Re: [Intel-gfx] [PATCH 6/8] drm/i915: add free_unused_pages support to i915

[Matthew Auld]

On 25/10/2021 14:00, Arunpravin wrote:
add drm_buddy_free_unused_pages() support on
contiguous allocation
Signed-off-by: Arunpravin <arunpravin.paneersel...@amd.com>
---
  drivers/gpu/drm/i915/i915_ttm_buddy_manager.c | 8 ++++++++
  1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c 
b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
index 963468228392..162947af8e04 100644
--- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
+++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
@@ -98,6 +98,14 @@ static int i915_ttm_buddy_man_alloc(struct 
ttm_resource_manager *man,
        if (unlikely(err))
                goto err_free_blocks;
  
+	if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
+               err = drm_buddy_free_unused_pages(mm, (uint64_t)n_pages << 
PAGE_SHIFT,
+                                                      &bman_res->blocks);
+
+               if (unlikely(err))
+                       goto err_free_blocks;

That needs some locking, mark_free/mark_split are all globally visible. 
Some concurrent user might steal the block, or worse.

+       }
+
        *res = &bman_res->base;
        return 0;