Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752140AbaB1XIZ (ORCPT ); Fri, 28 Feb 2014 18:08:25 -0500 Received: from mail-ve0-f177.google.com ([209.85.128.177]:43971 "EHLO mail-ve0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751723AbaB1XIX (ORCPT ); Fri, 28 Feb 2014 18:08:23 -0500 MIME-Version: 1.0 In-Reply-To: <20140228001039.GB8034@node.dhcp.inet.fi> References: <1393530827-25450-1-git-send-email-kirill.shutemov@linux.intel.com> <20140228001039.GB8034@node.dhcp.inet.fi> Date: Fri, 28 Feb 2014 17:08:22 -0600 X-Google-Sender-Auth: 9zC69jUj3bTpXS78o1CQTTdiTNc Message-ID: Subject: Re: [PATCHv3 0/2] mm: map few pages around fault address if they are in page cache From: Linus Torvalds To: "Kirill A. Shutemov" Cc: "Kirill A. Shutemov" , Andrew Morton , Mel Gorman , Rik van Riel , Andi Kleen , Matthew Wilcox , Dave Hansen , Alexander Viro , Dave Chinner , Ning Qu , linux-mm , linux-fsdevel , Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 27, 2014 at 6:10 PM, Kirill A. Shutemov wrote: > > Also Matthew noticed that some drivers do ugly hacks like fault in whole > VMA on first page fault. IIUC, it's for performance reasons. See > psbfb_vm_fault() or ttm_bo_vm_fault(). I guarantee it's not for performance reasons, it's probably some other breakage. And if anything really does want to populate things fully, doing so at fault time is wrong anyway, you should just use MAP_POPULATE at mmap time. So I'll believe the shm/tmpfs issue, and that's "mm internal" anyway. But random crappy drivers? No way in hell. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/