[Intel-gfx] [PATCH 07/11] drm/i915/gtt: Use NULL to encode scratch shadow entries
Chris Wilson
chris at chris-wilson.co.uk
Sun Jul 7 21:00:20 UTC 2019
We can simplify our gtt walking code by comparing against NULL for
scratch entries as opposed to looking up the distinct per-level scratch
pointer.
The only caveat is to remember to protect external parties and map the
NULL to the scratch top pd.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 124 +++++++++-------------------
drivers/gpu/drm/i915/i915_gem_gtt.h | 2 +-
2 files changed, 41 insertions(+), 85 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index b7882f06214a..a99b89502a90 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -596,18 +596,17 @@ static void cleanup_page_dma(struct i915_address_space *vm,
#define kmap_atomic_px(px) kmap_atomic(px_base(px)->page)
-#define fill_px(px, v) fill_page_dma(px_base(px), (v))
-#define fill32_px(px, v) fill_page_dma_32(px_base(px), (v))
-
-static void fill_page_dma(struct i915_page_dma *p, const u64 val)
+static void
+fill_page_dma(struct i915_page_dma *p, const u64 val, unsigned int count)
{
- kunmap_atomic(memset64(kmap_atomic(p->page), val, I915_PDES));
+ kunmap_atomic(memset64(kmap_atomic(p->page), val, count));
}
-static void fill_page_dma_32(struct i915_page_dma *p, const u32 v)
-{
- fill_page_dma(p, (u64)v << 32 | v);
-}
+#define fill_px(px, v) fill_page_dma(px_base(px), (v), I915_PDES)
+#define fill32_px(px, v) do { \
+ u64 vv = lower_32_bits(v); \
+ fill_px(px, vv << 32 | vv); \
+} while (0)
static int
setup_scratch_page(struct i915_address_space *vm, gfp_t gfp)
@@ -711,7 +710,6 @@ static struct i915_page_table *alloc_pt(struct i915_address_space *vm)
}
atomic_set(&pt->used, 0);
-
return pt;
}
@@ -719,13 +717,11 @@ static struct i915_page_directory *__alloc_pd(void)
{
struct i915_page_directory *pd;
- pd = kmalloc(sizeof(*pd), I915_GFP_ALLOW_FAIL);
+ pd = kzalloc(sizeof(*pd), I915_GFP_ALLOW_FAIL);
if (unlikely(!pd))
return NULL;
- atomic_set(px_used(pd), 0);
spin_lock_init(&pd->lock);
-
return pd;
}
@@ -753,63 +749,56 @@ static void free_pd(struct i915_address_space *vm, struct i915_page_dma *pd)
#define free_px(vm, px) free_pd(vm, px_base(px))
-static void init_pd(struct i915_page_directory *pd,
- struct i915_page_scratch *scratch)
-{
- fill_px(pd, scratch->encode);
- memset_p(pd->entry, scratch, 512);
-}
-
static inline void
write_dma_entry(struct i915_page_dma * const pdma,
- const unsigned short pde,
+ const unsigned short idx,
const u64 encoded_entry)
{
u64 * const vaddr = kmap_atomic(pdma->page);
- vaddr[pde] = encoded_entry;
+ vaddr[idx] = encoded_entry;
kunmap_atomic(vaddr);
}
static inline void
__set_pd_entry(struct i915_page_directory * const pd,
- const unsigned short pde,
+ const unsigned short idx,
struct i915_page_dma * const to,
u64 (*encode)(const dma_addr_t, const enum i915_cache_level))
{
GEM_BUG_ON(atomic_read(px_used(pd)) > 512);
atomic_inc(px_used(pd));
- pd->entry[pde] = to;
- write_dma_entry(px_base(pd), pde, encode(to->daddr, I915_CACHE_LLC));
+ pd->entry[idx] = to;
+ write_dma_entry(px_base(pd), idx, encode(to->daddr, I915_CACHE_LLC));
}
-#define set_pd_entry(pd, pde, to) \
