[Intel-gfx] [PATCH 1/7] drm/i915: Allocate power domain set wakerefs dynamically

Imre Deak
2022-11-02T17:15:49Z

Since the intel_display_power_domain_set struct, currently its current
size close 1kB, can be allocated on the stack, it's better to allocate
the per-domain wakeref pointer array - used for debugging - within the
struct dynamically, so do this.

The memory freeing is guaranteed by the fact that the acquired domain
references tracked by struct can't be leaked either.

Signed-off-by: Imre Deak <imre.deak@intel.com>
---
.../drm/i915/display/intel_display_power.c | 61 ++++++++++++++++---
.../drm/i915/display/intel_display_power.h | 2 +-
2 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 4c1de91e56ff9..e2da91c2a9638 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -830,19 +830,58 @@ void intel_display_power_put_unchecked(struct drm_i915_private *dev_priv,
}
#endif

+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
+static intel_wakeref_t *
+get_debug_wakerefs(struct drm_i915_private *i915,
+ struct intel_display_power_domain_set *power_domain_set)
+{
+ if (power_domain_set->wakerefs)
+ return power_domain_set->wakerefs;
+
+ power_domain_set->wakerefs = kcalloc(POWER_DOMAIN_NUM,
+ sizeof(*power_domain_set->wakerefs),
+ GFP_KERNEL);
+
+ drm_WARN_ON_ONCE(&i915->drm, !power_domain_set->wakerefs);
+
+ return power_domain_set->wakerefs;
+}
+
+static void
+free_empty_debug_wakerefs(struct intel_display_power_domain_set *power_domain_set)
+{
+ if (power_domain_set->wakerefs &&
+ bitmap_empty(power_domain_set->mask.bits, POWER_DOMAIN_NUM))
+ kfree(fetch_and_zero(&power_domain_set->wakerefs));
+}
+#else
+static intel_wakeref_t *
+get_debug_wakerefs(struct drm_i915_private *i915,
+ struct intel_display_power_domain_set *power_domain_set)
+{
+ return NULL;
+}
+
+static void
+free_empty_debug_wakerefs(struct intel_display_power_domain_set *power_domain_set)
+{
+}
+#endif
+
void
intel_display_power_get_in_set(struct drm_i915_private *i915,
struct intel_display_power_domain_set *power_domain_set,
enum intel_display_power_domain domain)
{
intel_wakeref_t __maybe_unused wf;
+ intel_wakeref_t *debug_wakerefs = get_debug_wakerefs(i915, power_domain_set);

drm_WARN_ON(&i915->drm, test_bit(domain, power_domain_set->mask.bits));

wf = intel_display_power_get(i915, domain);
-#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
- power_domain_set->wakerefs[domain] = wf;
-#endif
+ if (debug_wakerefs)
+ debug_wakerefs[domain] = wf;
+
set_bit(domain, power_domain_set->mask.bits);
}

@@ -852,6 +891,7 @@ intel_display_power_get_in_set_if_enabled(struct drm_i915_private *i915,
enum intel_display_power_domain domain)
{
intel_wakeref_t wf;
+ intel_wakeref_t *debug_wakerefs = get_debug_wakerefs(i915, power_domain_set);

drm_WARN_ON(&i915->drm, test_bit(domain, power_domain_set->mask.bits));

@@ -859,9 +899,9 @@ intel_display_power_get_in_set_if_enabled(struct drm_i915_private *i915,
if (!wf)
return false;

-#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
- power_domain_set->wakerefs[domain] = wf;
-#endif
+ if (debug_wakerefs)
+ debug_wakerefs[domain] = wf;
+
set_bit(domain, power_domain_set->mask.bits);

return true;
@@ -873,6 +913,7 @@ intel_display_power_put_mask_in_set(struct drm_i915_private *i915,
struct intel_power_domain_mask *mask)
{
enum intel_display_power_domain domain;
+ intel_wakeref_t *debug_wakerefs = get_debug_wakerefs(i915, power_domain_set);

drm_WARN_ON(&i915->drm,
!bitmap_subset(mask->bits, power_domain_set->mask.bits, POWER_DOMAIN_NUM));
@@ -880,12 +921,14 @@ intel_display_power_put_mask_in_set(struct drm_i915_private *i915,
for_each_power_domain(domain, mask) {
intel_wakeref_t __maybe_unused wf = -1;

-#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
- wf = fetch_and_zero(&power_domain_set->wakerefs[domain]);
-#endif
+ if (debug_wakerefs)
+ wf = fetch_and_zero(&debug_wakerefs[domain]);
+
intel_display_power_put(i915, domain, wf);
clear_bit(domain, power_domain_set->mask.bits);
}
+
+ free_empty_debug_wakerefs(power_domain_set);
}

static int
diff --git a/drivers/gpu/drm/i915/display/intel_display_power.h b/drivers/gpu/drm/i915/display/intel_display_power.h
index 7136ea3f233e9..c847aab7b2f88 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.h
+++ b/drivers/gpu/drm/i915/display/intel_display_power.h
@@ -146,7 +146,7 @@ struct i915_power_domains {
struct intel_display_power_domain_set {
struct intel_power_domain_mask mask;
#ifdef CONFIG_DRM_I915_DEBUG_RUNTIME_PM
- intel_wakeref_t wakerefs[POWER_DOMAIN_NUM];
+ intel_wakeref_t *wakerefs;
#endif
};

--
2.37.1