From: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Calculate how many nodes we need to allocate to split an old_order entry
into multiple entries, each of size new_order. The test suite checks that
we allocated exactly the right number of nodes; neither too many (checked
by rtp->nr == 0), nor too few (checked by comparing nr_allocated before
and after the call to radix_tree_split()).
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
---
include/linux/radix-tree.h | 1 +
lib/radix-tree.c | 24 +++++++++++++++++++++++-
tools/testing/radix-tree/multiorder.c | 32 ++++++++++++++++++++++++++++++--
tools/testing/radix-tree/test.h | 5 +++++
4 files changed, 59 insertions(+), 3 deletions(-)
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index f5518f1..8ffb051 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -319,6 +319,7 @@ static inline void radix_tree_preload_end(void)
preempt_enable();
}
+int radix_tree_split_preload(unsigned old_order, unsigned new_order, gfp_t);
int radix_tree_split(struct radix_tree_root *, unsigned long index,
unsigned new_order);
int radix_tree_join(struct radix_tree_root *, unsigned long index,
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index eaf0f353..6d73575 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -344,7 +344,7 @@ radix_tree_node_free(struct radix_tree_node *node)
* To make use of this facility, the radix tree must be initialised without
* __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE().
*/
-static int __radix_tree_preload(gfp_t gfp_mask, int nr)
+static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
{
struct radix_tree_preload *rtp;
struct radix_tree_node *node;
@@ -410,6 +410,28 @@ int radix_tree_maybe_preload(gfp_t gfp_mask)
}
EXPORT_SYMBOL(radix_tree_maybe_preload);
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+/*
+ * Preload with enough objects to ensure that we can split a single entry
+ * of order @old_order into many entries of size @new_order
+ */
+int radix_tree_split_preload(unsigned int old_order, unsigned int new_order,
+ gfp_t gfp_mask)
+{
+ unsigned top = 1 << (old_order % RADIX_TREE_MAP_SHIFT);
+ unsigned layers = (old_order / RADIX_TREE_MAP_SHIFT) -
+ (new_order / RADIX_TREE_MAP_SHIFT);
+ unsigned nr = 0;
+
+ WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask));
+ BUG_ON(new_order >= old_order);
+
+ while (layers--)
+ nr = nr * RADIX_TREE_MAP_SIZE + 1;
+ return __radix_tree_preload(gfp_mask, top * nr);
+}
+#endif
+
/*
* The same as function above, but preload number of nodes required to insert
* (1 << order) continuous naturally-aligned elements.
diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c
index d9e8155..25e0463 100644
--- a/tools/testing/radix-tree/multiorder.c
+++ b/tools/testing/radix-tree/multiorder.c
@@ -356,18 +356,46 @@ static void multiorder_join(void)
}
}
+static void check_mem(unsigned old_order, unsigned new_order, unsigned alloc)
+{
+ struct radix_tree_preload *rtp = &radix_tree_preloads;
+ if (rtp->nr != 0)
+ printf("split(%u %u) remaining %u\n", old_order, new_order,
+ rtp->nr);
+ /*
+ * Can't check for equality here as some nodes may have been
+ * RCU-freed while we ran. But we should never finish with more
+ * nodes allocated since they should have all been preloaded.
+ */
+ if (nr_allocated > alloc)
+ printf("split(%u %u) allocated %u %u\n", old_order, new_order,
+ alloc, nr_allocated);
+}
+
static void __multiorder_split(int old_order, int new_order)
{
- RADIX_TREE(tree, GFP_KERNEL);
+ RADIX_TREE(tree, GFP_ATOMIC);
void **slot;
struct radix_tree_iter iter;
+ unsigned alloc;
+
+ radix_tree_preload(GFP_KERNEL);
+ assert(item_insert_order(&tree, 0, old_order) == 0);
+ radix_tree_preload_end();
+
+ /* Wipe out the preloaded cache or it'll confuse check_mem() */
+ radix_tree_callback(NULL, CPU_DEAD, NULL);
- item_insert_order(&tree, 0, old_order);
radix_tree_tag_set(&tree, 0, 2);
+
+ radix_tree_split_preload(old_order, new_order, GFP_KERNEL);
+ alloc = nr_allocated;
radix_tree_split(&tree, 0, new_order);
+ check_mem(old_order, new_order, alloc);
radix_tree_for_each_slot(slot, &tree, &iter, 0) {
radix_tree_replace_slot(slot, item_create(iter.index));
}
+ radix_tree_preload_end();
item_kill_tree(&tree);
}
diff --git a/tools/testing/radix-tree/test.h b/tools/testing/radix-tree/test.h
index f2dc35f..33d2b6b 100644
--- a/tools/testing/radix-tree/test.h
+++ b/tools/testing/radix-tree/test.h
@@ -49,3 +49,8 @@ unsigned long node_maxindex(struct radix_tree_node *);
unsigned long shift_maxindex(unsigned int shift);
int radix_tree_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu);
+struct radix_tree_preload {
+ unsigned nr;
+ struct radix_tree_node *nodes;
+};
+extern struct radix_tree_preload radix_tree_preloads;
--
2.10.2
--
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