[PATCH 10/23] drm/i915/gtt: Recursive ppgtt clear for gen8
Chris Wilson
chris at chris-wilson.co.uk
Mon Jul 8 10:00:37 UTC 2019
With an explicit level, we can refactor the separate clear functions
as a simple recursive function. The additional knowledge of the level
allows us to spot when we can free an entire subtree at once.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/Kconfig.debug | 15 +++
drivers/gpu/drm/i915/i915_gem_gtt.c | 154 ++++++++++++++++------------
2 files changed, 105 insertions(+), 64 deletions(-)
diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug
index 8d922bb4d953..ed8c787058a5 100644
--- a/drivers/gpu/drm/i915/Kconfig.debug
+++ b/drivers/gpu/drm/i915/Kconfig.debug
@@ -94,6 +94,21 @@ config DRM_I915_TRACE_GEM
If in doubt, say "N".
+config DRM_I915_TRACE_GTT
+ bool "Insert extra ftrace output from the GTT internals"
+ depends on DRM_I915_DEBUG_GEM
+ select TRACING
+ default n
+ help
+ Enable additional and verbose debugging output that will spam
+ ordinary tests, but may be vital for post-mortem debugging when
+ used with /proc/sys/kernel/ftrace_dump_on_oops
+
+ Recommended for driver developers only.
+
+ If in doubt, say "N".
+
+
config DRM_I915_SW_FENCE_DEBUG_OBJECTS
bool "Enable additional driver debugging for fence objects"
depends on DRM_I915
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 0625b07a1132..e2d6169a8a66 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -46,6 +46,12 @@
#define I915_GFP_ALLOW_FAIL (GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN)
+#if IS_ENABLED(CONFIG_DRM_I915_TRACE_GTT)
+#define DBG(...) trace_printk(__VA_ARGS__)
+#else
+#define DBG(...)
+#endif
+
/**
* DOC: Global GTT views
*
@@ -796,6 +802,9 @@ release_pd_entry(struct i915_page_directory * const pd,
{
bool free = false;
+ if (atomic_add_unless(&pt->used, -1, 1))
+ return false;
+
spin_lock(&pd->lock);
if (atomic_dec_and_test(&pt->used)) {
clear_pd_entry(pd, idx, scratch);
@@ -924,86 +933,101 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
free_scratch(vm);
}
-/* 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 void gen8_ppgtt_clear_pt(const struct i915_address_space *vm,
- struct i915_page_table *pt,
- u64 start, u64 length)
+static u64 __gen8_ppgtt_clear(struct i915_address_space * const vm,
+ struct i915_page_directory * const pd,
+ u64 start, const u64 end, int lvl)
{
- const unsigned int num_entries = gen8_pte_count(start, length);
- gen8_pte_t *vaddr;
+ const struct i915_page_scratch * const scratch = &vm->scratch[lvl];
+ unsigned int idx, len;
- vaddr = kmap_atomic_px(pt);
- memset64(vaddr + gen8_pte_index(start),
- vm->scratch[0].encode,
- num_entries);
- kunmap_atomic(vaddr);
+ len = gen8_pd_range(start, end, lvl--, &idx);
+ DBG("%s(%p):{ lvl:%d, start:%llx, end:%llx, idx:%d, len:%d, used:%d}\n",
+ __func__, vm, lvl + 1, start, end,
+ idx, len, atomic_read(px_used(pd)));
+ GEM_BUG_ON(!len || len >= atomic_read(px_used(pd)));
