High 31 bits of 63 bit idle, user, nice, and system times are again
maintained on 32 bit platforms using a timer.
This may be considered creeping featurism, so I'll provide an alternate
patch that just exports the 64 bit values where available.
OTOH, the timer tricks are purely local to proc_fs, so you don't get them
when you don't mount /proc.
--- linux-2.5.15/include/linux/kernel_stat.h Sun May 5 08:32:04 2002
+++ linux-2.5.15-j64/include/linux/kernel_stat.h Thu May 9 17:48:21 2002
@@ -16,9 +16,9 @@
#define DK_MAX_DISK 16
struct kernel_stat {
- unsigned int per_cpu_user[NR_CPUS],
- per_cpu_nice[NR_CPUS],
- per_cpu_system[NR_CPUS];
+ unsigned long per_cpu_user[NR_CPUS],
+ per_cpu_nice[NR_CPUS],
+ per_cpu_system[NR_CPUS];
unsigned int dk_drive[DK_MAX_MAJOR][DK_MAX_DISK];
unsigned int dk_drive_rio[DK_MAX_MAJOR][DK_MAX_DISK];
unsigned int dk_drive_wio[DK_MAX_MAJOR][DK_MAX_DISK];
--- linux-2.5.15/fs/proc/proc_misc.c Sun May 5 08:32:03 2002
+++ linux-2.5.15-j64/fs/proc/proc_misc.c Thu May 9 18:02:05 2002
@@ -40,6 +40,7 @@
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/io.h>
+#include <asm/div64.h>
#define LOAD_INT(x) ((x) >> FSHIFT)
@@ -62,6 +63,92 @@
extern int get_ds1286_status(char *);
#endif
+#if BITS_PER_LONG < 48
+static unsigned int uidle_msb_flips, sidle_msb_flips;
+static unsigned int per_cpu_user_flips[NR_CPUS],
+ per_cpu_nice_flips[NR_CPUS],
+ per_cpu_system_flips[NR_CPUS];
+
+static u64 get_64bits(unsigned long *val, unsigned int *flips)
+{
+ unsigned long v;
+ unsigned int f;
+
+ f = *flips; /* avoid races */
+ rmb();
+ v = *val;
+
+ /* account for not yet detected MSB flips */
+ f += (f ^ (v>>(BITS_PER_LONG-1))) & 1;
+ return ((u64) f << (BITS_PER_LONG-1)) | v;
+}
+
+#define get_uidle64() get_64bits(&(init_task.times.tms_utime),\
+ &uidle_msb_flips)
+#define get_sidle64() get_64bits(&(init_task.times.tms_stime),\
+ &sidle_msb_flips)
+#define get_user64(cpu) get_64bits(&(kstat.per_cpu_user[cpu]),\
+ &(per_cpu_user_flips[cpu]))
+#define get_nice64(cpu) get_64bits(&(kstat.per_cpu_nice[cpu]),\
+ &(per_cpu_nice_flips[cpu]))
+#define get_system64(cpu) get_64bits(&(kstat.per_cpu_system[cpu]),\
+ &(per_cpu_system_flips[cpu]))
+
+/*
+ * Use a timer to periodically check for overflows.
+ * Instead of overflows we count flips of the highest bit so
+ * that we can easily check whether the latest flip is already
+ * accounted for.
+ * Not racy as invocations are several days apart in time and
+ * *_flips is not modified elsewhere.
+ */
+
+static struct timer_list check_wraps_timer;
+#define CHECK_WRAPS_INTERVAL (1ul << (BITS_PER_LONG-2))
+
+static inline void check_one(unsigned long val, unsigned int *flips)
+{
+ *flips += 1 & (*flips ^ (val>>(BITS_PER_LONG-1)));
+}
+
+static void check_wraps(unsigned long data)
+{
+ int i;
+
+ mod_timer(&check_wraps_timer, jiffies + CHECK_WRAPS_INTERVAL);
+
+ check_one(init_task.times.tms_utime, &uidle_msb_flips);
+ check_one(init_task.times.tms_stime, &sidle_msb_flips);
+ for(i=0; i<NR_CPUS; i++) {
+ check_one(kstat.per_cpu_user[i], &(per_cpu_user_flips[i]));
+ check_one(kstat.per_cpu_nice[i], &(per_cpu_nice_flips[i]));
+ check_one(kstat.per_cpu_system[i], &(per_cpu_system_flips[i]));
+ }
+}
+
+static inline void init_check_wraps_timer(void)
+{
+ init_timer(&check_wraps_timer);
+ check_wraps_timer.expires = jiffies + CHECK_WRAPS_INTERVAL;
+ check_wraps_timer.function = check_wraps;
+ add_timer(&check_wraps_timer);
+}
+
+#else
+ /* Times won't overflow for 8716 years at HZ==1024 */
+
+#define get_uidle64() (init_task.times.tms_utime)
+#define get_sidle64() (init_task.times.tms_stime)
+#define get_user64(cpu) (kstat.per_cpu_user[cpu])
+#define get_nice64(cpu) (kstat.per_cpu_nice[cpu])
+#define get_system64(cpu) (kstat.per_cpu_system[cpu])
+
+static inline void init_check_wraps_timer(void)
+{
+}
+
+#endif /* BITS_PER_LONG < 48 */
+
static int proc_calc_metrics(char *page, char **start, off_t off,
int count, int *eof, int len)
{
@@ -93,34 +180,27 @@
static int uptime_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
- unsigned long uptime;
- unsigned long idle;
+ u64 uptime, idle;
+ unsigned long uptime_remainder, idle_remainder;
int len;
- uptime = jiffies;
- idle = init_task.times.tms_utime + init_task.times.tms_stime;
+ uptime = get_jiffies64();
+ uptime_remainder = (unsigned long) do_div(uptime, HZ);
+ idle = get_sidle64() + get_uidle64();
+ idle_remainder = (unsigned long) do_div(idle, HZ);
- /* The formula for the fraction parts really is ((t * 100) / HZ) % 100, but
- that would overflow about every five days at HZ == 100.
