[Intel-gfx] [CI] drm/i915/gtt: Pull global wc page stash under its own locking
Chris Wilson
chris at chris-wilson.co.uk
Wed Jul 4 18:24:26 UTC 2018
Currently, the wc-stash used for providing flushed WC pages ready for
constructing the page directories is assumed to be protected by the
struct_mutex. However, we want to remove this global lock and so must
install a replacement global lock for accessing the global wc-stash (the
per-vm stash continues to be guarded by the vm).
We need to push ahead on this patch due to an oversight in hastily
removing the struct_mutex guard around the igt_ppgtt_alloc selftest. No
matter, it will prove very useful (i.e. will be required) in the near
future.
v2: Restore the onstack stash so that we can drop the vm->mutex in
future across the allocation.
v3: Restore the lost pagevec_init of the onstack allocation, and repaint
function names.
v4: Reorder init so that we don't try and use i915_address_space before
it is ininitialised.
Fixes: 1f6f00238abf ("drm/i915/selftests: Drop struct_mutex around lowlevel pggtt allocation")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 2 +-
drivers/gpu/drm/i915/i915_gem_context.c | 2 +-
drivers/gpu/drm/i915/i915_gem_gtt.c | 210 +++++++++++-------
drivers/gpu/drm/i915/i915_gem_gtt.h | 10 +-
drivers/gpu/drm/i915/selftests/huge_pages.c | 2 +-
drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 2 +-
drivers/gpu/drm/i915/selftests/mock_gtt.c | 2 +-
7 files changed, 144 insertions(+), 86 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 2cefe4c30f88..e5a0a65ec2e9 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -952,7 +952,7 @@ struct i915_gem_mm {
/**
* Small stash of WC pages
*/
- struct pagevec wc_stash;
+ struct pagestash wc_stash;
/**
* tmpfs instance used for shmem backed objects
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index ccf463ab6562..985ef70d9416 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -374,7 +374,7 @@ i915_gem_create_context(struct drm_i915_private *dev_priv,
if (USES_FULL_PPGTT(dev_priv)) {
struct i915_hw_ppgtt *ppgtt;
- ppgtt = i915_ppgtt_create(dev_priv, file_priv, ctx->name);
+ ppgtt = i915_ppgtt_create(dev_priv, file_priv);
if (IS_ERR(ppgtt)) {
DRM_DEBUG_DRIVER("PPGTT setup failed (%ld)\n",
PTR_ERR(ppgtt));
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index c6aa761ca085..a60c4e67bf6f 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -375,37 +375,70 @@ static gen6_pte_t iris_pte_encode(dma_addr_t addr,
return pte;
}
+static void stash_init(struct pagestash *stash)
+{
+ pagevec_init(&stash->pvec);
+ spin_lock_init(&stash->lock);
+}
+
+static struct page *stash_pop_page(struct pagestash *stash)
+{
+ struct page *page = NULL;
+
+ spin_lock(&stash->lock);
+ if (likely(stash->pvec.nr))
+ page = stash->pvec.pages[--stash->pvec.nr];
+ spin_unlock(&stash->lock);
+
+ return page;
+}
+
+static void stash_push_pagevec(struct pagestash *stash, struct pagevec *pvec)
+{
+ int nr;
+
+ spin_lock(&stash->lock);
+
+ nr = min_t(int, pvec->nr, pagevec_space(&stash->pvec));
+ memcpy(stash->pvec.pages + stash->pvec.nr,
+ pvec->pages + pvec->nr - nr,
+ sizeof(pvec->pages[0]) * nr);
+ stash->pvec.nr += nr;
+
+ spin_unlock(&stash->lock);
+
+ pvec->nr -= nr;
+}
+
static struct page *vm_alloc_page(struct i915_address_space *vm, gfp_t gfp)
{
- struct pagevec *pvec = &vm->free_pages;
- struct pagevec stash;
+ struct pagevec stack;
+ struct page *page;
if (I915_SELFTEST_ONLY(should_fail(&vm->fault_attr, 1)))
i915_gem_shrink_all(vm->i915);
- if (likely(pvec->nr))
- return pvec->pages[--pvec->nr];
+ page = stash_pop_page(&vm->free_pages);
+ if (page)
+ return page;
if (!vm->pt_kmap_wc)
return alloc_page(gfp);
- /* A placeholder for a specific mutex to guard the WC stash */
- lockdep_assert_held(&vm->i915->drm.struct_mutex);
-
/* Look in our global stash of WC pages... */
- pvec = &vm->i915->mm.wc_stash;
- if (likely(pvec->nr))
- return pvec->pages[--pvec->nr];
+ page = stash_pop_page(&vm->i915->mm.wc_stash);
+ if (page)
+ return page;
/*
- * Otherwise batch allocate pages to amoritize cost of set_pages_wc.
