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-rw-r--r--mm/cma.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/mm/cma.c b/mm/cma.c
index 20c4f6f40037..0ba69cd16aeb 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -336,6 +336,23 @@ int __init cma_declare_contiguous_nid(phys_addr_t base,
limit = highmem_start;
}
+ /*
+ * If there is enough memory, try a bottom-up allocation first.
+ * It will place the new cma area close to the start of the node
+ * and guarantee that the compaction is moving pages out of the
+ * cma area and not into it.
+ * Avoid using first 4GB to not interfere with constrained zones
+ * like DMA/DMA32.
+ */
+#ifdef CONFIG_PHYS_ADDR_T_64BIT
+ if (!memblock_bottom_up() && memblock_end >= SZ_4G + size) {
+ memblock_set_bottom_up(true);
+ addr = memblock_alloc_range_nid(size, alignment, SZ_4G,
+ limit, nid, true);
+ memblock_set_bottom_up(false);
+ }
+#endif
+
if (!addr) {
addr = memblock_alloc_range_nid(size, alignment, base,
limit, nid, true);