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Date: Fri, 2 Apr 2010 19:07:13 GMT
From: tip-bot for Peter Zijlstra <a.p.zijlstra@...llo.nl>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, eranian@...gle.com, hpa@...or.com,
mingo@...hat.com, a.p.zijlstra@...llo.nl, tglx@...utronix.de,
mingo@...e.hu
Subject: [tip:perf/core] perf, x86: Fix AMD hotplug & constraint initialization
Commit-ID: b38b24ead33417146e051453d04bf60b8d2d7e25
Gitweb: http://git.kernel.org/tip/b38b24ead33417146e051453d04bf60b8d2d7e25
Author: Peter Zijlstra <a.p.zijlstra@...llo.nl>
AuthorDate: Tue, 23 Mar 2010 19:31:15 +0100
Committer: Ingo Molnar <mingo@...e.hu>
CommitDate: Fri, 2 Apr 2010 19:30:02 +0200
perf, x86: Fix AMD hotplug & constraint initialization
Commit 3f6da39 ("perf: Rework and fix the arch CPU-hotplug hooks") moved
the amd northbridge allocation from CPUS_ONLINE to CPUS_PREPARE_UP
however amd_nb_id() doesn't work yet on prepare so it would simply bail
basically reverting to a state where we do not properly track node wide
constraints - causing weird perf results.
Fix up the AMD NorthBridge initialization code by allocating from
CPU_UP_PREPARE and installing it from CPU_STARTING once we have the
proper nb_id. It also properly deals with the allocation failing.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
[ robustify using amd_has_nb() ]
Signed-off-by: Stephane Eranian <eranian@...gle.com>
LKML-Reference: <1269353485.5109.48.camel@...ns>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
arch/x86/kernel/cpu/perf_event.c | 8 ++-
arch/x86/kernel/cpu/perf_event_amd.c | 80 ++++++++++++++++++++--------------
2 files changed, 52 insertions(+), 36 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 5fb490c..bd28cf9 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -158,7 +158,7 @@ struct x86_pmu {
struct perf_event *event);
struct event_constraint *event_constraints;
- void (*cpu_prepare)(int cpu);
+ int (*cpu_prepare)(int cpu);
void (*cpu_starting)(int cpu);
void (*cpu_dying)(int cpu);
void (*cpu_dead)(int cpu);
@@ -1333,11 +1333,12 @@ static int __cpuinit
x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
{
unsigned int cpu = (long)hcpu;
+ int ret = NOTIFY_OK;
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_UP_PREPARE:
if (x86_pmu.cpu_prepare)
- x86_pmu.cpu_prepare(cpu);
+ ret = x86_pmu.cpu_prepare(cpu);
break;
case CPU_STARTING:
@@ -1350,6 +1351,7 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
x86_pmu.cpu_dying(cpu);
break;
+ case CPU_UP_CANCELED:
case CPU_DEAD:
if (x86_pmu.cpu_dead)
x86_pmu.cpu_dead(cpu);
@@ -1359,7 +1361,7 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)
break;
}
- return NOTIFY_OK;
+ return ret;
}
static void __init pmu_check_apic(void)
diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c
index b87e0b6..db6f7d4 100644
--- a/arch/x86/kernel/cpu/perf_event_amd.c
+++ b/arch/x86/kernel/cpu/perf_event_amd.c
@@ -137,6 +137,13 @@ static inline int amd_is_nb_event(struct hw_perf_event *hwc)
return (hwc->config & 0xe0) == 0xe0;
}
+static inline int amd_has_nb(struct cpu_hw_events *cpuc)
