| Date | Sat, 16 Oct 2010 18:56:41 +1100 | From | Nick Piggin <> | Subject | Re: [PATCH 07/17] fs: icache atomic inodes_stat |
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On Wed, Sep 29, 2010 at 09:52:53PM -0700, Andrew Morton wrote: > On Wed, 29 Sep 2010 22:18:39 +1000 Dave Chinner <david@fromorbit.com> wrote: > > From: Nick Piggin <npiggin@suse.de> > > > > The inode use statistics are currently protected by the inode_lock. > > Before we can remove the inode_lock, we need to protect these > > counters against races. Do this by converting them to atomic > > counters so they ar enot dependent on any lock at all. > > typo
It's Dave, I swear :)
> > +struct inodes_stat_t { > > + atomic_t nr_inodes; > > + atomic_t nr_unused; > > + int dummy[5]; /* padding for sysctl ABI compatibility */ > > +}; > > OK, that's a hack. The first two "ints" are copied out to userspace. > This change assumes that sizeof(atomic_t)=4 and that an atomic_t has > the same layout, alignment and padding as an int. > > Probably that's true in current kernels and with current architectures > but it's a hack and it's presumptive. > > It shouldn't be snuck into the tree unchangelogged and uncommented. > > (time passes) > > OK, I see that all of this gets reverted later on. Please update the > changelog so the next reviewer doesn't get fooled.
Yeah it is. I might end up folding the per-cpu stuff back over it and avoid the issue completely. Otherwise I'll add a comment.
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