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Commit 6239901c authored by Chris Wilson's avatar Chris Wilson
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drm/i915/gtt: Use NULL to encode scratch shadow entries 

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: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190712094327.24437-6-chris@chris-wilson.co.uk
parent c03cbe4c
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Inline Side-by-side
Showing with 33 additions and 76 deletions
drivers/gpu/drm/i915/i915_gem_gtt.c
View file @ 6239901c
......@@ -710,7 +710,6 @@ static struct i915_page_table *alloc_pt(struct i915_address_space *vm)
}
atomic_set(&pt->used, 0);
return pt;
}
......@@ -718,13 +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;
}
......@@ -752,63 +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);
......@@ -912,7 +902,7 @@ 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]);
}
}
......@@ -924,7 +914,7 @@ 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]);
......@@ -942,7 +932,7 @@ 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);
......@@ -996,8 +986,6 @@ 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]))
......@@ -1016,8 +1004,6 @@ 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]))
......@@ -1046,8 +1032,6 @@ 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]))
......@@ -1068,7 +1052,7 @@ 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);
......@@ -1083,7 +1067,7 @@ 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;
......@@ -1115,7 +1099,7 @@ 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);
......@@ -1126,10 +1110,10 @@ 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;
......@@ -1179,7 +1163,7 @@ 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);
......@@ -1190,10 +1174,10 @@ 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;
......@@ -1529,7 +1513,7 @@ 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 +1542,19 @@ static void ppgtt_init(struct i915_ppgtt *ppgtt, struct intel_gt *gt)
ppgtt->vm.vma_ops.clear_pages = clear_pages;
}
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;
}
......
drivers/gpu/drm/i915/i915_gem_gtt.h
View file @ 6239901c
......@@ -609,7 +609,7 @@ 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 *
......
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