[PATCH v2 17/40] afs: Add a tracepoint for struct afs_addr_list

From: David Howells
Date: Wed Dec 13 2023 - 08:51:36 EST

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Add a tracepoint to track the lifetime of the afs_addr_list struct.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
cc: linux-afs@xxxxxxxxxxxxxxxxxxx
---
fs/afs/addr_list.c | 33 ++++++++++++++++++++++----
fs/afs/fs_probe.c | 4 ++--
fs/afs/internal.h | 10 +++-----
fs/afs/rotate.c | 4 ++--
fs/afs/rxrpc.c | 4 ++--
fs/afs/server.c | 9 ++++----
fs/afs/vl_list.c | 11 +++++----
fs/afs/vl_rotate.c | 9 ++------
fs/afs/vlclient.c | 4 ++--
include/trace/events/afs.h | 47 ++++++++++++++++++++++++++++++++++++++
10 files changed, 100 insertions(+), 35 deletions(-)

diff --git a/fs/afs/addr_list.c b/fs/afs/addr_list.c
index a1f3c995e328..41ef0c879239 100644
--- a/fs/afs/addr_list.c
+++ b/fs/afs/addr_list.c
@@ -20,17 +20,39 @@ static void afs_free_addrlist(struct rcu_head *rcu)

for (i = 0; i < alist->nr_addrs; i++)
rxrpc_kernel_put_peer(alist->addrs[i].peer);
+ trace_afs_alist(alist->debug_id, refcount_read(&alist->usage), afs_alist_trace_free);
+ kfree(alist);
}

/*
* Release an address list.
*/
-void afs_put_addrlist(struct afs_addr_list *alist)
+void afs_put_addrlist(struct afs_addr_list *alist, enum afs_alist_trace reason)
{
- if (alist && refcount_dec_and_test(&alist->usage))
+ unsigned int debug_id;
+ bool dead;
+ int r;
+
+ if (!alist)
+ return;
+ debug_id = alist->debug_id;
+ dead = __refcount_dec_and_test(&alist->usage, &r);
+ trace_afs_alist(debug_id, r - 1, reason);
+ if (dead)
call_rcu(&alist->rcu, afs_free_addrlist);
}

+struct afs_addr_list *afs_get_addrlist(struct afs_addr_list *alist, enum afs_alist_trace reason)
+{
+ int r;
+
+ if (alist) {
+ __refcount_inc(&alist->usage, &r);
+ trace_afs_alist(alist->debug_id, r + 1, reason);
+ }
+ return alist;
+}
+
/*
* Allocate an address list.
*/
@@ -38,6 +60,7 @@ struct afs_addr_list *afs_alloc_addrlist(unsigned int nr, u16 service_id)
{
struct afs_addr_list *alist;
unsigned int i;
+ static atomic_t debug_id;

_enter("%u,%u", nr, service_id);

@@ -50,9 +73,11 @@ struct afs_addr_list *afs_alloc_addrlist(unsigned int nr, u16 service_id)

refcount_set(&alist->usage, 1);
alist->max_addrs = nr;
+ alist->debug_id = atomic_inc_return(&debug_id);

for (i = 0; i < nr; i++)
alist->addrs[i].service_id = service_id;
+ trace_afs_alist(alist->debug_id, 1, afs_alist_trace_alloc);
return alist;
}

@@ -217,7 +242,7 @@ struct afs_vlserver_list *afs_parse_text_addrs(struct afs_net *net,
problem, p - text, (int)len, (int)len, text);
ret = -EINVAL;
error:
- afs_put_addrlist(alist);
+ afs_put_addrlist(alist, afs_alist_trace_put_parse_error);
error_vl:
afs_put_vlserverlist(net, vllist);
return ERR_PTR(ret);
@@ -403,7 +428,7 @@ void afs_end_cursor(struct afs_addr_cursor *ac)
ac->index != alist->preferred &&
test_bit(ac->alist->preferred, &ac->tried))
WRITE_ONCE(alist->preferred, ac->index);
- afs_put_addrlist(alist);
+ afs_put_addrlist(alist, afs_alist_trace_put_end_cursor);
ac->alist = NULL;
}
}
diff --git a/fs/afs/fs_probe.c b/fs/afs/fs_probe.c
index fbb91ad775b9..18891492c0b4 100644
--- a/fs/afs/fs_probe.c
+++ b/fs/afs/fs_probe.c
@@ -205,7 +205,7 @@ void afs_fs_probe_fileserver(struct afs_net *net, struct afs_server *server,
read_lock(&server->fs_lock);
ac.alist = rcu_dereference_protected(server->addresses,
lockdep_is_held(&server->fs_lock));
- afs_get_addrlist(ac.alist);
+ afs_get_addrlist(ac.alist, afs_alist_trace_get_probe);
read_unlock(&server->fs_lock);

server->probed_at = jiffies;
@@ -226,7 +226,7 @@ void afs_fs_probe_fileserver(struct afs_net *net, struct afs_server *server,
afs_fs_probe_not_done(net, server, &ac);
}

