From b5142d29a96d6c5bbd505d2ba299b1ef0416391a Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Mon, 29 Apr 2019 15:05:29 +0100 Subject: [PATCH v2 4.12 16/17] xen/arm: Add performance counters in guest atomic helpers Add performance counters in guest atomic helpers to be able to detect whether a guest is often paused during the operations. This is part of XSA-295. Signed-off-by: Julien Grall Acked-by: Stefano Stabellini --- xen/include/asm-arm/guest_atomics.h | 12 ++++++++++++ xen/include/asm-arm/perfc_defn.h | 3 +++ 2 files changed, 15 insertions(+) diff --git a/xen/include/asm-arm/guest_atomics.h b/xen/include/asm-arm/guest_atomics.h index 61925d313d..698508bf87 100644 --- a/xen/include/asm-arm/guest_atomics.h +++ b/xen/include/asm-arm/guest_atomics.h @@ -24,9 +24,13 @@ DECLARE_PER_CPU(unsigned int, guest_safe_atomic_max); #define guest_bitop(name) \ static inline void guest_##name(struct domain *d, int nr, volatile void *p) \ { \ + perfc_incr(atomics_guest); \ + \ if ( name##_timeout(nr, p, this_cpu(guest_safe_atomic_max)) ) \ return; \ \ + perfc_incr(atomics_guest_paused); \ + \ domain_pause_nosync(d); \ name(nr, p); \ domain_unpause(d); \ @@ -38,11 +42,15 @@ static inline int guest_##name(struct domain *d, int nr, volatile void *p) \ bool succeed; \ int oldbit; \ \ + perfc_incr(atomics_guest); \ + \ succeed = name##_timeout(nr, p, &oldbit, \ this_cpu(guest_safe_atomic_max)); \ if ( succeed ) \ return oldbit; \ \ + perfc_incr(atomics_guest_paused); \ + \ domain_pause_nosync(d); \ oldbit = name(nr, p); \ domain_unpause(d); \ @@ -73,10 +81,14 @@ static inline unsigned long __guest_cmpxchg(struct domain *d, { unsigned long oldval = old; + perfc_incr(atomics_guest); + if ( __cmpxchg_mb_timeout(ptr, &oldval, new, size, this_cpu(guest_safe_atomic_max)) ) return oldval; + perfc_incr(atomics_guest_paused); + domain_pause_nosync(d); oldval = __cmpxchg_mb(ptr, old, new, size); domain_unpause(d); diff --git a/xen/include/asm-arm/perfc_defn.h b/xen/include/asm-arm/perfc_defn.h index 8922e9525a..6a83185163 100644 --- a/xen/include/asm-arm/perfc_defn.h +++ b/xen/include/asm-arm/perfc_defn.h @@ -73,6 +73,9 @@ PERFCOUNTER(phys_timer_irqs, "Physical timer interrupts") PERFCOUNTER(virt_timer_irqs, "Virtual timer interrupts") PERFCOUNTER(maintenance_irqs, "Maintenance interrupts") +PERFCOUNTER(atomics_guest, "atomics: guest access") +PERFCOUNTER(atomics_guest_paused, "atomics: guest paused") + /*#endif*/ /* __XEN_PERFC_DEFN_H__ */ /* -- 2.17.1