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authorChris Wilson <chris@chris-wilson.co.uk>2019-10-09 17:09:06 +0100
committerRodrigo Vivi <rodrigo.vivi@intel.com>2019-10-09 14:39:31 -0700
commite137d3abdfca0fb6fc270da576a9d9d6a1f8d8b3 (patch)
treed19b413b597628c6d6c7a4cfc818460d6d6420f5
parent749085a2131f7e328dd33635eb3d37b519f451f9 (diff)
drm/i915/gt: execlists->active is serialised by the taskletdrm-intel-fixes-2019-10-10
The active/pending execlists is no longer protected by the engine->active.lock, but is serialised by the tasklet instead. Update the locking around the debug and stats to follow suit. v2: local_bh_disable() to prevent recursing into the tasklet in case we trigger a softirq (Tvrtko) Fixes: df403069029d ("drm/i915/execlists: Lift process_csb() out of the irq-off spinlock") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191009160906.16195-1-chris@chris-wilson.co.uk (cherry picked from commit c36eebd9ba5d70b84e1e7408ccc7632566f285c4) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
-rw-r--r--drivers/gpu/drm/i915/gt/intel_engine.h14
-rw-r--r--drivers/gpu/drm/i915/gt/intel_engine_cs.c16
-rw-r--r--drivers/gpu/drm/i915/i915_gem.h6
3 files changed, 27 insertions, 9 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_engine.h b/drivers/gpu/drm/i915/gt/intel_engine.h
index d3c6993f4f46..22aab8593abf 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine.h
@@ -136,6 +136,20 @@ execlists_active(const struct intel_engine_execlists *execlists)
return READ_ONCE(*execlists->active);
}
+static inline void
+execlists_active_lock_bh(struct intel_engine_execlists *execlists)
+{
+ local_bh_disable(); /* prevent local softirq and lock recursion */
+ tasklet_lock(&execlists->tasklet);
+}
+
+static inline void
+execlists_active_unlock_bh(struct intel_engine_execlists *execlists)
+{
+ tasklet_unlock(&execlists->tasklet);
+ local_bh_enable(); /* restore softirq, and kick ksoftirqd! */
+}
+
struct i915_request *
execlists_unwind_incomplete_requests(struct intel_engine_execlists *execlists);
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
index 82630db0394b..4ce8626b140e 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c
@@ -1197,9 +1197,7 @@ static void intel_engine_print_registers(struct intel_engine_cs *engine,
struct drm_printer *m)
{
struct drm_i915_private *dev_priv = engine->i915;
- const struct intel_engine_execlists * const execlists =
- &engine->execlists;
- unsigned long flags;
+ struct intel_engine_execlists * const execlists = &engine->execlists;
u64 addr;
if (engine->id == RENDER_CLASS && IS_GEN_RANGE(dev_priv, 4, 7))
@@ -1281,7 +1279,7 @@ static void intel_engine_print_registers(struct intel_engine_cs *engine,
idx, hws[idx * 2], hws[idx * 2 + 1]);
}
- spin_lock_irqsave(&engine->active.lock, flags);
+ execlists_active_lock_bh(execlists);
for (port = execlists->active; (rq = *port); port++) {
char hdr[80];
int len;
@@ -1309,7 +1307,7 @@ static void intel_engine_print_registers(struct intel_engine_cs *engine,
hwsp_seqno(rq));
print_request(m, rq, hdr);
}
- spin_unlock_irqrestore(&engine->active.lock, flags);
+ execlists_active_unlock_bh(execlists);
} else if (INTEL_GEN(dev_priv) > 6) {
drm_printf(m, "\tPP_DIR_BASE: 0x%08x\n",
ENGINE_READ(engine, RING_PP_DIR_BASE));
@@ -1440,8 +1438,8 @@ int intel_enable_engine_stats(struct intel_engine_cs *engine)
if (!intel_engine_supports_stats(engine))
return -ENODEV;
- spin_lock_irqsave(&engine->active.lock, flags);
- write_seqlock(&engine->stats.lock);
+ execlists_active_lock_bh(execlists);
+ write_seqlock_irqsave(&engine->stats.lock, flags);
if (unlikely(engine->stats.enabled == ~0)) {
err = -EBUSY;
@@ -1469,8 +1467,8 @@ int intel_enable_engine_stats(struct intel_engine_cs *engine)
}
unlock:
- write_sequnlock(&engine->stats.lock);
- spin_unlock_irqrestore(&engine->active.lock, flags);
+ write_sequnlock_irqrestore(&engine->stats.lock, flags);
+ execlists_active_unlock_bh(execlists);
return err;
}
diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index 167a7b56ed5b..6795f1daa3d5 100644
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -77,6 +77,12 @@ struct drm_i915_private;
#define I915_GEM_IDLE_TIMEOUT (HZ / 5)
+static inline void tasklet_lock(struct tasklet_struct *t)
+{
+ while (!tasklet_trylock(t))
+ cpu_relax();
+}
+
static inline void __tasklet_disable_sync_once(struct tasklet_struct *t)
{
if (!atomic_fetch_inc(&t->count))