The patch titled
Subject: DMA, CMA: support alignment constraint on CMA region
has been added to the -mm tree. Its filename is
dma-cma-support-alignment-constraint-on-cma-region.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/dma-cma-support-alignment-constraint-on-cma-region.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/dma-cma-support-alignment-constraint-on-cma-region.patch
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From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Subject: DMA, CMA: support alignment constraint on CMA region
PPC KVM's CMA area management needs alignment constraint on CMA region.
So support it to prepare generalization of CMA area management
functionality.
Additionally, add some comments which tell us why alignment
constraint is needed on CMA region.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Alexander Graf <agraf@xxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Gleb Natapov <gleb@xxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/dma-contiguous.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff -puN drivers/base/dma-contiguous.c~dma-cma-support-alignment-constraint-on-cma-region drivers/base/dma-contiguous.c
--- a/drivers/base/dma-contiguous.c~dma-cma-support-alignment-constraint-on-cma-region
+++ a/drivers/base/dma-contiguous.c
@@ -32,6 +32,7 @@
#include <linux/swap.h>
#include <linux/mm_types.h>
#include <linux/dma-contiguous.h>
+#include <linux/log2.h>
struct cma {
unsigned long base_pfn;
@@ -215,17 +216,16 @@ core_initcall(cma_init_reserved_areas);
static int __init __dma_contiguous_reserve_area(phys_addr_t size,
phys_addr_t base, phys_addr_t limit,
+ phys_addr_t alignment,
struct cma **res_cma, bool fixed)
{
struct cma *cma = &cma_areas[cma_area_count];
- phys_addr_t alignment;
int ret = 0;
- pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
- (unsigned long)size, (unsigned long)base,
- (unsigned long)limit);
+ pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
+ __func__, (unsigned long)size, (unsigned long)base,
+ (unsigned long)limit, (unsigned long)alignment);
- /* Sanity checks */
if (cma_area_count == ARRAY_SIZE(cma_areas)) {
pr_err("Not enough slots for CMA reserved regions!\n");
return -ENOSPC;
@@ -234,8 +234,17 @@ static int __init __dma_contiguous_reser
if (!size)
return -EINVAL;
- /* Sanitise input arguments */
- alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+ if (alignment && !is_power_of_2(alignment))
+ return -EINVAL;
+
+ /*
+ * Sanitise input arguments.
+ * Pages both ends in CMA area could be merged into adjacent unmovable
+ * migratetype page by page allocator's buddy algorithm. In the case,
+ * you couldn't get a contiguous memory, which is not what we want.
+ */
+ alignment = max(alignment,
+ (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
base = ALIGN(base, alignment);
size = ALIGN(size, alignment);
limit &= ~(alignment - 1);
@@ -299,7 +308,8 @@ int __init dma_contiguous_reserve_area(p
{
int ret;
- ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
+ ret = __dma_contiguous_reserve_area(size, base, limit, 0,
+ res_cma, fixed);
if (ret)
return ret;
_
Patches currently in -mm which might be from iamjoonsoo.kim@xxxxxxx are
slab-maintainer-update.patch
slab-fix-oops-when-reading-proc-slab_allocators.patch
mm-slabc-add-__init-to-init_lock_keys.patch
slab-common-add-functions-for-kmem_cache_node-access.patch
slub-use-new-node-functions.patch
slub-use-new-node-functions-fix.patch
slab-use-get_node-and-kmem_cache_node-functions.patch
slab-use-get_node-and-kmem_cache_node-functions-fix.patch
mm-slabh-wrap-the-whole-file-with-guarding-macro.patch
vmalloc-use-rcu-list-iterator-to-reduce-vmap_area_lock-contention.patch
memcg-cleanup-memcg_cache_params-refcnt-usage.patch
memcg-destroy-kmem-caches-when-last-slab-is-freed.patch
memcg-mark-caches-that-belong-to-offline-memcgs-as-dead.patch
slub-dont-fail-kmem_cache_shrink-if-slab-placement-optimization-fails.patch
slub-make-slab_free-non-preemptable.patch
memcg-wait-for-kfrees-to-finish-before-destroying-cache.patch
slub-make-dead-memcg-caches-discard-free-slabs-immediately.patch
slab-do-not-keep-free-objects-slabs-on-dead-memcg-caches.patch
dma-cma-fix-possible-memory-leak.patch
dma-cma-separate-core-cma-management-codes-from-dma-apis.patch
dma-cma-support-alignment-constraint-on-cma-region.patch
dma-cma-support-arbitrary-bitmap-granularity.patch
dma-cma-support-arbitrary-bitmap-granularity-fix.patch
cma-generalize-cma-reserved-area-management-functionality.patch
ppc-kvm-cma-use-general-cma-reserved-area-management-framework.patch
mm-cma-clean-up-cma-allocation-error-path.patch
mm-cma-change-cma_declare_contiguous-to-obey-coding-convention.patch
mm-cma-clean-up-log-message.patch
mm-compactionc-isolate_freepages_block-small-tuneup.patch
page-owners-correct-page-order-when-to-free-page.patch
--
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