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dev_cache: replace dm_hash with radix_tree

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For large device sets our dm_hash can produce larger amounf of mapping
collision and we would need to further increase our has size.

So instead use the radix_tree code which is immune agains growing size
of devices and uses memory more effiecently to store all the paths.
This commit is contained in:
Zdenek Kabelac 2024-06-19 13:49:48 +02:00
parent e0537559c6
commit cc344c3e69
3 changed files with 63 additions and 48 deletions
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2
lib/cache/lvmcache.c vendored
View File

@ -3231,7 +3231,7 @@ const char *devname_error_reason(const char *devname)
{
struct device *dev;
if ((dev = dev_hash_get(devname))) {
if ((dev = dev_cache_get_dev_by_name(devname))) {
if (dev->filtered_flags)
return dev_filtered_reason(dev);
if (lvmcache_dev_is_unused_duplicate(dev))

107
lib/device/dev-cache.c
View File

@ -49,7 +49,7 @@ struct dir_list {
static struct {
struct dm_pool *mem;
struct dm_hash_table *names;
struct radix_tree *names;
struct dm_hash_table *vgid_index;
struct dm_hash_table *lvid_index;
struct radix_tree *dm_uuids;
@ -348,9 +348,10 @@ static int _add_alias(struct device *dev, const char *path, enum add_hash hash)
struct dm_str_list *strl;
const char *oldpath;
int prefer_old = 1;
size_t path_len = strlen(path);
if (hash == REHASH)
dm_hash_remove(_cache.names, path);
radix_tree_remove(_cache.names, path, path_len);
/* Is name already there? */
dm_list_iterate_items(strl, &dev->aliases)
@ -381,7 +382,7 @@ static int _add_alias(struct device *dev, const char *path, enum add_hash hash)
dm_list_add_h(&dev->aliases, &sl->list);
out:
if ((hash != NO_HASH) &&
!dm_hash_insert(_cache.names, path, dev)) {
!radix_tree_insert_ptr(_cache.names, path, path_len, dev)) {
log_error("Couldn't add name to hash in dev cache.");
return 0;
}
@ -658,7 +659,7 @@ static int _index_dev_by_vgid_and_lvid(struct cmd_context *cmd, struct device *d
goto out;
}
if (!(holder_dev = (struct device *) dm_hash_lookup(_cache.names, devpath))) {
if (!(holder_dev = dev_cache_get_dev_by_name(devpath))) {
/*
* Cope with situation where canonical /<dev_dir>/<dirent->d_name>
* does not exist, but some other node name or symlink exists in
@ -752,8 +753,7 @@ void dev_cache_failed_path(struct device *dev, const char *path)
{
struct dm_str_list *strl;
if (dm_hash_lookup(_cache.names, path))
dm_hash_remove(_cache.names, path);
radix_tree_remove(_cache.names, path, strlen(path));
dm_list_iterate_items(strl, &dev->aliases) {
if (!strcmp(strl->str, path)) {
@ -774,7 +774,7 @@ static int _insert_dev(const char *path, dev_t d)
struct device *dev_by_path;
dev_by_devt = _dev_cache_get_dev_by_devno(_cache.devices, d);
dev_by_path = (struct device *) dm_hash_lookup(_cache.names, path);
dev_by_path = dev_cache_get_dev_by_name(path);
dev = dev_by_devt;
/*
@ -1241,7 +1241,7 @@ static void _drop_all_aliases(struct device *dev)
dm_list_iterate_items_safe(strl, strl2, &dev->aliases) {
log_debug("Drop alias for %u:%u %s.", MAJOR(dev->dev), MINOR(dev->dev), strl->str);
dm_hash_remove(_cache.names, strl->str);
