Messages in this thread | | | Date | Fri, 25 Mar 2011 10:45:24 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: [GIT PULL] SLAB changes for v2.6.39-rc1 |
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On Fri, 25 Mar 2011, Tejun Heo wrote:
> I've looked through the code but can't figure out what the difference > is. The memset code is in mm/percpu-vm.c::pcpu_populate_chunk(). > > for_each_possible_cpu(cpu) > memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size); > > (pcpu_chunk_addr(chunk, cpu, 0) + off) is the same vaddr as will be > obtained by per_cpu_ptr(ptr, cpu), so all allocated memory regions are > accessed before being returned. Dazed and confused (seems like the > theme of today for me). > > Could it be that the vmalloc page is taking more than one faults?
The vmalloc page only contains per cpu data from a single cpu right?
Could anyone have set write access restrictions that would require a fault to get rid of?
Or does an access from a different cpu require a "page table sync"?
There is some rather strange looking code in arch/x86/mm/fault.c:vmalloc_fault
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