From: NeilBrown <neilb@suse.de>
To: "J. Bruce Fields" <bfields@fieldses.org>,
Chuck Lever <chuck.lever@oracle.com>
Cc: linux-nfs@vger.kernel.org
Subject: [PATCH 04/19] nfsd: make nfsd_stats.th_cnt atomic_t
Date: Tue, 23 Nov 2021 12:29:35 +1100 [thread overview]
Message-ID: <163763097544.7284.7451205698169106567.stgit@noble.brown> (raw)
In-Reply-To: <163763078330.7284.10141477742275086758.stgit@noble.brown>
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>
---
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 5f605e7e8091..fc5899502a83 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 1d3b881e7382..a8c5a02a84f0 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 51ecda852e23..9b43dc3d9991 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;
next prev parent reply other threads:[~2021-11-23 1:31 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-23 1:29 [PATCH 00/19 v2] SUNRPC: clean up server thread management NeilBrown
2021-11-23 1:29 ` [PATCH 15/19] lockd: rename lockd_create_svc() to lockd_get() NeilBrown
2021-11-23 1:29 ` [PATCH 13/19] lockd: move svc_exit_thread() into the thread NeilBrown
2021-11-23 1:29 ` [PATCH 06/19] NFSD: narrow nfsd_mutex protection in nfsd thread NeilBrown
2021-11-23 1:29 ` [PATCH 05/19] SUNRPC: use sv_lock to protect updates to sv_nrthreads NeilBrown
2021-11-23 16:43 ` Chuck Lever III
2021-11-29 0:11 ` NeilBrown
2021-11-23 1:29 ` [PATCH 10/19] lockd: introduce nlmsvc_serv NeilBrown
2021-11-23 1:29 ` [PATCH 14/19] lockd: introduce lockd_put() NeilBrown
2021-11-23 1:29 ` [PATCH 02/19] NFSD: handle error better in write_ports_addfd() NeilBrown
2021-11-23 16:44 ` Chuck Lever III
2021-11-28 23:49 ` NeilBrown
2021-11-23 1:29 ` [PATCH 12/19] lockd: move lockd_start_svc() call into lockd_create_svc() NeilBrown
2021-11-23 1:29 ` [PATCH 16/19] SUNRPC: move the pool_map definitions (back) into svc.c NeilBrown
2021-11-23 1:29 ` [PATCH 07/19] NFSD: Make it possible to use svc_set_num_threads_sync NeilBrown
2021-11-23 1:29 ` NeilBrown [this message]
2021-11-23 1:29 ` [PATCH 01/19] SUNRPC/NFSD: clean up get/put functions NeilBrown
2021-11-23 16:45 ` Chuck Lever III
2021-11-28 23:36 ` NeilBrown
2021-11-23 1:29 ` [PATCH 18/19] lockd: use svc_set_num_threads() for thread start and stop NeilBrown
2021-11-23 1:29 ` [PATCH 09/19] NFSD: simplify locking for network notifier NeilBrown
2021-11-23 1:29 ` [PATCH 11/19] lockd: simplify management of network status notifiers NeilBrown
2021-11-23 1:29 ` [PATCH 08/19] SUNRPC: discard svo_setup and rename svc_set_num_threads_sync() NeilBrown
2021-11-23 1:29 ` [PATCH 19/19] NFS: switch the callback service back to non-pooled NeilBrown
2021-11-23 1:29 ` [PATCH 03/19] SUNRPC: stop using ->sv_nrthreads as a refcount NeilBrown
2021-11-23 1:29 ` [PATCH 17/19] SUNRPC: always treat sv_nrpools==1 as "not pooled" NeilBrown
2021-11-23 14:49 ` [PATCH 00/19 v2] SUNRPC: clean up server thread management J. Bruce Fields
2021-11-24 18:42 ` Chuck Lever III
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