From mboxrd@z Thu Jan 1 00:00:00 1970 From: Suparna Bhattacharya Subject: Re: [RFC][WIP] DIO simplification and AIO-DIO stability Date: Fri, 24 Feb 2006 15:07:56 +0530 Message-ID: <20060224093756.GA5241@in.ibm.com> References: <20060223072955.GA14244@in.ibm.com> <200602232001.34327.mason@suse.com> Reply-To: suparna@in.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: akpm@osdl.org, sct@redhat.com, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, kenneth.w.chen@intel.com, pbadari@us.ibm.com, linux-kernel@vger.kernel.org, sonny@burdell.org Return-path: Received: from e6.ny.us.ibm.com ([32.97.182.146]:46047 "EHLO e6.ny.us.ibm.com") by vger.kernel.org with ESMTP id S932169AbWBXJhl (ORCPT ); Fri, 24 Feb 2006 04:37:41 -0500 To: Chris Mason Content-Disposition: inline In-Reply-To: <200602232001.34327.mason@suse.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Thu, Feb 23, 2006 at 08:01:32PM -0500, Chris Mason wrote: > On Thursday 23 February 2006 02:29, Suparna Bhattacharya wrote: > > DIO code complexity and stability concerns were discussed way back during > > OLS and Kernel summit last year. Still, the lack of a solid alternative and > > motivation to subject oneself to the test of courage and delicate balance > > that fiddling with this code entails, has meant that gingerly applying > > fixes and bandaids as and when bugs are found, and moving on thereafter, > > continues to be the most palatable option. > > > > A recent AIO-DIO bug reported by Kenneth Chen, came very close > > to being the proverbial last straw for me. Hence, here is a rough attempt > > to put together a (currently WIP) draft towards DIO code simplication, > > based on suggestions that some of you have brought up at various times. > > Several details, e.g. range locking implementation still need to be fleshed > > out completely, ideas/comments/suggestions would be welcome. > > I'm really in favor of this, and had actually started an implementation a > while back. At the time, I posted a different version that added yet another > semaphore but simplified the rest of the locking (and held no locks during > the dio/aio). Yes I have saved that patch as a reference as well. With range locking I'm hoping that would be able to avoid the need for i_hole_sem. Also I wanted to push out all locking code out of the DIO code to avoid the various locking mode checks. > > I'll try to dig up my original radix tagging code. I'm not sure if I kept it, > but it did pass Daniel's dio vs buffer io racing tests at the time. Cool - that would be great ! Regards Suparna > > -chris > > -- > To unsubscribe, send a message with 'unsubscribe linux-aio' in > the body to majordomo@kvack.org. For more info on Linux AIO, > see: http://www.kvack.org/aio/ > Don't email: aart@kvack.org -- Suparna Bhattacharya (suparna@in.ibm.com) Linux Technology Center IBM Software Lab, India