Re: [PATCH] mm: Save soft-dirty bits on file pages

From: Pavel Emelyanov
Date: Mon Jul 29 2013 - 10:24:59 EST


On 07/29/2013 06:14 PM, Cyrill Gorcunov wrote:
> On Mon, Jul 29, 2013 at 06:08:55PM +0400, Pavel Emelyanov wrote:
>>>
>>> - if (!pte_none(*pte))
>>> + ptfile = pgoff_to_pte(pgoff);
>>> +
>>> + if (!pte_none(*pte)) {
>>> +#ifdef CONFIG_MEM_SOFT_DIRTY
>>> + if (pte_present(*pte) &&
>>> + pte_soft_dirty(*pte))
>>
>> I think there's no need in wrapping every such if () inside #ifdef CONFIG_...,
>> since the pte_soft_dirty() routine itself would be 0 for non-soft-dirty case
>> and compiler would optimize this code out.
>
> If only I'm not missing something obvious, this code compiles not only on x86,
> CONFIG_MEM_SOFT_DIRTY depends on x86 (otherwise I'll have to implement
> pte_soft_dirty for all archs).

For non-x86 case there are stubs in include/asm-generic/pgtable.h that would
act as if the CONFIG_MEM_SOFT_DIRTY is off.

Thanks,
Pavel
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