+ * Otherwise batch allocate pages to amortize cost of set_pages_wc.
*
* We have to be careful as page allocation may trigger the shrinker
* (via direct reclaim) which will fill up the WC stash underneath us.
* So we add our WB pages into a temporary pvec on the stack and merge
* them into the WC stash after all the allocations are complete.
*/
- pagevec_init(&stash);
+ pagevec_init(&stack);
do {
struct page *page;
@@ -413,59 +446,67 @@ static struct page *vm_alloc_page(struct i915_address_space *vm, gfp_t gfp)
if (unlikely(!page))
break;
- stash.pages[stash.nr++] = page;
- } while (stash.nr < pagevec_space(pvec));
+ stack.pages[stack.nr++] = page;
+ } while (pagevec_space(&stack));
- if (stash.nr) {
- int nr = min_t(int, stash.nr, pagevec_space(pvec));
- struct page **pages = stash.pages + stash.nr - nr;
+ if (stack.nr && !set_pages_array_wc(stack.pages, stack.nr)) {
+ page = stack.pages[--stack.nr];
- if (nr && !set_pages_array_wc(pages, nr)) {
- memcpy(pvec->pages + pvec->nr,
- pages, sizeof(pages[0]) * nr);
- pvec->nr += nr;
- stash.nr -= nr;
- }
+ /* Merge spare WC pages to the global stash */
+ stash_push_pagevec(&vm->i915->mm.wc_stash, &stack);
+
+ /* Push any surplus WC pages onto the local VM stash */
+ if (stack.nr)
+ stash_push_pagevec(&vm->free_pages, &stack);
+ }
- pagevec_release(&stash);
+ /* Return unwanted leftovers */
+ if (unlikely(stack.nr)) {
+ WARN_ON_ONCE(set_pages_array_wb(stack.pages, stack.nr));
+ __pagevec_release(&stack);
}
- return likely(pvec->nr) ? pvec->pages[--pvec->nr] : NULL;
+ return page;
}
static void vm_free_pages_release(struct i915_address_space *vm,
bool immediate)
{
- struct pagevec *pvec = &vm->free_pages;
+ struct pagevec *pvec = &vm->free_pages.pvec;
+ struct pagevec stack;
+ lockdep_assert_held(&vm->free_pages.lock);
GEM_BUG_ON(!pagevec_count(pvec));
if (vm->pt_kmap_wc) {
- struct pagevec *stash = &vm->i915->mm.wc_stash;
-
- /* When we use WC, first fill up the global stash and then
+ /*
+ * When we use WC, first fill up the global stash and then
* only if full immediately free the overflow.
*/
+ stash_push_pagevec(&vm->i915->mm.wc_stash, pvec);
- lockdep_assert_held(&vm->i915->drm.struct_mutex);
- if (pagevec_space(stash)) {
- do {
- stash->pages[stash->nr++] =
- pvec->pages[--pvec->nr];
- if (!pvec->nr)
- return;
- } while (pagevec_space(stash));
-
- /* As we have made some room in the VM's free_pages,
- * we can wait for it to fill again. Unless we are
- * inside i915_address_space_fini() and must
- * immediately release the pages!
- */
- if (!immediate)
- return;
- }
+ /*
+ * As we have made some room in the VM's free_pages,
+ * we can wait for it to fill again. Unless we are
+ * inside i915_address_space_fini() and must
+ * immediately release the pages!
+ */
+ if (pvec->nr <= (immediate ? 0 : PAGEVEC_SIZE - 1))
+ return;
+ /*
+ * We have to drop the lock to allow ourselves to sleep,
+ * so take a copy of the pvec and clear the stash for
+ * others to use it as we sleep.
+ */
+ stack = *pvec;
+ pagevec_reinit(pvec);
+ spin_unlock(&vm->free_pages.lock);
+
+ pvec = &stack;
set_pages_array_wb(pvec->pages, pvec->nr);
+
+ spin_lock(&vm->free_pages.lock);
}
__pagevec_release(pvec);
@@ -481,8 +522,38 @@ static void vm_free_page(struct i915_address_space *vm, struct page *page)
* unconditional might_sleep() for everybody.
