<div dir="ltr">It is an arbitrary question that popped in my mind. However, I came to know that the constraints I stated in the previous mail is only restricted to x86 only.Now besides my first questions , I have one more question, Why x86 only?<div class="gmail_extra">
<br><br><div class="gmail_quote">On Tue, May 14, 2013 at 2:34 AM, Sergio Andrés Gómez del Real <span dir="ltr"><<a href="mailto:sergio.g.delreal@gmail.com" target="_blank">sergio.g.delreal@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Sure, I forgot what you said; precisely the mechanism allows to use<br>
lots of linear space without necessarily allocating physical memory<br>
(demand paging and the like).<br>
What about the rest of what I said? Is it correct or is there<br>
something wrong about it?<br>
Thanks.<br>
<div class="HOEnZb"><div class="h5"><br>
On 5/13/13, <a href="mailto:Valdis.Kletnieks@vt.edu">Valdis.Kletnieks@vt.edu</a> <<a href="mailto:Valdis.Kletnieks@vt.edu">Valdis.Kletnieks@vt.edu</a>> wrote:<br>
> On Mon, 13 May 2013 14:11:22 -0500, Sergio Andr said:<br>
><br>
>> 2. When user applications allocates memory, the kernel must allocate<br>
>> virtual memory and physical memory, right?<br>
><br>
> Wrong. If userspace allocates (say) 15M of memory, the kernel has every<br>
> right<br>
> to overcommit and not actually allocate either physical memory or backing<br>
> page<br>
> space for all 15M. It instead maps it as a non-existent virtual address,<br>
> and<br>
> if/when the application actually touches the page, it generates a page<br>
> fault,<br>
> and *then* the kernel does the allocating of physical memory and maybe swap<br>
> space.<br>
><br>
><br>
</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br><div><font face="'arial narrow', sans-serif" color="#C0C0C0"><b>Regards,</b></font></div><div><font face="'arial narrow', sans-serif" color="#C0C0C0"><b>Paul Davies C</b></font></div>
<a href="http://vivafoss.blogspot.com" target="_blank">vivafoss.blogspot.com</a>
</div></div>