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drm/shmem-helper: Use refcount_t for pages_use_count

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Use atomic refcount_t helper for pages_use_count to optimize pin/unpin
functions by skipping reservation locking while GEM's pin refcount > 1.

Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.d>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250322212608.40511-9-dmitry.osipenko@collabora.com
This commit is contained in:
Dmitry Osipenko
2025-03-23 00:26:06 +03:00
parent d586b535f1
commit 051b6646d3
5 changed files with 22 additions and 25 deletions
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33
drivers/gpu/drm/drm_gem_shmem_helper.c
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@@ -176,7 +176,7 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
if (shmem->pages)
drm_gem_shmem_put_pages_locked(shmem);
drm_WARN_ON(obj->dev, shmem->pages_use_count);
drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_use_count));
drm_WARN_ON(obj->dev, refcount_read(&shmem->pages_pin_count));
dma_resv_unlock(shmem->base.resv);
@@ -194,14 +194,13 @@ static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
dma_resv_assert_held(shmem->base.resv);
if (shmem->pages_use_count++ > 0)
if (refcount_inc_not_zero(&shmem->pages_use_count))
return 0;
pages = drm_gem_get_pages(obj);
if (IS_ERR(pages)) {
drm_dbg_kms(obj->dev, "Failed to get pages (%ld)\n",
PTR_ERR(pages));
shmem->pages_use_count = 0;
return PTR_ERR(pages);
}
@@ -217,6 +216,8 @@ static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem)
shmem->pages = pages;
refcount_set(&shmem->pages_use_count, 1);
return 0;
}
@@ -232,21 +233,17 @@ void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem)
dma_resv_assert_held(shmem->base.resv);
if (drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
return;
if (--shmem->pages_use_count > 0)
return;
if (refcount_dec_and_test(&shmem->pages_use_count)) {
#ifdef CONFIG_X86
if (shmem->map_wc)
set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
if (shmem->map_wc)
set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
#endif
drm_gem_put_pages(obj, shmem->pages,
shmem->pages_mark_dirty_on_put,
shmem->pages_mark_accessed_on_put);
shmem->pages = NULL;
drm_gem_put_pages(obj, shmem->pages,
shmem->pages_mark_dirty_on_put,
shmem->pages_mark_accessed_on_put);
shmem->pages = NULL;
}
}
EXPORT_SYMBOL_GPL(drm_gem_shmem_put_pages_locked);
@@ -582,8 +579,8 @@ static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
* mmap'd, vm_open() just grabs an additional reference for the new
* mm the vma is getting copied into (ie. on fork()).
*/
if (!drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
shmem->pages_use_count++;
drm_WARN_ON_ONCE(obj->dev,
!refcount_inc_not_zero(&shmem->pages_use_count));
dma_resv_unlock(shmem->base.resv);
@@ -674,7 +671,7 @@ void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem,
return;
drm_printf_indent(p, indent, "pages_pin_count=%u\n", refcount_read(&shmem->pages_pin_count));
drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
drm_printf_indent(p, indent, "pages_use_count=%u\n", refcount_read(&shmem->pages_use_count));
drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
}