[10/19] netfs: Trace refcounting on the netfs_io_subrequest struct

Message ID	164622998584.3564931.5052255990645723639.stgit@warthog.procyon.org.uk (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-cifs-owner@kernel.org> Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 10/19] netfs: Trace refcounting on the netfs_io_subrequest struct From: David Howells <dhowells@redhat.com> To: linux-cachefs@redhat.com Cc: dhowells@redhat.com, Anna Schumaker <anna.schumaker@netapp.com>, Steve French <sfrench@samba.org>, Dominique Martinet <asmadeus@codewreck.org>, Jeff Layton <jlayton@redhat.com>, David Wysochanski <dwysocha@redhat.com>, Ilya Dryomov <idryomov@gmail.com>, Jeffle Xu <jefflexu@linux.alibaba.com>, Linus Torvalds <torvalds@linux-foundation.org>, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 02 Mar 2022 14:06:25 +0000 Message-ID: <164622998584.3564931.5052255990645723639.stgit@warthog.procyon.org.uk> In-Reply-To: <164622970143.3564931.3656393397237724303.stgit@warthog.procyon.org.uk> References: <164622970143.3564931.3656393397237724303.stgit@warthog.procyon.org.uk> User-Agent: StGit/1.4 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk
Series	netfs: Prep for write helpers \| expand [00/19] netfs: Prep for write helpers [01/19] fscache: export fscache_end_operation() [02/19] netfs: Generate enums from trace symbol mapping lists [03/19] netfs: Add a netfs inode context [04/19] netfs: Rename netfs_read_request to netfs_io_request [05/19] netfs: Refactor arguments for netfs_alloc_read_request [06/19] netfs: Finish off rename of netfs_read_request to netfs_io_request [07/19] netfs: Split netfs_io_* object handling out [08/19] netfs: Adjust the netfs_rreq tracepoint slightly [09/19] netfs: Trace refcounting on the netfs_io_request struct [10/19] netfs: Trace refcounting on the netfs_io_subrequest struct [11/19] netfs: Adjust the netfs_failure tracepoint to indicate non-subreq lines [12/19] netfs: Prepare to split read_helper.c [13/19] netfs: Add a function to consolidate beginning a read [14/19] netfs: Split fs/netfs/read_helper.c [15/19] netfs: Split some core bits out into their own file [16/19] netfs: Rename rename read_helper.c to io.c [17/19] netfs: Change ->init_rreq() to return an error code [18/19] netfs: Keep track of the actual remote file size [19/19] afs: Maintain netfs_i_context::remote_i_size

diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h index b3877e276a3a..ee2f64cde221 100644 --- a/fs/netfs/internal.h +++ b/fs/netfs/internal.h @@ -27,8 +27,6 @@ void netfs_clear_subrequests(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) diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c index 57d53f1f6741..c46d027c1692 100644 --- a/fs/netfs/objects.c +++ b/fs/netfs/objects.c @@ -59,7 +59,8 @@ void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async) subreq = list_first_entry(&rreq->subrequests, struct netfs_io_subrequest, rreq_link); list_del(&subreq->rreq_link); - netfs_put_subrequest(subreq, was_async); + netfs_put_subrequest(subreq, was_async, + netfs_sreq_trace_put_clear); } } @@ -107,7 +108,7 @@ struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq subreq = kzalloc(sizeof(struct netfs_io_subrequest), GFP_KERNEL); if (subreq) { INIT_LIST_HEAD(&subreq->rreq_link); - refcount_set(&subreq->usage, 2); + refcount_set(&subreq->ref, 2); subreq->rreq = rreq; netfs_get_request(rreq, netfs_rreq_trace_get_subreq); netfs_stat(&netfs_n_rh_sreq); @@ -116,9 +117,14 @@ struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq return subreq; } -void netfs_get_subrequest(struct netfs_io_subrequest *subreq) +void netfs_get_subrequest(struct netfs_io_subrequest *subreq, + enum netfs_sreq_ref_trace what) { - refcount_inc(&subreq->usage); + int r; + + __refcount_inc(&subreq->ref, &r); + trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1, + what); } static void netfs_free_subrequest(struct netfs_io_subrequest *subreq, @@ -132,8 +138,16 @@ static void netfs_free_subrequest(struct netfs_io_subrequest *subreq, netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq); } -void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async) +void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async, + enum netfs_sreq_ref_trace what) { - if (refcount_dec_and_test(&subreq->usage)) + unsigned int debug_index = subreq->debug_index; + unsigned int debug_id = subreq->rreq->debug_id; + bool dead; + int r; + + dead = __refcount_dec_and_test(&subreq->ref, &r); + trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what); + if (dead) netfs_free_subrequest(subreq, was_async); } diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c index 535b2cbde4c8..c953a573b6b6 100644 --- a/fs/netfs/read_helper.c +++ b/fs/netfs/read_helper.c @@ -166,7 +166,7 @@ static void netfs_rreq_copy_terminated(void *priv, ssize_t transferred_or_error, if (atomic_dec_and_test(&rreq->nr_copy_ops)) netfs_rreq_unmark_after_write(rreq, was_async); - netfs_put_subrequest(subreq, was_async); + netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated); } /* @@ -190,7 +190,8 @@ static void netfs_rreq_do_write_to_cache(struct netfs_io_request *rreq) list_for_each_entry_safe(subreq, p, &rreq->subrequests, rreq_link) { if (!test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags)) { list_del_init(&subreq->rreq_link); - netfs_put_subrequest(subreq, false); + netfs_put_subrequest(subreq, false, + netfs_sreq_trace_put_no_copy); } } @@ -202,7 +203,8 @@ static void netfs_rreq_do_write_to_cache(struct netfs_io_request *rreq) break; subreq->len += next->len; list_del_init(&next->rreq_link); - netfs_put_subrequest(next, false); + netfs_put_subrequest(next, false, + netfs_sreq_trace_put_merged); } ret = cres->ops->prepare_write(cres, &subreq->start, &subreq->len, @@ -218,7 +220,7 @@ static void netfs_rreq_do_write_to_cache(struct netfs_io_request *rreq) atomic_inc(&rreq->nr_copy_ops); netfs_stat(&netfs_n_rh_write); - netfs_get_subrequest(subreq); + netfs_get_subrequest(subreq, netfs_sreq_trace_get_copy_to_cache); trace_netfs_sreq(subreq, netfs_sreq_trace_write); cres->ops->write(cres, subreq->start, &iter, netfs_rreq_copy_terminated, subreq); @@ -341,7 +343,7 @@ static void netfs_rreq_short_read(struct netfs_io_request *rreq, netfs_stat(&netfs_n_rh_short_read); trace_netfs_sreq(subreq, netfs_sreq_trace_resubmit_short); - netfs_get_subrequest(subreq); + netfs_get_subrequest(subreq, netfs_sreq_trace_get_short_read); atomic_inc(&rreq->nr_outstanding); if (subreq->source == NETFS_READ_FROM_CACHE) netfs_read_from_cache(rreq, subreq, NETFS_READ_HOLE_CLEAR); @@ -375,7 +377,7 @@ static bool netfs_rreq_perform_resubmissions(struct netfs_io_request *rreq) subreq->error = 