Re: 2.6.24-rc6 reproducible raid5 hang

On Wednesday January 9, dan.j.williams@intel.com wrote:

On Jan 9, 2008 5:09 PM, Neil Brown [off-list ref] wrote:

quoted

On Wednesday January 9, dan.j.williams@intel.com wrote:

Can you test it please?

This passes my failure case.

Thanks!

quoted

Does it seem reasonable?

What do you think about limiting the number of stripes the submitting
thread handles to be equal to what it submitted?  If I'm a stripe that
only submits 1 stripe worth of work should I get stuck handling the
rest of the cache?

Dunno....
Someone has to do the work, and leaving it all to raid5d means that it
all gets done on one CPU.
I expect that most of the time the queue of ready stripes is empty so
make_request will mostly only handle it's own stripes anyway.
The times that it handles other thread's stripes will probably balance
out with the times that other threads handle this threads stripes.

So I'm incline to leave it as "do as much work as is available to be
done" as that is simplest.  But I can probably be talked out of it
with a convincing argument....

NeilBrown