I've been receiving increasingly concerned notes from 0day about how much
my recent changes have been bloating the radix tree. Make it happier by
only including multiorder support if CONFIG_TRANSPARENT_HUGEPAGES is set.
This is an independent Kconfig option, so other radix tree users can
also set it if they have a need.
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
---
lib/Kconfig | 3 +++
lib/radix-tree.c | 26 ++++++++++++++++++--------
mm/Kconfig | 1 +
tools/testing/radix-tree/linux/kernel.h | 1 +
4 files changed, 23 insertions(+), 8 deletions(-)
diff --git a/lib/Kconfig b/lib/Kconfig
index 3cca122..56403a6 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -362,6 +362,9 @@ config INTERVAL_TREE
for more information.
+config RADIX_TREE_MULTIORDER
+ bool
+
config ASSOCIATIVE_ARRAY
bool
help
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 1624c41..799f341 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -484,6 +484,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
slot = node->slots[offset];
}
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
/* Insert pointers to the canonical entry */
if ((shift - order) > 0) {
int i, n = 1 << (shift - order);
@@ -499,6 +500,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
node->count++;
}
}
+#endif
if (nodep)
*nodep = node;
@@ -1469,6 +1471,20 @@ bool __radix_tree_delete_node(struct radix_tree_root *root,
return deleted;
}
+static inline void delete_sibling_entries(struct radix_tree_node *node,
+ void *ptr, unsigned offset)
+{
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+ int i;
+ for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
+ if (node->slots[offset + i] != ptr)
+ break;
+ node->slots[offset + i] = NULL;
+ node->count--;
+ }
+#endif
+}
+
/**
* radix_tree_delete_item - delete an item from a radix tree
* @root: radix tree root
@@ -1484,7 +1500,7 @@ void *radix_tree_delete_item(struct radix_tree_root *root,
unsigned long index, void *item)
{
struct radix_tree_node *node;
- unsigned int offset, i;
+ unsigned int offset;
void **slot;
void *entry;
int tag;
@@ -1513,13 +1529,7 @@ void *radix_tree_delete_item(struct radix_tree_root *root,
radix_tree_tag_clear(root, index, tag);
}
- /* Delete any sibling slots pointing to this slot */
- for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
- if (node->slots[offset + i] != ptr_to_indirect(slot))
- break;
- node->slots[offset + i] = NULL;
- node->count--;
- }
+ delete_sibling_entries(node, ptr_to_indirect(slot), offset);
node->slots[offset] = NULL;
node->count--;
diff --git a/mm/Kconfig b/mm/Kconfig
index 989f8f3..6d5b39e 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -393,6 +393,7 @@ config TRANSPARENT_HUGEPAGE
bool "Transparent Hugepage Support"
depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
select COMPACTION
+ select RADIX_TREE_MULTIORDER
help
Transparent Hugepages allows the kernel to use huge pages and
huge tlb transparently to the applications whenever possible.
diff --git a/tools/testing/radix-tree/linux/kernel.h b/tools/testing/radix-tree/linux/kernel.h
index 31fe2c77..8ea0ed4 100644
--- a/tools/testing/radix-tree/linux/kernel.h
+++ b/tools/testing/radix-tree/linux/kernel.h
@@ -9,6 +9,7 @@
#include "../../include/linux/compiler.h"
+#define CONFIG_RADIX_TREE_MULTIORDER
#define CONFIG_SHMEM
#define CONFIG_SWAP
--
2.8.0.rc3
--
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