[Intel-gfx] [PATCH 2/9] drm/i915: Extract node allocation from bind

[Chris Wilson]

On Tue, May 06, 2014 at 10:21:31PM -0700, Ben Widawsky wrote:
> The DRM node allocation code was already a bit of an ugly bit of code
> within a complex function. Removing it serves the purpose of cleaning
> the function up. More importantly, it provides a way to have a
> preallocated (address space) VMA to easily skip this code. Something
> we're very likely to need.
> 
> This is essentially a wrapper for DRM node allocation with an eviction +
> retry. It is something which could be moved to core DRM eventually, if
> other drivers had similar eviction semantics.
> 
> This removes a goto used for something other than error unwinding, a
> generally reviled (I am neutral) practice, and replaces it with a
> function call to itself that should have the same effect. Note that it's
> not a recursive function as all the problem set reduction is done in the
> eviction code.
> 
> Some might say this change is worse than before because we are using
> stack for each subsequent call. Frankly, I'd rather overflow the stack
> and blow it up than loop forever. In either case, this is addressed in
> the next patch.
> 
> I believe, and intend, that other than the stack usage, there is no
> functional change here.

Nope, but decoupling evict_something() further does introduce lots more
implied magic.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre