Re: [patch 1/6] fs: icache RCU free inodes

From: Linus Torvalds
Date: Tue Nov 09 2010 - 11:03:51 EST


On Tue, Nov 9, 2010 at 4:46 AM, Nick Piggin <npiggin@xxxxxxxxx> 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
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