- afs_put_addrlist(ac.alist);
+ afs_put_addrlist(ac.alist, afs_alist_trace_put_probe);
}

/*
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index d67c75d4d2bd..d00fda99f401 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -85,6 +85,7 @@ struct afs_addr_list {
struct rcu_head rcu;
refcount_t usage;
u32 version; /* Version */
+ unsigned int debug_id;
unsigned char max_addrs;
unsigned char nr_addrs;
unsigned char preferred; /* Preferred address */
@@ -969,14 +970,9 @@ static inline bool afs_is_folio_dirty_mmapped(unsigned long priv)
/*
* addr_list.c
*/
-static inline struct afs_addr_list *afs_get_addrlist(struct afs_addr_list *alist)
-{
- if (alist)
- refcount_inc(&alist->usage);
- return alist;
-}
+struct afs_addr_list *afs_get_addrlist(struct afs_addr_list *alist, enum afs_alist_trace reason);
extern struct afs_addr_list *afs_alloc_addrlist(unsigned int nr, u16 service_id);
-extern void afs_put_addrlist(struct afs_addr_list *);
+extern void afs_put_addrlist(struct afs_addr_list *alist, enum afs_alist_trace reason);
extern struct afs_vlserver_list *afs_parse_text_addrs(struct afs_net *,
const char *, size_t, char,
unsigned short, unsigned short);
diff --git a/fs/afs/rotate.c b/fs/afs/rotate.c
index a778d53681fe..fa2ba45a5941 100644
--- a/fs/afs/rotate.c
+++ b/fs/afs/rotate.c
@@ -484,7 +484,7 @@ bool afs_select_fileserver(struct afs_operation *op)
read_lock(&server->fs_lock);
alist = rcu_dereference_protected(server->addresses,
lockdep_is_held(&server->fs_lock));
- afs_get_addrlist(alist);
+ afs_get_addrlist(alist, afs_alist_trace_get_fsrotate_set);
read_unlock(&server->fs_lock);

retry_server:
@@ -493,7 +493,7 @@ bool afs_select_fileserver(struct afs_operation *op)
if (!op->ac.alist)
op->ac.alist = alist;
else
- afs_put_addrlist(alist);
+ afs_put_addrlist(alist, afs_alist_trace_put_retry_server);

op->ac.index = -1;

diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 0b3e2f20b0e0..5bbf5a23af85 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -187,7 +187,7 @@ void afs_put_call(struct afs_call *call)
call->type->destructor(call);

afs_unuse_server_notime(call->net, call->server, afs_server_trace_put_call);
- afs_put_addrlist(call->alist);
+ afs_put_addrlist(call->alist, afs_alist_trace_put_call);
kfree(call->request);

trace_afs_call(call->debug_id, afs_call_trace_free, 0, o,
@@ -315,7 +315,7 @@ void afs_make_call(struct afs_addr_cursor *ac, struct afs_call *call, gfp_t gfp)
atomic_read(&call->net->nr_outstanding_calls));

call->addr_ix = ac->index;
- call->alist = afs_get_addrlist(ac->alist);
+ call->alist = afs_get_addrlist(ac->alist, afs_alist_trace_get_make_call);