+{
+ struct amd_nb *nb = cpuc->amd_nb;
+
+ return nb && nb->nb_id != -1;
+}
+
static void amd_put_event_constraints(struct cpu_hw_events *cpuc,
struct perf_event *event)
{
@@ -147,7 +154,7 @@ static void amd_put_event_constraints(struct cpu_hw_events *cpuc,
/*
* only care about NB events
*/
- if (!(nb && amd_is_nb_event(hwc)))
+ if (!(amd_has_nb(cpuc) && amd_is_nb_event(hwc)))
return;
/*
@@ -214,7 +221,7 @@ amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event)
/*
* if not NB event or no NB, then no constraints
*/
- if (!(nb && amd_is_nb_event(hwc)))
+ if (!(amd_has_nb(cpuc) && amd_is_nb_event(hwc)))
return &unconstrained;
/*
@@ -293,51 +300,55 @@ static struct amd_nb *amd_alloc_nb(int cpu, int nb_id)
return nb;
}
-static void amd_pmu_cpu_online(int cpu)
+static int amd_pmu_cpu_prepare(int cpu)
+{
+ struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
+
+ WARN_ON_ONCE(cpuc->amd_nb);
+
+ if (boot_cpu_data.x86_max_cores < 2)
+ return NOTIFY_OK;
+
+ cpuc->amd_nb = amd_alloc_nb(cpu, -1);
+ if (!cpuc->amd_nb)
+ return NOTIFY_BAD;
+
+ return NOTIFY_OK;
+}
+
+static void amd_pmu_cpu_starting(int cpu)
{
- struct cpu_hw_events *cpu1, *cpu2;
- struct amd_nb *nb = NULL;
+ struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
+ struct amd_nb *nb;
int i, nb_id;
if (boot_cpu_data.x86_max_cores < 2)
return;
- /*
- * function may be called too early in the
- * boot process, in which case nb_id is bogus
- */
nb_id = amd_get_nb_id(cpu);
- if (nb_id == BAD_APICID)
- return;
-
- cpu1 = &per_cpu(cpu_hw_events, cpu);
- cpu1->amd_nb = NULL;
+ WARN_ON_ONCE(nb_id == BAD_APICID);
raw_spin_lock(&amd_nb_lock);
for_each_online_cpu(i) {
- cpu2 = &per_cpu(cpu_hw_events, i);
- nb = cpu2->amd_nb;
- if (!nb)
+ nb = per_cpu(cpu_hw_events, i).amd_nb;
+ if (WARN_ON_ONCE(!nb))
continue;
- if (nb->nb_id == nb_id)
- goto found;
- }
- nb = amd_alloc_nb(cpu, nb_id);
- if (!nb) {
- pr_err("perf_events: failed NB allocation for CPU%d\n", cpu);
- raw_spin_unlock(&amd_nb_lock);
- return;
+ if (nb->nb_id == nb_id) {
+ kfree(cpuc->amd_nb);
+ cpuc->amd_nb = nb;
+ break;
+ }
}
-found:
- nb->refcnt++;
- cpu1->amd_nb = nb;
+
+ cpuc->amd_nb->nb_id = nb_id;
+ cpuc->amd_nb->refcnt++;
raw_spin_unlock(&amd_nb_lock);
}
-static void amd_pmu_cpu_offline(int cpu)
+static void amd_pmu_cpu_dead(int cpu)
{
struct cpu_hw_events *cpuhw;
@@ -349,8 +360,10 @@ static void amd_pmu_cpu_offline(int cpu)
raw_spin_lock(&amd_nb_lock);
if (cpuhw->amd_nb) {
- if (--cpuhw->amd_nb->refcnt == 0)
- kfree(cpuhw->amd_nb);
+ struct amd_nb *nb = cpuhw->amd_nb;
+
+ if (nb->nb_id == -1 || --nb->refcnt == 0)
+ kfree(nb);
cpuhw->amd_nb = NULL;
}
@@ -379,8 +392,9 @@ static __initconst struct x86_pmu amd_pmu = {
.get_event_constraints = amd_get_event_constraints,
.put_event_constraints = amd_put_event_constraints,
- .cpu_prepare = amd_pmu_cpu_online,
- .cpu_dead = amd_pmu_cpu_offline,
+ .cpu_prepare = amd_pmu_cpu_prepare,
+ .cpu_starting = amd_pmu_cpu_starting,
+ .cpu_dead = amd_pmu_cpu_dead,
};
static __init int amd_pmu_init(void)
--
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