[PATCH v2 06/11] perf/x86: Make WARNs consistent

[Peter Zijlstra <peterz@infradead.org>]

[-- Attachment #1: peterz-pmu-sched-5.patch --]
[-- Type: text/plain, Size: 2282 bytes --]

The commit_scheduling hook is pointlessly different from the start and
stop scheduling hook.

Furthermore, the constraint should never be NULL, so remove that test.
Even though we'll never get called (because we NULL the callbacks)
when !is_ht_workaround_enabled() put that test in.

Collapse the (pointless) WARN_ON_ONCE and bail on !cpuc->excl_cntrs --
this is doubly pointless, because its the same condition as
is_ht_workaround_enabled() which was already pointless because the
whole method won't ever be called.

Furthremore, make all the !excl_cntrs test WARN_ON_ONCE; they're all
pointless, because the above, either the function
({get,put}_excl_constraint) are already predicated on it existing or
the is_ht_workaround_enabled() thing is the same test.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kernel/cpu/perf_event_intel.c |   18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1915,7 +1915,7 @@ intel_start_scheduling(struct cpu_hw_eve
 	/*
 	 * no exclusion needed
 	 */
-	if (!excl_cntrs)
+	if (WARN_ON_ONCE(!excl_cntrs))
 		return;
 
 	xl = &excl_cntrs->states[tid];
@@ -1949,7 +1949,7 @@ intel_stop_scheduling(struct cpu_hw_even
 	/*
 	 * no exclusion needed
 	 */
-	if (!excl_cntrs)
+	if (WARN_ON_ONCE(!excl_cntrs))
 		return;
 
 	xl = &excl_cntrs->states[tid];
@@ -1985,7 +1985,7 @@ intel_get_excl_constraints(struct cpu_hw
 	/*
 	 * no exclusion needed
 	 */
-	if (!excl_cntrs)
+	if (WARN_ON_ONCE(!excl_cntrs))
 		return c;
 
 	/*
@@ -2121,9 +2121,7 @@ static void intel_put_excl_constraints(s
 	if (cpuc->is_fake)
 		return;
 
-	WARN_ON_ONCE(!excl_cntrs);
-
-	if (!excl_cntrs)
+	if (WARN_ON_ONCE(!excl_cntrs))
 		return;
 
 	xl = &excl_cntrs->states[tid];
@@ -2190,15 +2188,13 @@ static void intel_commit_scheduling(stru
 	struct intel_excl_states *xl;
 	int tid = cpuc->excl_thread_id;
 
-	if (cpuc->is_fake || !c)
+	if (cpuc->is_fake || !is_ht_workaround_enabled())
 		return;
 
-	if (!(c->flags & PERF_X86_EVENT_DYNAMIC))
+	if (WARN_ON_ONCE(!excl_cntrs))
 		return;
 
-	WARN_ON_ONCE(!excl_cntrs);
-
-	if (!excl_cntrs)
+	if (!(c->flags & PERF_X86_EVENT_DYNAMIC))
 		return;
 
 	xl = &excl_cntrs->states[tid];