*/
might_sleep();
- if (!pagevec_add(&vm->free_pages, page))
+ spin_lock(&vm->free_pages.lock);
+ if (!pagevec_add(&vm->free_pages.pvec, page))
vm_free_pages_release(vm, false);
+ spin_unlock(&vm->free_pages.lock);
+}
+
+static void i915_address_space_init(struct i915_address_space *vm,
+ struct drm_i915_private *dev_priv)
+{
+ GEM_BUG_ON(!vm->total);
+ drm_mm_init(&vm->mm, 0, vm->total);
+ vm->mm.head_node.color = I915_COLOR_UNEVICTABLE;
+
+ stash_init(&vm->free_pages);
+
+ INIT_LIST_HEAD(&vm->active_list);
+ INIT_LIST_HEAD(&vm->inactive_list);
+ INIT_LIST_HEAD(&vm->unbound_list);
+
+ list_add_tail(&vm->global_link, &dev_priv->vm_list);
+}
+
+static void i915_address_space_fini(struct i915_address_space *vm)
+{
+ spin_lock(&vm->free_pages.lock);
+ if (pagevec_count(&vm->free_pages.pvec))
+ vm_free_pages_release(vm, true);
+ GEM_BUG_ON(pagevec_count(&vm->free_pages.pvec));
+ spin_unlock(&vm->free_pages.lock);
+
+ drm_mm_takedown(&vm->mm);
+ list_del(&vm->global_link);
}
static int __setup_page_dma(struct i915_address_space *vm,
@@ -1562,6 +1633,8 @@ static struct i915_hw_ppgtt *gen8_ppgtt_create(struct drm_i915_private *i915)
if (!ppgtt)
return ERR_PTR(-ENOMEM);
+ kref_init(&ppgtt->ref);
+
ppgtt->vm.i915 = i915;
ppgtt->vm.dma = &i915->drm.pdev->dev;
@@ -1569,6 +1642,8 @@ static struct i915_hw_ppgtt *gen8_ppgtt_create(struct drm_i915_private *i915)
1ULL << 48 :
1ULL << 32;
+ i915_address_space_init(&ppgtt->vm, i915);
+
/* There are only few exceptions for gen >=6. chv and bxt.
* And we are not sure about the latter so play safe for now.
*/
@@ -2068,11 +2143,15 @@ static struct i915_hw_ppgtt *gen6_ppgtt_create(struct drm_i915_private *i915)
if (!ppgtt)
return ERR_PTR(-ENOMEM);
+ kref_init(&ppgtt->base.ref);
+
ppgtt->base.vm.i915 = i915;
ppgtt->base.vm.dma = &i915->drm.pdev->dev;
ppgtt->base.vm.total = I915_PDES * GEN6_PTES * PAGE_SIZE;
+ i915_address_space_init(&ppgtt->base.vm, i915);
+
ppgtt->base.vm.allocate_va_range = gen6_alloc_va_range;
ppgtt->base.vm.clear_range = gen6_ppgtt_clear_range;
ppgtt->base.vm.insert_entries = gen6_ppgtt_insert_entries;
@@ -2105,30 +2184,6 @@ static struct i915_hw_ppgtt *gen6_ppgtt_create(struct drm_i915_private *i915)
return ERR_PTR(err);
}
-static void i915_address_space_init(struct i915_address_space *vm,
- struct drm_i915_private *dev_priv,
- const char *name)
-{
- drm_mm_init(&vm->mm, 0, vm->total);
- vm->mm.head_node.color = I915_COLOR_UNEVICTABLE;
-
- INIT_LIST_HEAD(&vm->active_list);
- INIT_LIST_HEAD(&vm->inactive_list);
- INIT_LIST_HEAD(&vm->unbound_list);
-
- list_add_tail(&vm->global_link, &dev_priv->vm_list);
- pagevec_init(&vm->free_pages);
-}
-
-static void i915_address_space_fini(struct i915_address_space *vm)
-{
- if (pagevec_count(&vm->free_pages))
- vm_free_pages_release(vm, true);
-
- drm_mm_takedown(&vm->mm);
- list_del(&vm->global_link);
-}
-
static void gtt_write_workarounds(struct drm_i915_private *dev_priv)
{
/* This function is for gtt related workarounds. This function is
@@ -2199,8 +2254,7 @@ __hw_ppgtt_create(struct drm_i915_private *i915)
struct i915_hw_ppgtt *
i915_ppgtt_create(struct drm_i915_private *i915,
- struct drm_i915_file_private *fpriv,
- const char *name)
+ struct drm_i915_file_private *fpriv)
{
struct i915_hw_ppgtt *ppgtt;
@@ -2208,8 +2262,6 @@ i915_ppgtt_create(struct drm_i915_private *i915,
if (IS_ERR(ppgtt))
return ppgtt;
- kref_init(&ppgtt->ref);
- i915_address_space_init(&ppgtt->vm, i915, name);
ppgtt->vm.file = fpriv;
trace_i915_ppgtt_create(&ppgtt->vm);
@@ -2788,7 +2840,7 @@ int i915_gem_init_aliasing_ppgtt(struct drm_i915_private *i915)
struct i915_hw_ppgtt *ppgtt;
int err;
- ppgtt = i915_ppgtt_create(i915, ERR_PTR(-EPERM), "[alias]");
+ ppgtt = i915_ppgtt_create(i915, ERR_PTR(-EPERM));
if (IS_ERR(ppgtt))
return PTR_ERR(ppgtt);
@@ -2918,7 +2970,7 @@ void i915_ggtt_cleanup_hw(struct drm_i915_private *dev_priv)
ggtt->vm.cleanup(&ggtt->vm);
- pvec = &dev_priv->mm.wc_stash;
+ pvec = &dev_priv->mm.wc_stash.pvec;
if (pvec->nr) {
set_pages_array_wb(pvec->pages, pvec->nr);
__pagevec_release(pvec);
@@ -3518,6 +3570,8 @@ int i915_ggtt_init_hw(struct drm_i915_private *dev_priv)
struct i915_ggtt *ggtt = &dev_priv->ggtt;
int ret;
+ stash_init(&dev_priv->mm.wc_stash);
+
INIT_LIST_HEAD(&dev_priv->vm_list);
/* Note that we use page colouring to enforce a guard page at the
@@ -3526,7 +3580,7 @@ int i915_ggtt_init_hw(struct drm_i915_private *dev_priv)
* and beyond the end of the GTT if we do not provide a guard.
