From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [patch 38/52] fs: icache RCU free inodes Date: Wed, 30 Jun 2010 22:07:31 +1000 Message-ID: <20100630120731.GD21358@laptop> References: <20100624030212.676457061@suse.de> <20100624030731.710413510@suse.de> <20100630085711.GH24712@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, John Stultz , Frank Mayhar To: Dave Chinner Return-path: Content-Disposition: inline In-Reply-To: <20100630085711.GH24712@dastard> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Jun 30, 2010 at 06:57:11PM +1000, Dave Chinner wrote: > On Thu, Jun 24, 2010 at 01:02:50PM +1000, npiggin@suse.de wrote: > > RCU free the struct inode. This will allow: > > Rather than what it will allow, what are the constraints this > imposes on allocating and freeing a struct inode? e.g. XFS embeds > the struct inode in a larger inode structure and does it's own > allocation, caching and freeing of the larger structure outside of > the VFS functionality. > > Does this need to be converted to RCU? Do we need to do more > initialisation of the struct inode than we currently do? What > functions/call chains now implicitly require RCU freeing semantics > on the struct inode for safe operation? What else do we need to be > aware of? Yeah, filesystems with their own freeing functions will need to do a call_rcu to free it (many are not converted). Otherwise, there is nothing else to know. They could take advantage of RCU if they would like though.