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SubjectRe: per_cpu_ptr_to_phys() failure on UV x86_64

On Thu, Jun 17, 2010 at 07:35:16PM +0200, Tejun Heo wrote:
> On 06/17/2010 07:08 PM, Tejun Heo wrote:
> > (scratching head...) So, that means it's given an address for which
> > !pcpu_addr_in_first_chunk() but outside of vmalloc area. Strange.
> > I'll find out what's going on.
>
> Does the following patch work? The original patch assumed that @addr
> would be the address of the base cpu which isn't true. I only compile
> tested the patch so it might be broken (sorry, I gotta go somewhere
> now) but this should be the right direction.

Yes, your patch works. I tested it on a 32p UV system.

-Cliff

> diff --git a/mm/percpu.c b/mm/percpu.c
> index 46485e1..8956155 100644
> --- a/mm/percpu.c
> +++ b/mm/percpu.c
> @@ -978,14 +978,23 @@ bool is_kernel_percpu_address(unsigned long addr)
> */
> phys_addr_t per_cpu_ptr_to_phys(void *addr)
> {
> - if (pcpu_addr_in_first_chunk(addr)) {
> - if ((unsigned long)addr < VMALLOC_START ||
> - (unsigned long)addr >= VMALLOC_END)
> - return __pa(addr);
> - else
> - return page_to_phys(vmalloc_to_page(addr));
> - } else
> - return page_to_phys(pcpu_addr_to_page(addr));
> + void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
> + unsigned int cpu;
> +
> + for_each_possible_cpu(cpu) {
> + void *start = per_cpu_ptr(base, cpu);
> +
> + if (addr >= start && addr < start + pcpu_unit_size) {
> + /* in the first chunk */
> + if ((unsigned long)addr < VMALLOC_START ||
> + (unsigned long)addr >= VMALLOC_END)
> + return __pa(addr);
> + else
> + return page_to_phys(vmalloc_to_page(addr));
> + }
> + }
> + /* in one of the other chunks */
> + return page_to_phys(pcpu_addr_to_page(addr));
> }
>
> static inline size_t pcpu_calc_fc_sizes(size_t static_size,
>
>
> --
> tejun

--
Cliff Wickman
SGI
cpw@sgi.com
(651) 683-3824


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