[PATCH] cobalt: Avoid reading time twice via xnstat_exectime_update

[PATCH] cobalt: Avoid reading time twice via xnstat_exectime_update

[Jan Kiszka]

From: Jan Kiszka <jan.kiszka@siemens.com>

This macro may unroll to instantiating 'date' twice. If that is a call
to some get-time function, as via xnstat_exectime_switch, we needlessly
do that twice.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 include/cobalt/kernel/stat.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/cobalt/kernel/stat.h b/include/cobalt/kernel/stat.h
index b08567b41c..3c059a54ff 100644
--- a/include/cobalt/kernel/stat.h
+++ b/include/cobalt/kernel/stat.h
@@ -44,9 +44,10 @@ typedef struct xnstat_exectime {
 /* Accumulate exectime of the current account until the given date. */
 #define xnstat_exectime_update(sched, date) \
 do { \
+	xnticks_t __date = date; \
 	(sched)->current_account->total += \
-		date - (sched)->last_account_switch; \
-	(sched)->last_account_switch = date; \
+		__date - (sched)->last_account_switch; \
+	(sched)->last_account_switch = __date; \
 	/* All changes must be committed before changing the current_account \
 	   reference in sched (required for xnintr_sync_stat_references) */ \
 	smp_wmb(); \
-- 
2.26.2