XArray updates for 5.7-rc1

- Fix two bugs which affected multi-index entries larger than 2^26 indices
  - Fix some documentation
  - Remove unused IDA macros
  - Add a small optimisation for tiny configurations
  - Fix a bug which could cause an RCU walker to terminate a marked walk early
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Merge tag 'xarray-5.7' of git://git.infradead.org/users/willy/linux-dax

Pull XArray updates from Matthew Wilcox:

 - Fix two bugs which affected multi-index entries larger than 2^26
   indices

 - Fix some documentation

 - Remove unused IDA macros

 - Add a small optimisation for tiny configurations

 - Fix a bug which could cause an RCU walker to terminate a marked walk
   early

* tag 'xarray-5.7' of git://git.infradead.org/users/willy/linux-dax:
  xarray: Fix early termination of xas_for_each_marked
  radix tree test suite: Support kmem_cache alignment
  XArray: Optimise xas_sibling() if !CONFIG_XARRAY_MULTI
  ida: remove abandoned macros
  XArray: Fix incorrect comment in header file
  XArray: Fix xas_pause for large multi-index entries
  XArray: Fix xa_find_next for large multi-index entries
This commit is contained in:
Linus Torvalds 2020-04-01 17:35:47 -07:00
commit 193bc55b6d
10 changed files with 182 additions and 31 deletions

View File

@ -32,8 +32,8 @@
* The following internal entries have a special meaning:
*
* 0-62: Sibling entries
* 256: Zero entry
* 257: Retry entry
* 256: Retry entry
* 257: Zero entry
*
* Errors are also represented as internal entries, but use the negative
* space (-4094 to -2). They're never stored in the slots array; only
@ -1648,6 +1648,7 @@ static inline void *xas_next_marked(struct xa_state *xas, unsigned long max,
xa_mark_t mark)
{
struct xa_node *node = xas->xa_node;
void *entry;
unsigned int offset;
if (unlikely(xas_not_node(node) || node->shift))
@ -1659,7 +1660,10 @@ static inline void *xas_next_marked(struct xa_state *xas, unsigned long max,
return NULL;
if (offset == XA_CHUNK_SIZE)
return xas_find_marked(xas, max, mark);
return xa_entry(xas->xa, node, offset);
entry = xa_entry(xas->xa, node, offset);
if (!entry)
return xas_find_marked(xas, max, mark);
return entry;
}
/*

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@ -55,14 +55,6 @@ struct kmem_cache *radix_tree_node_cachep;
RADIX_TREE_MAP_SHIFT))
#define IDR_PRELOAD_SIZE (IDR_MAX_PATH * 2 - 1)
/*
* The IDA is even shorter since it uses a bitmap at the last level.
*/
#define IDA_INDEX_BITS (8 * sizeof(int) - 1 - ilog2(IDA_BITMAP_BITS))
#define IDA_MAX_PATH (DIV_ROUND_UP(IDA_INDEX_BITS, \
RADIX_TREE_MAP_SHIFT))
#define IDA_PRELOAD_SIZE (IDA_MAX_PATH * 2 - 1)
/*
* Per-cpu pool of preloaded nodes
*/