- __set_pd_entry((pd), (pde), px_base(to), gen8_pde_encode)
+#define set_pd_entry(pd, idx, to) \
+ __set_pd_entry((pd), (idx), px_base(to), gen8_pde_encode)
static inline void
clear_pd_entry(struct i915_page_directory * const pd,
- const unsigned short pde,
- struct i915_page_scratch * const scratch)
+ const unsigned short idx,
+ const struct i915_page_scratch * const scratch)
{
GEM_BUG_ON(atomic_read(px_used(pd)) == 0);
- write_dma_entry(px_base(pd), pde, scratch->encode);
- pd->entry[pde] = scratch;
+ write_dma_entry(px_base(pd), idx, scratch->encode);
+ pd->entry[idx] = NULL;
atomic_dec(px_used(pd));
}
static bool
release_pd_entry(struct i915_page_directory * const pd,
- const unsigned short pde,
+ const unsigned short idx,
struct i915_page_table * const pt,
- struct i915_page_scratch * const scratch)
+ const struct i915_page_scratch * const scratch)
{
bool free = false;
spin_lock(&pd->lock);
if (atomic_dec_and_test(&pt->used)) {
- clear_pd_entry(pd, pde, scratch);
+ clear_pd_entry(pd, idx, scratch);
free = true;
}
spin_unlock(&pd->lock);
@@ -910,7 +899,7 @@ static void gen8_free_page_tables(struct i915_address_space *vm,
int i;
for (i = 0; i < I915_PDES; i++) {
- if (pd->entry[i] != &vm->scratch[1])
+ if (pd->entry[i])
free_pd(vm, pd->entry[i]);
}
}
@@ -922,7 +911,7 @@ static void gen8_ppgtt_cleanup_3lvl(struct i915_address_space *vm,
int i;
for (i = 0; i < pdpes; i++) {
- if (pdp->entry[i] == &vm->scratch[2])
+ if (!pdp->entry[i])
continue;
gen8_free_page_tables(vm, pdp->entry[i]);
@@ -940,7 +929,7 @@ static void gen8_ppgtt_cleanup_4lvl(struct i915_ppgtt *ppgtt)
for (i = 0; i < GEN8_PML4ES_PER_PML4; i++) {
struct i915_page_directory *pdp = i915_pdp_entry(pml4, i);
- if (px_base(pdp) == px_base(&ppgtt->vm.scratch[3]))
+ if (!pdp)
continue;
gen8_ppgtt_cleanup_3lvl(&ppgtt->vm, pdp);
@@ -994,8 +983,6 @@ static void gen8_ppgtt_clear_pd(struct i915_address_space *vm,
u32 pde;
gen8_for_each_pde(pt, pd, start, length, pde) {
- GEM_BUG_ON(px_base(pt) == px_base(&vm->scratch[1]));
-
atomic_inc(&pt->used);
gen8_ppgtt_clear_pt(vm, pt, start, length);
if (release_pd_entry(pd, pde, pt, &vm->scratch[1]))
@@ -1014,8 +1001,6 @@ static void gen8_ppgtt_clear_pdp(struct i915_address_space *vm,
unsigned int pdpe;
gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
- GEM_BUG_ON(px_base(pd) == px_base(&vm->scratch[2]));
-
atomic_inc(px_used(pd));
gen8_ppgtt_clear_pd(vm, pd, start, length);
if (release_pd_entry(pdp, pdpe, &pd->pt, &vm->scratch[2]))
@@ -1044,8 +1029,6 @@ 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) {
- GEM_BUG_ON(px_base(pdp) == px_base(&vm->scratch[3]));
-
atomic_inc(px_used(pdp));
gen8_ppgtt_clear_pdp(vm, pdp, start, length);
if (release_pd_entry(pml4, pml4e, &pdp->pt, &vm->scratch[3]))
@@ -1066,7 +1049,7 @@ static int gen8_ppgtt_alloc_pd(struct i915_address_space *vm,
gen8_for_each_pde(pt, pd, start, length, pde) {
const int count = gen8_pte_count(start, length);
- if (px_base(pt) == px_base(&vm->scratch[1])) {
+ if (!pt) {
spin_unlock(&pd->lock);
pt = fetch_and_zero(&alloc);
@@ -1081,7 +1064,7 @@ static int gen8_ppgtt_alloc_pd(struct i915_address_space *vm,
fill_px(pt, vm->scratch[0].encode);
spin_lock(&pd->lock);
- if (pd->entry[pde] == &vm->scratch[1]) {
