On Mon, 2019-09-23 at 12:58 -0700, John Hubbard wrote:
>
> CPU 0 CPU 1
> ------ --------------
> READ(pte) (re-ordered at run time)
> atomic_inc(val) (no run-time memory barrier!)
>
> pmd_clear(pte)
> if (val)
> run_on_all_cpus(): IPI
> local_irq_disable() (also not a mem barrier)
>
> if(pte)
> walk page tables
Let me see if I can understand,
On most patches, it would be:
CPU 0 CPU 1
------ --------------
ptep = __find_linux_pte
(re-ordered at run time)
atomic_inc(val)
pmd_clear(pte)
smp_mb()
if (val)
run_on_all_cpus(): IPI
local_irq_disable()
if(ptep)
pte = *ptep;
Is that what you meant?
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