Commit 904940e9 authored by Chuck Lever's avatar Chuck Lever
Browse files

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: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent d6329327

fs/nfsd/filecache.c

+10 −1
Original line number Diff line number Diff line
@@ -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;

}

fs/nfsd/filecache.h

+1 −0
Original line number Diff line number Diff line
@@ -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);