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| author | Chuck Lever <chuck.lever@oracle.com> | 2022-07-08 14:24:12 -0400 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2022-07-29 20:09:22 -0400 |
| commit | 904940e94a887701db24401e3ed6928a1d4e329f (patch) | |
| tree | 72f74dc052c0fc5ae0a1f27ea05c2b90bf1ffcb4 | |
| parent | d63293272abb51c02457f1017dfd61c3270d9ae3 (diff) | |
| download | lwn-904940e94a887701db24401e3ed6928a1d4e329f.tar.gz lwn-904940e94a887701db24401e3ed6928a1d4e329f.zip | |
NFSD: Report average age of filecache items
This is a measure of how long items stay in the filecache, to help
assess how efficient the cache is.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
| -rw-r--r-- | fs/nfsd/filecache.c | 11 | ||||
| -rw-r--r-- | fs/nfsd/filecache.h | 1 |
2 files changed, 11 insertions, 1 deletions
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index e15e719ede9d..27611aca16a4 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -45,6 +45,7 @@ struct nfsd_fcache_bucket { static DEFINE_PER_CPU(unsigned long, nfsd_file_cache_hits); static DEFINE_PER_CPU(unsigned long, nfsd_file_acquisitions); static DEFINE_PER_CPU(unsigned long, nfsd_file_releases); +static DEFINE_PER_CPU(unsigned long, nfsd_file_total_age); struct nfsd_fcache_disposal { struct work_struct work; @@ -178,6 +179,7 @@ nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval, if (nf) { INIT_HLIST_NODE(&nf->nf_node); INIT_LIST_HEAD(&nf->nf_lru); + nf->nf_birthtime = ktime_get(); nf->nf_file = NULL; nf->nf_cred = get_current_cred(); nf->nf_net = net; @@ -195,9 +197,11 @@ nfsd_file_alloc(struct inode *inode, unsigned int may, unsigned int hashval, static bool nfsd_file_free(struct nfsd_file *nf) { + s64 age = ktime_to_ms(ktime_sub(ktime_get(), nf->nf_birthtime)); bool flush = false; this_cpu_inc(nfsd_file_releases); + this_cpu_add(nfsd_file_total_age, age); trace_nfsd_file_put_final(nf); if (nf->nf_mark) @@ -1055,7 +1059,7 @@ static int nfsd_file_cache_stats_show(struct seq_file *m, void *v) { unsigned long hits = 0, acquisitions = 0, releases = 0; unsigned int i, count = 0, longest = 0; - unsigned long lru = 0; + unsigned long lru = 0, total_age = 0; /* * No need for spinlocks here since we're not terribly interested in @@ -1076,6 +1080,7 @@ static int nfsd_file_cache_stats_show(struct seq_file *m, void *v) hits += per_cpu(nfsd_file_cache_hits, i); acquisitions += per_cpu(nfsd_file_acquisitions, i); releases += per_cpu(nfsd_file_releases, i); + total_age += per_cpu(nfsd_file_total_age, i); } seq_printf(m, "total entries: %u\n", count); @@ -1084,6 +1089,10 @@ static int nfsd_file_cache_stats_show(struct seq_file *m, void *v) seq_printf(m, "cache hits: %lu\n", hits); seq_printf(m, "acquisitions: %lu\n", acquisitions); seq_printf(m, "releases: %lu\n", releases); + if (releases) + seq_printf(m, "mean age (ms): %ld\n", total_age / releases); + else + seq_printf(m, "mean age (ms): -\n"); return 0; } diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h index c9e3c6eb4776..c6ad5fe47f12 100644 --- a/fs/nfsd/filecache.h +++ b/fs/nfsd/filecache.h @@ -44,6 +44,7 @@ struct nfsd_file { refcount_t nf_ref; unsigned char nf_may; struct nfsd_file_mark *nf_mark; + ktime_t nf_birthtime; }; int nfsd_file_cache_init(void); |