/* Work out the length we're going to transmit. This is awkward for
* calls such as FS.StoreData where there's an extra injection of data
diff --git a/fs/afs/server.c b/fs/afs/server.c
index f7791ef13618..6c13f00b10d8 100644
--- a/fs/afs/server.c
+++ b/fs/afs/server.c
@@ -275,13 +275,13 @@ struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key,

candidate = afs_alloc_server(cell, uuid, alist);
if (!candidate) {
- afs_put_addrlist(alist);
+ afs_put_addrlist(alist, afs_alist_trace_put_server_oom);
return ERR_PTR(-ENOMEM);
}

server = afs_install_server(cell, candidate);
if (server != candidate) {
- afs_put_addrlist(alist);
+ afs_put_addrlist(alist, afs_alist_trace_put_server_dup);
kfree(candidate);
} else {
/* Immediately dispatch an asynchronous probe to each interface
@@ -421,7 +421,8 @@ static void afs_server_rcu(struct rcu_head *rcu)

trace_afs_server(server->debug_id, refcount_read(&server->ref),
atomic_read(&server->active), afs_server_trace_free);
- afs_put_addrlist(rcu_access_pointer(server->addresses));
+ afs_put_addrlist(rcu_access_pointer(server->addresses),
+ afs_alist_trace_put_server);
kfree(server);
}

@@ -643,7 +644,7 @@ static noinline bool afs_update_server_record(struct afs_operation *op,
write_unlock(&server->fs_lock);
}

- afs_put_addrlist(discard);
+ afs_put_addrlist(discard, afs_alist_trace_put_server_update);
_leave(" = t");
return true;
}
diff --git a/fs/afs/vl_list.c b/fs/afs/vl_list.c
index ba89140eee9e..3a2875933261 100644
--- a/fs/afs/vl_list.c
+++ b/fs/afs/vl_list.c
@@ -33,7 +33,8 @@ static void afs_vlserver_rcu(struct rcu_head *rcu)
{
struct afs_vlserver *vlserver = container_of(rcu, struct afs_vlserver, rcu);

- afs_put_addrlist(rcu_access_pointer(vlserver->addresses));
+ afs_put_addrlist(rcu_access_pointer(vlserver->addresses),
+ afs_alist_trace_put_vlserver);
kfree_rcu(vlserver, rcu);
}

@@ -145,7 +146,7 @@ static struct afs_addr_list *afs_extract_vl_addrs(struct afs_net *net,

error:
*_b = b;
- afs_put_addrlist(alist);
+ afs_put_addrlist(alist, afs_alist_trace_put_parse_error);
return ERR_PTR(ret);
}

@@ -260,7 +261,7 @@ struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell,

if (vllist->nr_servers >= nr_servers) {
_debug("skip %u >= %u", vllist->nr_servers, nr_servers);
- afs_put_addrlist(addrs);
+ afs_put_addrlist(addrs, afs_alist_trace_put_parse_empty);
afs_put_vlserver(cell->net, server);
continue;
}
@@ -269,7 +270,7 @@ struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell,
addrs->status = bs.status;

if (addrs->nr_addrs == 0) {
- afs_put_addrlist(addrs);
+ afs_put_addrlist(addrs, afs_alist_trace_put_parse_empty);
if (!rcu_access_pointer(server->addresses)) {
afs_put_vlserver(cell->net, server);
continue;
@@ -281,7 +282,7 @@ struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell,
old = rcu_replace_pointer(server->addresses, old,
lockdep_is_held(&server->lock));
write_unlock(&server->lock);
- afs_put_addrlist(old);
+ afs_put_addrlist(old, afs_alist_trace_put_vlserver_old);
}

diff --git a/fs/afs/vl_rotate.c b/fs/afs/vl_rotate.c
index 7ae73418697d..e8fbbeb551bb 100644
--- a/fs/afs/vl_rotate.c
+++ b/fs/afs/vl_rotate.c
@@ -231,16 +231,11 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc)
read_lock(&vlserver->lock);
alist = rcu_dereference_protected(vlserver->addresses,
lockdep_is_held(&vlserver->lock));
- afs_get_addrlist(alist);
+ afs_get_addrlist(alist, afs_alist_trace_get_vlrotate_set);
read_unlock(&vlserver->lock);

memset(&vc->ac, 0, sizeof(vc->ac));
-
- if (!vc->ac.alist)
- vc->ac.alist = alist;
- else
- afs_put_addrlist(alist);
-
+ vc->ac.alist = alist;
vc->ac.index = -1;

