Add refcount tracing for the netfs_io_request structure. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> cc: linux-cachefs@xxxxxxxxxx Link: https://lore.kernel.org/r/164622997668.3564931.14456171619219324968.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v1 --- fs/netfs/internal.h | 11 +++++++++-- fs/netfs/objects.c | 24 +++++++++++++++++------- fs/netfs/read_helper.c | 14 +++++++------- include/linux/netfs.h | 2 +- include/trace/events/netfs.h | 35 +++++++++++++++++++++++++++++++++++ 5 files changed, 69 insertions(+), 17 deletions(-) diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h index cf7a3ddb16a4..89b02357500d 100644 --- a/fs/netfs/internal.h +++ b/fs/netfs/internal.h @@ -20,13 +20,20 @@ struct netfs_io_request *netfs_alloc_request(const struct netfs_request_ops *ops, void *netfs_priv, struct file *file); -void netfs_get_request(struct netfs_io_request *rreq); +void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what); void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async); -void netfs_put_request(struct netfs_io_request *rreq, bool was_async); +void netfs_put_request(struct netfs_io_request *rreq, bool was_async, + enum netfs_rreq_ref_trace what); struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq); void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async); void netfs_get_subrequest(struct netfs_io_subrequest *subreq); +static inline void netfs_see_request(struct netfs_io_request *rreq, + enum netfs_rreq_ref_trace what) +{ + trace_netfs_rreq_ref(rreq->debug_id, refcount_read(&rreq->ref), what); +} + /* * read_helper.c */ diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c index f7383c28dc6e..4e29c3bb6e5a 100644 --- a/fs/netfs/objects.c +++ b/fs/netfs/objects.c @@ -27,7 +27,7 @@ struct netfs_io_request *netfs_alloc_request( rreq->debug_id = atomic_inc_return(&debug_ids); INIT_LIST_HEAD(&rreq->subrequests); INIT_WORK(&rreq->work, netfs_rreq_work); - refcount_set(&rreq->usage, 1); + refcount_set(&rreq->ref, 1); __set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags); if (ops->init_request) ops->init_request(rreq, file); @@ -37,9 +37,12 @@ struct netfs_io_request *netfs_alloc_request( return rreq; } -void netfs_get_request(struct netfs_io_request *rreq) +void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what) { - refcount_inc(&rreq->usage); + int r; + + __refcount_inc(&rreq->ref, &r); + trace_netfs_rreq_ref(rreq->debug_id, r + 1, what); } void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async) @@ -68,9 +71,16 @@ static void netfs_free_request(struct work_struct *work) netfs_stat_d(&netfs_n_rh_rreq); } -void netfs_put_request(struct netfs_io_request *rreq, bool was_async) +void netfs_put_request(struct netfs_io_request *rreq, bool was_async, + enum netfs_rreq_ref_trace what) { - if (refcount_dec_and_test(&rreq->usage)) { + unsigned int debug_id = rreq->debug_id; + bool dead; + int r; + + dead = __refcount_dec_and_test(&rreq->ref, &r); + trace_netfs_rreq_ref(debug_id, r - 1, what); + if (dead) { if (was_async) { rreq->work.func = netfs_free_request; if (!queue_work(system_unbound_wq, &rreq->work)) @@ -93,7 +103,7 @@ struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq INIT_LIST_HEAD(&subreq->rreq_link); refcount_set(&subreq->usage, 2); subreq->rreq = rreq; - netfs_get_request(rreq); + netfs_get_request(rreq, netfs_rreq_trace_get_subreq); netfs_stat(&netfs_n_rh_sreq); } @@ -113,7 +123,7 @@ static void __netfs_put_subrequest(struct netfs_io_subrequest *subreq, trace_netfs_sreq(subreq, netfs_sreq_trace_free); kfree(subreq); netfs_stat_d(&netfs_n_rh_sreq); - netfs_put_request(rreq, was_async); + netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq); } void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async) diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c index 181aeda32649..620c3be5ec0a 100644 --- a/fs/netfs/read_helper.c +++ b/fs/netfs/read_helper.c @@ -109,7 +109,7 @@ static void netfs_rreq_completed(struct netfs_io_request *rreq, bool was_async) { trace_netfs_rreq(rreq, netfs_rreq_trace_done); netfs_clear_subrequests(rreq, was_async); - netfs_put_request(rreq, was_async); + netfs_put_request(rreq, was_async, netfs_rreq_trace_put_complete); } /* @@ -799,7 +799,7 @@ void netfs_readahead(struct readahead_control *ractl, return; cleanup_free: - netfs_put_request(rreq, false); + netfs_put_request(rreq, false, netfs_rreq_trace_put_failed); return; cleanup: if (netfs_priv) @@ -858,7 +858,7 @@ int netfs_readpage(struct file *file, netfs_stat(&netfs_n_rh_readpage); trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage); - netfs_get_request(rreq); + netfs_get_request(rreq, netfs_rreq_trace_get_hold); atomic_set(&rreq->nr_outstanding, 1); do { @@ -883,7 +883,7 @@ int netfs_readpage(struct file *file, ret = -EIO; } out: - netfs_put_request(rreq, false); + netfs_put_request(rreq, false, netfs_rreq_trace_put_hold); return ret; } EXPORT_SYMBOL(netfs_readpage); @@ -1030,13 +1030,13 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, */ ractl._nr_pages = folio_nr_pages(folio); netfs_rreq_expand(rreq, &ractl); - netfs_get_request(rreq); /* We hold the folio locks, so we can drop the references */ folio_get(folio); while (readahead_folio(&ractl)) ; + netfs_get_request(rreq, netfs_rreq_trace_get_hold); atomic_set(&rreq->nr_outstanding, 1); do { if (!netfs_rreq_submit_slice(rreq, &debug_index)) @@ -1062,7 +1062,7 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_write_begin); ret = -EIO; } - netfs_put_request(rreq, false); + netfs_put_request(rreq, false, netfs_rreq_trace_put_hold); if (ret < 0) goto error; @@ -1078,7 +1078,7 @@ int netfs_write_begin(struct file *file, struct address_space *mapping, return 0; error_put: - netfs_put_request(rreq, false); + netfs_put_request(rreq, false, netfs_rreq_trace_put_failed); error: folio_unlock(folio); folio_put(folio); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index f63de27d6f29..541aebe828f3 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -168,7 +168,7 @@ struct netfs_io_request { loff_t i_size; /* Size of the file */ loff_t start; /* Start position */ pgoff_t no_unlock_folio; /* Don't unlock this folio after read */ - refcount_t usage; + refcount_t ref; unsigned long flags; #define NETFS_RREQ_INCOMPLETE_IO 0 /* Some ioreqs terminated short or with error */ #define NETFS_RREQ_COPY_TO_CACHE 1 /* Need to write to the cache */ diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index daf171de2142..602f3854da81 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -55,6 +55,15 @@ EM(netfs_fail_short_write_begin, "short-write-begin") \ E_(netfs_fail_prepare_write, "prep-write") +#define netfs_rreq_ref_traces \ + EM(netfs_rreq_trace_get_hold, "GET HOLD ") \ + EM(netfs_rreq_trace_get_subreq, "GET SUBREQ ") \ + EM(netfs_rreq_trace_put_complete, "PUT COMPLT ") \ + EM(netfs_rreq_trace_put_failed, "PUT FAILED ") \ + EM(netfs_rreq_trace_put_hold, "PUT HOLD ") \ + EM(netfs_rreq_trace_put_subreq, "PUT SUBREQ ") \ + E_(netfs_rreq_trace_new, "NEW ") + #ifndef __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY #define __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY @@ -67,6 +76,7 @@ enum netfs_read_trace { netfs_read_traces } __mode(byte); enum netfs_rreq_trace { netfs_rreq_traces } __mode(byte); enum netfs_sreq_trace { netfs_sreq_traces } __mode(byte); enum netfs_failure { netfs_failures } __mode(byte); +enum netfs_rreq_ref_trace { netfs_rreq_ref_traces } __mode(byte); #endif @@ -83,6 +93,7 @@ netfs_rreq_traces; netfs_sreq_sources; netfs_sreq_traces; netfs_failures; +netfs_rreq_ref_traces; /* * Now redefine the EM() and E_() macros to map the enums to the strings that @@ -229,6 +240,30 @@ TRACE_EVENT(netfs_failure, __entry->error) ); +TRACE_EVENT(netfs_rreq_ref, + TP_PROTO(unsigned int rreq_debug_id, int ref, + enum netfs_rreq_ref_trace what), + + TP_ARGS(rreq_debug_id, ref, what), + + TP_STRUCT__entry( + __field(unsigned int, rreq ) + __field(int, ref ) + __field(enum netfs_rreq_ref_trace, what ) + ), + + TP_fast_assign( + __entry->rreq = rreq_debug_id; + __entry->ref = ref; + __entry->what = what; + ), + + TP_printk("W=%08x %s r=%u", + __entry->rreq, + __print_symbolic(__entry->what, netfs_rreq_ref_traces), + __entry->ref) + ); + #endif /* _TRACE_NETFS_H */ /* This part must be outside protection */
