Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1757499Ab1CNXSJ (ORCPT <rfc822;w@1wt.eu>);
	Mon, 14 Mar 2011 19:18:09 -0400
Received: from li9-11.members.linode.com ([67.18.176.11]:57262 "EHLO
	test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1753915Ab1CNXSH (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Mon, 14 Mar 2011 19:18:07 -0400
Date: Mon, 14 Mar 2011 19:17:53 -0400
From: "Ted Ts'o" <tytso@mit.edu>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: G@thunk.org, Indan Zupancic <indan@nul.nu>, Greg KH <greg@kroah.com>,
        Jonathan Nieder <jrnieder@gmail.com>, Arnd Bergmann <arnd@arndb.de>,
        Sage Weil <sage@newdream.net>, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        "Aneesh Kumar K. V" <aneesh.kumar@linux.vnet.ibm.com>,
        linux-api@vger.kernel.org, mtk.manpages@gmail.com,
        viro@zeniv.linux.org.uk, hch@lst.de, l@jasper.es
Subject: Re: [PATCH v3] introduce sys_syncfs to sync a single file system
Message-ID: <20110314231753.GF8120@thunk.org>
Mail-Followup-To: Ted Ts'o <tytso@mit.edu>,
	Andrew Morton <akpm@linux-foundation.org>, G@thunk.org,
	Indan Zupancic <indan@nul.nu>, Greg KH <greg@kroah.com>,
	Jonathan Nieder <jrnieder@gmail.com>, Arnd Bergmann <arnd@arndb.de>,
	Sage Weil <sage@newdream.net>, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Aneesh Kumar K. V" <aneesh.kumar@linux.vnet.ibm.com>,
	linux-api@vger.kernel.org, mtk.manpages@gmail.com,
	viro@zeniv.linux.org.uk, hch@lst.de, l@jasper.es
References: <201103111255.44979.arnd@arndb.de>
 <ffafd3ccb3fd1be7c40348c9cee84aef.squirrel@webmail.greenhost.nl>
 <20110311235607.GB15853@elie>
 <9446ab1a2315c0d2476c30f8315a0503.squirrel@webmail.greenhost.nl>
 <20110312021001.GA16833@elie>
 <20110312173217.GA24981@kroah.com>
 <1e597aedd3d7825dcc0630b1cf2399fa.squirrel@webmail.greenhost.nl>
 <20110314131042.5a7fb32f.akpm@linux-foundation.org>
 <20110314211119.GC8120@thunk.org>
 <20110314142032.b9523309.akpm@linux-foundation.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20110314142032.b9523309.akpm@linux-foundation.org>
User-Agent: Mutt/1.5.20 (2009-06-14)
X-SA-Exim-Connect-IP: <locally generated>
X-SA-Exim-Mail-From: tytso@thunk.org
X-SA-Exim-Scanned: No (on test.thunk.org); SAEximRunCond expanded to false
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1027
Lines: 22

On Mon, Mar 14, 2011 at 02:20:32PM -0700, Andrew Morton wrote:
> > I'm a bit nervous about exposing WB_SYNC_NONE to userspace, because
> > its semantics are *definitely* hard to describe.  For example, at the
> > moment if you do a WB_SYNC_NONE writeback, the writeback code will
> > clamp the amount of data written back for each inode to
> > MAX_WRITEBACK_PAGES (1024) pages.
> 
> Wha?  It does?  When did that get broken?

Oops, sorry, I misread the code in wb_writeback().  My bad!  I
misinterpreted what write_chunk does in that function.
MAX_WRITEBACK_PAGES now really is the minimum amount of pages that
wb_writeback() will request the file system to write back.  I'm not
sure why we bother with write_chunk any more, but it shouldn't be
doing any harm any more.

					- Ted
--
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/