From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH 1/2] ext4: introduce new i_write_mutex to protect fallocate Date: Thu, 29 May 2014 12:28:10 -0400 Message-ID: <20140529162810.GG25041@thunk.org> References: <001701cf6e40$fab98be0$f02ca3a0$@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Namjae Jeon , linux-ext4 , Ashish Sangwan To: =?utf-8?B?THVrw6HFoQ==?= Czerner Return-path: Received: from imap.thunk.org ([74.207.234.97]:39858 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756336AbaE2Q2Q (ORCPT ); Thu, 29 May 2014 12:28:16 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, May 29, 2014 at 02:42:04PM +0200, Luk=C3=A1=C5=A1 Czerner wrote= : >=20 > I wonder what is the performance impact of this change ? Especially > since we're not longer taking the lock only in unaligned aio/dio > case but in all cases ? Thinking about this some more, this is also going to break parallel writes, which would be unfortunate. We might want to change this to using a rw mutex, where writes take a shared lock, and require fallocate to take an exclusive lock.... - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html