From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211]:52715 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753811AbdBDJ4J (ORCPT ); Sat, 4 Feb 2017 04:56:09 -0500 Date: Sat, 4 Feb 2017 10:56:06 +0100 From: Christoph Hellwig Subject: Re: [PATCH 2/4] xfs: improve handling of busy extents in the low-level allocator Message-ID: <20170204095606.GC18472@lst.de> References: <1485715421-17182-1-git-send-email-hch@lst.de> <1485715421-17182-3-git-send-email-hch@lst.de> <20170203162243.GF45388@bfoster.bfoster> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170203162243.GF45388@bfoster.bfoster> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Brian Foster Cc: Christoph Hellwig , linux-xfs@vger.kernel.org On Fri, Feb 03, 2017 at 11:22:43AM -0500, Brian Foster wrote: > I didn't catch this until looking through everything after the next > patch, but I think there's a problem with the wakeup here as well. If we > have a busy extent with XFS_EXTENT_BUSY_SKIP_DISCARD set, we immediately > issue a wake from the first xfs_extent_busy_clear() in the cil committed > handler, regardless of whether !SKIP_DISCARD extents exist as well > under the current gen value. I think that means we'd get a premature > wake any time a busy_list has at least one of each type..? We'll need to wake as soon as a previously busy extent in the AG becomes available, and that includes XFS_EXTENT_BUSY_SKIP_DISCARD ones. Otherwise e.g. a transaction only containing XFS_EXTENT_BUSY_SKIP_DISCARD will never wake at all.