radix_tree_remove(_cache.names, strl->str, strlen(strl->str));
dm_list_del(&strl->list);
}
}
@ -1403,7 +1403,7 @@ int dev_cache_init(struct cmd_context *cmd)
if (!(_cache.mem = dm_pool_create("dev_cache", 10 * 1024)))
return_0;
if (!(_cache.names = dm_hash_create(8190)) ||
if (!(_cache.names = radix_tree_create(NULL, NULL)) ||
!(_cache.vgid_index = dm_hash_create(30)) ||
!(_cache.lvid_index = dm_hash_create(29))) {
dm_pool_destroy(_cache.mem);
@ -1439,27 +1439,36 @@ int dev_cache_init(struct cmd_context *cmd)
return 0;
}
struct dev_visitor {
struct radix_tree_iterator it;
int close_immediate;
int free;
unsigned num_open;
};
/*
* Returns number of devices still open.
*/
static int _check_for_open_devices(int close_immediate)
static bool _visit_check_for_open_devices(struct radix_tree_iterator *it,
const void *key, size_t keylen,
union radix_value v)
{
struct device *dev;
struct dm_hash_node *n;
int num_open = 0;
struct dev_visitor *vt = container_of(it, struct dev_visitor, it);
struct device *dev = v.ptr;
dm_hash_iterate(n, _cache.names) {
dev = (struct device *) dm_hash_get_data(_cache.names, n);
if (dev->fd >= 0) {
log_error("Device '%s' has been left open (%d remaining references).",
dev_name(dev), dev->open_count);
num_open++;
if (close_immediate && !dev_close_immediate(dev))
stack;
}
if (dev->fd >= 0) {
log_error("Device '%s' has been left open (%d remaining references).",
dev_name(dev), dev->open_count);
vt->num_open++;
if (vt->close_immediate && !dev_close_immediate(dev))
stack;
}
return num_open;
if (vt->free) {
free_dids(&dev->ids);
free_wwids(&dev->wwids);
}
return true;
}
/*
@ -1467,31 +1476,37 @@ static int _check_for_open_devices(int close_immediate)
*/
int dev_cache_check_for_open_devices(void)
{
return _check_for_open_devices(0);
struct dev_visitor vt = {
.it.visit = _visit_check_for_open_devices,
};
radix_tree_iterate(_cache.names, NULL, 0, &vt.it);
return vt.num_open;
}
int dev_cache_exit(void)
{
struct device *dev;
struct dm_hash_node *n;
int num_open = 0;
struct dev_visitor vt = {
.it.visit = _visit_check_for_open_devices,
.close_immediate = 1, /* close open devices */
.free = 1, /* free dids, wwids */
};
if (_cache.names) {
if ((num_open = _check_for_open_devices(1)) > 0)
log_error(INTERNAL_ERROR "%d device(s) were left open and have been closed.", num_open);
/* check for open devices */
radix_tree_iterate(_cache.names, NULL, 0, &vt.it);
dm_hash_iterate(n, _cache.names) {
dev = (struct device *) dm_hash_get_data(_cache.names, n);
free_dids(&dev->ids);
free_wwids(&dev->wwids);
}
if (vt.num_open)
log_error(INTERNAL_ERROR "%d device(s) were left open and have been closed.",
vt.num_open);
}
if (_cache.mem)
dm_pool_destroy(_cache.mem);
if (_cache.names)
dm_hash_destroy(_cache.names);
radix_tree_destroy(_cache.names);
if (_cache.vgid_index)
dm_hash_destroy(_cache.vgid_index);
@ -1513,7 +1528,7 @@ int dev_cache_exit(void)
memset(&_cache, 0, sizeof(_cache));
return (!num_open);
return (!vt.num_open);
}
int dev_cache_add_dir(const char *path)
@ -1544,9 +1559,9 @@ int dev_cache_add_dir(const char *path)
return 1;
}
struct device *dev_hash_get(const char *name)
struct device *dev_cache_get_dev_by_name(const char *name)
{
