radix-tree: delete radix_tree_range_tag_if_tagged()
This is an exceptionally complicated function with just one caller
(tag_pages_for_writeback). We devote a large portion of the runtime of
the test suite to testing this one function which has one caller. By
introducing the new function radix_tree_iter_tag_set(), we can eliminate
all of the complexity while keeping the performance. The caller can now
use a fairly standard radix_tree_for_each() loop, and it doesn't need to
worry about tricksy things like 'start' wrapping.
The test suite continues to spend a large amount of time investigating
this function, but now it's testing the underlying primitives such as
radix_tree_iter_resume() and the radix_tree_for_each_tagged() iterator
which are also used by other parts of the kernel.
Link: http://lkml.kernel.org/r/1480369871-5271-57-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/tools/testing/radix-tree/main.c b/tools/testing/radix-tree/main.c
index a028dae..170175c 100644
--- a/tools/testing/radix-tree/main.c
+++ b/tools/testing/radix-tree/main.c
@@ -205,8 +205,7 @@ void copy_tag_check(void)
}
// printf("\ncopying tags...\n");
- cur = start;
- tagged = radix_tree_range_tag_if_tagged(&tree, &cur, end, ITEMS, 0, 1);
+ tagged = tag_tagged_items(&tree, NULL, start, end, ITEMS, 0, 1);
// printf("checking copied tags\n");
assert(tagged == count);
@@ -214,16 +213,13 @@ void copy_tag_check(void)
/* Copy tags in several rounds */
// printf("\ncopying tags...\n");
- cur = start;
- do {
- tmp = rand() % (count/10+2);
- tagged = radix_tree_range_tag_if_tagged(&tree, &cur, end, tmp, 0, 2);
- } while (tmp == tagged);
+ tmp = rand() % (count / 10 + 2);
+ tagged = tag_tagged_items(&tree, NULL, start, end, tmp, 0, 2);
+ assert(tagged == count);
// printf("%lu %lu %lu\n", tagged, tmp, count);
// printf("checking copied tags\n");
check_copied_tags(&tree, start, end, idx, ITEMS, 0, 2);
- assert(tagged < tmp);
verify_tag_consistency(&tree, 0);
verify_tag_consistency(&tree, 1);
verify_tag_consistency(&tree, 2);
diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c
index b9be885..86daf23 100644
--- a/tools/testing/radix-tree/multiorder.c
+++ b/tools/testing/radix-tree/multiorder.c
@@ -26,7 +26,6 @@ static void __multiorder_tag_test(int index, int order)
{
RADIX_TREE(tree, GFP_KERNEL);
int base, err, i;
- unsigned long first = 0;
/* our canonical entry */
base = index & ~((1 << order) - 1);
@@ -60,7 +59,7 @@ static void __multiorder_tag_test(int index, int order)
assert(!radix_tree_tag_get(&tree, i, 1));
}
- assert(radix_tree_range_tag_if_tagged(&tree, &first, ~0UL, 10, 0, 1) == 1);
+ assert(tag_tagged_items(&tree, NULL, 0, ~0UL, 10, 0, 1) == 1);
assert(radix_tree_tag_clear(&tree, index, 0));
for_each_index(i, base, order) {
@@ -251,7 +250,6 @@ void multiorder_tagged_iteration(void)
RADIX_TREE(tree, GFP_KERNEL);
struct radix_tree_iter iter;
void **slot;
- unsigned long first = 0;
int i, j;
printf("Multiorder tagged iteration test\n");
@@ -296,8 +294,8 @@ void multiorder_tagged_iteration(void)
}
}
- radix_tree_range_tag_if_tagged(&tree, &first, ~0UL,
- MT_NUM_ENTRIES, 1, 2);
+ assert(tag_tagged_items(&tree, NULL, 0, ~0UL, TAG_ENTRIES, 1, 2) ==
+ TAG_ENTRIES);
for (j = 0; j < 256; j++) {
int mask, k;
@@ -323,9 +321,8 @@ void multiorder_tagged_iteration(void)
}
}
- first = 1;
- radix_tree_range_tag_if_tagged(&tree, &first, ~0UL,
- MT_NUM_ENTRIES, 1, 0);
+ assert(tag_tagged_items(&tree, NULL, 1, ~0UL, MT_NUM_ENTRIES * 2, 1, 0)
+ == TAG_ENTRIES);
i = 0;