View File

@ -12,6 +12,9 @@
static unsigned int tests_run;
static unsigned int tests_passed;
static const unsigned int order_limit =
IS_ENABLED(CONFIG_XARRAY_MULTI) ? BITS_PER_LONG : 1;
#ifndef XA_DEBUG
# ifdef __KERNEL__
void xa_dump(const struct xarray *xa) { }
@ -959,6 +962,20 @@ static noinline void check_multi_find_2(struct xarray *xa)
}
}
static noinline void check_multi_find_3(struct xarray *xa)
{
unsigned int order;
for (order = 5; order < order_limit; order++) {
unsigned long index = 1UL << (order - 5);
XA_BUG_ON(xa, !xa_empty(xa));
xa_store_order(xa, 0, order - 4, xa_mk_index(0), GFP_KERNEL);
XA_BUG_ON(xa, xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT));
xa_erase_index(xa, 0);
}
}
static noinline void check_find_1(struct xarray *xa)
{
unsigned long i, j, k;
@ -1081,6 +1098,7 @@ static noinline void check_find(struct xarray *xa)
for (i = 2; i < 10; i++)
check_multi_find_1(xa, i);
check_multi_find_2(xa);
check_multi_find_3(xa);
}
/* See find_swap_entry() in mm/shmem.c */
@ -1138,6 +1156,42 @@ static noinline void check_find_entry(struct xarray *xa)
XA_BUG_ON(xa, !xa_empty(xa));
}
static noinline void check_pause(struct xarray *xa)
{
XA_STATE(xas, xa, 0);
void *entry;
unsigned int order;
unsigned long index = 1;
unsigned int count = 0;
for (order = 0; order < order_limit; order++) {
XA_BUG_ON(xa, xa_store_order(xa, index, order,
xa_mk_index(index), GFP_KERNEL));
index += 1UL << order;
}
rcu_read_lock();
xas_for_each(&xas, entry, ULONG_MAX) {
XA_BUG_ON(xa, entry != xa_mk_index(1UL << count));
count++;
}
rcu_read_unlock();
XA_BUG_ON(xa, count != order_limit);
count = 0;
xas_set(&xas, 0);
rcu_read_lock();
xas_for_each(&xas, entry, ULONG_MAX) {
XA_BUG_ON(xa, entry != xa_mk_index(1UL << count));
count++;
xas_pause(&xas);
}
rcu_read_unlock();
XA_BUG_ON(xa, count != order_limit);
xa_destroy(xa);
}
static noinline void check_move_tiny(struct xarray *xa)
{
XA_STATE(xas, xa, 0);
@ -1646,6 +1700,7 @@ static int xarray_checks(void)
check_xa_alloc();
check_find(&array);
check_find_entry(&array);
check_pause(&array);
check_account(&array);
check_destroy(&array);
check_move(&array);

View File

@ -970,7 +970,7 @@ void xas_pause(struct xa_state *xas)
xas->xa_node = XAS_RESTART;
if (node) {
unsigned int offset = xas->xa_offset;
unsigned long offset = xas->xa_offset;
while (++offset < XA_CHUNK_SIZE) {
if (!xa_is_sibling(xa_entry(xas->xa, node, offset)))
break;
@ -1208,6 +1208,8 @@ void *xas_find_marked(struct xa_state *xas, unsigned long max, xa_mark_t mark)
}
entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset);
if (!entry && !(xa_track_free(xas->xa) && mark == XA_FREE_MARK))
continue;
if (!xa_is_node(entry))
return entry;
xas->xa_node = xa_to_node(entry);
@ -1836,10 +1838,11 @@ static bool xas_sibling(struct xa_state *xas)
struct xa_node *node = xas->xa_node;
unsigned long mask;
if (!node)
if (!IS_ENABLED(CONFIG_XARRAY_MULTI) || !node)
return false;
mask = (XA_CHUNK_SIZE << node->shift) - 1;
return (xas->xa_index & mask) > (xas->xa_offset << node->shift);
return (xas->xa_index & mask) >
((unsigned long)xas->xa_offset << node->shift);
}
/**

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@ -7,8 +7,8 @@ LDLIBS+= -lpthread -lurcu
TARGETS = main idr-test multiorder xarray
CORE_OFILES := xarray.o radix-tree.o idr.o linux.o test.o find_bit.o bitmap.o
OFILES = main.o $(CORE_OFILES) regression1.o regression2.o regression3.o \
regression4.o \
tag_check.o multiorder.o idr-test.o iteration_check.o benchmark.o
regression4.o tag_check.o multiorder.o idr-test.o iteration_check.o \
iteration_check_2.o benchmark.o
ifndef SHIFT
SHIFT=3

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@ -0,0 +1,87 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* iteration_check_2.c: Check that deleting a tagged entry doesn't cause
* an RCU walker to finish early.
* Copyright (c) 2020 Oracle
* Author: Matthew Wilcox <willy@infradead.org>
*/
#include <pthread.h>
#include "test.h"
static volatile bool test_complete;
static void *iterator(void *arg)
{
XA_STATE(xas, arg, 0);
void *entry;
rcu_register_thread();
while (!test_complete) {
xas_set(&xas, 0);
rcu_read_lock();
xas_for_each_marked(&xas, entry, ULONG_MAX, XA_MARK_0)
;
rcu_read_unlock();
assert(xas.xa_index >= 100);
}
rcu_unregister_thread();
return NULL;
}
static void *throbber(void *arg)
{
struct xarray *xa = arg;
rcu_register_thread();
while (!test_complete) {
int i;
for (i = 0; i < 100; i++) {
xa_store(xa, i, xa_mk_value(i), GFP_KERNEL);
xa_set_mark(xa, i, XA_MARK_0);
}
for (i = 0; i < 100; i++)
xa_erase(xa, i);
}
rcu_unregister_thread();
return NULL;
}
void iteration_test2(unsigned test_duration)
{
pthread_t threads[2];
DEFINE_XARRAY(array);
int i;
printv(1, "Running iteration test 2 for %d seconds\n", test_duration);
test_complete = false;
xa_store(&array, 100, xa_mk_value(100), GFP_KERNEL);
xa_set_mark(&array, 100, XA_MARK_0);
if (pthread_create(&threads[0], NULL, iterator, &array)) {
perror("create iterator thread");
exit(1);
}
if (pthread_create(&threads[1], NULL, throbber, &array)) {
perror("create throbber thread");
exit(1);
}
sleep(test_duration);
test_complete = true;
for (i = 0; i < 2; i++) {
if (pthread_join(threads[i], NULL)) {
perror("pthread_join");
exit(1);
}
}
xa_destroy(&array);
}