*/
mutex_lock(&dev_priv->drm.struct_mutex);
- i915_address_space_init(&ggtt->vm, dev_priv, "[global]");
+ i915_address_space_init(&ggtt->vm, dev_priv);
if (!HAS_LLC(dev_priv) && !USES_PPGTT(dev_priv))
ggtt->vm.mm.color_adjust = i915_gtt_color_adjust;
mutex_unlock(&dev_priv->drm.struct_mutex);
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index 9a4824cae68d..f298e72b79ca 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -270,6 +270,11 @@ struct i915_vma_ops {
void (*clear_pages)(struct i915_vma *vma);
};
+struct pagestash {
+ spinlock_t lock;
+ struct pagevec pvec;
+};
+
struct i915_address_space {
struct drm_mm mm;
struct drm_i915_private *i915;
@@ -324,7 +329,7 @@ struct i915_address_space {
*/
struct list_head unbound_list;
- struct pagevec free_pages;
+ struct pagestash free_pages;
bool pt_kmap_wc;
/* FIXME: Need a more generic return type */
@@ -615,8 +620,7 @@ void i915_ggtt_cleanup_hw(struct drm_i915_private *dev_priv);
int i915_ppgtt_init_hw(struct drm_i915_private *dev_priv);
void i915_ppgtt_release(struct kref *kref);
struct i915_hw_ppgtt *i915_ppgtt_create(struct drm_i915_private *dev_priv,
- struct drm_i915_file_private *fpriv,
- const char *name);
+ struct drm_i915_file_private *fpriv);
void i915_ppgtt_close(struct i915_address_space *vm);
static inline void i915_ppgtt_get(struct i915_hw_ppgtt *ppgtt)
{
diff --git a/drivers/gpu/drm/i915/selftests/huge_pages.c b/drivers/gpu/drm/i915/selftests/huge_pages.c
index b5e87fcdcdae..39699939587d 100644
--- a/drivers/gpu/drm/i915/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/selftests/huge_pages.c
@@ -1694,7 +1694,7 @@ int i915_gem_huge_page_mock_selftests(void)
dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(39));
mutex_lock(&dev_priv->drm.struct_mutex);
- ppgtt = i915_ppgtt_create(dev_priv, ERR_PTR(-ENODEV), "mock");
+ ppgtt = i915_ppgtt_create(dev_priv, ERR_PTR(-ENODEV));
if (IS_ERR(ppgtt)) {
err = PTR_ERR(ppgtt);
goto out_unlock;
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index a7956ecc3e1f..4bfb0537f9be 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -1004,7 +1004,7 @@ static int exercise_ppgtt(struct drm_i915_private *dev_priv,
return PTR_ERR(file);
mutex_lock(&dev_priv->drm.struct_mutex);
- ppgtt = i915_ppgtt_create(dev_priv, file->driver_priv, "mock");
+ ppgtt = i915_ppgtt_create(dev_priv, file->driver_priv);
if (IS_ERR(ppgtt)) {
err = PTR_ERR(ppgtt);
goto out_unlock;
diff --git a/drivers/gpu/drm/i915/selftests/mock_gtt.c b/drivers/gpu/drm/i915/selftests/mock_gtt.c
index 6a7f4da7b523..0da5b8c6d912 100644
--- a/drivers/gpu/drm/i915/selftests/mock_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/mock_gtt.c
@@ -124,7 +124,7 @@ void mock_init_ggtt(struct drm_i915_private *i915)
ggtt->vm.vma_ops.set_pages = ggtt_set_pages;
ggtt->vm.vma_ops.clear_pages = clear_pages;
- i915_address_space_init(&ggtt->vm, i915, "global");
+ i915_address_space_init(&ggtt->vm, i915);
}
void mock_fini_ggtt(struct drm_i915_private *i915)
--
2.18.0
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