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perf/x86/intel/bts: Allocate bts_ctx only if necessary

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Avoid unnecessary per-CPU memory allocation on unsupported CPUs,
this can save 12K memory for each CPU

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20250122074103.3091-1-lirongqing@baidu.com
This commit is contained in:
Li RongQing 2025-01-22 15:41:03 +08:00 • committed by Ingo Molnar
parent 8aeacf2570
commit 3acfcefa79
1 changed files with 13 additions and 9 deletions
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22
arch/x86/events/intel/bts.c
View file

@ -36,7 +36,7 @@ enum {
BTS_STATE_ACTIVE,
};
static DEFINE_PER_CPU(struct bts_ctx, bts_ctx);
static struct bts_ctx __percpu *bts_ctx;
#define BTS_RECORD_SIZE 24
#define BTS_SAFETY_MARGIN 4080
@ -231,7 +231,7 @@ bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle);
static void __bts_event_start(struct perf_event *event)
{
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
struct bts_buffer *buf = perf_get_aux(&bts->handle);
u64 config = 0;
@ -260,7 +260,7 @@ static void __bts_event_start(struct perf_event *event)
static void bts_event_start(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
struct bts_buffer *buf;
buf = perf_aux_output_begin(&bts->handle, event);
@ -290,7 +290,7 @@ fail_stop:
static void __bts_event_stop(struct perf_event *event, int state)
{
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
/* ACTIVE -> INACTIVE(PMI)/STOPPED(->stop()) */
WRITE_ONCE(bts->state, state);
@ -305,7 +305,7 @@ static void __bts_event_stop(struct perf_event *event, int state)
static void bts_event_stop(struct perf_event *event, int flags)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
struct bts_buffer *buf = NULL;
int state = READ_ONCE(bts->state);
@ -338,7 +338,7 @@ static void bts_event_stop(struct perf_event *event, int flags)
void intel_bts_enable_local(void)
{
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
int state = READ_ONCE(bts->state);
/*
@ -358,7 +358,7 @@ void intel_bts_enable_local(void)
void intel_bts_disable_local(void)
{
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
/*
* Here we transition from ACTIVE to INACTIVE;
@ -450,7 +450,7 @@ bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle)
int intel_bts_interrupt(void)
{
struct debug_store *ds = this_cpu_ptr(&cpu_hw_events)->ds;
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
struct perf_event *event = bts->handle.event;
struct bts_buffer *buf;
s64 old_head;
@ -518,7 +518,7 @@ static void bts_event_del(struct perf_event *event, int mode)
static int bts_event_add(struct perf_event *event, int mode)
{
struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);
struct bts_ctx *bts = this_cpu_ptr(bts_ctx);
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
@ -605,6 +605,10 @@ static __init int bts_init(void)
return -ENODEV;
}
bts_ctx = alloc_percpu(struct bts_ctx);
if (!bts_ctx)
return -ENOMEM;
bts_pmu.capabilities = PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_ITRACE |
PERF_PMU_CAP_EXCLUSIVE;
bts_pmu.task_ctx_nr = perf_sw_context;