- GEM_BUG_ON(num_entries > atomic_read(&pt->used));
+ do {
+ struct i915_page_table *pt = pd->entry[idx];
+
+ if (atomic_fetch_inc(&pt->used) >> gen8_pd_shift(1) &&
+ gen8_pd_subsumes(start, end, lvl)) {
+ DBG("%s(%p):{ lvl:%d, idx:%d, start:%llx, end:%llx } removing pd\n",
+ __func__, vm, lvl + 1, idx, start, end);
+ clear_pd_entry(pd, idx, scratch);
+ __gen8_ppgtt_cleanup(vm, as_pd(pt), I915_PDES, lvl);
+ start += (u64)I915_PDES << gen8_pd_shift(lvl);
+ continue;
+ }
- atomic_sub(num_entries, &pt->used);
-}
+ if (lvl) {
+ start = __gen8_ppgtt_clear(vm, as_pd(pt),
+ start, end, lvl);
+ } else {
+ unsigned int count;
+ u64 *vaddr;
-static void gen8_ppgtt_clear_pd(struct i915_address_space *vm,
- struct i915_page_directory *pd,
- u64 start, u64 length)
-{
- struct i915_page_table *pt;
- u32 pde;
+ count = gen8_pt_count(start, end);
+ DBG("%s(%p):{ lvl:%d, start:%llx, end:%llx, idx:%d, len:%d, used:%d} removing pte\n",
+ __func__, vm, lvl, start, end,
+ gen8_pd_index(start, 0), count,
+ atomic_read(&pt->used));
+ GEM_BUG_ON(!count || count >= atomic_read(&pt->used));
- gen8_for_each_pde(pt, pd, start, length, pde) {
- atomic_inc(&pt->used);
- gen8_ppgtt_clear_pt(vm, pt, start, length);
- if (release_pd_entry(pd, pde, pt, &vm->scratch[1]))
+ vaddr = kmap_atomic_px(pt);
+ memset64(vaddr + gen8_pd_index(start, 0),
+ vm->scratch[0].encode,
+ count);
+ kunmap_atomic(vaddr);
+
+ atomic_sub(count, &pt->used);
+ start += count;
+ }
+
+ if (release_pd_entry(pd, idx, pt, scratch))
free_px(vm, pt);
- }
+ } while (idx++, --len);
+
+ return start;
}
-/* 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 void gen8_ppgtt_clear_pdp(struct i915_address_space *vm,
- struct i915_page_directory * const pdp,
- u64 start, u64 length)
+static void gen8_ppgtt_clear(struct i915_address_space *vm,
+ u64 start, u64 length)
{
- struct i915_page_directory *pd;
- unsigned int pdpe;
+ GEM_BUG_ON(!IS_ALIGNED(start, BIT_ULL(GEN8_PTE_SHIFT)));
+ GEM_BUG_ON(!IS_ALIGNED(length, BIT_ULL(GEN8_PTE_SHIFT)));
- gen8_for_each_pdpe(pd, pdp, start, length, pdpe) {
- atomic_inc(px_used(pd));
- gen8_ppgtt_clear_pd(vm, pd, start, length);
- if (release_pd_entry(pdp, pdpe, &pd->pt, &vm->scratch[2]))
- free_px(vm, pd);
- }
+ start >>= GEN8_PTE_SHIFT;
+ length >>= GEN8_PTE_SHIFT;
+ GEM_BUG_ON(length == 0);
+
+ __gen8_ppgtt_clear(vm, i915_vm_to_ppgtt(vm)->pd,
+ start, start + length, vm->top);
}
-static void gen8_ppgtt_clear_3lvl(struct i915_address_space *vm,
- u64 start, u64 length)
+static void gen8_ppgtt_clear_pd(struct i915_address_space *vm,
+ struct i915_page_directory *pd,
+ u64 start, u64 length)
{
- gen8_ppgtt_clear_pdp(vm, i915_vm_to_ppgtt(vm)->pd, start, length);
+ GEM_BUG_ON(!IS_ALIGNED(start, BIT_ULL(GEN8_PTE_SHIFT)));
+ GEM_BUG_ON(!IS_ALIGNED(length, BIT_ULL(GEN8_PTE_SHIFT)));
+
+ start >>= GEN8_PTE_SHIFT;
+ length >>= GEN8_PTE_SHIFT;
+
+ __gen8_ppgtt_clear(vm, pd, start, start + length, 1);
}
-/* Removes entries from a single pml4.
