X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fposix-timers.c;h=55b3761edaa9afe42273a7b3adaa42b1547fb5ee;hb=496634217e5671ed876a0348e9f5b7165e830b20;hp=44318ca71978d9afae52c6149153d323e08a06b5;hpb=5c56f466835d20fc4f7119063a8c029f7170a317;p=linux-2.6

diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index 44318ca719..55b3761eda 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -31,7 +31,6 @@
  * POSIX clocks & timers
  */
 #include <linux/mm.h>
-#include <linux/smp_lock.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/time.h>
@@ -242,7 +241,7 @@ static __init int init_posix_timers(void)
 	register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
 
 	posix_timers_cache = kmem_cache_create("posix_timers_cache",
-					sizeof (struct k_itimer), 0, 0, NULL, NULL);
+					sizeof (struct k_itimer), 0, 0, NULL);
 	idr_init(&posix_timers_id);
 	return 0;
 }
@@ -354,9 +353,40 @@ static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
 		 * it should be restarted.
 		 */
 		if (timr->it.real.interval.tv64 != 0) {
+			ktime_t now = hrtimer_cb_get_time(timer);
+
+			/*
+			 * FIXME: What we really want, is to stop this
+			 * timer completely and restart it in case the
+			 * SIG_IGN is removed. This is a non trivial
+			 * change which involves sighand locking
+			 * (sigh !), which we don't want to do late in
+			 * the release cycle.
+			 *
+			 * For now we just let timers with an interval
+			 * less than a jiffie expire every jiffie to
+			 * avoid softirq starvation in case of SIG_IGN
+			 * and a very small interval, which would put
+			 * the timer right back on the softirq pending
+			 * list. By moving now ahead of time we trick
+			 * hrtimer_forward() to expire the timer
+			 * later, while we still maintain the overrun
+			 * accuracy, but have some inconsistency in
+			 * the timer_gettime() case. This is at least
+			 * better than a starved softirq. A more
+			 * complex fix which solves also another related
+			 * inconsistency is already in the pipeline.
+			 */
+#ifdef CONFIG_HIGH_RES_TIMERS
+			{
+				ktime_t kj = ktime_set(0, NSEC_PER_SEC / HZ);
+
+				if (timr->it.real.interval.tv64 < kj.tv64)
+					now = ktime_add(now, kj);
+			}
+#endif
 			timr->it_overrun +=
-				hrtimer_forward(timer,
-						hrtimer_cb_get_time(timer),
+				hrtimer_forward(timer, now,
 						timr->it.real.interval);
 			ret = HRTIMER_RESTART;
 			++timr->it_requeue_pending;