* 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!
> [...] With GFP_KERNEL we might hang the system.
Yes, that's a bug that should be fixed - but not via GFP_ATOMIC, which
adds insult to injury.
Thanks,
Ingo
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