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Commit 50b38bc4 authored by Mika Kuoppala's avatar Mika Kuoppala Committed by Chris Wilson
Browse files

drm/i915/gtt: Introduce release_pd_entry 



By encapsulating the locking upper level and used check for entry
into a helper function, we can use it in all callsites.

v2: get rid of atomic_reads on lower level clears (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190705215204.4559-4-chris@chris-wilson.co.uk
parent 73a8fdef

drivers/gpu/drm/i915/i915_gem_gtt.c

+42 −72
Original line number Diff line number Diff line
@@ -811,7 +811,25 @@ __clear_pd_entry(struct i915_page_directory * const pd, 
	__set_pd_entry((pd), (pde), px_base(to), gen8_pde_encode)



#define clear_pd_entry(pd, pde, to) \

	__clear_pd_entry((pd), (pde), px_base(to), gen8_pde_encode)

	__clear_pd_entry((pd), (pde), (to), gen8_pde_encode)



static bool

release_pd_entry(struct i915_page_directory * const pd,

		 const unsigned short pde,

		 atomic_t *counter,

		 struct i915_page_dma * const scratch)

{

	bool free = false;



	spin_lock(&pd->lock);

	if (atomic_dec_and_test(counter)) {

		clear_pd_entry(pd, pde, scratch);

		free = true;

	}

	spin_unlock(&pd->lock);



	return free;

}



/*

 * PDE TLBs are a pain to invalidate on GEN8+. When we modify
@@ -827,11 +845,11 @@ static void mark_tlbs_dirty(struct i915_ppgtt *ppgtt) 
/* Removes entries from a single page table, releasing it if it's empty.

 * Caller can use the return value to update higher-level entries.

 */

static bool gen8_ppgtt_clear_pt(const struct i915_address_space *vm,

static void gen8_ppgtt_clear_pt(const struct i915_address_space *vm,

				struct i915_page_table *pt,

				u64 start, u64 length)

{

	unsigned int num_entries = gen8_pte_count(start, length);

	const unsigned int num_entries = gen8_pte_count(start, length);

	gen8_pte_t *vaddr;



	vaddr = kmap_atomic_px(pt);
@@ -839,10 +857,11 @@ static bool gen8_ppgtt_clear_pt(const struct i915_address_space *vm, 
	kunmap_atomic(vaddr);



	GEM_BUG_ON(num_entries > atomic_read(&pt->used));

	return !atomic_sub_return(num_entries, &pt->used);



	atomic_sub(num_entries, &pt->used);

}



static bool gen8_ppgtt_clear_pd(struct i915_address_space *vm,

static void gen8_ppgtt_clear_pd(struct i915_address_space *vm,

				struct i915_page_directory *pd,

				u64 start, u64 length)

{
@@ -850,30 +869,20 @@ static bool gen8_ppgtt_clear_pd(struct i915_address_space *vm, 
	u32 pde;



	gen8_for_each_pde(pt, pd, start, length, pde) {

		bool free = false;



		GEM_BUG_ON(pt == vm->scratch_pt);



		if (!gen8_ppgtt_clear_pt(vm, pt, start, length))

			continue;



		spin_lock(&pd->lock);

		if (!atomic_read(&pt->used)) {

			clear_pd_entry(pd, pde, vm->scratch_pt);

			free = true;

		}

		spin_unlock(&pd->lock);

		if (free)

		atomic_inc(&pt->used);

		gen8_ppgtt_clear_pt(vm, pt, start, length);

		if (release_pd_entry(pd, pde, &pt->used,

				     px_base(vm->scratch_pt)))

			free_pt(vm, pt);

	}



	return !atomic_read(&pd->used);

}



/* Removes entries from a single page dir pointer, releasing it if it's empty.

 * Caller can use the return value to update higher-level entries

 */

static bool gen8_ppgtt_clear_pdp(struct i915_address_space *vm,

static void gen8_ppgtt_clear_pdp(struct i915_address_space *vm,

				 struct i915_page_directory * const pdp,

				 u64 start, u64 length)

{
@@ -881,24 +890,14 @@ static bool gen8_ppgtt_clear_pdp(struct i915_address_space *vm, 
	unsigned int pdpe;



	gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {

		bool free = false;



		GEM_BUG_ON(pd == vm->scratch_pd);



		if (!gen8_ppgtt_clear_pd(vm, pd, start, length))

			continue;



		spin_lock(&pdp->lock);

		if (!atomic_read(&pd->used)) {

			clear_pd_entry(pdp, pdpe, vm->scratch_pd);

			free = true;

		}

		spin_unlock(&pdp->lock);

		if (free)

		atomic_inc(&pd->used);

		gen8_ppgtt_clear_pd(vm, pd, start, length);

		if (release_pd_entry(pdp, pdpe, &pd->used,

				     px_base(vm->scratch_pd)))

			free_pd(vm, pd);

	}



	return !atomic_read(&pdp->used);

}



static void gen8_ppgtt_clear_3lvl(struct i915_address_space *vm,
@@ -922,19 +921,12 @@ static void gen8_ppgtt_clear_4lvl(struct i915_address_space *vm, 
	GEM_BUG_ON(!i915_vm_is_4lvl(vm));



	gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) {

		bool free = false;

		GEM_BUG_ON(pdp == vm->scratch_pdp);



		if (!gen8_ppgtt_clear_pdp(vm, pdp, start, length))

			continue;



		spin_lock(&pml4->lock);

		if (!atomic_read(&pdp->used)) {

			clear_pd_entry(pml4, pml4e, vm->scratch_pdp);

			free = true;

		}

		spin_unlock(&pml4->lock);

		if (free)

		atomic_inc(&pdp->used);

		gen8_ppgtt_clear_pdp(vm, pdp, start, length);

		if (release_pd_entry(pml4, pml4e, &pdp->used,

				     px_base(vm->scratch_pdp)))

			free_pd(vm, pdp);

	}

}
@@ -1457,17 +1449,8 @@ static int gen8_ppgtt_alloc_pdp(struct i915_address_space *vm, 
	goto out;



unwind_pd:

	if (alloc) {

		free_pd(vm, alloc);

		alloc = NULL;

	}

	spin_lock(&pdp->lock);

	if (atomic_dec_and_test(&pd->used)) {

		GEM_BUG_ON(alloc);

		alloc = pd; /* defer the free to after the lock */

		clear_pd_entry(pdp, pdpe, vm->scratch_pd);

	}

	spin_unlock(&pdp->lock);

	if (release_pd_entry(pdp, pdpe, &pd->used, px_base(vm->scratch_pd)))

		free_pd(vm, pd);

unwind:

	gen8_ppgtt_clear_pdp(vm, pdp, from, start - from);

out:
@@ -1530,17 +1513,8 @@ static int gen8_ppgtt_alloc_4lvl(struct i915_address_space *vm, 
	goto out;



unwind_pdp:

	if (alloc) {

		free_pd(vm, alloc);

		alloc = NULL;

	}

	spin_lock(&pml4->lock);

	if (atomic_dec_and_test(&pdp->used)) {

		GEM_BUG_ON(alloc);

		alloc = pdp; /* defer the free until after the lock */

		clear_pd_entry(pml4, pml4e, vm->scratch_pdp);

	}

	spin_unlock(&pml4->lock);

	if (release_pd_entry(pml4, pml4e, &pdp->used, px_base(vm->scratch_pdp)))

		free_pd(vm, pdp);

unwind:

	gen8_ppgtt_clear_4lvl(vm, from, start - from);

out:
@@ -1570,11 +1544,7 @@ static int gen8_preallocate_top_level_pdp(struct i915_ppgtt *ppgtt) 
	return 0;



unwind:

	start -= from;

	gen8_for_each_pdpe(pd, pdp, from, start, pdpe) {

		clear_pd_entry(pdp, pdpe, vm->scratch_pd);

		free_pd(vm, pd);

	}

	gen8_ppgtt_clear_pdp(vm, pdp, from, start - from);

	atomic_set(&pdp->used, 0);

	return -ENOMEM;

}