radix_tree_for_each_tagged(slot, &tree, &iter, 0, 0) {
assert(iter.index == tag_index[i]);
diff --git a/tools/testing/radix-tree/regression2.c b/tools/testing/radix-tree/regression2.c
index 63bf347..a41325d 100644
--- a/tools/testing/radix-tree/regression2.c
+++ b/tools/testing/radix-tree/regression2.c
@@ -50,6 +50,7 @@
#include <stdio.h>
#include "regression.h"
+#include "test.h"
#define PAGECACHE_TAG_DIRTY 0
#define PAGECACHE_TAG_WRITEBACK 1
@@ -90,7 +91,7 @@ void regression2_test(void)
/* 1. */
start = 0;
end = max_slots - 2;
- radix_tree_range_tag_if_tagged(&mt_tree, &start, end, 1,
+ tag_tagged_items(&mt_tree, NULL, start, end, 1,
PAGECACHE_TAG_DIRTY, PAGECACHE_TAG_TOWRITE);
/* 2. */
diff --git a/tools/testing/radix-tree/tag_check.c b/tools/testing/radix-tree/tag_check.c
index 186f6e4..ed5f87d 100644
--- a/tools/testing/radix-tree/tag_check.c
+++ b/tools/testing/radix-tree/tag_check.c
@@ -23,7 +23,7 @@ __simple_checks(struct radix_tree_root *tree, unsigned long index, int tag)
item_tag_set(tree, index, tag);
ret = item_tag_get(tree, index, tag);
assert(ret != 0);
- ret = radix_tree_range_tag_if_tagged(tree, &first, ~0UL, 10, tag, !tag);
+ ret = tag_tagged_items(tree, NULL, first, ~0UL, 10, tag, !tag);
assert(ret == 1);
ret = item_tag_get(tree, index, !tag);
assert(ret != 0);
@@ -320,7 +320,7 @@ static void single_check(void)
assert(ret == 0);
verify_tag_consistency(&tree, 0);
verify_tag_consistency(&tree, 1);
- ret = radix_tree_range_tag_if_tagged(&tree, &first, 10, 10, 0, 1);
+ ret = tag_tagged_items(&tree, NULL, first, 10, 10, 0, 1);
assert(ret == 1);
ret = radix_tree_gang_lookup_tag(&tree, (void **)items, 0, BATCH, 1);
assert(ret == 1);
diff --git a/tools/testing/radix-tree/test.c b/tools/testing/radix-tree/test.c
index 88bf57f..e5726e3 100644
--- a/tools/testing/radix-tree/test.c
+++ b/tools/testing/radix-tree/test.c
@@ -151,6 +151,40 @@ void item_full_scan(struct radix_tree_root *root, unsigned long start,
assert(nfound == 0);
}
+/* Use the same pattern as tag_pages_for_writeback() in mm/page-writeback.c */
+int tag_tagged_items(struct radix_tree_root *root, pthread_mutex_t *lock,
+ unsigned long start, unsigned long end, unsigned batch,
+ unsigned iftag, unsigned thentag)
+{
+ unsigned long tagged = 0;
+ struct radix_tree_iter iter;
+ void **slot;
+
+ if (batch == 0)
+ batch = 1;
+
+ if (lock)
+ pthread_mutex_lock(lock);
+ radix_tree_for_each_tagged(slot, root, &iter, start, iftag) {
+ if (iter.index > end)
+ break;
+ radix_tree_iter_tag_set(root, &iter, thentag);
+ tagged++;
+ if ((tagged % batch) != 0)
+ continue;
+ slot = radix_tree_iter_resume(slot, &iter);
+ if (lock) {
+ pthread_mutex_unlock(lock);
+ rcu_barrier();
+ pthread_mutex_lock(lock);
+ }
+ }
+ if (lock)
+ pthread_mutex_unlock(lock);
+
+ return tagged;
+}
+
/* Use the same pattern as find_swap_entry() in mm/shmem.c */
unsigned long find_item(struct radix_tree_root *root, void *item)
{
diff --git a/tools/testing/radix-tree/test.h b/tools/testing/radix-tree/test.h
index 3d9d1d3..e11e4d2 100644
--- a/tools/testing/radix-tree/test.h
+++ b/tools/testing/radix-tree/test.h
@@ -25,6 +25,9 @@ void item_full_scan(struct radix_tree_root *root, unsigned long start,
unsigned long nr, int chunk);
void item_kill_tree(struct radix_tree_root *root);
+int tag_tagged_items(struct radix_tree_root *, pthread_mutex_t *,
+ unsigned long start, unsigned long end, unsigned batch,
+ unsigned iftag, unsigned thentag);
unsigned long find_item(struct radix_tree_root *, void *item);
void tag_check(void);