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fscache: Use refcount_t for the cookie refcount instead of atomic_t

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Use refcount_t for the fscache_cookie refcount instead of atomic_t and
rename the 'usage' member to 'ref' in such cases.  The tracepoints that
reference it change from showing "u=%d" to "r=%d".

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162431204358.2908479.8006938388213098079.stgit@warthog.procyon.org.uk/
This commit is contained in:
David Howells 2021-03-29 13:53:50 +01:00
parent 33cba85922
commit 20ec197bfa
6 changed files with 55 additions and 43 deletions
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2
fs/fscache/cache.c
View file

@ -269,7 +269,7 @@ int fscache_add_cache(struct fscache_cache *cache,
hlist_add_head(&ifsdef->cookie_link,
&fscache_fsdef_index.backing_objects);
atomic_inc(&fscache_fsdef_index.usage);
refcount_inc(&fscache_fsdef_index.ref);
/* done */
spin_unlock(&fscache_fsdef_index.lock);

31
fs/fscache/cookie.c
View file

@ -164,7 +164,7 @@ struct fscache_cookie *fscache_alloc_cookie(
goto nomem;
}
atomic_set(&cookie->usage, 1);
refcount_set(&cookie->ref, 1);
atomic_set(&cookie->n_children, 0);
cookie->debug_id = atomic_inc_return(&fscache_cookie_debug_id);
@ -225,7 +225,7 @@ struct fscache_cookie *fscache_hash_cookie(struct fscache_cookie *candidate)
collision:
if (test_and_set_bit(FSCACHE_COOKIE_ACQUIRED, &cursor->flags)) {
trace_fscache_cookie(cursor->debug_id, atomic_read(&cursor->usage),
trace_fscache_cookie(cursor->debug_id, refcount_read(&cursor->ref),
fscache_cookie_collision);
pr_err("Duplicate cookie detected\n");
fscache_print_cookie(cursor, 'O');
@ -826,13 +826,12 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie,
BUG_ON(!radix_tree_empty(&cookie->stores));
if (cookie->parent) {
ASSERTCMP(atomic_read(&cookie->parent->usage), >, 0);
ASSERTCMP(refcount_read(&cookie->parent->ref), >, 0);
ASSERTCMP(atomic_read(&cookie->parent->n_children), >, 0);
atomic_dec(&cookie->parent->n_children);
}
/* Dispose of the netfs's link to the cookie */
ASSERTCMP(atomic_read(&cookie->usage), >, 0);
fscache_cookie_put(cookie, fscache_cookie_put_relinquish);
_leave("");
@ -862,18 +861,17 @@ void fscache_cookie_put(struct fscache_cookie *cookie,
enum fscache_cookie_trace where)
{
struct fscache_cookie *parent;
int usage;
int ref;
_enter("%x", cookie->debug_id);
do {
unsigned int cookie_debug_id = cookie->debug_id;
usage = atomic_dec_return(&cookie->usage);
trace_fscache_cookie(cookie_debug_id, usage, where);
bool zero = __refcount_dec_and_test(&cookie->ref, &ref);
if (usage > 0)
trace_fscache_cookie(cookie_debug_id, ref - 1, where);
if (!zero)
return;
BUG_ON(usage < 0);
parent = cookie->parent;
fscache_unhash_cookie(cookie);
@ -886,6 +884,19 @@ void fscache_cookie_put(struct fscache_cookie *cookie,
_leave("");
}
/*
* Get a reference to a cookie.
*/
struct fscache_cookie *fscache_cookie_get(struct fscache_cookie *cookie,
enum fscache_cookie_trace where)
{
int ref;
__refcount_inc(&cookie->ref, &ref);
trace_fscache_cookie(cookie->debug_id, ref + 1, where);
return cookie;
}
/*
* check the consistency between the netfs inode and the backing cache
*
@ -1003,7 +1014,7 @@ static int fscache_cookies_seq_show(struct seq_file *m, void *v)
"%08x %08x %5u %5u %3u %s %03lx %-16s %px",
cookie->debug_id,
cookie->parent ? cookie->parent->debug_id : 0,
atomic_read(&cookie->usage),
refcount_read(&cookie->ref),
atomic_read(&cookie->n_children),
atomic_read(&cookie->n_active),
type,

