[PATCHv3 08/41] Revert "radix-tree: implement radix_tree_maybe_preload_order()"

Kirill A. Shutemov
2016-09-15T11:54:50Z

This reverts commit 356e1c23292a4f63cfdf1daf0e0ddada51f32de8.

After conversion of huge tmpfs to multi-order entries, we don't need
this anymore.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
include/linux/radix-tree.h | 1 -
lib/radix-tree.c | 74 ----------------------------------------------
2 files changed, 75 deletions(-)

diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index c4cea311d901..7a271f662320 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -290,7 +290,6 @@ unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root,
unsigned long first_index, unsigned int max_items);
int radix_tree_preload(gfp_t gfp_mask);
int radix_tree_maybe_preload(gfp_t gfp_mask);
-int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order);
void radix_tree_init(void);
void *radix_tree_tag_set(struct radix_tree_root *root,
unsigned long index, unsigned int tag);
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 57c15c4d0796..307e517b2479 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -38,9 +38,6 @@
#include <linux/preempt.h> /* in_interrupt() */

-/* Number of nodes in fully populated tree of given height */
-static unsigned long height_to_maxnodes[RADIX_TREE_MAX_PATH + 1] __read_mostly;
-
/*
* Radix tree node cache.
*/
@@ -433,51 +430,6 @@ int radix_tree_split_preload(unsigned int old_order, unsigned int new_order,
#endif

/*
- * The same as function above, but preload number of nodes required to insert
- * (1 << order) continuous naturally-aligned elements.
- */
-int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order)
-{
- unsigned long nr_subtrees;
- int nr_nodes, subtree_height;
-
- /* Preloading doesn't help anything with this gfp mask, skip it */
- if (!gfpflags_allow_blocking(gfp_mask)) {
- preempt_disable();
- return 0;
- }
-
- /*
- * Calculate number and height of fully populated subtrees it takes to
- * store (1 << order) elements.
- */
- nr_subtrees = 1 << order;
- for (subtree_height = 0; nr_subtrees > RADIX_TREE_MAP_SIZE;
- subtree_height++)
- nr_subtrees >>= RADIX_TREE_MAP_SHIFT;
-
- /*
- * The worst case is zero height tree with a single item at index 0 and
- * then inserting items starting at ULONG_MAX - (1 << order).
- *
- * This requires RADIX_TREE_MAX_PATH nodes to build branch from root to
- * 0-index item.
- */
- nr_nodes = RADIX_TREE_MAX_PATH;
-
- /* Plus branch to fully populated subtrees. */
- nr_nodes += RADIX_TREE_MAX_PATH - subtree_height;
-
- /* Root node is shared. */
- nr_nodes--;
-
- /* Plus nodes required to build subtrees. */
- nr_nodes += nr_subtrees * height_to_maxnodes[subtree_height];
-
- return __radix_tree_preload(gfp_mask, nr_nodes);
-}
-
-/*
* The maximum index which can be stored in a radix tree
*/
static inline unsigned long shift_maxindex(unsigned int shift)
@@ -1856,31 +1808,6 @@ radix_tree_node_ctor(void *arg)
INIT_LIST_HEAD(&node->private_list);
}

-static __init unsigned long __maxindex(unsigned int height)
-{
- unsigned int width = height * RADIX_TREE_MAP_SHIFT;
- int shift = RADIX_TREE_INDEX_BITS - width;
-
- if (shift < 0)
- return ~0UL;
- if (shift >= BITS_PER_LONG)
- return 0UL;
- return ~0UL >> shift;
-}
-
-static __init void radix_tree_init_maxnodes(void)
-{
- unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1];
- unsigned int i, j;
-
- for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++)
- height_to_maxindex[i] = __maxindex(i);
- for (i = 0; i < ARRAY_SIZE(height_to_maxnodes); i++) {
- for (j = i; j > 0; j--)
- height_to_maxnodes[i] += height_to_maxindex[j - 1] + 1;
- }
-}
-
static int radix_tree_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
@@ -1907,6 +1834,5 @@ void __init radix_tree_init(void)
sizeof(struct radix_tree_node), 0,
SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
radix_tree_node_ctor);
- radix_tree_init_maxnodes();
hotcpu_notifier(radix_tree_callback, 0);
}