5.10-stable review patch. If anyone has any objections, please let me know.
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From: NeilBrown neilb@suse.de
[ Upstream commit 9b6c8c9bebccd5fb785c306b948c08874a88874d ]
This allows us to move the updates for th_cnt out of the mutex. This is a step towards reducing mutex coverage in nfsd().
Signed-off-by: NeilBrown neilb@suse.de Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/nfssvc.c | 6 +++--- fs/nfsd/stats.c | 2 +- fs/nfsd/stats.h | 4 +--- 3 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index 141d884fee4f4..32f2c46a38323 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -57,7 +57,7 @@ static __be32 nfsd_init_request(struct svc_rqst *, /* * nfsd_mutex protects nn->nfsd_serv -- both the pointer itself and the members * of the svc_serv struct. In particular, ->sv_nrthreads but also to some - * extent ->sv_temp_socks and ->sv_permsocks. It also protects nfsdstats.th_cnt + * extent ->sv_temp_socks and ->sv_permsocks. * * If (out side the lock) nn->nfsd_serv is non-NULL, then it must point to a * properly initialised 'struct svc_serv' with ->sv_nrthreads > 0 (unless @@ -955,8 +955,8 @@ nfsd(void *vrqstp) allow_signal(SIGINT); allow_signal(SIGQUIT);
- nfsdstats.th_cnt++; mutex_unlock(&nfsd_mutex); + atomic_inc(&nfsdstats.th_cnt);
set_freezable();
@@ -983,8 +983,8 @@ nfsd(void *vrqstp) /* Clear signals before calling svc_exit_thread() */ flush_signals(current);
+ atomic_dec(&nfsdstats.th_cnt); mutex_lock(&nfsd_mutex); - nfsdstats.th_cnt --;
out: /* Take an extra ref so that the svc_put in svc_exit_thread() diff --git a/fs/nfsd/stats.c b/fs/nfsd/stats.c index 1d3b881e73821..a8c5a02a84f04 100644 --- a/fs/nfsd/stats.c +++ b/fs/nfsd/stats.c @@ -45,7 +45,7 @@ static int nfsd_proc_show(struct seq_file *seq, void *v) percpu_counter_sum_positive(&nfsdstats.counter[NFSD_STATS_IO_WRITE]));
/* thread usage: */ - seq_printf(seq, "th %u 0", nfsdstats.th_cnt); + seq_printf(seq, "th %u 0", atomic_read(&nfsdstats.th_cnt));
/* deprecated thread usage histogram stats */ for (i = 0; i < 10; i++) diff --git a/fs/nfsd/stats.h b/fs/nfsd/stats.h index 51ecda852e23b..9b43dc3d99913 100644 --- a/fs/nfsd/stats.h +++ b/fs/nfsd/stats.h @@ -29,11 +29,9 @@ enum { struct nfsd_stats { struct percpu_counter counter[NFSD_STATS_COUNTERS_NUM];
- /* Protected by nfsd_mutex */ - unsigned int th_cnt; /* number of available threads */ + atomic_t th_cnt; /* number of available threads */ };
- extern struct nfsd_stats nfsdstats;
extern struct svc_stat nfsd_svcstats;