- * This is the top-level structure in 4-level page tables used on gen8+.
- * Empty entries are always scratch pml4e.
- */
-static void gen8_ppgtt_clear_4lvl(struct i915_address_space *vm,
- u64 start, u64 length)
+static void gen8_ppgtt_clear_pdp(struct i915_address_space *vm,
+ struct i915_page_directory * const pdp,
+ u64 start, u64 length)
{
- struct i915_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
- struct i915_page_directory * const pml4 = ppgtt->pd;
- struct i915_page_directory *pdp;
- unsigned int pml4e;
+ GEM_BUG_ON(!IS_ALIGNED(start, BIT_ULL(GEN8_PTE_SHIFT)));
+ GEM_BUG_ON(!IS_ALIGNED(length, BIT_ULL(GEN8_PTE_SHIFT)));
- GEM_BUG_ON(!i915_vm_is_4lvl(vm));
+ start >>= GEN8_PTE_SHIFT;
+ length >>= GEN8_PTE_SHIFT;
- gen8_for_each_pml4e(pdp, pml4, start, length, pml4e) {
- atomic_inc(px_used(pdp));
- gen8_ppgtt_clear_pdp(vm, pdp, start, length);
- if (release_pd_entry(pml4, pml4e, &pdp->pt, &vm->scratch[3]))
- free_px(vm, pdp);
- }
+ __gen8_ppgtt_clear(vm, pdp, start, start + length, 2);
}
static int gen8_ppgtt_alloc_pd(struct i915_address_space *vm,
@@ -1168,7 +1192,7 @@ static int gen8_ppgtt_alloc_4lvl(struct i915_address_space *vm,
if (release_pd_entry(pml4, pml4e, &pdp->pt, &vm->scratch[3]))
free_px(vm, pdp);
unwind:
- gen8_ppgtt_clear_4lvl(vm, from, start - from);
+ gen8_ppgtt_clear(vm, from, start - from);
out:
if (alloc)
free_px(vm, alloc);
@@ -1481,6 +1505,7 @@ static int gen8_preallocate_top_level_pdp(struct i915_ppgtt *ppgtt)
fill_px(pd, vm->scratch[1].encode);
set_pd_entry(pdp, pdpe, pd);
+ atomic_inc(px_used(pd)); /* keep pinned */
}
return 0;
@@ -1523,6 +1548,7 @@ gen8_alloc_top_pd(struct i915_address_space *vm)
}
fill_page_dma(px_base(pd), vm->scratch[vm->top].encode, count);
+ atomic_inc(px_used(pd)); /* mark as pinned */
return pd;
}
@@ -1571,7 +1597,6 @@ static struct i915_ppgtt *gen8_ppgtt_create(struct drm_i915_private *i915)
if (i915_vm_is_4lvl(&ppgtt->vm)) {
ppgtt->vm.allocate_va_range = gen8_ppgtt_alloc_4lvl;
ppgtt->vm.insert_entries = gen8_ppgtt_insert_4lvl;
- ppgtt->vm.clear_range = gen8_ppgtt_clear_4lvl;
} else {
if (intel_vgpu_active(i915)) {
err = gen8_preallocate_top_level_pdp(ppgtt);
@@ -1581,9 +1606,10 @@ static struct i915_ppgtt *gen8_ppgtt_create(struct drm_i915_private *i915)
ppgtt->vm.allocate_va_range = gen8_ppgtt_alloc_3lvl;
ppgtt->vm.insert_entries = gen8_ppgtt_insert_3lvl;
- ppgtt->vm.clear_range = gen8_ppgtt_clear_3lvl;
}
+ ppgtt->vm.clear_range = gen8_ppgtt_clear;
+
if (intel_vgpu_active(i915))
gen8_ppgtt_notify_vgt(ppgtt, true);
--
2.20.1
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