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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>
This commit is contained in:
Matthew Wilcox 2016-05-20 17:01:54 -07:00 committed by Linus Torvalds
parent 6c4bd68a29
commit 57578c2ea2
4 changed files with 23 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
lib/Kconfig
View File

@ -362,6 +362,9 @@ config INTERVAL_TREE
for more information.
config RADIX_TREE_MULTIORDER
bool
config ASSOCIATIVE_ARRAY
bool
help

26
lib/radix-tree.c
View File

@ -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--;

1
mm/Kconfig
View File

@ -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.

1
tools/testing/radix-tree/linux/kernel.h
View File

@ -9,6 +9,7 @@
#include "../../include/linux/compiler.h"
#define CONFIG_RADIX_TREE_MULTIORDER
#define CONFIG_SHMEM
#define CONFIG_SWAP