+ if (!pd->entry[pde]) {
set_pd_entry(pd, pde, pt);
} else {
alloc = pt;
@@ -1113,7 +1096,7 @@ static int gen8_ppgtt_alloc_pdp(struct i915_address_space *vm,
spin_lock(&pdp->lock);
gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
- if (px_base(pd) == px_base(&vm->scratch[2])) {
+ if (!pd) {
spin_unlock(&pdp->lock);
pd = fetch_and_zero(&alloc);
@@ -1124,10 +1107,10 @@ static int gen8_ppgtt_alloc_pdp(struct i915_address_space *vm,
goto unwind;
}
- init_pd(pd, &vm->scratch[1]);
+ fill_px(pd, vm->scratch[1].encode);
spin_lock(&pdp->lock);
- if (pdp->entry[pdpe] == &vm->scratch[2]) {
+ if (!pdp->entry[pdpe]) {
set_pd_entry(pdp, pdpe, pd);
} else {
alloc = pd;
@@ -1177,7 +1160,7 @@ static int gen8_ppgtt_alloc_4lvl(struct i915_address_space *vm,
spin_lock(&pml4->lock);
gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) {
- if (px_base(pdp) == px_base(&vm->scratch[3])) {
+ if (!pdp) {
spin_unlock(&pml4->lock);
pdp = fetch_and_zero(&alloc);
@@ -1188,10 +1171,10 @@ static int gen8_ppgtt_alloc_4lvl(struct i915_address_space *vm,
goto unwind;
}
- init_pd(pdp, &vm->scratch[2]);
+ fill_px(pdp, vm->scratch[2].encode);
spin_lock(&pml4->lock);
- if (pml4->entry[pml4e] == &vm->scratch[3]) {
+ if (!pml4->entry[pml4e]) {
set_pd_entry(pml4, pml4e, pdp);
} else {
alloc = pdp;
@@ -1527,7 +1510,7 @@ static int gen8_preallocate_top_level_pdp(struct i915_ppgtt *ppgtt)
if (IS_ERR(pd))
goto unwind;
- init_pd(pd, &vm->scratch[1]);
+ fill_px(pd, vm->scratch[1].encode);
set_pd_entry(pdp, pdpe, pd);
}
@@ -1558,46 +1541,19 @@ static void ppgtt_init(struct i915_ppgtt *ppgtt, struct intel_gt *gt)
ppgtt->vm.top = i915_vm_is_4lvl(&ppgtt->vm) ? 3 : 2;
}
-static void init_pd_n(struct i915_address_space *vm,
- struct i915_page_directory *pd,
- struct i915_page_scratch *scratch,
- const unsigned int entries)
-{
- u64 * const vaddr = kmap_atomic_px(pd);
-
- memset64(vaddr, scratch->encode, entries);
- kunmap_atomic(vaddr);
-
- memset_p(pd->entry, scratch, entries);
-}
-
static struct i915_page_directory *
gen8_alloc_top_pd(struct i915_address_space *vm)
{
+ const unsigned int count = vm->total >> __gen8_pte_shift(vm->top);
struct i915_page_directory *pd;
- if (i915_vm_is_4lvl(vm)) {
- pd = alloc_pd(vm);
- if (!IS_ERR(pd))
- init_pd(pd, &vm->scratch[3]);
+ GEM_BUG_ON(count > ARRAY_SIZE(pd->entry));
+ pd = alloc_pd(vm);
+ if (IS_ERR(pd))
return pd;
- }
-
- /* 3lvl */
- pd = __alloc_pd();
- if (!pd)
- return ERR_PTR(-ENOMEM);
-
- pd->entry[GEN8_3LVL_PDPES] = NULL;
-
- if (unlikely(setup_page_dma(vm, px_base(pd)))) {
- kfree(pd);
- return ERR_PTR(-ENOMEM);
- }
-
- init_pd_n(vm, pd, &vm->scratch[2], GEN8_3LVL_PDPES);
+ fill_page_dma(px_base(pd), vm->scratch[vm->top].encode, count);
return pd;
}
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index 669b204d4c13..2341944b9b17 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -610,7 +610,7 @@ i915_page_dir_dma_addr(const struct i915_ppgtt *ppgtt, const unsigned int n)
{
struct i915_page_dma *pt = ppgtt->pd->entry[n];
- return px_dma(pt);
+ return px_dma(pt ?: px_base(&ppgtt->vm.scratch[ppgtt->vm.top]));
}
static inline struct i915_ggtt *
--
2.20.1
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