[Intel-gfx] [PATCH v5 0/7] Command parser batch buffer copy

[Chris Wilson]

On Mon, Dec 01, 2014 at 02:39:51PM -0800, Michael H. Nguyen wrote:
> Re: madvise on creation
> 
> Were you referring to this?
> 
> from http://lists.freedesktop.org/archives/intel-gfx/2014-November/055060.htm
> 
> 	obj = i915_gem_obj_alloc();
> 	i915_gem_object_get_pages(obj);
> 	obj->madv = I915_MADV_DONTNEED;
> 
> If so, I don't understand . _get is returning obj and it'll be
> needed so would expect to set 'obj->madv = I915_MADV_WILLNEED' which
> is the case now.

madv is only evaluated at get_pages(). Once you have the pages, you keep
them until the shrinker purges them. Hence you only need to call
get_pages() once and set obj->madv = DONTNEED afterwards, and then you
only need to check whether the obj is purged before your next reuse (you
do not need to touch madv ever again). Whilst the object is active it is
a low priority target for the shrinker. That greatly simplifies the pool
code.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre