Commit 3a41a05d authored by Michał Winiarski's avatar Michał Winiarski Committed by Daniel Vetter
Browse files

drm/i915/gtt: Avoid calling kcalloc in a loop when allocating temp bitmaps 



On each call to gen8_alloc_va_range_3lvl we're allocating temporary
bitmaps needed for error handling. Unfortunately, when we increase
address space size (48b ppgtt) we do additional (512 - 4) calls to
kcalloc, increasing latency between exec and actual start of execution
on the GPU. Let's just do a single kcalloc, we can also drop the size
from free_gen8_temp_bitmaps since it's no longer used.

v2: Use GFP_TEMPORARY to make the allocations reclaimable.
v3: Drop the 2D array, just allocate a single block.
v4: Rebase to handle gen8_preallocate_top_level_pdps.
v5: Align misaligned bracket.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: default avatarMichał Winiarski <michal.winiarski@intel.com>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
[danvet: Correct kcalloc arguments as suggested by Chris.]
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent ea916ea0

drivers/gpu/drm/i915/i915_gem_gtt.c

+18 −31
Original line number Diff line number Diff line
@@ -1164,13 +1164,8 @@ unwind_out: 
}



static void

free_gen8_temp_bitmaps(unsigned long *new_pds, unsigned long **new_pts,

		       uint32_t pdpes)

free_gen8_temp_bitmaps(unsigned long *new_pds, unsigned long *new_pts)

{

	int i;



	for (i = 0; i < pdpes; i++)

		kfree(new_pts[i]);

	kfree(new_pts);

	kfree(new_pds);

}
@@ -1180,29 +1175,20 @@ free_gen8_temp_bitmaps(unsigned long *new_pds, unsigned long **new_pts, 
 */

static

int __must_check alloc_gen8_temp_bitmaps(unsigned long **new_pds,

					 unsigned long ***new_pts,

					 unsigned long **new_pts,

					 uint32_t pdpes)

{

	int i;

	unsigned long *pds;

	unsigned long **pts;

	unsigned long *pts;



	pds = kcalloc(BITS_TO_LONGS(pdpes), sizeof(unsigned long), GFP_KERNEL);

	pds = kcalloc(BITS_TO_LONGS(pdpes), sizeof(unsigned long), GFP_TEMPORARY);

	if (!pds)

		return -ENOMEM;



	pts = kcalloc(pdpes, sizeof(unsigned long *), GFP_KERNEL);

	if (!pts) {

		kfree(pds);

		return -ENOMEM;

	}



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

		pts[i] = kcalloc(BITS_TO_LONGS(I915_PDES),

				 sizeof(unsigned long), GFP_KERNEL);

		if (!pts[i])

	pts = kcalloc(pdpes, BITS_TO_LONGS(I915_PDES) * sizeof(unsigned long),

		      GFP_TEMPORARY);

	if (!pts)

		goto err_out;

	}



	*new_pds = pds;

	*new_pts = pts;
@@ -1210,7 +1196,7 @@ int __must_check alloc_gen8_temp_bitmaps(unsigned long **new_pds, 
	return 0;



err_out:

	free_gen8_temp_bitmaps(pds, pts, pdpes);

	free_gen8_temp_bitmaps(pds, pts);

	return -ENOMEM;

}
@@ -1231,7 +1217,7 @@ static int gen8_alloc_va_range_3lvl(struct i915_address_space *vm, 
{

	struct i915_hw_ppgtt *ppgtt =

		container_of(vm, struct i915_hw_ppgtt, base);

	unsigned long *new_page_dirs, **new_page_tables;

	unsigned long *new_page_dirs, *new_page_tables;

	struct drm_device *dev = vm->dev;

	struct i915_page_directory *pd;

	const uint64_t orig_start = start;
@@ -1258,14 +1244,14 @@ static int gen8_alloc_va_range_3lvl(struct i915_address_space *vm, 
	ret = gen8_ppgtt_alloc_page_directories(vm, pdp, start, length,

						new_page_dirs);

	if (ret) {

		free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);

		free_gen8_temp_bitmaps(new_page_dirs, new_page_tables);

		return ret;

	}



	/* For every page directory referenced, allocate page tables */

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

		ret = gen8_ppgtt_alloc_pagetabs(vm, pd, start, length,

						new_page_tables[pdpe]);

						new_page_tables + pdpe * BITS_TO_LONGS(I915_PDES));

		if (ret)

			goto err_out;

	}
@@ -1316,20 +1302,21 @@ static int gen8_alloc_va_range_3lvl(struct i915_address_space *vm, 
		gen8_setup_page_directory(ppgtt, pdp, pd, pdpe);

	}



	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);

	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables);

	mark_tlbs_dirty(ppgtt);

	return 0;



err_out:

	while (pdpe--) {

		for_each_set_bit(temp, new_page_tables[pdpe], I915_PDES)

		for_each_set_bit(temp, new_page_tables + pdpe *

				BITS_TO_LONGS(I915_PDES), I915_PDES)

			free_pt(dev, pdp->page_directory[pdpe]->page_table[temp]);

	}



	for_each_set_bit(pdpe, new_page_dirs, pdpes)

		free_pd(dev, pdp->page_directory[pdpe]);



	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);

	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables);

	mark_tlbs_dirty(ppgtt);

	return ret;

}
@@ -1481,7 +1468,7 @@ static void gen8_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m) 


static int gen8_preallocate_top_level_pdps(struct i915_hw_ppgtt *ppgtt)

{

	unsigned long *new_page_dirs, **new_page_tables;

	unsigned long *new_page_dirs, *new_page_tables;

	uint32_t pdpes = I915_PDPES_PER_PDP(dev);

	int ret;
@@ -1501,7 +1488,7 @@ static int gen8_preallocate_top_level_pdps(struct i915_hw_ppgtt *ppgtt) 
	if (!ret)

		*ppgtt->pdp.used_pdpes = *new_page_dirs;



	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);

	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables);



	return ret;

}

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