Re: [this_cpu_xx V7 1/8] this_cpu_ops: page allocator conversion

From: Tejun Heo
Date: Mon Dec 14 2009 - 22:53:47 EST


Hello,

On 12/15/2009 07:03 AM, Christoph Lameter wrote:
> static __meminit void zone_pcp_init(struct zone *zone)
> {
> - int cpu;
> - unsigned long batch = zone_batchsize(zone);
> + /* Use boot pagesets until we have the per cpu allocator up */
> + zone->pageset = &per_cpu_var(boot_pageset);

Ummm... this scares me a little bit. Before it was a pointer to
statically allocated area which can be used from basically anywhere.
Now, it's being initialized to a percpu pointer which won't be
available before setup_per_cpu_areas() is complete and the above
initialization takes place from setup_arch() which is before percpu
initialization. I don't think there's anything which would access
page allocator between the two places, but it still seems a bit risky.
Maybe it's better to keep the boot_pageset a static array? Or am I
misunderstanding something?

Thanks.

--
tejun
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