Messages in this thread Patch in this message | | | Date | Wed, 24 Oct 2007 11:09:07 +0530 | From | Gautham R Shenoy <> | Subject | [RFC PATCH 5/5] Update get_online_cpus() in Documentation/cpu-hotplug.c |
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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 <ego@in.ibm.com>
--- 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!" - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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