Re: [PATCH 17/18] fs: icache remove inode_lock

Nick Piggin
2010-10-13T07:21:04Z

On Fri, Oct 08, 2010 at 04:21:31PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> All the functionality that the inode_lock protected has now been
> wrapped up in new independent locks and/or functionality. Hence the
> inode_lock does not serve a purpose any longer and hence can now be
> removed.
>
> Based on work originally done by Nick Piggin.

Sorry about being offline for so long. I had some work finishing with
SUSE and then took some vacation without much net access for several
weeks :P

Unfortunate timing that everybody is suddenly interested in the
scalability work :) I didn't want to dump a lot of patches just
before I went and not be able to support them if they were merged /
respond to review in a timely way. But I still want to maintain my
vfs-scale stack. I'm glad to see lots of interest in it now.

So I will like criticism of that and hopefully fold improvements back.
The problem I guess with taking the patches and reworking them a bit is
just that I have lost a bit of context of what you're doing, and also
it loses it's verification within the entire series (ie. the end goal
of doing store free path walking relies a bit on RCU inode for example),
and I've done a lot of microbenchmarking.

I don't see any radical changes that you've done yet, although it's
hard to tell exactly.

I'm not sure about trylocking. I don't think it is an unmaintainable
mess in inode, because it is confined to the core inode (fs/inode,
fs/fs-writeback.c etc), and not visible to outside.

But let me get back up to speed and see what you've done here.

I might need a little more time than 2.6.37! But I'll try my best.
I don't think the patchset has suddenly become vastly more urgent
in the past month, so I think my approach of having it get a lot
of testing and go in Al's vfs tree for a while is best.

Thanks,
Nick