Update the documentation for cpu hotplug to reflect the use
of newly added API's get_online_cpus()/put_online_cpus();
Signed-off-by: Gautham R Shenoy <[EMAIL PROTECTED]>
---
Documentation/cpu-hotplug.txt | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
Index: linux-2.6.23/Documentation/cpu-hotplug.txt
===================================================================
--- linux-2.6.23.orig/Documentation/cpu-hotplug.txt
+++ linux-2.6.23/Documentation/cpu-hotplug.txt
@@ -109,12 +109,13 @@ Never use anything other than cpumask_t
for_each_cpu_mask(x,mask) - Iterate over some random collection of cpu
mask.
#include <linux/cpu.h>
- lock_cpu_hotplug() and unlock_cpu_hotplug():
+ get_online_cpus() and put_online_cpus():
-The above calls are used to inhibit cpu hotplug operations. While holding the
-cpucontrol mutex, cpu_online_map will not change. If you merely need to avoid
-cpus going away, you could also use preempt_disable() and preempt_enable()
-for those sections. Just remember the critical section cannot call any
+The above calls are used to inhibit cpu hotplug operations. While the
+cpu_hotplug.refcount is non zero, the cpu_online_map will not change.
+If you merely need to avoid cpus going away, you could also use
+preempt_disable() and preempt_enable() for those sections.
+Just remember the critical section cannot call any
function that can sleep or schedule this process away. The preempt_disable()
will work as long as stop_machine_run() is used to take a cpu down.
--
Gautham R Shenoy
Linux Technology Center
IBM India.
"Freedom comes with a price tag of responsibility, which is still a bargain,
because Freedom is priceless!"
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