4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
commit 1aa6cfd33df492939b0be15ebdbcff1f8ae5ddb6 upstream.
The recent conversion to the hotplug state machine kept two mechanisms from
the original code:
1) The first_init logic which adds the number of online CPUs in a package
to the refcount. That's wrong because the callbacks are executed for
all online CPUs.
Remove it so the refcounting is correct.
2) The on_each_cpu() call to undo box->init() in the error handling
path. That's bogus because when the prepare callback fails no box has
been initialized yet.
Remove it.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Sebastian Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Cc: Yasuaki Ishimatsu <yasu.isimatu@xxxxxxxxx>
Fixes: 1a246b9f58c6 ("perf/x86/intel/uncore: Convert to hotplug state machine")
Link: http://lkml.kernel.org/r/20170131230141.298032324@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/events/intel/uncore.c | 44 +++--------------------------------------
1 file changed, 4 insertions(+), 40 deletions(-)
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -763,30 +763,6 @@ static void uncore_pmu_unregister(struct
pmu->registered = false;
}
-static void __uncore_exit_boxes(struct intel_uncore_type *type, int cpu)
-{
- struct intel_uncore_pmu *pmu = type->pmus;
- struct intel_uncore_box *box;
- int i, pkg;
-
- if (pmu) {
- pkg = topology_physical_package_id(cpu);
- for (i = 0; i < type->num_boxes; i++, pmu++) {
- box = pmu->boxes[pkg];
- if (box)
- uncore_box_exit(box);
- }
- }
-}
-
-static void uncore_exit_boxes(void *dummy)
-{
- struct intel_uncore_type **types;
-
- for (types = uncore_msr_uncores; *types; types++)
- __uncore_exit_boxes(*types++, smp_processor_id());
-}
-
static void uncore_free_boxes(struct intel_uncore_pmu *pmu)
{
int pkg;
@@ -1077,22 +1053,12 @@ static int uncore_cpu_dying(unsigned int
return 0;
}
-static int first_init;
-
static int uncore_cpu_starting(unsigned int cpu)
{
struct intel_uncore_type *type, **types = uncore_msr_uncores;
struct intel_uncore_pmu *pmu;
struct intel_uncore_box *box;
- int i, pkg, ncpus = 1;
-
- if (first_init) {
- /*
- * On init we get the number of online cpus in the package
- * and set refcount for all of them.
- */
- ncpus = cpumask_weight(topology_core_cpumask(cpu));
- }
+ int i, pkg;
pkg = topology_logical_package_id(cpu);
for (; *types; types++) {
@@ -1103,7 +1069,7 @@ static int uncore_cpu_starting(unsigned
if (!box)
continue;
/* The first cpu on a package activates the box */
- if (atomic_add_return(ncpus, &box->refcnt) == ncpus)
+ if (atomic_inc_return(&box->refcnt) == 1)
uncore_box_init(box);
}
}
@@ -1407,19 +1373,17 @@ static int __init intel_uncore_init(void
"PERF_X86_UNCORE_PREP",
uncore_cpu_prepare, NULL);
}
- first_init = 1;
+
cpuhp_setup_state(CPUHP_AP_PERF_X86_UNCORE_STARTING,
"AP_PERF_X86_UNCORE_STARTING",
uncore_cpu_starting, uncore_cpu_dying);
- first_init = 0;
+
cpuhp_setup_state(CPUHP_AP_PERF_X86_UNCORE_ONLINE,
"AP_PERF_X86_UNCORE_ONLINE",
uncore_event_cpu_online, uncore_event_cpu_offline);
return 0;
err:
- /* Undo box->init_box() */
- on_each_cpu_mask(&uncore_cpu_mask, uncore_exit_boxes, NULL, 1);
uncore_types_exit(uncore_msr_uncores);
uncore_pci_exit();
return ret;
--
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