Commit 1d1b5490 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gtt: Replace struct_mutex serialisation for allocation



Instead of relying on the caller holding struct_mutex across the
allocation, push the allocation under a tree of spinlocks stored inside
the page tables. Not only should this allow us to avoid struct_mutex
here, but it will allow multiple users to lock independent ranges for
concurrent allocations, and operate independently. This is vital for
pushing the GTT manipulation into a background thread where dependency
on struct_mutex is verboten, and for allowing other callers to avoid
struct_mutex altogether.

v2: Restore lost GEM_BUG_ON for removing too many PTE from
gen6_ppgtt_clear_range.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: default avatarMika Kuoppala <mika.kuoppala@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190604153830.19096-1-chris@chris-wilson.co.uk
parent 59ec84ec
......@@ -659,7 +659,7 @@ static struct i915_page_table *alloc_pt(struct i915_address_space *vm)
return ERR_PTR(-ENOMEM);
}
pt->used_ptes = 0;
atomic_set(&pt->used_ptes, 0);
return pt;
}
......@@ -694,7 +694,8 @@ static struct i915_page_directory *alloc_pd(struct i915_address_space *vm)
return ERR_PTR(-ENOMEM);
}
pd->used_pdes = 0;
atomic_set(&pd->used_pdes, 0);
spin_lock_init(&pd->lock);
return pd;
}
......@@ -725,6 +726,8 @@ static int __pdp_init(struct i915_address_space *vm,
memset_p((void **)pdp->page_directory, vm->scratch_pd, pdpes);
atomic_set(&pdp->used_pdpes, 0);
spin_lock_init(&pdp->lock);
return 0;
}
......@@ -779,11 +782,8 @@ static void free_pdp(struct i915_address_space *vm,
static void gen8_initialize_pdp(struct i915_address_space *vm,
struct i915_page_directory_pointer *pdp)
{
gen8_ppgtt_pdpe_t scratch_pdpe;
scratch_pdpe = gen8_pdpe_encode(px_dma(vm->scratch_pd), I915_CACHE_LLC);
fill_px(vm, pdp, scratch_pdpe);
fill_px(vm, pdp,
gen8_pdpe_encode(px_dma(vm->scratch_pd), I915_CACHE_LLC));
}
static void gen8_initialize_pml4(struct i915_address_space *vm,
......@@ -792,6 +792,7 @@ static void gen8_initialize_pml4(struct i915_address_space *vm,
fill_px(vm, pml4,
gen8_pml4e_encode(px_dma(vm->scratch_pdp), I915_CACHE_LLC));
memset_p((void **)pml4->pdps, vm->scratch_pdp, GEN8_PML4ES_PER_PML4);
spin_lock_init(&pml4->lock);
}
/*
......@@ -815,17 +816,12 @@ static bool gen8_ppgtt_clear_pt(const struct i915_address_space *vm,
unsigned int num_entries = gen8_pte_count(start, length);
gen8_pte_t *vaddr;
GEM_BUG_ON(num_entries > pt->used_ptes);
pt->used_ptes -= num_entries;
if (!pt->used_ptes)
return true;
vaddr = kmap_atomic_px(pt);
memset64(vaddr + gen8_pte_index(start), vm->scratch_pte, num_entries);
kunmap_atomic(vaddr);
return false;
GEM_BUG_ON(num_entries > atomic_read(&pt->used_ptes));
return !atomic_sub_return(num_entries, &pt->used_ptes);
}
static void gen8_ppgtt_set_pde(struct i915_address_space *vm,
......@@ -835,8 +831,6 @@ static void gen8_ppgtt_set_pde(struct i915_address_space *vm,