return (struct device *) dm_hash_lookup(_cache.names, name);
return radix_tree_lookup_ptr(_cache.names, name, strlen(name));
}
static void _remove_alias(struct device *dev, const char *name)
@ -1582,7 +1597,7 @@ void dev_cache_verify_aliases(struct device *dev)
log_debug("Drop alias for %u:%u invalid path %s %u:%u.",
MAJOR(dev->dev), MINOR(dev->dev), strl->str,
MAJOR(st.st_rdev), MINOR(st.st_rdev));
dm_hash_remove(_cache.names, strl->str);
radix_tree_remove(_cache.names, strl->str, strlen(strl->str));
dm_list_del(&strl->list);
}
}
@ -1590,7 +1605,7 @@ void dev_cache_verify_aliases(struct device *dev)
static struct device *_dev_cache_get(struct cmd_context *cmd, const char *name, struct dev_filter *f, int existing)
{
struct device *dev = (struct device *) dm_hash_lookup(_cache.names, name);
struct device *dev = dev_cache_get_dev_by_name(name);
struct stat st;
int ret;
@ -1616,7 +1631,7 @@ static struct device *_dev_cache_get(struct cmd_context *cmd, const char *name,
log_debug("Device path %s is invalid for %u:%u %s.",
name, MAJOR(dev->dev), MINOR(dev->dev), dev_name(dev));
dm_hash_remove(_cache.names, name);
radix_tree_remove(_cache.names, name, strlen(name));
_remove_alias(dev, name);
@ -1681,7 +1696,7 @@ static struct device *_dev_cache_get(struct cmd_context *cmd, const char *name,
return_NULL;
/* Get the struct dev that was just added. */
dev = (struct device *) dm_hash_lookup(_cache.names, name);
dev = dev_cache_get_dev_by_name(name);
if (!dev) {
log_error("Failed to get device %s", name);
@ -1751,7 +1766,7 @@ static struct device *_dev_cache_get(struct cmd_context *cmd, const char *name,
return_NULL;
/* Get the struct dev that was just added. */
dev = (struct device *) dm_hash_lookup(_cache.names, name);
dev = dev_cache_get_dev_by_name(name);
if (!dev) {
log_error("Failed to get device %s", name);
@ -2275,7 +2290,7 @@ int setup_device(struct cmd_context *cmd, const char *devname)
if (!_insert_dev(devname, buf.st_rdev))
return_0;
if (!(dev = (struct device *) dm_hash_lookup(_cache.names, devname)))
if (!(dev = dev_cache_get_dev_by_name(devname)))
return_0;
/* Match this device to an entry in devices_file so it will not
@ -2462,7 +2477,7 @@ int setup_devname_in_dev_cache(struct cmd_context *cmd, const char *devname)
if (!_insert_dev(devname, buf.st_rdev))
return_0;
if (!dm_hash_lookup(_cache.names, devname))
if (!dev_cache_get_dev_by_name(devname))
return_0;
return 1;
@ -2523,7 +2538,7 @@ struct device *setup_dev_in_dev_cache(struct cmd_context *cmd, dev_t devno, cons
if (!_insert_dev(devname, buf.st_rdev))
return_NULL;
if (!(dev = (struct device *) dm_hash_lookup(_cache.names, devname))) {
if (!(dev = dev_cache_get_dev_by_name(devname))) {
log_error("Device lookup failed for %u:%u %s", major, minor, devname);
return_NULL;
}

2
lib/device/dev-cache.h
View File

@ -64,7 +64,7 @@ struct device *dev_cache_get_by_devt(struct cmd_context *cmd, dev_t devt);
struct device *dev_cache_get_by_pvid(struct cmd_context *cmd, const char *pvid);
void dev_cache_verify_aliases(struct device *dev);
struct device *dev_hash_get(const char *name);
struct device *dev_cache_get_dev_by_name(const char *name);
void dev_set_preferred_name(struct dm_str_list *sl, struct device *dev);