Two simple uses of 64 bit jiffies:
- export correct uptime through sysinfo after 32 bit jiffies wrap.
Note that this does not change the ABI, which exports uptime in seconds.
It just prevents internal overflow.
- use 64 bit jiffies in the OOM-killer. Before, deaemons and very
long-running jobs were likely to be killed in OOM situations after
jiffies wrap.
The uptime exported through /proc/uptime will be corrected in patch 5/6.
--- linux-2.5.15/kernel/info.c Mon Mar 18 21:37:05 2002
+++ linux-2.5.15-j64/kernel/info.c Thu May 9 17:48:21 2002
@@ -12,15 +12,19 @@
#include <linux/smp_lock.h>
#include <asm/uaccess.h>
+#include <asm/div64.h>
asmlinkage long sys_sysinfo(struct sysinfo *info)
{
struct sysinfo val;
+ u64 uptime;
memset((char *)&val, 0, sizeof(struct sysinfo));
cli();
- val.uptime = jiffies / HZ;
+ uptime = get_jiffies64();
+ do_div(uptime, HZ);
+ val.uptime = (unsigned long) uptime;
val.loads[0] = avenrun[0] << (SI_LOAD_SHIFT - FSHIFT);
val.loads[1] = avenrun[1] << (SI_LOAD_SHIFT - FSHIFT);
--- linux-2.5.15/mm/oom_kill.c Mon Mar 18 21:37:02 2002
+++ linux-2.5.15-j64/mm/oom_kill.c Thu May 9 17:48:21 2002
@@ -69,11 +69,10 @@
/*
* CPU time is in seconds and run time is in minutes. There is no
* particular reason for this other than that it turned out to work
- * very well in practice. This is not safe against jiffie wraps
- * but we don't care _that_ much...
+ * very well in practice.
*/
cpu_time = (p->times.tms_utime + p->times.tms_stime) >> (SHIFT_HZ + 3);
- run_time = (jiffies - p->start_time) >> (SHIFT_HZ + 10);
+ run_time = (get_jiffies64() - p->start_time) >> (SHIFT_HZ + 10);
points /= int_sqrt(cpu_time);
points /= int_sqrt(int_sqrt(run_time));
-
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This archive was generated by hypermail 2b29 : Tue May 14 2002 - 12:00:16 EST