Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752332Ab0FKEeu (ORCPT ); Fri, 11 Jun 2010 00:34:50 -0400 Received: from mail-vw0-f46.google.com ([209.85.212.46]:35976 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751026Ab0FKEes convert rfc822-to-8bit (ORCPT ); Fri, 11 Jun 2010 00:34:48 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=J69Zqel+NbxIWr+QO1bnnrjZlgh5JtLKdjqNtLJ8rMHnVZqkgjwAEeRPkAynmmLejk YILWemzJLJerm2/ylyxMfJSXMtJJgyJi7aOnLE7awZ7+kvG6Z8ANRl1jQhJtp12IeBFK vNlI13LguzjdrkNgfuOYhalk0IO/4M9E+EeyU= MIME-Version: 1.0 In-Reply-To: <4C118844.2020401@gmail.com> References: <4C118844.2020401@gmail.com> Date: Fri, 11 Jun 2010 10:04:46 +0530 Message-ID: Subject: Re: O_NONBLOCK with Ext2/3 From: "Yedire, Sandeep" To: Robert Hancock Cc: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1195 Lines: 33 On 11 June 2010 06:20, Robert Hancock wrote: > On 06/10/2010 06:44 AM, Yedire, Sandeep wrote: >> >> Hi All, >> What is the effect ?on filesystem blocks,data blocks if O_NONBLOCK >> flag is used with a test application doing write to a file(64MB) on >> NAND Flash. >> Can any one please let me know >> Regards, >> Sandeep.Yedire > > O_NONBLOCK doesn't do anything on regular files, as far as I'm aware. It's > only useful on sockets, serial ports/TTYs, etc. > [Sandeep] In Ext2 fs, I have noticed many frequent updates to data blocks as compared to without this flag. I also noticed Dirty page limit (44MB max) with O_NONBLOCK and 18 to 20MB max without this flag. Because of this there is less Filesystem block updates with O_NONBLOCK flag. In case of Ext3, Dirty page limit is 18-20MB with or without this flag. Its same with all modes of Ext3(data, ordered, writeback). This is actually my concern. Many Thanks, Sandeep -- 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/