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perf/x86/intel: Convert x86_perf_regs to per-cpu variables

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Currently, the drain_pebs() helpers, e.g., intel_pmu_drain_arch_pebs()
define an on-stack x86_perf_regs. Upcoming patches will add new fields
like *ymm_regs and *zmm_regs to the x86_perf_regs structure to support
sampling for these SIMD registers. This would increase the stack size
consumed by these helpers, potentially triggering the warning:

"the frame size of 1048 bytes is larger than 1024 bytes
 [-Wframe-larger-than=]".

To eliminate this warning, convert x86_perf_regs to per-cpu variables.

Please note drain_pebs() can't be interrupted by other NMIs since
either it's already in NMI context or PMU is already disabled.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260824082731.1013973-4-dapeng1.mi@linux.intel.com
This commit is contained in:
Dapeng Mi 2026-08-24 16:27:11 +08:00 committed by Peter Zijlstra
parent 62e074f55f
commit bbdf84fced
1 changed files with 8 additions and 6 deletions
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14
arch/x86/events/intel/ds.c
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@ -2917,6 +2917,8 @@ __intel_pmu_pebs_last_event(struct perf_event *event,
}
}
static DEFINE_PER_CPU(struct x86_perf_regs, x86_pebs_regs);
static __always_inline void
__intel_pmu_pebs_events(struct perf_event *event,
struct pt_regs *iregs,
@ -2926,8 +2928,8 @@ __intel_pmu_pebs_events(struct perf_event *event,
setup_fn setup_sample)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct x86_perf_regs perf_regs;
struct pt_regs *regs = &perf_regs.regs;
struct x86_perf_regs *perf_regs = this_cpu_ptr(&x86_pebs_regs);
struct pt_regs *regs = &perf_regs->regs;
void *at = get_next_pebs_record_by_bit(base, top, bit);
int cnt = count;
@ -3175,8 +3177,8 @@ static void intel_pmu_drain_pebs_icl(struct pt_regs *iregs, struct perf_sample_d
void *last[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS];
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct debug_store *ds = cpuc->ds;
struct x86_perf_regs perf_regs;
struct pt_regs *regs = &perf_regs.regs;
struct x86_perf_regs *perf_regs = this_cpu_ptr(&x86_pebs_regs);
struct pt_regs *regs = &perf_regs->regs;
struct pebs_basic *basic;
void *base, *at, *top;
u64 mask;
@ -3226,8 +3228,8 @@ static void intel_pmu_drain_arch_pebs(struct pt_regs *iregs,
void *last[INTEL_PMC_IDX_FIXED + MAX_FIXED_PEBS_EVENTS];
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
union arch_pebs_index index;
struct x86_perf_regs perf_regs;
struct pt_regs *regs = &perf_regs.regs;
struct x86_perf_regs *perf_regs = this_cpu_ptr(&x86_pebs_regs);
struct pt_regs *regs = &perf_regs->regs;
void *base, *at, *top;
u64 mask;