[Intel-gfx] [PATCH v2 4/5] drm/i915: Change locking for struct_mutex, v2.

[Maarten Lankhorst]

Op 02-11-15 om 14:06 schreef Chris Wilson:
> On Mon, Nov 02, 2015 at 01:57:59PM +0100, Maarten Lankhorst wrote:
>> struct_mutex is being locked for every plane in intel_prepare_plane_fb and
>> intel_cleanup_plane_fb. This can be optimized by acquiring struct_mutex first
>> before calling the atomic helpers. This way the lock only needs to be acquired
>> twice in ->atomic_commit(). Once for pinning new framebuffers at the start,
>> the second time for unpinning old framebuffer.
> A little explanation that you move the locking into the caller would
> help clarify the patch.
>
>> @@ -13453,10 +13461,6 @@ intel_prepare_plane_fb(struct drm_plane *plane,
>> @@ -13520,7 +13521,6 @@ intel_cleanup_plane_fb(struct drm_plane *plane,
> Please document that you now expect both of these functions to be called
> with struct_mutex held. Also is there any opportunity to reduce the
> struct_mutex lock time?
>
Patch 5/5 reduces locking time. It moves most waiting out of struct_mutex except for the full idle during modesets. :)