iterate_address:
diff --git a/fs/afs/vlclient.c b/fs/afs/vlclient.c
index db7e94584e87..8dea7b56b75a 100644
--- a/fs/afs/vlclient.c
+++ b/fs/afs/vlclient.c
@@ -314,7 +314,7 @@ struct afs_addr_list *afs_vl_get_addrs_u(struct afs_vl_cursor *vc,
alist = call->ret_alist;
afs_put_call(call);
if (vc->call_error) {
- afs_put_addrlist(alist);
+ afs_put_addrlist(alist, afs_alist_trace_put_getaddru);
return ERR_PTR(vc->call_error);
}
return alist;
@@ -668,7 +668,7 @@ struct afs_addr_list *afs_yfsvl_get_endpoints(struct afs_vl_cursor *vc,
alist = call->ret_alist;
afs_put_call(call);
if (vc->call_error) {
- afs_put_addrlist(alist);
+ afs_put_addrlist(alist, afs_alist_trace_put_getaddru);
return ERR_PTR(vc->call_error);
}
return alist;
diff --git a/include/trace/events/afs.h b/include/trace/events/afs.h
index 597677acc6b1..ed91666ca4cc 100644
--- a/include/trace/events/afs.h
+++ b/include/trace/events/afs.h
@@ -202,6 +202,27 @@ enum yfs_cm_operation {
EM(afs_cell_trace_use_sbi, "USE sbi ") \
E_(afs_cell_trace_wait, "WAIT ")

+#define afs_alist_traces \
+ EM(afs_alist_trace_alloc, "ALLOC ") \
+ EM(afs_alist_trace_get_fsrotate_set, "GET fs-rot") \
+ EM(afs_alist_trace_get_make_call, "GET mkcall") \
+ EM(afs_alist_trace_get_probe, "GET probe ") \
+ EM(afs_alist_trace_get_vlrotate_set, "GET vl-rot") \
+ EM(afs_alist_trace_put_call, "PUT call ") \
+ EM(afs_alist_trace_put_end_cursor, "PUT endcur") \
+ EM(afs_alist_trace_put_getaddru, "PUT GtAdrU") \
+ EM(afs_alist_trace_put_parse_empty, "PUT p-empt") \
+ EM(afs_alist_trace_put_parse_error, "PUT p-err ") \
+ EM(afs_alist_trace_put_probe, "PUT probe ") \
+ EM(afs_alist_trace_put_retry_server, "PUT retry ") \
+ EM(afs_alist_trace_put_server, "PUT server") \
+ EM(afs_alist_trace_put_server_dup, "PUT sv-dup") \
+ EM(afs_alist_trace_put_server_oom, "PUT sv-oom") \
+ EM(afs_alist_trace_put_server_update, "PUT sv-upd") \
+ EM(afs_alist_trace_put_vlserver, "PUT vlsrvr") \
+ EM(afs_alist_trace_put_vlserver_old, "PUT vs-old") \
+ E_(afs_alist_trace_free, "FREE ")
+
#define afs_fs_operations \
EM(afs_FS_FetchData, "FS.FetchData") \
EM(afs_FS_FetchStatus, "FS.FetchStatus") \
@@ -420,6 +441,7 @@ enum yfs_cm_operation {
#define EM(a, b) a,
#define E_(a, b) a

+enum afs_alist_trace { afs_alist_traces } __mode(byte);
enum afs_call_trace { afs_call_traces } __mode(byte);
enum afs_cb_break_reason { afs_cb_break_reasons } __mode(byte);
enum afs_cell_trace { afs_cell_traces } __mode(byte);
@@ -443,6 +465,7 @@ enum afs_volume_trace { afs_volume_traces } __mode(byte);
#define EM(a, b) TRACE_DEFINE_ENUM(a);
#define E_(a, b) TRACE_DEFINE_ENUM(a);

+afs_alist_traces;
afs_call_traces;
afs_server_traces;
afs_cell_traces;
@@ -1330,6 +1353,30 @@ TRACE_EVENT(afs_cell,
__entry->active)
);

+TRACE_EVENT(afs_alist,
+ TP_PROTO(unsigned int alist_debug_id, int ref, enum afs_alist_trace reason),
+
+ TP_ARGS(alist_debug_id, ref, reason),
+
+ TP_STRUCT__entry(
+ __field(unsigned int, alist)
+ __field(int, ref)
+ __field(int, active)
+ __field(int, reason)
+ ),
+
+ TP_fast_assign(
+ __entry->alist = alist_debug_id;
+ __entry->ref = ref;
+ __entry->reason = reason;
+ ),
+
+ TP_printk("AL=%08x %s r=%d",
+ __entry->alist,
+ __print_symbolic(__entry->reason, afs_alist_traces),
+ __entry->ref)
+ );
+
#endif /* _TRACE_AFS_H */

/* This part must be outside protection */

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