View File

@ -19,37 +19,44 @@ int test_verbose;
struct kmem_cache {
pthread_mutex_t lock;
int size;
unsigned int size;
unsigned int align;
int nr_objs;
void *objs;
void (*ctor)(void *);
};
void *kmem_cache_alloc(struct kmem_cache *cachep, int flags)
void *kmem_cache_alloc(struct kmem_cache *cachep, int gfp)
{
struct radix_tree_node *node;
void *p;
if (!(flags & __GFP_DIRECT_RECLAIM))
if (!(gfp & __GFP_DIRECT_RECLAIM))
return NULL;
pthread_mutex_lock(&cachep->lock);
if (cachep->nr_objs) {
struct radix_tree_node *node = cachep->objs;
cachep->nr_objs--;
node = cachep->objs;
cachep->objs = node->parent;
pthread_mutex_unlock(&cachep->lock);
node->parent = NULL;
p = node;
} else {
pthread_mutex_unlock(&cachep->lock);
node = malloc(cachep->size);
if (cachep->align)
posix_memalign(&p, cachep->align, cachep->size);
else
p = malloc(cachep->size);
if (cachep->ctor)
cachep->ctor(node);
cachep->ctor(p);
else if (gfp & __GFP_ZERO)
memset(p, 0, cachep->size);
}
uatomic_inc(&nr_allocated);
if (kmalloc_verbose)
printf("Allocating %p from slab\n", node);
return node;
printf("Allocating %p from slab\n", p);
return p;
}
void kmem_cache_free(struct kmem_cache *cachep, void *objp)
@ -59,7 +66,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
if (kmalloc_verbose)
printf("Freeing %p to slab\n", objp);
pthread_mutex_lock(&cachep->lock);
if (cachep->nr_objs > 10) {
if (cachep->nr_objs > 10 || cachep->align) {
memset(objp, POISON_FREE, cachep->size);
free(objp);
} else {
@ -98,13 +105,14 @@ void kfree(void *p)
}
struct kmem_cache *
kmem_cache_create(const char *name, size_t size, size_t offset,
unsigned long flags, void (*ctor)(void *))
kmem_cache_create(const char *name, unsigned int size, unsigned int align,
unsigned int flags, void (*ctor)(void *))
{
struct kmem_cache *ret = malloc(sizeof(*ret));
pthread_mutex_init(&ret->lock, NULL);
ret->size = size;
ret->align = align;
ret->nr_objs = 0;
ret->objs = NULL;
ret->ctor = ctor;

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@ -20,8 +20,8 @@ static inline void *kzalloc(size_t size, gfp_t gfp)
void *kmem_cache_alloc(struct kmem_cache *cachep, int flags);
void kmem_cache_free(struct kmem_cache *cachep, void *objp);
struct kmem_cache *
kmem_cache_create(const char *name, size_t size, size_t offset,
unsigned long flags, void (*ctor)(void *));
struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
unsigned int align, unsigned int flags,
void (*ctor)(void *));
#endif /* SLAB_H */

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@ -311,6 +311,7 @@ int main(int argc, char **argv)
regression4_test();
iteration_test(0, 10 + 90 * long_run);
iteration_test(7, 10 + 90 * long_run);
iteration_test2(10 + 90 * long_run);
single_thread_tests(long_run);
/* Free any remaining preallocated nodes */

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@ -34,6 +34,7 @@ void xarray_tests(void);
void tag_check(void);
void multiorder_checks(void);
void iteration_test(unsigned order, unsigned duration);
void iteration_test2(unsigned duration);
void benchmark(void);
void idr_checks(void);
void ida_tests(void);