Gather statistics from the netfs interface that can be exported through a seqfile. This is intended to be called by a later patch when viewing /proc/fs/fscache/stats. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx> cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> cc: linux-mm@xxxxxxxxx cc: linux-cachefs@xxxxxxxxxx cc: linux-afs@xxxxxxxxxxxxxxxxxxx cc: linux-nfs@xxxxxxxxxxxxxxx cc: linux-cifs@xxxxxxxxxxxxxxx cc: ceph-devel@xxxxxxxxxxxxxxx cc: v9fs-developer@xxxxxxxxxxxxxxxxxxxxx cc: linux-fsdevel@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/161118139247.1232039.10556850937548511068.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # rfc Link: https://lore.kernel.org/r/161161034669.2537118.2761232524997091480.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v2 Link: https://lore.kernel.org/r/161340397101.1303470.17581910581108378458.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v3 Link: https://lore.kernel.org/r/161539539959.286939.6794352576462965914.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v4 --- fs/netfs/Kconfig | 15 +++++++++++++ fs/netfs/Makefile | 3 +-- fs/netfs/internal.h | 34 ++++++++++++++++++++++++++++++ fs/netfs/read_helper.c | 23 ++++++++++++++++++++ fs/netfs/stats.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/netfs.h | 1 + 6 files changed, 128 insertions(+), 2 deletions(-) create mode 100644 fs/netfs/stats.c diff --git a/fs/netfs/Kconfig b/fs/netfs/Kconfig index 2ebf90e6ca95..578112713703 100644 --- a/fs/netfs/Kconfig +++ b/fs/netfs/Kconfig @@ -6,3 +6,18 @@ config NETFS_SUPPORT This option enables support for network filesystems, including helpers for high-level buffered I/O, abstracting out read segmentation, local caching and transparent huge page support. + +config NETFS_STATS + bool "Gather statistical information on local caching" + depends on NETFS_SUPPORT && PROC_FS + help + This option causes statistical information to be gathered on local + caching and exported through file: + + /proc/fs/fscache/stats + + The gathering of statistics adds a certain amount of overhead to + execution as there are a quite a few stats gathered, and on a + multi-CPU system these may be on cachelines that keep bouncing + between CPUs. On the other hand, the stats are very useful for + debugging purposes. Saying 'Y' here is recommended. diff --git a/fs/netfs/Makefile b/fs/netfs/Makefile index 4b4eff2ba369..c15bfc966d96 100644 --- a/fs/netfs/Makefile +++ b/fs/netfs/Makefile @@ -1,6 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 -netfs-y := \ - read_helper.o +netfs-y := read_helper.o stats.o obj-$(CONFIG_NETFS_SUPPORT) := netfs.o diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h index ee665c0e7dc8..98b6f4516da1 100644 --- a/fs/netfs/internal.h +++ b/fs/netfs/internal.h @@ -16,8 +16,42 @@ */ extern unsigned int netfs_debug; +/* + * stats.c + */ +#ifdef CONFIG_NETFS_STATS +extern atomic_t netfs_n_rh_readahead; +extern atomic_t netfs_n_rh_readpage; +extern atomic_t netfs_n_rh_rreq; +extern atomic_t netfs_n_rh_sreq; +extern atomic_t netfs_n_rh_download; +extern atomic_t netfs_n_rh_download_done; +extern atomic_t netfs_n_rh_download_failed; +extern atomic_t netfs_n_rh_download_instead; +extern atomic_t netfs_n_rh_read; +extern