{
gen8_pde_t *vaddr;
pd->page_table[pde] = pt;
vaddr = kmap_atomic_px(pd);
vaddr[pde] = gen8_pde_encode(px_dma(pt), I915_CACHE_LLC);
kunmap_atomic(vaddr);
......@@ -850,19 +844,28 @@ 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;
gen8_ppgtt_set_pde(vm, pd, vm->scratch_pt, pde);
GEM_BUG_ON(!pd->used_pdes);
pd->used_pdes--;
spin_lock(&pd->lock);
if (!atomic_read(&pt->used_ptes)) {
gen8_ppgtt_set_pde(vm, pd, vm->scratch_pt, pde);
pd->page_table[pde] = vm->scratch_pt;
free_pt(vm, pt);
GEM_BUG_ON(!atomic_read(&pd->used_pdes));
atomic_dec(&pd->used_pdes);
free = true;
}
spin_unlock(&pd->lock);
if (free)
free_pt(vm, pt);
}
return !pd->used_pdes;
return !atomic_read(&pd->used_pdes);
}
static void gen8_ppgtt_set_pdpe(struct i915_address_space *vm,
......@@ -872,7 +875,6 @@ static void gen8_ppgtt_set_pdpe(struct i915_address_space *vm,
{
gen8_ppgtt_pdpe_t *vaddr;
pdp->page_directory[pdpe] = pd;
if (!i915_vm_is_4lvl(vm))
return;
......@@ -892,19 +894,28 @@ 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;
gen8_ppgtt_set_pdpe(vm, pdp, vm->scratch_pd, pdpe);
GEM_BUG_ON(!pdp->used_pdpes);
pdp->used_pdpes--;
spin_lock(&pdp->lock);
if (!atomic_read(&pd->used_pdes)) {
gen8_ppgtt_set_pdpe(vm, pdp, vm->scratch_pd, pdpe);
pdp->page_directory[pdpe] = vm->scratch_pd;
free_pd(vm, pd);
GEM_BUG_ON(!atomic_read(&pdp->used_pdpes));
atomic_dec(&pdp->used_pdpes);
free = true;
}
spin_unlock(&pdp->lock);
if (free)
free_pd(vm, pd);
}
return !pdp->used_pdpes;
return !atomic_read(&pdp->used_pdpes);
}
static void gen8_ppgtt_clear_3lvl(struct i915_address_space *vm,
......@@ -919,8 +930,6 @@ static void gen8_ppgtt_set_pml4e(struct i915_pml4 *pml4,
{
gen8_ppgtt_pml4e_t *vaddr;
pml4->pdps[pml4e] = pdp;
vaddr = kmap_atomic_px(pml4);
vaddr[pml4e] = gen8_pml4e_encode(px_dma(pdp), I915_CACHE_LLC);
kunmap_atomic(vaddr);
......@@ -941,14 +950,21 @@ 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;
gen8_ppgtt_set_pml4e(pml4, vm->scratch_pdp, pml4e);
free_pdp(vm, pdp);
spin_lock(&pml4->lock);
if (!atomic_read(&pdp->used_pdpes)) {
gen8_ppgtt_set_pml4e(pml4, vm->scratch_pdp, pml4e);
pml4->pdps[pml4e] = vm->scratch_pdp;
free = true;
}
spin_unlock(&pml4->lock);
if (free)
free_pdp(vm, pdp);
}
}
......@@ -1373,27 +1389,38 @@ static int gen8_ppgtt_alloc_pd(struct i915_address_space *vm,
u64 from = start;
unsigned int pde;
spin_lock(&pd->lock);
gen8_for_each_pde(pt, pd, start, length, pde) {
int count = gen8_pte_count(start, length);
const int count = gen8_pte_count(start, length);
if (pt == vm->scratch_pt) {
pd->used_pdes++;
struct i915_page_table *old;
spin_unlock(&pd->lock);
pt = alloc_pt(vm);
if (IS_ERR(pt)) {
pd->used_pdes--;
if (IS_ERR(pt))
goto unwind;
}
if (count < GEN8_PTES || intel_vgpu_active(vm->i915))
gen8_initialize_pt(vm, pt);
gen8_ppgtt_set_pde(vm, pd, pt, pde);
GEM_BUG_ON(pd->used_pdes > I915_PDES);
old = cmpxchg(&pd->page_table[pde], vm->scratch_pt, pt);
if (old == vm->scratch_pt) {
gen8_ppgtt_set_pde(vm, pd, pt, pde);
