[Intel-gfx] [PATCH 4/4] drm/i915: Invalidate our pages under memory pressure

[Barbalho, Rafael]

> -----Original Message-----
> From: Intel-gfx [mailto:intel-gfx-bounces at lists.freedesktop.org] On Behalf
> Of Chris Wilson
> Sent: Tuesday, March 25, 2014 1:23 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Hugh Dickins
> Subject: [Intel-gfx] [PATCH 4/4] drm/i915: Invalidate our pages under
> memory pressure
> 
> Try to flush out dirty pages into the swapcache (and from there into the
> swapfile) when under memory pressure and forced to drop GEM objects
> from memory. In effect, this should just allow us to discard unused pages for
> memory reclaim and to start writeback earlier.
> 
> v2: Hugh Dickins warned that explicitly starting writeback from shrink_slab
> was prone to deadlocks within shmemfs.
> 
> Cc: Hugh Dickins <hughd at google.com>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Reviewed-by: Rafael Barbalho <rafael.barbalho at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 38 +++++++++++++++++++++++++++--
> ---------
>  1 file changed, 27 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c
> b/drivers/gpu/drm/i915/i915_gem.c index 135ee8bd55f6..8287fd6701c6
> 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -60,7 +60,6 @@ static unsigned long i915_gem_shrinker_scan(struct
> shrinker *shrinker,
>  					    struct shrink_control *sc);
>  static unsigned long i915_gem_purge(struct drm_i915_private *dev_priv,
> long target);  static unsigned long i915_gem_shrink_all(struct
> drm_i915_private *dev_priv); -static void i915_gem_object_truncate(struct
> drm_i915_gem_object *obj);  static void
> i915_gem_retire_requests_ring(struct intel_ring_buffer *ring);
> 
>  static bool cpu_cache_is_coherent(struct drm_device *dev, @@ -1685,12
> +1684,16 @@ i915_gem_mmap_gtt_ioctl(struct drm_device *dev, void
> *data,
>  	return i915_gem_mmap_gtt(file, dev, args->handle, &args->offset);
> }
> 
> +static inline int
> +i915_gem_object_is_purgeable(struct drm_i915_gem_object *obj) {
> +	return obj->madv == I915_MADV_DONTNEED; }
> +
>  /* Immediately discard the backing storage */  static void
> i915_gem_object_truncate(struct drm_i915_gem_object *obj)  {
> -	struct inode *inode;
> -
>  	i915_gem_object_free_mmap_offset(obj);
> 
>  	if (obj->base.filp == NULL)
> @@ -1701,16 +1704,28 @@ i915_gem_object_truncate(struct
> drm_i915_gem_object *obj)
>  	 * To do this we must instruct the shmfs to drop all of its
>  	 * backing pages, *now*.
>  	 */
> -	inode = file_inode(obj->base.filp);
> -	shmem_truncate_range(inode, 0, (loff_t)-1);
> -
> +	shmem_truncate_range(file_inode(obj->base.filp), 0, (loff_t)-1);
>  	obj->madv = __I915_MADV_PURGED;
>  }
> 
> -static inline int
> -i915_gem_object_is_purgeable(struct drm_i915_gem_object *obj)
> +/* Try to discard unwanted pages */
> +static void
> +i915_gem_object_invalidate(struct drm_i915_gem_object *obj)
>  {
> -	return obj->madv == I915_MADV_DONTNEED;
> +	struct address_space *mapping;
> +
> +	switch (obj->madv) {
> +	case I915_MADV_DONTNEED:
> +		i915_gem_object_truncate(obj);
> +	case __I915_MADV_PURGED:
> +		return;
> +	}
> +
> +	if (obj->base.filp == NULL)
> +		return;
> +
> +	mapping = file_inode(obj->base.filp)->i_mapping,
> +	invalidate_mapping_pages(mapping, 0, (loff_t)-1);
>  }
> 
>  static void
> @@ -1775,8 +1790,7 @@ i915_gem_object_put_pages(struct
> drm_i915_gem_object *obj)
>  	ops->put_pages(obj);
>  	obj->pages = NULL;
> 
> -	if (i915_gem_object_is_purgeable(obj))
> -		i915_gem_object_truncate(obj);
> +	i915_gem_object_invalidate(obj);
> 
>  	return 0;
>  }
> @@ -4201,6 +4215,8 @@ void i915_gem_free_object(struct
> drm_gem_object *gem_obj)
> 
>  	if (WARN_ON(obj->pages_pin_count))
>  		obj->pages_pin_count = 0;
> +	if (obj->madv != __I915_MADV_PURGED)
> +		obj->madv = I915_MADV_DONTNEED;
>  	i915_gem_object_put_pages(obj);
>  	i915_gem_object_free_mmap_offset(obj);
>  	i915_gem_object_release_stolen(obj);
> --
> 1.9.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx