kernel: time: Rollback tight loop delays in lieu of queued spin locks

This reverts the following commits: 10078b3 ("alarmtimer: Add ndelay for tight loop" 3a6efbd ("kernel: time: Add delay after cpu_relax() in tight loops") Signed-off-by: Adam W. Willis <return.of.octobot@gmail.com>
0ctobot · Jun 27, 2020 · 5164fcf · 5164fcf
1 parent bfb2eac
commit 5164fcf
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Showing 4 changed files with 0 additions and 9 deletions.
diff --git a/include/linux/time.h b/include/linux/time.h
@@ -7,8 +7,6 @@
 # include <linux/math64.h>
 # include <linux/time64.h>
 
-#define TIMER_LOCK_TIGHT_LOOP_DELAY_NS	350
-
 extern struct timezone sys_tz;
 
 int get_timespec64(struct timespec64 *ts,

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
@@ -27,7 +27,6 @@
 #include <linux/posix-timers.h>
 #include <linux/workqueue.h>
 #include <linux/freezer.h>
-#include <linux/delay.h>
 #include <linux/compat.h>
 #include <linux/module.h>
 
@@ -465,7 +464,6 @@ int alarm_cancel(struct alarm *alarm)
 		if (ret >= 0)
 			return ret;
 		cpu_relax();
-		ndelay(TIMER_LOCK_TIGHT_LOOP_DELAY_NS);
 	}
 }
 EXPORT_SYMBOL_GPL(alarm_cancel);

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
@@ -52,7 +52,6 @@
 #include <linux/timer.h>
 #include <linux/freezer.h>
 #include <linux/compat.h>
-#include <linux/delay.h>
 
 #include <linux/uaccess.h>
 
@@ -153,7 +152,6 @@ struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
 			raw_spin_unlock_irqrestore(&base->cpu_base->lock, *flags);
 		}
 		cpu_relax();
-		ndelay(TIMER_LOCK_TIGHT_LOOP_DELAY_NS);
 	}
 }
 
@@ -1069,7 +1067,6 @@ int hrtimer_cancel(struct hrtimer *timer)
 		if (ret >= 0)
 			return ret;
 		cpu_relax();
-		ndelay(TIMER_LOCK_TIGHT_LOOP_DELAY_NS);
 	}
 }
 EXPORT_SYMBOL_GPL(hrtimer_cancel);

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
@@ -944,7 +944,6 @@ static struct timer_base *lock_timer_base(struct timer_list *timer,
 			raw_spin_unlock_irqrestore(&base->lock, *flags);
 		}
 		cpu_relax();
-		ndelay(TIMER_LOCK_TIGHT_LOOP_DELAY_NS);
 	}
 }
 
@@ -1267,7 +1266,6 @@ int del_timer_sync(struct timer_list *timer)
 		if (ret >= 0)
 			return ret;
 		cpu_relax();
-		ndelay(TIMER_LOCK_TIGHT_LOOP_DELAY_NS);
 	}
 }
 EXPORT_SYMBOL(del_timer_sync);