perf/x86/ibs: Add IBS interrupt to the dynamic throttle

Interrupt throttling is normally only done against
sysctl_perf_event_sample_rate. This means that if that number is too
high (for whatever reason) you can lock up your machine.

We have, however, a dynamic throttling scheme too, but for that to
work, we need to add a callback to the interrupt handler, IBS did not
have this, so add it.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/events/amd/ibs.c

@@ -637,6 +637,7 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
 static int
 perf_ibs_nmi_handler(unsigned int cmd, struct pt_regs *regs)
 {
+	u64 stamp = sched_clock();
 	int handled = 0;
 
 	handled += perf_ibs_handle_irq(&perf_ibs_fetch, regs);
@@ -645,6 +646,8 @@ perf_ibs_nmi_handler(unsigned int cmd, struct pt_regs *regs)
 	if (handled)
 		inc_irq_stat(apic_perf_irqs);
 
+	perf_sample_event_took(sched_clock() - stamp);
+
 	return handled;
 }
 NOKPROBE_SYMBOL(perf_ibs_nmi_handler);