Commit decbfaf0 authored by Nirmoy Das's avatar Nirmoy Das
Browse files

drm/ttm: Add a flag to allow drivers to skip clear-on-free 



Add TTM_TT_FLAG_CLEARED_ON_FREE, which DRM drivers can set before
releasing backing stores if they want to skip clear-on-free.

Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Suggested-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240816135154.19678-1-nirmoy.das@intel.com


Signed-off-by: default avatarNirmoy Das <nirmoy.das@intel.com>
parent 6841a26e

drivers/gpu/drm/ttm/ttm_pool.c

+11 −7
Original line number Diff line number Diff line
@@ -222,16 +222,19 @@ static void ttm_pool_unmap(struct ttm_pool *pool, dma_addr_t dma_addr, 
}



/* Give pages into a specific pool_type */

static void ttm_pool_type_give(struct ttm_pool_type *pt, struct page *p)

static void ttm_pool_type_give(struct ttm_pool_type *pt, struct page *p,

			       bool cleared)

{

	unsigned int i, num_pages = 1 << pt->order;



	if (!cleared) {

		for (i = 0; i < num_pages; ++i) {

			if (PageHighMem(p))

				clear_highpage(p + i);

			else

				clear_page(page_address(p + i));

		}

	}



	spin_lock(&pt->lock);

	list_add(&p->lru, &pt->pages);
@@ -394,6 +397,7 @@ static void ttm_pool_free_range(struct ttm_pool *pool, struct ttm_tt *tt, 
				pgoff_t start_page, pgoff_t end_page)

{

	struct page **pages = &tt->pages[start_page];

	bool cleared = tt->page_flags & TTM_TT_FLAG_CLEARED_ON_FREE;

	unsigned int order;

	pgoff_t i, nr;
@@ -407,7 +411,7 @@ static void ttm_pool_free_range(struct ttm_pool *pool, struct ttm_tt *tt, 


		pt = ttm_pool_select_type(pool, caching, order);

		if (pt)

			ttm_pool_type_give(pt, *pages);

			ttm_pool_type_give(pt, *pages, cleared);

		else

			ttm_pool_free_page(pool, caching, order, *pages);

	}

include/drm/ttm/ttm_tt.h

+5 −1
Original line number Diff line number Diff line
@@ -85,6 +85,9 @@ struct ttm_tt { 
	 * fault handling abuses the DMA api a bit and dma_map_attrs can't be

	 * used to assure pgprot always matches.

	 *

	 * TTM_TT_FLAG_CLEARED_ON_FREE: Set this if a drm driver handles

	 * clearing backing store

	 *

	 * TTM_TT_FLAG_PRIV_POPULATED: TTM internal only. DO NOT USE. This is

	 * set by TTM after ttm_tt_populate() has successfully returned, and is

	 * then unset when TTM calls ttm_tt_unpopulate().
@@ -94,8 +97,9 @@ struct ttm_tt { 
#define TTM_TT_FLAG_EXTERNAL		BIT(2)

#define TTM_TT_FLAG_EXTERNAL_MAPPABLE	BIT(3)

#define TTM_TT_FLAG_DECRYPTED		BIT(4)

#define TTM_TT_FLAG_CLEARED_ON_FREE	BIT(5)



#define TTM_TT_FLAG_PRIV_POPULATED	BIT(5)

#define TTM_TT_FLAG_PRIV_POPULATED	BIT(6)

	uint32_t page_flags;

	/** @num_pages: Number of pages in the page array. */

	uint32_t num_pages;