Re: [patch 0/3] j_state_lock, j_list_lock, remove-bitlocks

Andrew Morton
2005-03-16T10:04:37Z

Ingo Molnar <mingo@elte.hu> wrote:
>
> > There's a little lock ranking diagram in jbd.h which tells us that
> > these locks nest inside j_list_lock and j_state_lock. So I guess
> > you'll need to turn those into semaphores.
>
> indeed. I did this (see the three followup patches, against BK-curr),
> and it builds/boots/works just fine on an ext3 box. Do we want to try
> this in -mm?

ooh, I'd rather not. I spent an intense three days removing all the
sleeping locks from ext3 (and three months debugging the result). Ended up
gaining 1000% on 16-way.

Putting them back in will really hurt the SMP performance.