anon memory > > cannot be subject for the bug. Unless I miss something obvious. > > I've modified the test-case attached to the bug and now it doesn't use > malloc()'ed memory but file backed mmap shared memory. Yes, that's consistent with your analysis. You can post the patch with my Acked-by. -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org