Re: [RFC PATCH] sparse_irq aka dyn_irq

From: Yinghai Lu
Date: Mon Nov 10 2008 - 14:47:31 EST


On Mon, Nov 10, 2008 at 2:09 AM, Ingo Molnar <mingo@xxxxxxx> wrote:
>
> * Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
>
>> Ingo Molnar wrote:
>> > * Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
>> >
>> >> Andrew Morton wrote:
>> >>> On Mon, 10 Nov 2008 10:40:33 +0100 Ingo Molnar <mingo@xxxxxxx> wrote:
>> >>>
>> >>>>>>> @@ -987,6 +988,8 @@ void __init mem_init(void)
>> >>>>>>>
>> >>>>>>> set_highmem_pages_init();
>> >>>>>>>
>> >>>>>>> + after_bootmem = 1;
>> >>>>>> this hack can go away once we have a proper percpu_alloc() that can be
>> >>>>>> used early enough.
>> >>>>> where is that fancy patch? current percpu_alloc(), will keep big
>> >>>>> pointer in array..., instead of put that pointer in percpu_area
>> >>>>>
>> >>>>> 64bit has that after_bootmem already.
>> >>>> or at least introduce a "bootmem agnostic" allocator instead of
>> >>>> open-coding the after_bootmem flag.
>> >>>>
>> >>>> Something like:
>> >>>>
>> >>>> early_kzalloc()
>> >>>>
>> >>>> ?
>> >>>>
>> >>>> Andrew, any preferences?
>> >>> My mind reading ain't what it was, and this after_bootmem flag is
>> >>> write-only in this patch.
>> >>>
>> >>> So what's all this about?
>> >> if i use alloc_bootmem to get some memory, and later after_bootmem,
>> >> can I use kfree to free it?
>> >
>> > hm, no. If we used alloc_bootmem(), then we must not free it after
>> > after_bootmem has been set.
>>
>> ok, let keep irq_desc for legacy irqs not movable...
>
> most of them are movable right now, correct? If we restrict their
> movability now that might surprise existing usecases negatively.

i mean irq_desc will not be allocated one one on new cpus...

YH
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