atomic_inc(&pd->used_pdes);
} else {
free_pt(vm, pt);
pt = old;
}
spin_lock(&pd->lock);
}
pt->used_ptes += count;
atomic_add(count, &pt->used_ptes);
}
spin_unlock(&pd->lock);
return 0;
unwind:
......@@ -1410,35 +1437,54 @@ static int gen8_ppgtt_alloc_pdp(struct i915_address_space *vm,
unsigned int pdpe;
int ret;
spin_lock(&pdp->lock);
gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
if (pd == vm->scratch_pd) {
pdp->used_pdpes++;
struct i915_page_directory *old;
spin_unlock(&pdp->lock);
pd = alloc_pd(vm);
if (IS_ERR(pd)) {
pdp->used_pdpes--;
if (IS_ERR(pd))
goto unwind;
}
gen8_initialize_pd(vm, pd);
gen8_ppgtt_set_pdpe(vm, pdp, pd, pdpe);
GEM_BUG_ON(pdp->used_pdpes > i915_pdpes_per_pdp(vm));
old = cmpxchg(&pdp->page_directory[pdpe],
vm->scratch_pd, pd);
if (old == vm->scratch_pd) {
gen8_ppgtt_set_pdpe(vm, pdp, pd, pdpe);
atomic_inc(&pdp->used_pdpes);
} else {
free_pd(vm, pd);
pd = old;
}
spin_lock(&pdp->lock);
}
atomic_inc(&pd->used_pdes);
spin_unlock(&pdp->lock);
ret = gen8_ppgtt_alloc_pd(vm, pd, start, length);
if (unlikely(ret))
goto unwind_pd;
spin_lock(&pdp->lock);
atomic_dec(&pd->used_pdes);
}
spin_unlock(&pdp->lock);
return 0;
unwind_pd:
if (!pd->used_pdes) {
spin_lock(&pdp->lock);
if (atomic_dec_and_test(&pd->used_pdes)) {
gen8_ppgtt_set_pdpe(vm, pdp, vm->scratch_pd, pdpe);
GEM_BUG_ON(!pdp->used_pdpes);
pdp->used_pdpes--;
GEM_BUG_ON(!atomic_read(&pdp->used_pdpes));
atomic_dec(&pdp->used_pdpes);
free_pd(vm, pd);
}
spin_unlock(&pdp->lock);
unwind:
gen8_ppgtt_clear_pdp(vm, pdp, from, start - from);
return -ENOMEM;
......@@ -1461,28 +1507,50 @@ static int gen8_ppgtt_alloc_4lvl(struct i915_address_space *vm,
u32 pml4e;
int ret;
spin_lock(&pml4->lock);
gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) {
if (pml4->pdps[pml4e] == vm->scratch_pdp) {
if (pdp == vm->scratch_pdp) {
struct i915_page_directory_pointer *old;
spin_unlock(&pml4->lock);
pdp = alloc_pdp(vm);
if (IS_ERR(pdp))
goto unwind;
gen8_initialize_pdp(vm, pdp);
gen8_ppgtt_set_pml4e(pml4, pdp, pml4e);
old = cmpxchg(&pml4->pdps[pml4e], vm->scratch_pdp, pdp);
if (old == vm->scratch_pdp) {
gen8_ppgtt_set_pml4e(pml4, pdp, pml4e);
} else {
free_pdp(vm, pdp);
pdp = old;
}
spin_lock(&pml4->lock);
}
atomic_inc(&pdp->used_pdpes);
spin_unlock(&pml4->lock);
ret = gen8_ppgtt_alloc_pdp(vm, pdp, start, length);
if (unlikely(ret))
goto unwind_pdp;
spin_lock(&pml4->lock);
atomic_dec(&pdp->used_pdpes);
}
spin_unlock(&pml4->lock);
return 0;
unwind_pdp:
if (!pdp->used_pdpes) {
spin_lock(&pml4->lock);
if (atomic_dec_and_test(&pdp->used_pdpes)) {
gen8_ppgtt_set_pml4e(pml4, vm->scratch_pdp, pml4e);
free_pdp(vm, pdp);
}
spin_unlock(&pml4->lock);
unwind:
gen8_ppgtt_clear_4lvl(vm, from, start - from);
return -ENOMEM;
......@@ -1504,10 +1572,10 @@ static int gen8_preallocate_top_level_pdp(struct i915_hw_ppgtt *ppgtt)
gen8_initialize_pd(vm, pd);
gen8_ppgtt_set_pdpe(vm, pdp, pd, pdpe);
pdp->used_pdpes++;
atomic_inc(&pdp->used_pdpes);
}
