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Registered in England and Wales under Company Registration No. 3798903 Subject: [RFC PATCH 35/76] fscache: read-helper: Add tracepoints From: David Howells To: Trond Myklebust , Anna Schumaker , Steve French , Dominique Martinet Cc: dhowells@redhat.com, Jeff Layton , Matthew Wilcox , Alexander Viro , linux-cachefs@redhat.com, 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: Fri, 20 Nov 2020 15:10:14 +0000 Message-ID: <160588501418.3465195.3819311073293372410.stgit@warthog.procyon.org.uk> In-Reply-To: <160588455242.3465195.3214733858273019178.stgit@warthog.procyon.org.uk> References: <160588455242.3465195.3214733858273019178.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org Add three tracepoints to track the activity of the read helpers: (1) fscache_support/fscache_read This logs entry to the read helpers and also expansion of the range in a readahead request. (2) fscache_support/fscache_rreq This logs the progress of fscache_read_request objects which track read requests. A read request may be a compound of multiple subrequests. (3) fscache_support/fscache_sreq This logs the progress of fscache_read_subrequest objects, which track the contributions from various sources to a read request. Signed-off-by: David Howells --- fs/netfs/read_helper.c | 37 ++++++++ include/linux/netfs.h | 2 include/trace/events/netfs.h | 200 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 239 insertions(+) create mode 100644 include/trace/events/netfs.h diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c index f5185402b504..21d3578c6979 100644 --- a/fs/netfs/read_helper.c +++ b/fs/netfs/read_helper.c @@ -16,6 +16,8 @@ #include #include #include "internal.h" +#define CREATE_TRACE_POINTS +#include MODULE_DESCRIPTION("Network fs support"); MODULE_AUTHOR("Red Hat, Inc."); @@ -38,6 +40,7 @@ static struct netfs_read_request *netfs_alloc_read_request( const struct netfs_read_request_ops *ops, void *netfs_priv, struct file *file) { + static atomic_t debug_ids; struct netfs_read_request *rreq; rreq = kzalloc(sizeof(struct netfs_read_request), GFP_KERNEL); @@ -46,6 +49,7 @@ static struct netfs_read_request *netfs_alloc_read_request( rreq->netfs_priv = netfs_priv; rreq->inode = file_inode(file); rreq->i_size = i_size_read(rreq->inode); + 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); @@ -80,6 +84,7 @@ static void netfs_put_read_request(struct netfs_read_request *rreq) if (rreq->netfs_priv) rreq->netfs_ops->cleanup(rreq->mapping, rreq->netfs_priv); fscache_end_operation(&rreq->cache_resources); + trace_netfs_rreq(rreq, netfs_rreq_trace_free); kfree(rreq); } } @@ -109,6 +114,7 @@ static void netfs_get_read_subrequest(struct netfs_read_subrequest *subreq) static void __netfs_put_subrequest(struct netfs_read_subrequest *subreq) { + trace_netfs_sreq(subreq, netfs_sreq_trace_free); netfs_put_read_request(subreq->rreq); kfree(subreq); } @@ -188,6 +194,7 @@ static void netfs_read_from_server(struct netfs_read_request *rreq, */ static void netfs_rreq_completed(struct netfs_read_request *rreq) { + trace_netfs_rreq(rreq, netfs_rreq_trace_done); netfs_rreq_clear_subreqs(rreq); netfs_put_read_request(rreq); } @@ -205,6 +212,8 @@ static void netfs_rreq_unmark_after_write(struct netfs_read_request *rreq) pgoff_t unlocked = 0; bool