__get_free_pages and free_page

__get_free_pages and free_page

[Timur Tabi]

Let's say I allocate a block of memory with __get_free_pages, which requires
that I specify the order.  To free the memory, I need to call free_pages, also
specifying the same order.

What happens if I specify a smaller order?  Will it free a subset of that block?

Example:

	unsigned long addr;

	addr = __get_free_pages(GFP_ATOMIC, 3);  // allocate 2^3 pages = 32KB

	free_pages(addr, 2);			// frees the 1st 16KB only???

	addr += 16384;				// addr points to 2nd 16KB block

At this point, will addr point to a valid 16KB block of memory?  Will the heap
be intact?  Or will it screw things up?

This is with Linux 2.4.


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Timur Tabi - ttabi@interactivesi.com
Interactive Silicon - http://www.interactivesi.com

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