pdp->used_pdpes++; /* never remove */
atomic_inc(&pdp->used_pdpes); /* never remove */
return 0;
unwind:
......@@ -1516,7 +1584,7 @@ unwind:
gen8_ppgtt_set_pdpe(vm, pdp, vm->scratch_pd, pdpe);
free_pd(vm, pd);
}
pdp->used_pdpes = 0;
atomic_set(&pdp->used_pdpes, 0);
return -ENOMEM;
}
......@@ -1688,9 +1756,8 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
num_entries -= count;
GEM_BUG_ON(count > pt->used_ptes);
pt->used_ptes -= count;
if (!pt->used_ptes)
GEM_BUG_ON(count > atomic_read(&pt->used_ptes));
if (!atomic_sub_return(count, &pt->used_ptes))
ppgtt->scan_for_unused_pt = true;
/*
......@@ -1760,28 +1827,41 @@ static int gen6_alloc_va_range(struct i915_address_space *vm,
wakeref = intel_runtime_pm_get(vm->i915);
spin_lock(&ppgtt->base.pd.lock);
gen6_for_each_pde(pt, &ppgtt->base.pd, start, length, pde) {
const unsigned int count = gen6_pte_count(start, length);
if (pt == vm->scratch_pt) {
struct i915_page_table *old;
spin_unlock(&ppgtt->base.pd.lock);
pt = alloc_pt(vm);
if (IS_ERR(pt))
goto unwind_out;
gen6_initialize_pt(vm, pt);
ppgtt->base.pd.page_table[pde] = pt;
if (i915_vma_is_bound(ppgtt->vma,
I915_VMA_GLOBAL_BIND)) {
gen6_write_pde(ppgtt, pde, pt);
flush = true;
old = cmpxchg(&ppgtt->base.pd.page_table[pde],
vm->scratch_pt, pt);
if (old == vm->scratch_pt) {
ppgtt->base.pd.page_table[pde] = pt;
if (i915_vma_is_bound(ppgtt->vma,
I915_VMA_GLOBAL_BIND)) {
gen6_write_pde(ppgtt, pde, pt);
flush = true;
}
} else {
free_pt(vm, pt);
pt = old;
}
GEM_BUG_ON(pt->used_ptes);
spin_lock(&ppgtt->base.pd.lock);
}
pt->used_ptes += count;
atomic_add(count, &pt->used_ptes);
}
spin_unlock(&ppgtt->base.pd.lock);
if (flush) {
mark_tlbs_dirty(&ppgtt->base);
......@@ -1822,6 +1902,7 @@ static int gen6_ppgtt_init_scratch(struct gen6_hw_ppgtt *ppgtt)
gen6_initialize_pt(vm, vm->scratch_pt);
gen6_for_all_pdes(unused, &ppgtt->base.pd, pde)
ppgtt->base.pd.page_table[pde] = vm->scratch_pt;
spin_lock_init(&ppgtt->base.pd.lock);
return 0;
}
......@@ -1950,7 +2031,7 @@ static void pd_vma_unbind(struct i915_vma *vma)
/* Free all no longer used page tables */
gen6_for_all_pdes(pt, &ppgtt->base.pd, pde) {
if (pt->used_ptes || pt == scratch_pt)
if (atomic_read(&pt->used_ptes) || pt == scratch_pt)
continue;
free_pt(&ppgtt->base.vm, pt);
......
......@@ -248,25 +248,28 @@ struct i915_page_dma {
struct i915_page_table {
struct i915_page_dma base;
unsigned int used_ptes;
atomic_t used_ptes;
};
struct i915_page_directory {
struct i915_page_dma base;
struct i915_page_table *page_table[I915_PDES]; /* PDEs */
unsigned int used_pdes;
atomic_t used_pdes;
spinlock_t lock;
};
struct i915_page_directory_pointer {
struct i915_page_dma base;
struct i915_page_directory **page_directory;
unsigned int used_pdpes;
atomic_t used_pdpes;
spinlock_t lock;
};
struct i915_pml4 {
struct i915_page_dma base;
struct i915_page_directory_pointer *pdps[GEN8_PML4ES_PER_PML4];
spinlock_t lock;
};
struct i915_vma_ops {
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment