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From: John Baldwin <jhb@freebsd.org>
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Cc: kalash nainwal <kalash.nainwal@gmail.com>
Subject: Re: how to do page level mem alloc in freebsd kernel?
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On Thursday, July 15, 2010 6:28:53 am kalash nainwal wrote:
> Hi,
> 
> I want to allocate one (or more) pages in kernel space.
> I'm not sure what is the api in freebsd (something which
> is similar to __get_free_pages() of linux).
> 
> Would malloc(4096, ...) guarantee that the returned
> address is aligned on page boundary?

Well, malloc(PAGE_SIZE) will align it on a page boundary. :)  malloc(4096) 
will be aligned on a 4096-byte boundary if PAGE_SIZE is >= 4096.  My 
understanding is that objects returned from malloc() are aligned to the 
smallest power-of-2 value >= the requested size up to a page.  Allocations 
larger than a page are page aligned.  So a malloc of 24 bytes or 32 bytes is 
32-byte aligned for example.

-- 
John Baldwin