2
fs/fscache/fsdef.c
View file

@ -46,7 +46,7 @@ static struct fscache_cookie_def fscache_fsdef_index_def = {
struct fscache_cookie fscache_fsdef_index = {
.debug_id = 1,
.usage = ATOMIC_INIT(1),
.ref = REFCOUNT_INIT(1),
.n_active = ATOMIC_INIT(1),
.lock = __SPIN_LOCK_UNLOCKED(fscache_fsdef_index.lock),
.backing_objects = HLIST_HEAD_INIT,

17
fs/fscache/internal.h
View file

@ -54,9 +54,18 @@ extern struct fscache_cookie *fscache_alloc_cookie(struct fscache_cookie *,
const void *, size_t,
void *, loff_t);
extern struct fscache_cookie *fscache_hash_cookie(struct fscache_cookie *);
extern struct fscache_cookie *fscache_cookie_get(struct fscache_cookie *,
enum fscache_cookie_trace);
extern void fscache_cookie_put(struct fscache_cookie *,
enum fscache_cookie_trace);
static inline void fscache_cookie_see(struct fscache_cookie *cookie,
enum fscache_cookie_trace where)
{
trace_fscache_cookie(cookie->debug_id, refcount_read(&cookie->ref),
where);
}
/*
* fsdef.c
*/
@ -286,14 +295,6 @@ static inline void fscache_raise_event(struct fscache_object *object,
fscache_enqueue_object(object);
}
static inline void fscache_cookie_get(struct fscache_cookie *cookie,
enum fscache_cookie_trace where)
{
int usage = atomic_inc_return(&cookie->usage);
trace_fscache_cookie(cookie->debug_id, usage, where);
}
/*
* get an extra reference to a netfs retrieval context
*/

2
include/linux/fscache.h
View file

@ -123,7 +123,7 @@ struct fscache_netfs {
* - indices are created on disk just-in-time
*/
struct fscache_cookie {
atomic_t usage; /* number of users of this cookie */
refcount_t ref; /* number of users of this cookie */
atomic_t n_children; /* number of children of this cookie */
atomic_t n_active; /* number of active users of netfs ptrs */
unsigned int debug_id;