- Therefore the identity a = (a / b) * b + a % b is used so that it is
- calculated as (((t / HZ) * 100) + ((t % HZ) * 100) / HZ) % 100.
- The part in front of the '+' always evaluates as 0 (mod 100). All divisions
- in the above formulas are truncating. For HZ being a power of 10, the
- calculations simplify to the version in the #else part (if the printf
- format is adapted to the same number of digits as zeroes in HZ.
- */
#if HZ!=100
len = sprintf(page,"%lu.%02lu %lu.%02lu\n",
- uptime / HZ,
- (((uptime % HZ) * 100) / HZ) % 100,
- idle / HZ,
- (((idle % HZ) * 100) / HZ) % 100);
+ (unsigned long) uptime,
+ (uptime_remainder * 100) / HZ,
+ (unsigned long) idle,
+ (idle_remainder * 100) / HZ);
#else
len = sprintf(page,"%lu.%02lu %lu.%02lu\n",
- uptime / HZ,
- uptime % HZ,
- idle / HZ,
- idle % HZ);
+ (unsigned long) uptime,
+ uptime_remainder,
+ (unsigned long) idle,
+ idle_remainder);
#endif
return proc_calc_metrics(page, start, off, count, eof, len);
}
@@ -281,33 +361,39 @@
{
int i, len;
extern unsigned long total_forks;
- unsigned long jif = jiffies;
- unsigned int sum = 0, user = 0, nice = 0, system = 0;
+ unsigned int sum = 0;
+ u64 jif = get_jiffies64(), user = 0, nice = 0, system = 0;
int major, disk;
for (i = 0 ; i < smp_num_cpus; i++) {
int cpu = cpu_logical_map(i), j;
- user += kstat.per_cpu_user[cpu];
- nice += kstat.per_cpu_nice[cpu];
- system += kstat.per_cpu_system[cpu];
+ user += get_user64(cpu);
+ nice += get_nice64(cpu);
+ system += get_system64(cpu);
#if !defined(CONFIG_ARCH_S390)
for (j = 0 ; j < NR_IRQS ; j++)
sum += kstat.irqs[cpu][j];
#endif
}
- len = sprintf(page, "cpu %u %u %u %lu\n", user, nice, system,
- jif * smp_num_cpus - (user + nice + system));
- for (i = 0 ; i < smp_num_cpus; i++)
- len += sprintf(page + len, "cpu%d %u %u %u %lu\n",
+ len = sprintf(page, "cpu %llu %llu %llu %llu\n",
+ (unsigned long long) user,
+ (unsigned long long) nice,
+ (unsigned long long) system,
+ (unsigned long long) jif * smp_num_cpus
+ - user - nice - system);
+ for (i = 0 ; i < smp_num_cpus; i++) {
+ user = get_user64(cpu_logical_map(i));
+ nice = get_nice64(cpu_logical_map(i));
+ system = get_system64(cpu_logical_map(i));
+ len += sprintf(page + len, "cpu%d %llu %llu %llu %llu\n",
i,
- kstat.per_cpu_user[cpu_logical_map(i)],
- kstat.per_cpu_nice[cpu_logical_map(i)],
- kstat.per_cpu_system[cpu_logical_map(i)],
- jif - ( kstat.per_cpu_user[cpu_logical_map(i)] \
- + kstat.per_cpu_nice[cpu_logical_map(i)] \
- + kstat.per_cpu_system[cpu_logical_map(i)]));
+ (unsigned long long) user,
+ (unsigned long long) nice,
+ (unsigned long long) system,
+ (unsigned long long) jif -user -nice -system);
+ }
len += sprintf(page + len,
"page %u %u\n"
"swap %u %u\n"
@@ -343,12 +429,13 @@
}
}
+ do_div(jif, HZ);
len += sprintf(page + len,
"\nctxt %lu\n"
"btime %lu\n"
"processes %lu\n",
nr_context_switches(),
- xtime.tv_sec - jif / HZ,
+ xtime.tv_sec - (unsigned long) jif,
total_forks);
return proc_calc_metrics(page, start, off, count, eof, len);
@@ -625,4 +722,6 @@
entry->proc_fops = &ppc_htab_operations;
}
#endif
+
+ init_check_wraps_timer();
}
-
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