On 01/26/2014 08:32 AM, Ingo Molnar wrote:
>
> * Prarit Bhargava <pra...@redhat.com> wrote:
>
>> On 01/25/2014 03:02 AM, Ingo Molnar wrote:
>>>
>>> * Yinghai Lu <ying...@kernel.org> wrote:
>>>
>>>> Fix warning:
>>>> arch/x86/kernel/irq.c: In function check_irq_vectors_for_cpu_disable:
>>>> arch/x86/kernel/irq.c:337:1: warning: the frame size of 2052 bytes is
>>>> larger than 2048 bytes
>>>>
>>>> when NR_CPUS=8192
>>>>
>>>> We should use zalloc_cpumask_var() instead.
>>>>
>>>> -v2: update to GFP_ATOMIC instead and free the allocated cpumask at last.
>>>>
>>>> Signed-off-by: Yinghai Lu <ying...@kernel.org>
>>>> Cc: Prarit Bhargava <pra...@redhat.com>
>>>>
>>>> ---
>>>> arch/x86/kernel/irq.c | 24 +++++++++++++++++-------
>>>> 1 file changed, 17 insertions(+), 7 deletions(-)
>>>>
>>>> Index: linux-2.6/arch/x86/kernel/irq.c
>>>> ===================================================================
>>>> --- linux-2.6.orig/arch/x86/kernel/irq.c
>>>> +++ linux-2.6/arch/x86/kernel/irq.c
>>>> @@ -277,11 +277,18 @@ int check_irq_vectors_for_cpu_disable(vo
>>>> unsigned int this_cpu, vector, this_count, count;
>>>> struct irq_desc *desc;
>>>> struct irq_data *data;
>>>> - struct cpumask affinity_new, online_new;
>>>> + cpumask_var_t affinity_new, online_new;
>>>> +
>>>> + if (!alloc_cpumask_var(&affinity_new, GFP_ATOMIC))
>>>> + return -ENOMEM;
>>>> + if (!alloc_cpumask_var(&online_new, GFP_ATOMIC)) {
>>>> + free_cpumask_var(affinity_new);
>>>> + return -ENOMEM;
>>>> + }
>>>
>>> Atomic allocations can fail easily if the system is under duress.
>>
>> Then the hotplug attempt will fail which IMO is okay. [...]
>
> Which is not OK at all for reliable operation, if the system has
> otherwise gobs of RAM, which just don't happen to be atomic
> allocatable!
Ingo, I'm really not sure what other option there is here. Care to suggest one?
P.
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