libhsakmt: change memory allocation alignment

it is to optimize memory allocation latency, which
changes alignment from 2MB to 1GB.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Signed-off-by: Eric Huang <jinhuieric.huang@amd.com>
Change-Id: I7818e9f13b17e2c0992e75b17f978dc03a018a57

src/fmm.c

@@ -714,10 +714,10 @@ static void *mmap_aperture_allocate_aligned(manageable_aperture_t *aper,
 		return NULL;
 	}
 
-	/* Align big buffers to the next power-of-2 up to huge page
-	 * size for flexible fragment size TLB optimizations
+	/* Align big buffers to the next power-of-2 up to 1GB
+	 * size for memory allocation optimization
 	 */
-	while (align < GPU_HUGE_PAGE_SIZE && size >= (align << 1))
+	while (align < GPU_GIANT_PAGE_SIZE && size >= (align << 1))
 		align <<= 1;
 
 	/* Add padding to guarantee proper alignment and leave guard

src/libhsakmt.h

@@ -72,6 +72,7 @@ extern int PAGE_SHIFT;
 
 /* 2MB huge page size for 4-level page tables on Vega10 and later GPUs */
 #define GPU_HUGE_PAGE_SIZE (2 << 20)
+#define GPU_GIANT_PAGE_SIZE (1 << 30)
 
 #define CHECK_PAGE_MULTIPLE(x) \
 	do { if ((uint64_t)PORT_VPTR_TO_UINT64(x) % PAGE_SIZE) return HSAKMT_STATUS_INVALID_PARAMETER; } while(0)