On Saturday 09 November 2013 11:55 AM, Konrad Rzeszutek Wilk wrote:

Santosh Shilimkar [off-list ref] wrote:

quoted

Switch to memblock interfaces for early memory allocator instead of
bootmem allocator. No functional change in beahvior than what it is
in current code from bootmem users points of view.

Archs already converted to NO_BOOTMEM now directly use memblock
interfaces instead of bootmem wrappers build on top of memblock. And
the
archs which still uses bootmem, these new apis just fallback to exiting
bootmem APIs.

Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Konrad Rzeszutek Wilk <redacted>

Signed-off-by: Santosh Shilimkar <redacted>
---
lib/swiotlb.c |   36 +++++++++++++++++++++---------------
1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 4e8686c..78ac01a 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c

@@ -169,8 +169,9 @@ int __init swiotlb_init_with_tbl(char *tlb,

unsigned long nslabs, int verbose)
	/*
	 * Get the overflow emergency buffer
	 */
-	v_overflow_buffer = alloc_bootmem_low_pages_nopanic(
-						PAGE_ALIGN(io_tlb_overflow));
+	v_overflow_buffer = memblock_virt_alloc_align_nopanic(
+						PAGE_ALIGN(io_tlb_overflow),
+						PAGE_SIZE);

Does this guarantee that the pages will be allocated below 4GB?

Yes. The memblock layer still allocates memory from lowmem. As I
mentioned, there is no change in the behavior than what is today
apart from just the interface change.

Regards,
Santosh