X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=wrapper%2Ftrace-clock.h;h=561094b3ae924a6545cf795f0ba838040c1273fe;hb=215c7520fb6e8e3dce00d674859544da6598b747;hp=5705d0c25a9477fe3b80710fb97ef0ad66ab2261;hpb=4ebfd673ca1faf26c8a1a2c83a18153f4474e835;p=lttng-modules.git

diff --git a/wrapper/trace-clock.h b/wrapper/trace-clock.h
index 5705d0c2..561094b3 100644
--- a/wrapper/trace-clock.h
+++ b/wrapper/trace-clock.h
@@ -36,9 +36,11 @@
 #include <linux/version.h>
 #include <asm/local.h>
 #include "../lttng-kernel-version.h"
+#include "percpu-defs.h"
 #include "random.h"
 
-#if LTTNG_KERNEL_RANGE(3,10,0, 3,10,14) || LTTNG_KERNEL_RANGE(3,11,0, 3,11,3)
+#if ((LTTNG_KERNEL_RANGE(3,10,0, 3,10,14) && !LTTNG_RHEL_KERNEL_RANGE(3,10,0,7,0, 3,10,14,0,0)) \
+	|| LTTNG_KERNEL_RANGE(3,11,0, 3,11,3))
 #error "Linux kernels 3.10 and 3.11 introduce a deadlock in the timekeeping subsystem. Fixed by commit 7bd36014460f793c19e7d6c94dab67b0afcfcb7f \"timekeeping: Fix HRTICK related deadlock from ntp lock changes\" in Linux."
 #endif
 
@@ -88,7 +90,7 @@ static inline u64 trace_clock_fixup(u64 src_now, u64 last)
 #endif /* #else #if (BITS_PER_LONG == 32) */
 
 /*
- * Always called with preemption disabled. Can be interrupted.
+ * Sometimes called with preemption enabled. Can be interrupted.
  */
 static inline u64 trace_clock_monotonic_wrapper(void)
 {
@@ -97,7 +99,8 @@ static inline u64 trace_clock_monotonic_wrapper(void)
 	local_t *last_tsc;
 
 	/* Use fast nmi-safe monotonic clock provided by the Linux kernel. */
-	last_tsc = &__get_cpu_var(lttng_last_tsc);
+	preempt_disable();
+	last_tsc = lttng_this_cpu_ptr(&lttng_last_tsc);
 	last = local_read(last_tsc);
 	/*
 	 * Read "last" before "now". It is not strictly required, but it ensures
@@ -110,6 +113,7 @@ static inline u64 trace_clock_monotonic_wrapper(void)
 	if (((long) now - (long) last) < 0)
 		now = trace_clock_fixup(now, last);
 	result = local_cmpxchg(last_tsc, last, (unsigned long) now);
+	preempt_enable();
 	if (result == last) {
 		/* Update done. */
 		return now;