44
include/trace/events/fscache.h
View file

@ -161,26 +161,26 @@ fscache_cookie_traces;
TRACE_EVENT(fscache_cookie,
TP_PROTO(unsigned int cookie_debug_id,
int usage,
int ref,
enum fscache_cookie_trace where),
TP_ARGS(cookie_debug_id, usage, where),
TP_ARGS(cookie_debug_id, ref, where),
TP_STRUCT__entry(
__field(unsigned int, cookie )
__field(enum fscache_cookie_trace, where )
__field(int, usage )
__field(int, ref )
),
TP_fast_assign(
__entry->cookie = cookie_debug_id;
__entry->where = where;
__entry->usage = usage;
__entry->ref = ref;
),
TP_printk("%s c=%08x u=%d",
TP_printk("%s c=%08x r=%d",
__print_symbolic(__entry->where, fscache_cookie_traces),
__entry->cookie, __entry->usage)
__entry->cookie, __entry->ref)
);
TRACE_EVENT(fscache_netfs,
@ -212,7 +212,7 @@ TRACE_EVENT(fscache_acquire,
__field(unsigned int, cookie )
__field(unsigned int, parent )
__array(char, name, 8 )
__field(int, p_usage )
__field(int, p_ref )
__field(int, p_n_children )
__field(u8, p_flags )
),
@ -220,15 +220,15 @@ TRACE_EVENT(fscache_acquire,
TP_fast_assign(
__entry->cookie = cookie->debug_id;
__entry->parent = cookie->parent->debug_id;
__entry->p_usage = atomic_read(&cookie->parent->usage);
__entry->p_ref = refcount_read(&cookie->parent->ref);
__entry->p_n_children = atomic_read(&cookie->parent->n_children);
__entry->p_flags = cookie->parent->flags;
memcpy(__entry->name, cookie->def->name, 8);
__entry->name[7] = 0;
),
TP_printk("c=%08x p=%08x pu=%d pc=%d pf=%02x n=%s",
__entry->cookie, __entry->parent, __entry->p_usage,
TP_printk("c=%08x p=%08x pr=%d pc=%d pf=%02x n=%s",
__entry->cookie, __entry->parent, __entry->p_ref,
__entry->p_n_children, __entry->p_flags, __entry->name)
);
@ -240,7 +240,7 @@ TRACE_EVENT(fscache_relinquish,
TP_STRUCT__entry(
__field(unsigned int, cookie )
__field(unsigned int, parent )
__field(int, usage )
__field(int, ref )
__field(int, n_children )
__field(int, n_active )
__field(u8, flags )
@ -250,15 +250,15 @@ TRACE_EVENT(fscache_relinquish,
TP_fast_assign(
__entry->cookie = cookie->debug_id;
__entry->parent = cookie->parent->debug_id;
__entry->usage = atomic_read(&cookie->usage);
__entry->ref = refcount_read(&cookie->ref);
__entry->n_children = atomic_read(&cookie->n_children);
__entry->n_active = atomic_read(&cookie->n_active);
__entry->flags = cookie->flags;
__entry->retire = retire;
),
TP_printk("c=%08x u=%d p=%08x Nc=%d Na=%d f=%02x r=%u",
__entry->cookie, __entry->usage,
TP_printk("c=%08x r=%d p=%08x Nc=%d Na=%d f=%02x r=%u",
__entry->cookie, __entry->ref,
__entry->parent, __entry->n_children, __entry->n_active,
__entry->flags, __entry->retire)
);
@ -270,7 +270,7 @@ TRACE_EVENT(fscache_enable,
TP_STRUCT__entry(
__field(unsigned int, cookie )
__field(int, usage )
__field(int, ref )
__field(int, n_children )
__field(int, n_active )
__field(u8, flags )
@ -278,14 +278,14 @@ TRACE_EVENT(fscache_enable,
TP_fast_assign(
__entry->cookie = cookie->debug_id;
__entry->usage = atomic_read(&cookie->usage);
__entry->ref = refcount_read(&cookie->ref);
__entry->n_children = atomic_read(&cookie->n_children);
__entry->n_active = atomic_read(&cookie->n_active);
__entry->flags = cookie->flags;
),
TP_printk("c=%08x u=%d Nc=%d Na=%d f=%02x",
__entry->cookie, __entry->usage,
TP_printk("c=%08x r=%d Nc=%d Na=%d f=%02x",
__entry->cookie, __entry->ref,
__entry->n_children, __entry->n_active, __entry->flags)
);
@ -296,7 +296,7 @@ TRACE_EVENT(fscache_disable,
TP_STRUCT__entry(
__field(unsigned int, cookie )
__field(int, usage )
__field(int, ref )
__field(int, n_children )
__field(int, n_active )
__field(u8, flags )
@ -304,14 +304,14 @@ TRACE_EVENT(fscache_disable,
TP_fast_assign(
__entry->cookie = cookie->debug_id;
__entry->usage = atomic_read(&cookie->usage);
__entry->ref = refcount_read(&cookie->ref);
__entry->n_children = atomic_read(&cookie->n_children);
__entry->n_active = atomic_read(&cookie->n_active);
__entry->flags = cookie->flags;
),
TP_printk("c=%08x u=%d Nc=%d Na=%d f=%02x",
__entry->cookie, __entry->usage,
TP_printk("c=%08x r=%d Nc=%d Na=%d f=%02x",
__entry->cookie, __entry->ref,
__entry->n_children, __entry->n_active, __entry->flags)
);