Re: [PATCH] improve jbd fsync batching

[Andreas Dilger]

On Nov 03, 2008  12:27 -0800, Andrew Morton wrote:
> On Tue, 28 Oct 2008 16:16:15 -0400
> Josef Bacik <jbacik@xxxxxxxxxx> wrote:
> > +		spin_lock(&journal->j_state_lock);
> > +		commit_time = journal->j_average_commit_time;
> > +		spin_unlock(&journal->j_state_lock);
> 
> OK, the lock is needed on 32-bit machines, I guess.

Should we pessimize the 64-bit performance in that case, for 32-bit
increasingly rare 32-bit platforms?

It might be useful to have a spin_{,un}lock_64bit_word() helper that
evaluates to a no-op on plaforms that don't need a hammer to do an atomic
64-bit update.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.

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