Re: -rc7 Re: Linux 2.4.21-rc6

[Andrea Arcangeli <andrea@suse.de>]

On Thu, May 29, 2003 at 04:11:12PM -0300, Marcelo Tosatti wrote:
> 
> 
> On Thu, 29 May 2003, Georg Nikodym wrote:
> 
> > On Wed, 28 May 2003 21:55:39 -0300 (BRT)
> > Marcelo Tosatti <marcelo@conectiva.com.br> wrote:
> >
> > > Here goes -rc6. I've decided to delay 2.4.21 a bit and try Andrew's
> > > fix for the IO stalls/deadlocks.
> >
> > While others may be dubious about the efficacy of this patch, I've been
> > running -rc6 on my laptop now since sometime last night and have seen
> > nothing odd.
> >
> > In case anybody cares, I'm using both ide and a ieee1394 (for a large
> > external drive [which implies scsi]) and I do a _lot_ of big work with
> > BK so I was seeing the problem within hours previously.
> 
> Great!

are you really sure that it is the right fix?

I mean, the batching has a basic problem (I was discussing it with Jens
two days ago and he said he's already addressed in 2.5, I wonder if that
could also have an influence on the fact 2.5 is so much better in
fariness)

the issue with batching in 2.4, is that it is blocking at 0 and waking
at batch_requests. But it's not blocking new get_request to eat requests
in the way back from 0 to batch_requests. I mean, there are two
directions, when we move from batch_requests to 0 get_requests should
return requests. in the way back from 0 to batch_requests the
get_request should block (and it doesn't in 2.4, that is the problem)

> 
> -rc7 will have to be released due to some problems :(
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Andrea