From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id p0IERj1p135600 for ; Tue, 18 Jan 2011 08:27:45 -0600 Date: Tue, 18 Jan 2011 08:30:00 -0600 From: Geoffrey Wehrman Subject: Re: Issues with delalloc->real extent allocation Message-ID: <20110118143000.GB8803@sgi.com> References: <20110114002900.GF16267@dastard> <20110114164016.GB30134@sgi.com> <20110114225907.GH16267@dastard> <20110115041629.GC11968@sgi.com> <20110117051827.GL16267@dastard> <20110117143708.GE11968@sgi.com> <20110118002437.GS28803@dastard> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110118002437.GS28803@dastard> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: xfs@oss.sgi.com On Tue, Jan 18, 2011 at 11:24:37AM +1100, Dave Chinner wrote: | On Mon, Jan 17, 2011 at 08:37:08AM -0600, Geoffrey Wehrman wrote: | > On Mon, Jan 17, 2011 at 04:18:28PM +1100, Dave Chinner wrote: | > | However, this does not solve the extsize allocation issues where we | > | don't have dirty pages in the page cache covering parts of the | > | delayed allocation extent so we still need a solution for that. I'm | > | tending towards zeroing in .aio_write as the simplest solution | > | because it doesn't cause buffer head/extent tree mapping mismatches, | > | and it would use the above intent/done operations for crash | > | resilience so there's no additional, rarely used code path to test | > | through .writepage. Does that sound reasonable? | > | > Zeroing in .aio_write will create zeroed pages covering the entire | > allocation, correct? | | Yes, though it only needs to zero the regions that the write does | not cover itself - no need to zero what we're about to put data | into. ;) Glad you were able to understand what I meant. Something I didn't think of earlier though: What happens when I try to use an 8 GB on a system with only 4 GB of memory? I'm not really worried about this pathological case, but I do wonder what the effects will be of allocating what could be significant quantities of memory in .aio_write. -- Geoffrey Wehrman 651-683-5496 gwehrman@sgi.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs