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Commit 2579d019 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull perf fix from Thomas Gleixner:
 "A single fix for the intel cqm perf facility to prevent IPIs from
  interrupt context"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel/cqm: Return cached counter value from IRQ context
parents 28003486 2c534c0d

arch/x86/kernel/cpu/perf_event_intel_cqm.c

+8 −0
Original line number Diff line number Diff line
@@ -951,6 +951,14 @@ static u64 intel_cqm_event_count(struct perf_event *event) 
	if (!cqm_group_leader(event))

		return 0;



	/*

	 * Getting up-to-date values requires an SMP IPI which is not

	 * possible if we're being called in interrupt context. Return

	 * the cached values instead.

	 */

	if (unlikely(in_interrupt()))

		goto out;



	/*

	 * Notice that we don't perform the reading of an RMID

	 * atomically, because we can't hold a spin lock across the