[Mesa-dev] [PATCH 2/2] panfrost: Add madvise support to BO cache

[Tomeu Vizoso]

Both patches look good to me.

Reviewed-by: Tomeu Vizoso <tomeu.vizoso at collabora.com>

Thanks!

Tomeu

On Fri, 9 Aug 2019 at 21:53, Rob Herring <robh at kernel.org> wrote:
>
> The kernel now supports madvise ioctl to indicate which BOs can be freed
> when there is memory pressure. Mark BOs purgeable when they are in the
> BO cache. The BOs must also be munmapped when they are in the cache or
> they cannot be purged.
>
> We could optimize avoiding the madvise ioctl on older kernels once the
> driver version bump lands, but probably not worth it given the other
> driver features also being added.
>
> Signed-off-by: Rob Herring <robh at kernel.org>
> ---
>  src/gallium/drivers/panfrost/pan_bo_cache.c | 21 +++++++++++++++++++++
>  src/gallium/drivers/panfrost/pan_drm.c      |  4 ++--
>  2 files changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/src/gallium/drivers/panfrost/pan_bo_cache.c b/src/gallium/drivers/panfrost/pan_bo_cache.c
> index 7378d0a8abea..239ea0b46cb2 100644
> --- a/src/gallium/drivers/panfrost/pan_bo_cache.c
> +++ b/src/gallium/drivers/panfrost/pan_bo_cache.c
> @@ -23,6 +23,8 @@
>   * Authors (Collabora):
>   *   Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
>   */
> +#include <xf86drm.h>
> +#include "drm-uapi/panfrost_drm.h"
>
>  #include "pan_screen.h"
>  #include "util/u_math.h"
> @@ -88,9 +90,21 @@ panfrost_bo_cache_fetch(
>          list_for_each_entry_safe(struct panfrost_bo, entry, bucket, link) {
>                  if (entry->size >= size &&
>                      entry->flags == flags) {
> +                        int ret;
> +                        struct drm_panfrost_madvise madv;
> +
>                          /* This one works, splice it out of the cache */
>                          list_del(&entry->link);
>
> +                        madv.handle = entry->gem_handle;
> +                        madv.madv = PANFROST_MADV_WILLNEED;
> +                       madv.retained = 0;
> +
> +                        ret = drmIoctl(screen->fd, DRM_IOCTL_PANFROST_MADVISE, &madv);
> +                       if (!ret && !madv.retained) {
> +                               panfrost_drm_release_bo(screen, entry, false);
> +                               continue;
> +                       }
>                          /* Let's go! */
>                          return entry;
>                  }
> @@ -109,6 +123,13 @@ panfrost_bo_cache_put(
>                  struct panfrost_bo *bo)
>  {
>          struct list_head *bucket = pan_bucket(screen, bo->size);
> +        struct drm_panfrost_madvise madv;
> +
> +        madv.handle = bo->gem_handle;
> +        madv.madv = PANFROST_MADV_DONTNEED;
> +       madv.retained = 0;
> +
> +        drmIoctl(screen->fd, DRM_IOCTL_PANFROST_MADVISE, &madv);
>
>          /* Add us to the bucket */
>          list_addtail(&bo->link, bucket);
> diff --git a/src/gallium/drivers/panfrost/pan_drm.c b/src/gallium/drivers/panfrost/pan_drm.c
> index 36a6b975680a..28a4287202bd 100644
> --- a/src/gallium/drivers/panfrost/pan_drm.c
> +++ b/src/gallium/drivers/panfrost/pan_drm.c
> @@ -163,6 +163,8 @@ panfrost_drm_release_bo(struct panfrost_screen *screen, struct panfrost_bo *bo,
>          /* Rather than freeing the BO now, we'll cache the BO for later
>           * allocations if we're allowed to */
>
> +        panfrost_drm_munmap_bo(screen, bo);
> +
>          if (cacheable) {
>                  bool cached = panfrost_bo_cache_put(screen, bo);
>
> @@ -172,8 +174,6 @@ panfrost_drm_release_bo(struct panfrost_screen *screen, struct panfrost_bo *bo,
>
>          /* Otherwise, if the BO wasn't cached, we'll legitimately free the BO */
>
> -        panfrost_drm_munmap_bo(screen, bo);
> -
>          ret = drmIoctl(screen->fd, DRM_IOCTL_GEM_CLOSE, &gem_close);
>          if (ret) {
>                  fprintf(stderr, "DRM_IOCTL_GEM_CLOSE failed: %m\n");
> --
> 2.20.1
>
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