Re: locking hierarchy based on lockdep

[Pavel Machek <pavel@ucw.cz>]

Hi!

> > * Jason Baron <jbaron@redhat.com> wrote:
> > 
> > > I've implemented this as a /proc file, but Ingo suggested that it 
> > > might be better for us to simply produce an adjaceny list, and then 
> > > generate a locking hierarchy or anything else of interest off of that 
> > > list.... [...]
> > 
> > this would certainly be the simplest thing to do - we could extend 
> > /proc/lockdep with the list of 'immediately after' locks separated by 
> > commas. (that list already exists: it's the lock_class.locks_after list)
> > 
> > i like your idea of using lockdep to document locking hierarchies.
> > 
> > 	Ingo
> > 
> 
> hi,
> 
> So below is patch that does what you suggest, although i had to add the 
> concept of 'distance' to the patch since the locks_after list loses this 
> dependency info afaict. i also wrote a user space program to sort the 
> locks into cluster of interelated locks and then sorted within these 
> clusters...the results show one large clump of locks...perhaps there are a 
> few locks that time them all together like scheduler locks...but i 
> couldn't figure out which ones to exclude to make the list look really 
> pretty (also, there could be a bug in my program :). Anyways i'm including 
> my test program and its output too...

Perhaps presenting it as a tree is worth it?
									Pavel
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