* [PATCH v2] x86/perf: Use static_call for x86_pmu.guest_get_msrs
@ 2021-01-22 3:03 Like Xu
2021-01-25 10:55 ` Peter Zijlstra
0 siblings, 1 reply; 2+ messages in thread
From: Like Xu @ 2021-01-22 3:03 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Mark Rutland,
Alexander Shishkin, Jiri Olsa, Namhyung Kim, Thomas Gleixner,
Borislav Petkov, x86, H . Peter Anvin, linux-kernel
Clean up that CONFIG_RETPOLINE crud and replace the
indirect call x86_pmu.guest_get_msrs with static_call().
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Like Xu <like.xu@linux.intel.com>
---
arch/x86/events/core.c | 20 ++++++++++++++++++++
arch/x86/events/intel/core.c | 20 --------------------
arch/x86/include/asm/perf_event.h | 5 -----
3 files changed, 20 insertions(+), 25 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index e37de298a495..cf0a52c80408 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -81,6 +81,8 @@ DEFINE_STATIC_CALL_NULL(x86_pmu_swap_task_ctx, *x86_pmu.swap_task_ctx);
DEFINE_STATIC_CALL_NULL(x86_pmu_drain_pebs, *x86_pmu.drain_pebs);
DEFINE_STATIC_CALL_NULL(x86_pmu_pebs_aliases, *x86_pmu.pebs_aliases);
+DEFINE_STATIC_CALL_NULL(x86_pmu_guest_get_msrs, *x86_pmu.guest_get_msrs);
+
u64 __read_mostly hw_cache_event_ids
[PERF_COUNT_HW_CACHE_MAX]
[PERF_COUNT_HW_CACHE_OP_MAX]
@@ -665,6 +667,12 @@ void x86_pmu_disable_all(void)
}
}
+struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr)
+{
+ return static_call(x86_pmu_guest_get_msrs)(nr);
+}
+EXPORT_SYMBOL_GPL(perf_guest_get_msrs);
+
/*
* There may be PMI landing after enabled=0. The PMI hitting could be before or
* after disable_all.
@@ -1923,6 +1931,8 @@ static void x86_pmu_static_call_update(void)
static_call_update(x86_pmu_drain_pebs, x86_pmu.drain_pebs);
static_call_update(x86_pmu_pebs_aliases, x86_pmu.pebs_aliases);
+
+ static_call_update(x86_pmu_guest_get_msrs, x86_pmu.guest_get_msrs);
}
static void _x86_pmu_read(struct perf_event *event)
@@ -1930,6 +1940,13 @@ static void _x86_pmu_read(struct perf_event *event)
x86_perf_event_update(event);
}
+static inline struct perf_guest_switch_msr *
+perf_guest_get_msrs_nop(int *nr)
+{
+ *nr = 0;
+ return NULL;
+}
+
static int __init init_hw_perf_events(void)
{
struct x86_pmu_quirk *quirk;
@@ -2001,6 +2018,9 @@ static int __init init_hw_perf_events(void)
if (!x86_pmu.read)
x86_pmu.read = _x86_pmu_read;
+ if (!x86_pmu.guest_get_msrs)
+ x86_pmu.guest_get_msrs = perf_guest_get_msrs_nop;
+
x86_pmu_static_call_update();
/*
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index d4569bfa83e3..93adf53cce5f 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3680,26 +3680,6 @@ static int intel_pmu_hw_config(struct perf_event *event)
return 0;
}
-#ifdef CONFIG_RETPOLINE
-static struct perf_guest_switch_msr *core_guest_get_msrs(int *nr);
-static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr);
-#endif
-
-struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr)
-{
-#ifdef CONFIG_RETPOLINE
- if (x86_pmu.guest_get_msrs == intel_guest_get_msrs)
- return intel_guest_get_msrs(nr);
- else if (x86_pmu.guest_get_msrs == core_guest_get_msrs)
- return core_guest_get_msrs(nr);
-#endif
- if (x86_pmu.guest_get_msrs)
- return x86_pmu.guest_get_msrs(nr);
- *nr = 0;
- return NULL;
-}
-EXPORT_SYMBOL_GPL(perf_guest_get_msrs);
-
static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index b9a7fd0a27e2..fac31b4cd61c 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -483,11 +483,6 @@ static inline void perf_check_microcode(void) { }
extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr);
extern int x86_perf_get_lbr(struct x86_pmu_lbr *lbr);
#else
-static inline struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr)
-{
- *nr = 0;
- return NULL;
-}
static inline int x86_perf_get_lbr(struct x86_pmu_lbr *lbr)
{
return -1;
--
2.29.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] x86/perf: Use static_call for x86_pmu.guest_get_msrs
2021-01-22 3:03 [PATCH v2] x86/perf: Use static_call for x86_pmu.guest_get_msrs Like Xu
@ 2021-01-25 10:55 ` Peter Zijlstra
0 siblings, 0 replies; 2+ messages in thread
From: Peter Zijlstra @ 2021-01-25 10:55 UTC (permalink / raw)
To: Like Xu
Cc: Ingo Molnar, Arnaldo Carvalho de Melo, Mark Rutland,
Alexander Shishkin, Jiri Olsa, Namhyung Kim, Thomas Gleixner,
Borislav Petkov, x86, H . Peter Anvin, linux-kernel
On Fri, Jan 22, 2021 at 11:03:24AM +0800, Like Xu wrote:
> Clean up that CONFIG_RETPOLINE crud and replace the
> indirect call x86_pmu.guest_get_msrs with static_call().
>
Looks good in principle, but the robot complains about a missing func
decl. I think you removed a little too much when you killed the inline
thing.
^ permalink raw reply [flat|nested] 2+ messages in thread
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