The patch titled
radixtree: hole scanning functions
has been added to the -mm tree. Its filename is
radixtree-hole-scanning-functions.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: radixtree: hole scanning functions
From: Wu Fengguang <wfg@xxxxxxxxxxxxxxxx>
Introduce a pair of functions to scan radix tree for hole/empty item.
Signed-off-by: Wu Fengguang <wfg@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
include/linux/radix-tree.h | 4 +
lib/radix-tree.c | 104 +++++++++++++++++++++++++++++++++++
2 files changed, 108 insertions(+)
diff -puN include/linux/radix-tree.h~radixtree-hole-scanning-functions include/linux/radix-tree.h
--- 25/include/linux/radix-tree.h~radixtree-hole-scanning-functions Wed May 24 16:48:50 2006
+++ 25-akpm/include/linux/radix-tree.h Wed May 24 16:48:50 2006
@@ -74,6 +74,10 @@ unsigned int radix_tree_cache_count(stru
void *radix_tree_cache_lookup_parent(struct radix_tree_root *root,
struct radix_tree_cache *cache,
unsigned long index, unsigned int level);
+unsigned long radix_tree_scan_hole_backward(struct radix_tree_root *root,
+ unsigned long index, unsigned long max_scan);
+unsigned long radix_tree_scan_hole(struct radix_tree_root *root,
+ unsigned long index, unsigned long max_scan);
unsigned int
radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
unsigned long first_index, unsigned int max_items);
diff -puN lib/radix-tree.c~radixtree-hole-scanning-functions lib/radix-tree.c
--- 25/lib/radix-tree.c~radixtree-hole-scanning-functions Wed May 24 16:48:50 2006
+++ 25-akpm/lib/radix-tree.c Wed May 24 16:48:50 2006
@@ -426,6 +426,110 @@ unsigned int radix_tree_cache_count(stru
EXPORT_SYMBOL(radix_tree_cache_count);
/**
+ * radix_tree_scan_hole_backward - scan backward for hole
+ * @root: radix tree root
+ * @index: index key
+ * @max_scan: advice on max items to scan (it may scan a little more)
+ *
+ * Scan backward from @index for a hole/empty item, stop when
+ * - hit hole
+ * - @max_scan or more items scanned
+ * - hit index 0
+ *
+ * Return the correponding index.
+ */
+unsigned long radix_tree_scan_hole_backward(struct radix_tree_root *root,
+ unsigned long index, unsigned long max_scan)
+{
+ struct radix_tree_cache cache;
+ struct radix_tree_node *node;
+ unsigned long origin;
+ int i;
+
+ origin = index;
+ radix_tree_cache_init(&cache);
+
+ while (origin - index < max_scan) {
+ node = radix_tree_cache_lookup_parent(root, &cache, index, 1);
+ if (!node)
+ break;
+
+ if (node->count == RADIX_TREE_MAP_SIZE) {
+ index = (index - RADIX_TREE_MAP_SIZE) |
+ RADIX_TREE_MAP_MASK;
+ goto check_underflow;
+ }
+
+ for (i = index & RADIX_TREE_MAP_MASK; i >= 0; i--, index--) {
+ if (!node->slots[i])
+ goto out;
+ }
+
+check_underflow:
+ if (unlikely(index == ULONG_MAX)) {
+ index = 0;
+ break;
+ }
+ }
+
+out:
+ return index;
+}
+EXPORT_SYMBOL(radix_tree_scan_hole_backward);
+
+/**
+ * radix_tree_scan_hole - scan for hole
+ * @root: radix tree root
+ * @index: index key
+ * @max_scan: advice on max items to scan (it may scan a little more)
+ *
+ * Scan forward from @index for a hole/empty item, stop when
+ * - hit hole
+ * - hit EOF
+ * - hit index ULONG_MAX
+ * - @max_scan or more items scanned
+ *
+ * Return the correponding index.
+ */
+unsigned long radix_tree_scan_hole(struct radix_tree_root *root,
+ unsigned long index, unsigned long max_scan)
+{
+ struct radix_tree_cache cache;
+ struct radix_tree_node *node;
+ unsigned long origin;
+ int i;
+
+ origin = index;
+ radix_tree_cache_init(&cache);
+
+ while (index - origin < max_scan) {
+ node = radix_tree_cache_lookup_parent(root, &cache, index, 1);
+ if (!node)
+ break;
+
+ if (node->count == RADIX_TREE_MAP_SIZE) {
+ index = (index | RADIX_TREE_MAP_MASK) + 1;
+ goto check_overflow;
+ }
+
+ for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE;
+ i++, index++) {
+ if (!node->slots[i])
+ goto out;
+ }
+
+check_overflow:
+ if (unlikely(!index)) {
+ index = ULONG_MAX;
+ break;
+ }
+ }
+out:
+ return index;
+}
+EXPORT_SYMBOL(radix_tree_scan_hole);
+
+/**
* radix_tree_tag_set - set a tag on a radix tree node
* @root: radix tree root
* @index: index key
_
Patches currently in -mm which might be from wfg@xxxxxxxxxxxxxxxx are
readahead-kconfig-options.patch
radixtree-look-aside-cache.patch
radixtree-hole-scanning-functions.patch
readahead-page-flag-pg_readahead.patch
readahead-refactor-do_generic_mapping_read.patch
readahead-refactor-__do_page_cache_readahead.patch
readahead-insert-cond_resched-calls.patch
readahead-common-macros.patch
readahead-events-accounting.patch
readahead-support-functions.patch
readahead-sysctl-parameters.patch
readahead-min-max-sizes.patch
readahead-state-based-method-aging-accounting.patch
readahead-state-based-method-data-structure.patch
readahead-state-based-method-routines.patch
readahead-state-based-method.patch
readahead-context-based-method.patch
readahead-initial-method-guiding-sizes.patch
readahead-initial-method-thrashing-guard-size.patch
readahead-initial-method-expected-read-size.patch
readahead-initial-method-user-recommended-size.patch
readahead-initial-method.patch
readahead-backward-prefetching-method.patch
readahead-seeking-reads-method.patch
readahead-thrashing-recovery-method.patch
readahead-call-scheme.patch
readahead-laptop-mode.patch
readahead-loop-case.patch
readahead-nfsd-case.patch
readahead-turn-on-by-default.patch
readahead-debug-radix-tree-new-functions.patch
readahead-debug-traces-showing-accessed-file-names.patch
readahead-debug-traces-showing-read-patterns.patch
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