have_unlocked = false; + trace_netfs_rreq(rreq, netfs_rreq_trace_unmark); + rcu_read_lock(); list_for_each_entry(subreq, &rreq->subrequests, rreq_link) { @@ -236,6 +245,8 @@ static void netfs_rreq_copy_terminated(void *priv, ssize_t transferred_or_error) else subreq->error = 0; + trace_netfs_sreq(subreq, netfs_sreq_trace_write_term); + /* If we decrement nr_wr_ops to 0, the ref belongs to us. */ if (atomic_dec_and_test(&rreq->nr_wr_ops)) netfs_rreq_unmark_after_write(rreq); @@ -252,6 +263,8 @@ static void netfs_rreq_do_write_to_cache(struct netfs_read_request *rreq) struct netfs_read_subrequest *subreq, *next, *p; struct iov_iter iter; + trace_netfs_rreq(rreq, netfs_rreq_trace_write); + /* We don't want terminating writes trying to wake us up whilst we're * still going through the list. */ @@ -275,6 +288,8 @@ static void netfs_rreq_do_write_to_cache(struct netfs_read_request *rreq) netfs_put_subrequest(next); } + trace_netfs_sreq(subreq, netfs_sreq_trace_write); + iov_iter_xarray(&iter, WRITE, &rreq->mapping->i_pages, subreq->start, subreq->len); @@ -342,6 +357,8 @@ static void netfs_rreq_unlock(struct netfs_read_request *rreq) iopos = 0; subreq_failed = (subreq->error < 0); + trace_netfs_rreq(rreq, netfs_rreq_trace_unlock); + rcu_read_lock(); xas_for_each(&xas, page, last_page) { unsigned int pgpos = (page->index - start_page) * PAGE_SIZE; @@ -398,6 +415,8 @@ static void netfs_rreq_short_read(struct netfs_read_request *rreq, __clear_bit(NETFS_SREQ_SHORT_READ, &subreq->flags); __set_bit(NETFS_SREQ_SEEK_DATA_READ, &subreq->flags); + trace_netfs_sreq(subreq, netfs_sreq_trace_resubmit_short); + netfs_get_read_subrequest(subreq); atomic_inc(&rreq->nr_rd_ops); if (subreq->source == NETFS_READ_FROM_CACHE) @@ -416,6 +435,8 @@ static bool netfs_rreq_perform_resubmissions(struct netfs_read_request *rreq) WARN_ON(in_softirq()); + trace_netfs_rreq(rreq, netfs_rreq_trace_resubmit); + /* We don't want terminating submissions trying to wake us up whilst * we're still going through the list. */ @@ -428,6 +449,7 @@ static bool netfs_rreq_perform_resubmissions(struct netfs_read_request *rreq) break; subreq->source = NETFS_DOWNLOAD_FROM_SERVER; subreq->error = 0; + trace_netfs_sreq(subreq, netfs_sreq_trace_download_instead); netfs_get_read_subrequest(subreq); atomic_inc(&rreq->nr_rd_ops); netfs_read_from_server(rreq, subreq); @@ -471,6 +493,8 @@ static void netfs_rreq_is_still_valid(struct netfs_read_request *rreq) */ static void netfs_rreq_assess(struct netfs_read_request *rreq) { + trace_netfs_rreq(rreq, netfs_rreq_trace_assess); + again: netfs_rreq_is_still_valid(rreq); @@ -558,6 +582,8 @@ void netfs_subreq_terminated(struct netfs_read_subrequest *subreq, set_bit(NETFS_RREQ_WRITE_TO_CACHE, &rreq->flags); out: + trace_netfs_sreq(subreq, netfs_sreq_trace_terminated); + /* If we decrement nr_rd_ops to 0, the ref belongs to us. */ u = atomic_dec_return(&rreq->nr_rd_ops); if (u == 0) @@ -650,6 +676,7 @@ netfs_rreq_prepare_read(struct netfs_read_request *rreq, out: subreq->source = source; + trace_netfs_sreq(subreq, netfs_sreq_trace_prepare); return source; } @@ -690,6 +717,7 @@ static bool netfs_rreq_submit_slice(struct netfs_read_request *rreq, rreq->submitted += subreq->len; + trace_netfs_sreq(subreq, netfs_sreq_trace_submit); switch (source) { case NETFS_FILL_WITH_ZEROES: netfs_fill_with_zeroes(rreq, subreq); @@ -750,6 +778,9 @@ static void netfs_rreq_expand(struct netfs_read_request *rreq, readahead_expand(ractl, rreq->start, rreq->len); rreq->start = readahead_pos(ractl); rreq->len = readahead_length(ractl); + + trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl), + netfs_read_trace_expanded); } } @@ -791,6 +822,9 @@ void netfs_readahead(struct readahead_control *ractl, rreq->start = readahead_pos(ractl); rreq->len = readahead_length(ractl); + trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl), + netfs_read_trace_readahead); + if (ops->begin_cache_operation) ops->begin_cache_operation(rreq); netfs_rreq_expand(rreq, ractl); @@ -863,6 +897,9 @@ int netfs_readpage(struct file *file, rreq->start = page->index * PAGE_SIZE; rreq->len = thp_size(page); + trace_netfs_read(rreq, page->index * PAGE_SIZE, thp_size(page), + netfs_read_trace_readpage); + if (ops->begin_cache_operation) ops->begin_cache_operation(rreq); netfs_get_read_request(rreq); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index f2ffea11ea9b..c4276eb9914d 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -53,6 +53,8 @@ struct netfs_read_request { struct list_head subrequests; /* Requests to fetch I/O from disk or net */ struct work_struct work; void *netfs_priv; /* Private data for the netfs */ + unsigned int debug_id; + unsigned int cookie_debug_id; atomic_t nr_rd_ops; /* Number of read ops in progress */ atomic_t nr_wr_ops; /* Number of write ops in progress */ size_t submitted; /* Amount submitted for I/O so far */ diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h new file mode 100644 index 000000000000..56a734a3fb0d --- /dev/null +++ b/include/trace/events/netfs.h @@ -0,0 +1,200 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* Network filesystem support module tracepoints + * + * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM netfs + +#if !defined(_TRACE_NETFS_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_NETFS_H + +#include +#include + +/* + * Define enums for tracing information. + */ +#ifndef __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY +#define __NETFS_DECLARE_TRACE_ENUMS_ONCE_ONLY + +enum netfs_read_trace { + netfs_read_trace_expanded, + netfs_read_trace_readahead, + netfs_read_trace_readpage, +}; + +enum netfs_rreq_trace { + netfs_rreq_trace_assess, + netfs_rreq_trace_done, + netfs_rreq_trace_free, + netfs_rreq_trace_resubmit, + netfs_rreq_trace_unlock, + netfs_rreq_trace_unmark, + netfs_rreq_trace_write, +}; + +enum netfs_sreq_trace { + netfs_sreq_trace_download_instead, + netfs_sreq_trace_free, + netfs_sreq_trace_prepare, + netfs_sreq_trace_resubmit_short, + netfs_sreq_trace_submit, + netfs_sreq_trace_terminated, + netfs_sreq_trace_write, + netfs_sreq_trace_write_term, +}; + +#endif + +#define netfs_read_traces \ + EM(netfs_read_trace_expanded, "EXPANDED ") \ + EM(netfs_read_trace_readahead, "READAHEAD") \ + E_(netfs_read_trace_readpage, "READPAGE ") + +#define netfs_rreq_traces \ + EM(netfs_rreq_trace_assess, "ASSESS") \ + EM(netfs_rreq_trace_done, "DONE ") \ + EM(netfs_rreq_trace_free, "FREE ") \ + EM(netfs_rreq_trace_resubmit, "RESUBM") \ + EM(netfs_rreq_trace_unlock, "UNLOCK") \ + EM(netfs_rreq_trace_unmark, "UNMARK") \ + E_(netfs_rreq_trace_write, "WRITE ") + +#define netfs_sreq_sources \ + EM(NETFS_FILL_WITH_ZEROES, "ZERO") \ + EM(NETFS_DOWNLOAD_FROM_SERVER, "DOWN") \ + EM(NETFS_READ_FROM_CACHE, "READ") \ + E_(NETFS_INVALID_READ, "INVL") \ + +#define netfs_sreq_traces \ + EM(netfs_sreq_trace_download_instead, "RDOWN") \ + EM(netfs_sreq_trace_free, "FREE ") \ + EM(netfs_sreq_trace_prepare, "PREP ") \ + EM(netfs_sreq_trace_resubmit_short, "SHORT") \ + EM(netfs_sreq_trace_submit, "SUBMT") \ + EM(netfs_sreq_trace_terminated, "TERM ") \ + EM(netfs_sreq_trace_write, "WRITE") \ + E_(netfs_sreq_trace_write_term, "WTERM") + + +/* + * Export enum symbols via userspace. + */ +#undef EM +#undef E_ +#define EM(a, b) TRACE_DEFINE_ENUM(a); +#define E_(a, b) TRACE_DEFINE_ENUM(a); + +netfs_read_traces; +netfs_rreq_traces; +netfs_sreq_sources; +netfs_sreq_traces; + +/* + * Now redefine the EM() and E_() macros to map the enums to the strings that + * will be printed in the output. + */ +#undef EM +#undef E_ +#define EM(a, b) { a, b }, +#define E_(a, b) { a, b } + +TRACE_EVENT(netfs_read, + TP_PROTO(struct netfs_read_request *rreq, + loff_t start, size_t len, + enum netfs_read_trace what), + + TP_ARGS(rreq, start, len, what), + + TP_STRUCT__entry( + __field(unsigned int, rreq ) + __field(unsigned int, cookie ) + __field(loff_t, start ) + __field(size_t, len ) + __field(enum netfs_read_trace, what ) + ), + + TP_fast_assign( + __entry->rreq = rreq->debug_id; + __entry->cookie = rreq->cookie_debug_id; + __entry->start = start; + __entry->len = len; + __entry->what = what; + ), + + TP_printk("R=%08x %s c=%08x s=%llx %zx", + __entry->rreq, + __print_symbolic(__entry->what, netfs_read_traces), + __entry->cookie, + __entry->start, __entry->len) + ); + +TRACE_EVENT(netfs_rreq, + TP_PROTO(struct netfs_read_request *rreq, + enum netfs_rreq_trace what), + + TP_ARGS(rreq, what), + + TP_STRUCT__entry( + __field(unsigned int, rreq ) + __field(unsigned short, flags ) + __field(enum netfs_rreq_trace, what ) + ), + + TP_fast_assign( + __entry->rreq = rreq->debug_id; + __entry->flags = rreq->flags; + __entry->what = what; + ), + + TP_printk("R=%08x %s f=%02x", + __entry->rreq, + __print_symbolic(__entry->what, netfs_rreq_traces), + __entry->flags) + ); + +TRACE_EVENT(netfs_sreq, + TP_PROTO(struct netfs_read_subrequest *sreq, + enum netfs_sreq_trace what), + + TP_ARGS(sreq, what), + + TP_STRUCT__entry( + __field(unsigned int, rreq ) + __field(unsigned short, index ) + __field(short, error ) + __field(unsigned short, flags ) + __field(enum netfs_read_source, source ) + __field(enum netfs_sreq_trace, what ) + __field(size_t, len ) + __field(size_t, transferred ) + __field(loff_t, start ) + ), + + TP_fast_assign( + __entry->rreq = sreq->rreq->debug_id; + __entry->index = sreq->debug_index; + __entry->error = sreq->error; + __entry->flags = sreq->flags; + __entry->source = sreq->source; + __entry->what = what; + __entry->len = sreq->len; + __entry->transferred = sreq->transferred; + __entry->start = sreq->start; + ), + + TP_printk("R=%08x[%u] %s %s f=%02x s=%llx %zx/%zx e=%d", + __entry->rreq, __entry->index, + __print_symbolic(__entry->what, netfs_sreq_traces), + __print_symbolic(__entry->source, netfs_sreq_sources), + __entry->flags, + __entry->start, __entry->transferred, __entry->len, + __entry->error) + ); + +#endif /* _TRACE_NETFS_H */ + +/* This part must be outside protection */ +#include