atomic_t netfs_n_rh_read_done; +extern atomic_t netfs_n_rh_read_failed; +extern atomic_t netfs_n_rh_zero; +extern atomic_t netfs_n_rh_short_read; +extern atomic_t netfs_n_rh_write; +extern atomic_t netfs_n_rh_write_done; +extern atomic_t netfs_n_rh_write_failed; + + +static inline void netfs_stat(atomic_t *stat) +{ + atomic_inc(stat); +} + +static inline void netfs_stat_d(atomic_t *stat) +{ + atomic_dec(stat); +} + +#else #define netfs_stat(x) do {} while(0) #define netfs_stat_d(x) do {} while(0) +#endif /*****************************************************************************/ /* diff --git a/fs/netfs/read_helper.c b/fs/netfs/read_helper.c index 799eee7f4ee6..6d6ed30f417e 100644 --- a/fs/netfs/read_helper.c +++ b/fs/netfs/read_helper.c @@ -56,6 +56,7 @@ static struct netfs_read_request *netfs_alloc_read_request( refcount_set(&rreq->usage, 1); __set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags); ops->init_rreq(rreq, file); + netfs_stat(&netfs_n_rh_rreq); } return rreq; @@ -88,6 +89,7 @@ static void netfs_free_read_request(struct work_struct *work) rreq->netfs_ops->cleanup(rreq->mapping, rreq->netfs_priv); trace_netfs_rreq(rreq, netfs_rreq_trace_free); kfree(rreq); + netfs_stat_d(&netfs_n_rh_rreq); } static void netfs_put_read_request(struct netfs_read_request *rreq, bool was_async) @@ -117,6 +119,7 @@ static struct netfs_read_subrequest *netfs_alloc_subrequest( refcount_set(&subreq->usage, 2); subreq->rreq = rreq; netfs_get_read_request(rreq); + netfs_stat(&netfs_n_rh_sreq); } return subreq; @@ -134,6 +137,7 @@ static void __netfs_put_subrequest(struct netfs_read_subrequest *subreq, trace_netfs_sreq(subreq, netfs_sreq_trace_free); kfree(subreq); + netfs_stat_d(&netfs_n_rh_sreq); netfs_put_read_request(rreq, was_async); } @@ -156,6 +160,7 @@ static void netfs_clear_unread(struct netfs_read_subrequest *subreq) static void netfs_fill_with_zeroes(struct netfs_read_request *rreq, struct netfs_read_subrequest *subreq) { + netfs_stat(&netfs_n_rh_zero); __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags); netfs_subreq_terminated(subreq, 0, false); } @@ -179,6 +184,7 @@ static void netfs_fill_with_zeroes(struct netfs_read_request *rreq, static void netfs_read_from_server(struct netfs_read_request *rreq, struct netfs_read_subrequest *subreq) { + netfs_stat(&netfs_n_rh_download); rreq->netfs_ops->issue_op(subreq); } @@ -288,6 +294,7 @@ 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); + netfs_stat(&netfs_n_rh_short_read); trace_netfs_sreq(subreq, netfs_sreq_trace_resubmit_short); netfs_get_read_subrequest(subreq); @@ -319,6 +326,7 @@ static bool netfs_rreq_perform_resubmissions(struct netfs_read_request *rreq) break; subreq->source = NETFS_DOWNLOAD_FROM_SERVER; subreq->error = 0; + netfs_stat(&netfs_n_rh_download_instead); trace_netfs_sreq(subreq, netfs_sreq_trace_download_instead); netfs_get_read_subrequest(subreq); atomic_inc(&rreq->nr_rd_ops); @@ -414,6 +422,17 @@ void netfs_subreq_terminated(struct netfs_read_subrequest *subreq, subreq->debug_index, subreq->start, subreq->flags, transferred_or_error); + switch (subreq->source) { + case NETFS_READ_FROM_CACHE: + netfs_stat(&netfs_n_rh_read_done); + break; + case NETFS_DOWNLOAD_FROM_SERVER: + netfs_stat(&netfs_n_rh_download_done); + break; + default: + break; + } + if (IS_ERR_VALUE(transferred_or_error)) { subreq->error = transferred_or_error; goto failed; @@ -470,8 +489,10 @@ void netfs_subreq_terminated(struct netfs_read_subrequest *subreq, failed: if (subreq->source == NETFS_READ_FROM_CACHE) { + netfs_stat(&netfs_n_rh_read_failed); set_bit(NETFS_RREQ_INCOMPLETE_IO, &rreq->flags); } else { + netfs_stat(&netfs_n_rh_download_failed); set_bit(NETFS_RREQ_FAILED, &rreq->flags); rreq->error = subreq->error; } @@ -653,6 +674,7 @@ void netfs_readahead(struct readahead_control *ractl, rreq->start = readahead_pos(ractl); rreq->len = readahead_length(ractl); + netfs_stat(&netfs_n_rh_readahead); trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl), netfs_read_trace_readahead); @@ -722,6 +744,7 @@ int netfs_readpage(struct file *file, rreq->start = page_index(page) * PAGE_SIZE; rreq->len = thp_size(page); + netfs_stat(&netfs_n_rh_readpage); trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage); netfs_get_read_request(rreq); diff --git a/fs/netfs/stats.c b/fs/netfs/stats.c new file mode 100644 index 000000000000..df6ff5718f25 --- /dev/null +++ b/fs/netfs/stats.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Netfs support statistics + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@xxxxxxxxxx) + */ + +#include <linux/export.h> +#include <linux/seq_file.h> +#include <linux/netfs.h> +#include "internal.h" + +atomic_t netfs_n_rh_readahead; +atomic_t netfs_n_rh_readpage; +atomic_t netfs_n_rh_rreq; +atomic_t netfs_n_rh_sreq; +atomic_t netfs_n_rh_download; +atomic_t netfs_n_rh_download_done; +atomic_t netfs_n_rh_download_failed; +atomic_t netfs_n_rh_download_instead; +atomic_t netfs_n_rh_read; +atomic_t netfs_n_rh_read_done; +atomic_t netfs_n_rh_read_failed; +atomic_t netfs_n_rh_zero; +atomic_t netfs_n_rh_short_read; +atomic_t netfs_n_rh_write; +atomic_t netfs_n_rh_write_done; +atomic_t netfs_n_rh_write_failed; + +void netfs_stats_show(struct seq_file *m) +{ + seq_printf(m, "RdHelp : RA=%u RP=%u rr=%u sr=%u\n", + atomic_read(&netfs_n_rh_readahead), + atomic_read(&netfs_n_rh_readpage), + atomic_read(&netfs_n_rh_rreq), + atomic_read(&netfs_n_rh_sreq)); + seq_printf(m, "RdHelp : ZR=%u sh=%u\n", + atomic_read(&netfs_n_rh_zero), + atomic_read(&netfs_n_rh_short_read)); + seq_printf(m, "RdHelp : DL=%u ds=%u df=%u di=%u\n", + atomic_read(&netfs_n_rh_download), + atomic_read(&netfs_n_rh_download_done), + atomic_read(&netfs_n_rh_download_failed), + atomic_read(&netfs_n_rh_download_instead)); + seq_printf(m, "RdHelp : RD=%u rs=%u rf=%u\n", + atomic_read(&netfs_n_rh_read), + atomic_read(&netfs_n_rh_read_done), + atomic_read(&netfs_n_rh_read_failed)); + seq_printf(m, "RdHelp : WR=%u ws=%u wf=%u\n", + atomic_read(&netfs_n_rh_write), + atomic_read(&netfs_n_rh_write_done), + atomic_read(&netfs_n_rh_write_failed)); +} +EXPORT_SYMBOL(netfs_stats_show); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index 8e8c6a4e4dde..db4af80cbae3 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -166,5 +166,6 @@ extern int netfs_readpage(struct file *, void *); extern void netfs_subreq_terminated(struct netfs_read_subrequest *, ssize_t, bool); +extern void netfs_stats_show(struct seq_file *); #endif /* _LINUX_NETFS_H */
