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Date: Fri, 30 Oct 2020 16:13:47 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: mingo@...nel.org, tglx@...utronix.de, rostedt@...dmis.org
Cc: linux-kernel@...r.kernel.org, kan.liang@...ux.intel.com,
acme@...nel.org, mark.rutland@....com,
alexander.shishkin@...ux.intel.com, jolsa@...hat.com,
namhyung@...nel.org, ak@...ux.intel.com, eranian@...gle.com,
peterz@...radead.org
Subject: [PATCH 2/6] perf/x86: Reduce stack usage for x86_pmu::drain_pebs()
intel_pmu_drain_pebs_*() is typically called from handle_pmi_common(),
both have an on-stack struct perf_sample_data, which is *big*. Rewire
things so that drain_pebs() can use the one handle_pmi_common() has.
Reported-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
arch/x86/events/intel/core.c | 2 -
arch/x86/events/intel/ds.c | 47 ++++++++++++++++++++++---------------------
arch/x86/events/perf_event.h | 2 -
3 files changed, 27 insertions(+), 24 deletions(-)
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2630,7 +2630,7 @@ static int handle_pmi_common(struct pt_r
u64 pebs_enabled = cpuc->pebs_enabled;
handled++;
- x86_pmu.drain_pebs(regs);
+ x86_pmu.drain_pebs(regs, &data);
status &= x86_pmu.intel_ctrl | GLOBAL_STATUS_TRACE_TOPAPMI;
/*
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -670,7 +670,9 @@ int intel_pmu_drain_bts_buffer(void)
static inline void intel_pmu_drain_pebs_buffer(void)
{
- x86_pmu.drain_pebs(NULL);
+ struct perf_sample_data data;
+
+ x86_pmu.drain_pebs(NULL, &data);
}
/*
@@ -1719,19 +1721,20 @@ intel_pmu_save_and_restart_reload(struct
return 0;
}
-static void __intel_pmu_pebs_event(struct perf_event *event,
- struct pt_regs *iregs,
- void *base, void *top,
- int bit, int count,
- void (*setup_sample)(struct perf_event *,
- struct pt_regs *,
- void *,
- struct perf_sample_data *,
- struct pt_regs *))
+static __always_inline void
+__intel_pmu_pebs_event(struct perf_event *event,
+ struct pt_regs *iregs,
+ struct perf_sample_data *data,
+ void *base, void *top,
+ int bit, int count,
+ void (*setup_sample)(struct perf_event *,
+ struct pt_regs *,
+ void *,
+ struct perf_sample_data *,
+ struct pt_regs *))
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
- struct perf_sample_data data;
struct x86_perf_regs perf_regs;
struct pt_regs *regs = &perf_regs.regs;
void *at = get_next_pebs_record_by_bit(base, top, bit);
@@ -1752,14 +1755,14 @@ static void __intel_pmu_pebs_event(struc
iregs = &dummy_iregs;
while (count > 1) {
- setup_sample(event, iregs, at, &data, regs);
- perf_event_output(event, &data, regs);
+ setup_sample(event, iregs, at, data, regs);
+ perf_event_output(event, data, regs);
at += cpuc->pebs_record_size;
at = get_next_pebs_record_by_bit(at, top, bit);
count--;
}
- setup_sample(event, iregs, at, &data, regs);
+ setup_sample(event, iregs, at, data, regs);
if (iregs == &dummy_iregs) {
/*
* The PEBS records may be drained in the non-overflow context,
@@ -1767,18 +1770,18 @@ static void __intel_pmu_pebs_event(struc
* last record the same as other PEBS records, and doesn't
* invoke the generic overflow handler.
*/
- perf_event_output(event, &data, regs);
+ perf_event_output(event, data, regs);
} else {
/*
* All but the last records are processed.
* The last one is left to be able to call the overflow handler.
*/
- if (perf_event_overflow(event, &data, regs))
+ if (perf_event_overflow(event, data, regs))
x86_pmu_stop(event, 0);
}
}
-static void intel_pmu_drain_pebs_core(struct pt_regs *iregs)
+static void intel_pmu_drain_pebs_core(struct pt_regs *iregs, struct perf_sample_data *data)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct debug_store *ds = cpuc->ds;
@@ -1812,7 +1815,7 @@ static void intel_pmu_drain_pebs_core(st
return;
}
- __intel_pmu_pebs_event(event, iregs, at, top, 0, n,
+ __intel_pmu_pebs_event(event, iregs, data, at, top, 0, n,
setup_pebs_fixed_sample_data);
}
@@ -1835,7 +1838,7 @@ static void intel_pmu_pebs_event_update_
}
}
-static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
+static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs, struct perf_sample_data *data)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct debug_store *ds = cpuc->ds;
@@ -1942,14 +1945,14 @@ static void intel_pmu_drain_pebs_nhm(str
}
if (counts[bit]) {
- __intel_pmu_pebs_event(event, iregs, base,
+ __intel_pmu_pebs_event(event, iregs, data, base,
top, bit, counts[bit],
setup_pebs_fixed_sample_data);
}
}
}
-static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs)
+static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_data *data)
{
short counts[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS] = {};
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
@@ -1997,7 +2000,7 @@ static void intel_pmu_drain_pebs_icl(str
if (WARN_ON_ONCE(!event->attr.precise_ip))
continue;
- __intel_pmu_pebs_event(event, iregs, base,
+ __intel_pmu_pebs_event(event, iregs, data, base,
top, bit, counts[bit],
setup_pebs_adaptive_sample_data);
}
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -727,7 +727,7 @@ struct x86_pmu {
int pebs_record_size;
int pebs_buffer_size;
int max_pebs_events;
- void (*drain_pebs)(struct pt_regs *regs);
+ void (*drain_pebs)(struct pt_regs *regs, struct perf_sample_data *data);
struct event_constraint *pebs_constraints;
void (*pebs_aliases)(struct perf_event *event);
unsigned long large_pebs_flags;
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