From 2791653a6814d170fa893344618563a7b1da95c6 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 14 Dec 2016 15:09:04 -0800 Subject: [PATCH] radix-tree: add radix_tree_split_preload() 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()). Link: http://lkml.kernel.org/r/1480369871-5271-60-git-send-email-mawilcox@linuxonhyperv.com Signed-off-by: Matthew Wilcox Tested-by: Kirill A. Shutemov Cc: Konstantin Khlebnikov Cc: Ross Zwisler Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/radix-tree.h | 1 + lib/radix-tree.c | 24 ++++++++++++++- tools/testing/radix-tree/multiorder.c | 42 +++++++++++++++++++++++++-- tools/testing/radix-tree/test.h | 5 ++++ 4 files changed, 69 insertions(+), 3 deletions(-) diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 1f4b56120de8..5dea8f6440e4 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -345,6 +345,7 @@ 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 ade2ed3f5190..be1183e62590 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -368,7 +368,7 @@ 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; @@ -434,6 +434,28 @@ 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 fa6effe997a3..5421f015f46c 100644 --- a/tools/testing/radix-tree/multiorder.c +++ b/tools/testing/radix-tree/multiorder.c @@ -389,35 +389,67 @@ 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; struct radix_tree_node *node; void *item; + 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_cpu_dead(0); - 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_iter_replace(&tree, &iter, slot, item_create(iter.index, new_order)); } + radix_tree_preload_end(); item_kill_tree(&tree); + radix_tree_preload(GFP_KERNEL); __radix_tree_insert(&tree, 0, old_order, (void *)0x12); + radix_tree_preload_end(); item = __radix_tree_lookup(&tree, 0, &node, NULL); assert(item == (void *)0x12); assert(node->exceptional > 0); + radix_tree_split_preload(old_order, new_order, GFP_KERNEL); radix_tree_split(&tree, 0, new_order); radix_tree_for_each_slot(slot, &tree, &iter, 0) { radix_tree_iter_replace(&tree, &iter, slot, item_create(iter.index, new_order)); } + radix_tree_preload_end(); item = __radix_tree_lookup(&tree, 0, &node, NULL); assert(item != (void *)0x12); @@ -425,16 +457,20 @@ static void __multiorder_split(int old_order, int new_order) item_kill_tree(&tree); + radix_tree_preload(GFP_KERNEL); __radix_tree_insert(&tree, 0, old_order, (void *)0x12); + radix_tree_preload_end(); item = __radix_tree_lookup(&tree, 0, &node, NULL); assert(item == (void *)0x12); assert(node->exceptional > 0); + radix_tree_split_preload(old_order, new_order, GFP_KERNEL); radix_tree_split(&tree, 0, new_order); radix_tree_for_each_slot(slot, &tree, &iter, 0) { radix_tree_iter_replace(&tree, &iter, slot, (void *)0x16); } + radix_tree_preload_end(); item = __radix_tree_lookup(&tree, 0, &node, NULL); assert(item == (void *)0x16); @@ -471,4 +507,6 @@ void multiorder_checks(void) multiorder_tagged_iteration(); multiorder_join(); multiorder_split(); + + radix_tree_cpu_dead(0); } diff --git a/tools/testing/radix-tree/test.h b/tools/testing/radix-tree/test.h index e11e4d260b4e..7c2611caa6d2 100644 --- a/tools/testing/radix-tree/test.h +++ b/tools/testing/radix-tree/test.h @@ -52,3 +52,8 @@ int root_tag_get(struct radix_tree_root *root, unsigned int tag); unsigned long node_maxindex(struct radix_tree_node *); unsigned long shift_maxindex(unsigned int shift); int radix_tree_cpu_dead(unsigned int cpu); +struct radix_tree_preload { + unsigned nr; + struct radix_tree_node *nodes; +}; +extern struct radix_tree_preload radix_tree_preloads;