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Commit c555e520 authored by Dave Hansen's avatar Dave Hansen Committed by Benjamin Herrenschmidt
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powerpc/mm: Add better comment on careful_allocation() 



The behavior in careful_allocation() really confused me
at first.  Add a comment to hopefully make it easier
on the next doofus that looks at it.

Signed-off-by: default avatarDave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent afcb0654

arch/powerpc/mm/numa.c

+10 −2
Original line number Diff line number Diff line
@@ -840,8 +840,16 @@ static void __init *careful_allocation(int nid, unsigned long size, 
		      size, nid);



	/*

	 * If the memory came from a previously allocated node, we must

	 * retry with the bootmem allocator.

	 * We initialize the nodes in numeric order: 0, 1, 2...

	 * and hand over control from the LMB allocator to the

	 * bootmem allocator.  If this function is called for

	 * node 5, then we know that all nodes <5 are using the

	 * bootmem allocator instead of the LMB allocator.

	 *

	 * So, check the nid from which this allocation came

	 * and double check to see if we need to use bootmem

	 * instead of the LMB.  We don't free the LMB memory

	 * since it would be useless.

	 */

	new_nid = early_pfn_to_nid(ret >> PAGE_SHIFT);

	if (new_nid < nid) {