Re: [patch] Real-Time Preemption, -RT-2.6.12-rc1-V0.7.41-07

[Steven Rostedt]

On Fri, 2005-04-01 at 07:19 +0200, Ingo Molnar wrote:
> * Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> 
> > > could you send me your latest patch for the bit-spin issue? My main 
> > > issue was cleanliness, so that the patch doesnt get stuck in the -RT 
> > > tree forever.
> > 
> > I think that's the main problem. Without changing the design of the 
> > ext3 system, I don't think there is a clean patch.  The implementation 
> > that I finally settled down with was to make the j_state and 
> > j_journal_head locks two global locks. I had to make a few 
> > modifications to some spots to avoid deadlocks, but this worked out 
> > well. The problem I was worried about was this causing too much 
> > overhead. So the ext3 buffers would have to contend with each other. I 
> > don't have any tests to see if this had too much of an impact.
> 
> yeah - i think Andrew said that a global lock at that particular place 
> might not be that much of an issue.
> 

OK, I'll start stripping it out of my kernel today and make a clean
patch for you.

-- Steve

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