On Wed, Dec 15, 2010 at 09:34:27PM +0100, Michal Nazarewicz wrote:

quoted

+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 [off-list ref] 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.

quoted

+	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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