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SubjectRe: [PATCHv8 07/12] mm: cma: Contiguous Memory Allocator added
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> On Wed, Dec 15, 2010 at 09:34:27PM +0100, Michal Nazarewicz wrote:
>> +unsigned long cma_reserve(unsigned long start, unsigned long size,
>> + unsigned long alignment)
>> +{
>> + pr_debug("%s(%p+%p/%p)\n", __func__, (void *)start, (void *)size,
>> + (void *)alignment);
>> +
>> + /* Sanity checks */
>> + if (!size || (alignment & (alignment - 1)))
>> + return (unsigned long)-EINVAL;
>> +
>> + /* Sanitise input arguments */
>> + start = PAGE_ALIGN(start);
>> + size = PAGE_ALIGN(size);
>> + if (alignment < PAGE_SIZE)
>> + alignment = PAGE_SIZE;
>> +
>> + /* Reserve memory */
>> + if (start) {
>> + if (memblock_is_region_reserved(start, size) ||
>> + memblock_reserve(start, size) < 0)
>> + return (unsigned long)-EBUSY;
>> + } else {
>> + /*
>> + * Use __memblock_alloc_base() since
>> + * memblock_alloc_base() panic()s.
>> + */
>> + u64 addr = __memblock_alloc_base(size, alignment, 0);
>> + if (!addr) {
>> + return (unsigned long)-ENOMEM;
>> + } else if (addr + size > ~(unsigned long)0) {
>> + memblock_free(addr, size);
>> + return (unsigned long)-EOVERFLOW;
>> + } else {
>> + start = addr;
>> + }
>> + }
>> +

On Wed, 02 Feb 2011 13:43:33 +0100, Ankita Garg <ankita@in.ibm.com> wrote:
> Reserving the areas of memory belonging to CMA using memblock_reserve,
> would preclude that range from the zones, due to which it would not be
> available for buddy allocations right ?

Correct. CMA however, injects allocated pageblocks to buddy so they end
up in buddy with migratetype set to MIGRATE_CMA.

>> + return start;
>> +}

--
Best regards, _ _
.o. | Liege of Serenly Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michal "mina86" Nazarewicz (o o)
ooo +-<email/jid: mnazarewicz@google.com>--------ooO--(_)--Ooo--


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