From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [patch 1/6] fs: icache RCU free inodes Date: Tue, 9 Nov 2010 08:02:38 -0800 Message-ID: References: <20101109124610.GB11477@amd> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: Al Viro , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org To: Nick Piggin Return-path: In-Reply-To: <20101109124610.GB11477@amd> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Tue, Nov 9, 2010 at 4:46 AM, Nick Piggin wrote: > So here is the inode RCU code. It's obviously not worth doing until the > actual rcu-walk path walking is in, but I'd like to get opinions on it. > It would be nice to merge it in Al's tree at some point, though. Remind me why it wasn't sufficient to just use SLAB_DESTROY_BY_RCU? Especially if we still lock things for the actual (few) inode list operations, the added complexity of actually freeing _individual_ inodes by RCU seems to be a bad thing. The only thing we care about is the pathname walk - there are no other inode operations that are common enough to worry about. And the only thing _that_ needs is the ability to look at the inode under RCU, and SLAB_DESTROY_BY_RCU should be entirely sufficient for that. But we had some discussion about this long ago, and I may have forgotten some of the context. Linus