[PATCH] minor cleanups for hotplug CPUs

Note that without CONFIG_HOTPLUG_CPU, online cpus == possible cpus, so
substitutions are a noop.

- Changes show_stat to print out stats for every possible cpu, not
  just online CPUs.

- Allocate mem in stat_open on possible, not online_cpus.

- Add conventient macros to cpu.h: especially cpu_is_offline() for
  testing if a cpu is still online.

- Add a num_possible_cpus() similar to num_online_cpus(), and define
  cpu_possible_mask for UP.

- Allow printk on down cpus once system is running.

- Mask cpumask with possible, not online cpus, for sys_getaffinity().

diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index dcb20c541addae88d0a75db535990c827f7019c0..328bcd3405cc4546cb5b95d06a7241481bba7dd8 100644 (file)
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -389,7 +389,7 @@ int show_stat(struct seq_file *p, void *v)
                jiffies_to_clock_t(iowait),
                jiffies_to_clock_t(irq),
                jiffies_to_clock_t(softirq));
-       for_each_online_cpu(i) {
+       for_each_cpu(i) {
                seq_printf(p, "cpu%d %u %u %u %u %u %u %u\n",
                        i,
                        jiffies_to_clock_t(kstat_cpu(i).cpustat.user),
@@ -424,7 +424,7 @@ int show_stat(struct seq_file *p, void *v)
 
 static int stat_open(struct inode *inode, struct file *file)
 {
-       unsigned size = 4096 * (1 + num_online_cpus() / 32);
+       unsigned size = 4096 * (1 + num_possible_cpus() / 32);
        char *buf;
        struct seq_file *m;
        int res;

diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 5ecc291dc138ff291e83ae557c03a0c3bd5cd79d..83a37dc0ec3f5e7badd605f2e29cfbea2f875ab2 100644 (file)
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -21,6 +21,8 @@
 
 #include <linux/sysdev.h>
 #include <linux/node.h>
+#include <linux/compiler.h>
+#include <linux/cpumask.h>
 #include <asm/semaphore.h>
 
 struct cpu {
@@ -56,9 +58,20 @@ extern struct sysdev_class cpu_sysdev_class;
 extern struct semaphore cpucontrol;
 #define lock_cpu_hotplug()     down(&cpucontrol)
 #define unlock_cpu_hotplug()   up(&cpucontrol)
+#define lock_cpu_hotplug_interruptible() down_interruptible(&cpucontrol)
+#define hotcpu_notifier(fn, pri) {                             \
+       static struct notifier_block fn##_nb = { fn, pri };     \
+       register_cpu_notifier(&fn##_nb);                        \
+}
+#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
 #else
 #define lock_cpu_hotplug()     do { } while (0)
 #define unlock_cpu_hotplug()   do { } while (0)
+#define lock_cpu_hotplug_interruptible() 0
+#define hotcpu_notifier(fn, pri)
+
+/* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */
+#define cpu_is_offline(cpu) 0
 #endif
 
 #endif /* _LINUX_CPU_H_ */

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 5731bdb3c7d843be9b9e2c331f9316ce7b686e3f..090c3f2dc6ec57725ae0d396aeac680518c7c835 100644 (file)
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -12,6 +12,7 @@ extern cpumask_t cpu_online_map;
 extern cpumask_t cpu_possible_map;
 
 #define num_online_cpus()              cpus_weight(cpu_online_map)
+#define num_possible_cpus()            cpus_weight(cpu_possible_map)
 #define cpu_online(cpu)                        cpu_isset(cpu, cpu_online_map)
 #define cpu_possible(cpu)              cpu_isset(cpu, cpu_possible_map)
 
@@ -24,7 +25,9 @@ extern cpumask_t cpu_possible_map;
 #define for_each_online_cpu(cpu) for_each_cpu_mask(cpu, cpu_online_map)
 #else
 #define        cpu_online_map                  cpumask_of_cpu(0)
+#define        cpu_possible_map                cpumask_of_cpu(0)
 #define num_online_cpus()              1
+#define num_possible_cpus()            1
 #define cpu_online(cpu)                        ({ BUG_ON((cpu) != 0); 1; })
 #define cpu_possible(cpu)              ({ BUG_ON((cpu) != 0); 1; })
 

diff --git a/kernel/printk.c b/kernel/printk.c
index 900c60f981576723570062335f6a1115b93ea822..a7be1f922f34ce51c9ed7dac4dc65ec9f3b2506e 100644 (file)
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -522,7 +522,7 @@ asmlinkage int printk(const char *fmt, ...)
                        log_level_unknown = 1;
        }
 
-       if (!cpu_online(smp_processor_id())) {
+       if (!cpu_online(smp_processor_id()) && !system_running) {
                /*
                 * Some console drivers may assume that per-cpu resources have
                 * been allocated.  So don't allow them to be called by this

diff --git a/kernel/sched.c b/kernel/sched.c
index 4f6fbe7d0b95a89479af7c0d6fe1f3d082c4f58d..28cd05aba0ec72f763c5c0af43d4e77eb5751a8b 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2366,7 +2366,7 @@ asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len,
                goto out_unlock;
 
        retval = 0;
-       cpus_and(mask, p->cpus_allowed, cpu_online_map);
+       cpus_and(mask, p->cpus_allowed, cpu_possible_map);
 
 out_unlock:
        read_unlock(&tasklist_lock);