Re: [PATCH v2 1/4] introduce zero filled pages handler

[Konrad Rzeszutek Wilk]

On Sat, Mar 16, 2013 at 2:24 PM, Dan Magenheimer
<dan.magenheimer@xxxxxxxxxx> wrote:
>> From: Konrad Rzeszutek Wilk [mailto:konrad@xxxxxxxxxx]
>> Subject: Re: [PATCH v2 1/4] introduce zero filled pages handler
>>
>> > +
>> > +   for (pos = 0; pos < PAGE_SIZE / sizeof(*page); pos++) {
>> > +           if (page[pos])
>> > +                   return false;
>>
>> Perhaps allocate a static page filled with zeros and just do memcmp?
>
> That seems like a bad idea.  Why compare two different
> memory locations when comparing one memory location
> to a register will do?
>

Good point. I was hoping there was an fast memcmp that would
do fancy SSE registers. But it is memory against memory instead of
registers.

Perhaps a cunning trick would be to check (as a shortcircuit)
check against 'empty_zero_page' and if that check fails, then try
to do the check for each byte in the code?

>
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