raxix-tree: introduce CONFIG_RADIX_TREE_MULTIORDER

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@linux.intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/Kconfig b/lib/Kconfig
index 61d55bd0ed898d0fc3945d1f0445a94ae7bfca35..d79909dc01ec8365ab1cf29b1c7ce6dd4c78b0ab 100644 (file)
--- 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 1624c41179614321728bcdd878c7fb4153a91748..799f341977d05884464288df057fee70dde5e67c 100644 (file)
--- 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 1a6a28ebcb8b7fe85d266fcb113a0b882931e61c..2664c118b5d2eea6eee0aae18b9f62c333790a4e 100644 (file)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -404,6 +404,7 @@ 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 31fe2c77d7aee3f430046622f0fc878ca26f4dde..8ea0ed4508104be56b74fe4f9488113f3cde0819 100644 (file)
--- 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