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Commit d2cd563b authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
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memblock: Add arch function to control coalescing of memblock memory regions 



Some archs such as ARM want to avoid coalescing accross things such
as the lowmem/highmem boundary or similar. This provides the option
to control it via an arch callback for which a weak default is provided
which always allows coalescing.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 142b45a7

include/linux/memblock.h

+2 −0
Original line number Diff line number Diff line
@@ -72,6 +72,8 @@ extern void memblock_dump_all(void); 


/* Provided by the architecture */

extern phys_addr_t memblock_nid_range(phys_addr_t start, phys_addr_t end, int *nid);

extern int memblock_memory_can_coalesce(phys_addr_t addr1, phys_addr_t size1,

				   phys_addr_t addr2, phys_addr_t size2);



/**

 * memblock_set_current_limit - Set the current allocation limit to allow

mm/memblock.c

+18 −1
Original line number Diff line number Diff line
@@ -241,6 +241,12 @@ static int memblock_double_array(struct memblock_type *type) 
	return 0;

}



extern int __weak memblock_memory_can_coalesce(phys_addr_t addr1, phys_addr_t size1,

					  phys_addr_t addr2, phys_addr_t size2)

{

	return 1;

}



static long memblock_add_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size)

{

	unsigned long coalesced = 0;
@@ -262,6 +268,10 @@ static long memblock_add_region(struct memblock_type *type, phys_addr_t base, ph 
			return 0;



		adjacent = memblock_addrs_adjacent(base, size, rgnbase, rgnsize);

		/* Check if arch allows coalescing */

		if (adjacent != 0 && type == &memblock.memory &&

		    !memblock_memory_can_coalesce(base, size, rgnbase, rgnsize))

			break;

		if (adjacent > 0) {

			type->regions[i].base -= size;

			type->regions[i].size += size;
@@ -274,7 +284,14 @@ static long memblock_add_region(struct memblock_type *type, phys_addr_t base, ph 
		}

	}



	if ((i < type->cnt - 1) && memblock_regions_adjacent(type, i, i+1)) {

	/* If we plugged a hole, we may want to also coalesce with the

	 * next region

	 */

	if ((i < type->cnt - 1) && memblock_regions_adjacent(type, i, i+1) &&

	    ((type != &memblock.memory || memblock_memory_can_coalesce(type->regions[i].base,

							     type->regions[i].size,

							     type->regions[i+1].base,

							     type->regions[i+1].size)))) {

		memblock_coalesce_regions(type, i, i+1);

		coalesced++;

	}