Messages in this thread | | | Date | Mon, 9 Feb 2009 09:37:39 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] irq: optimize init_kstat_irqs/init_copy_kstat_irqs |
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* Andrew Morton <akpm@linux-foundation.org> wrote:
> On Mon, 9 Feb 2009 09:11:24 +0100 Ingo Molnar <mingo@elte.hu> wrote: > > > > > * Andrew Morton <akpm@linux-foundation.org> wrote: > > > > > On Sat, 7 Feb 2009 01:01:03 -0800 Yinghai Lu <yinghai@kernel.org> wrote: > > > > > > > > > > > add kzalloc_node_safe()? > > > > > > I cannot find that function. > > > > His suggestion is to provide that allocator variant. > > > > Oh. > > It isn't possible to write a kzalloc_node_safe(GFP_ATOMIC). Or at > least, we've never worked out a way. > > Maybe I'm confused again.
Indeed - duh - more morning tea needed.
Yinghai, why are those allocations GFP_ATOMIC to begin with? These:
earth4:~/tip> grep GFP_ATOMIC kernel/irq/*.c kernel/irq/handle.c: ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs), GFP_ATOMIC, node); kernel/irq/handle.c: desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node); kernel/irq/manage.c: action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
Should all be GFP_KERNEL. Wherever they are within a spinlocked section the code should be restructured. All descriptor data structures should be preallocated at __setup_irq() time. If we ever need to allocate dynamically later on, in the middle of some difficult codepath that's a structure bug in the code.
and this one:
kernel/irq/numa_migrate.c: desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
should fail the migration silently if GFP_ATOMIC returns NULL.
Ingo
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