0; netfs_stat(&netfs_n_rh_download_instead); trace_netfs_sreq(subreq, netfs_sreq_trace_download_instead); - netfs_get_subrequest(subreq); + netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit); atomic_inc(&rreq->nr_outstanding); netfs_read_from_server(rreq, subreq); } else if (test_bit(NETFS_SREQ_SHORT_IO, &subreq->flags)) { @@ -537,7 +539,7 @@ void netfs_subreq_terminated(struct netfs_io_subrequest *subreq, else if (u == 1) wake_up_var(&rreq->nr_outstanding); - netfs_put_subrequest(subreq, was_async); + netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated); return; incomplete: @@ -682,7 +684,7 @@ static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq, subreq_failed: rreq->error = subreq->error; - netfs_put_subrequest(subreq, false); + netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_failed); return false; } @@ -1024,13 +1026,13 @@ 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, netfs_rreq_trace_get_hold); /* 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)) diff --git a/include/linux/netfs.h b/include/linux/netfs.h index e5c049a25746..725b8fb8e4bb 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -18,6 +18,8 @@ #include <linux/fs.h> #include <linux/pagemap.h> +enum netfs_sreq_ref_trace; + /* * Overload PG_private_2 to give us PG_fscache - this is used to indicate that * a page is currently backed by a local disk cache @@ -146,7 +148,7 @@ struct netfs_io_subrequest { loff_t start; /* Where to start the I/O */ size_t len; /* Size of the I/O */ size_t transferred; /* Amount of data transferred */ - refcount_t usage; + refcount_t ref; short error; /* 0 or error that occurred */ unsigned short debug_index; /* Index in list (for debugging output) */ enum netfs_io_source source; /* Where to read from/write to */ @@ -277,6 +279,10 @@ extern int netfs_write_begin(struct file *, struct address_space *, void **); extern void netfs_subreq_terminated(struct netfs_io_subrequest *, ssize_t, bool); +extern void netfs_get_subrequest(struct netfs_io_subrequest *subreq, + enum netfs_sreq_ref_trace what); +extern void netfs_put_subrequest(struct netfs_io_subrequest *subreq, + bool was_async, enum netfs_sreq_ref_trace what); extern void netfs_stats_show(struct seq_file *); /** diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index 8c700e2bcd5c..507c5e612293 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -69,6 +69,17 @@ EM(netfs_rreq_trace_put_subreq, "PUT SUBREQ ") \ E_(netfs_rreq_trace_new, "NEW ") +#define netfs_sreq_ref_traces \ + EM(netfs_sreq_trace_get_copy_to_cache, "GET COPY2C ") \ + EM(netfs_sreq_trace_get_resubmit, "GET RESUBMIT") \ + EM(netfs_sreq_trace_get_short_read, "GET SHORTRD") \ + EM(netfs_sreq_trace_new, "NEW ") \ + EM(netfs_sreq_trace_put_clear, "PUT CLEAR ") \ + EM(netfs_sreq_trace_put_failed, "PUT FAILED ") \ + EM(netfs_sreq_trace_put_merged, "PUT MERGED ") \ + EM(netfs_sreq_trace_put_no_copy, "PUT NO COPY") \ + E_(netfs_sreq_trace_put_terminated, "PUT TERM ") + #ifndef __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY #define __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY @@ -82,6 +93,7 @@ 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); +enum netfs_sreq_ref_trace { netfs_sreq_ref_traces } __mode(byte); #endif @@ -100,6 +112,7 @@ netfs_sreq_sources; netfs_sreq_traces; netfs_failures; netfs_rreq_ref_traces; +netfs_sreq_ref_traces; /* * Now redefine the EM() and E_() macros to map the enums to the strings that @@ -273,6 +286,33 @@ TRACE_EVENT(netfs_rreq_ref, __entry->ref) ); +TRACE_EVENT(netfs_sreq_ref, + TP_PROTO(unsigned int rreq_debug_id, unsigned int subreq_debug_index, + int ref, enum netfs_sreq_ref_trace what), + + TP_ARGS(rreq_debug_id, subreq_debug_index, ref, what), + + TP_STRUCT__entry( + __field(unsigned int, rreq ) + __field(unsigned int, subreq ) + __field(int, ref ) + __field(enum netfs_sreq_ref_trace, what ) + ), + + TP_fast_assign( + __entry->rreq = rreq_debug_id; + __entry->subreq = subreq_debug_index; + __entry->ref = ref; + __entry->what = what; + ), + + TP_printk("W=%08x[%x] %s r=%u", + __entry->rreq, + __entry->subreq, + __print_symbolic(__entry->what, netfs_sreq_ref_traces), + __entry->ref) + ); + #endif /* _TRACE_NETFS_H */ /* This part must be outside protection */

[10/19] netfs: Trace refcounting on the netfs_io_subrequest struct

Commit Message

Patch