Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754892Ab1EDCpp (ORCPT ); Tue, 3 May 2011 22:45:45 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:58732 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754719Ab1EDCpn (ORCPT ); Tue, 3 May 2011 22:45:43 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=hDHGwj2RoYryquL8DV/RFIv3HFaQNYymno6HRnGGX/8nSSoLjsUtFfYUdsetuV8Xp8 qY+l6mMJwpSx5CIRNHX0a8iMaF+X5KYEOtTiq0fNv5ElyCGZvNMiooi3GDf7M+de10UV dvCrKHGRP6YLiE5A2mobPObAVP/Wz2ZY7w2vM= MIME-Version: 1.0 Date: Wed, 4 May 2011 10:45:42 +0800 Message-ID: Subject: COW page cache for file hole? From: Dave Young To: Linux Kernel Mailing List , linux-mm , linux-fsdevel@vger.kernel.org, Wu Fengguang Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 707 Lines: 21 Hi, During test fengguang's readahead alloc-noretry patch, I have some thoughts In the 1000 dd case, page cache of sparse file hole are all zero indeed. So what about make a global zero page for that purpose, fs level know it is a hole, when write occurs on that page we can alloc a new page for that. I have no enough knowledge to implement it so just give out the question without patch, sorry. BTW, was there any attempt for this before? -- Regards dave -- 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/