From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with ESMTP id F3CC06B0011 for ; Tue, 3 May 2011 22:45:46 -0400 (EDT) Received: by wwi36 with SMTP id 36so646764wwi.26 for ; Tue, 03 May 2011 19:45:42 -0700 (PDT) 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 Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Linux Kernel Mailing List , linux-mm , linux-fsdevel@vger.kernel.org, Wu Fengguang 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, 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org