From: Mike Snitzer <snitzer@kernel.org>
To: Anna Schumaker <anna@kernel.org>, Trond Myklebust <trondmy@kernel.org>
Cc: Mike Snitzer <snitzer@hammerspace.com>,
linux-nfs@vger.kernel.org,
Jonathan Flynn <jonathan.flynn@hammerspace.com>
Subject: [PATCH v2 05/12] NFSv4/flexfiles: drop the redundant atomic from the busy timer
Date: Thu, 5 Nov 2026 19:12:42 -0500 [thread overview]
Message-ID: <20261106001251.73472-6-snitzer@kernel.org> (raw)
In-Reply-To: <20261106001251.73472-1-snitzer@kernel.org>
From: Mike Snitzer <snitzer@hammerspace.com>
nfs4_ff_busy_timer::n_ops is an atomic_t, but the stripe lock already
serializes every access to it. Make it a plain int.
Signed-off-by: Mike Snitzer <snitzer@hammerspace.com>
---
fs/nfs/flexfilelayout/flexfilelayout.c | 6 ++----
fs/nfs/flexfilelayout/flexfilelayout.h | 3 ++-
2 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index eddedb1c6bf38..f5591d4451ab3 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -711,9 +711,8 @@ static void
nfs4_ff_start_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
{
/* first IO request? */
- if (atomic_inc_return(&timer->n_ops) == 1) {
+ if (++timer->n_ops == 1)
timer->start_time = now;
- }
}
static ktime_t
@@ -721,8 +720,7 @@ nfs4_ff_end_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
{
ktime_t start;
- if (atomic_dec_return(&timer->n_ops) < 0)
- WARN_ON_ONCE(1);
+ WARN_ON_ONCE(--timer->n_ops < 0);
start = timer->start_time;
timer->start_time = now;
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h
index 8119da3073423..4b2aaa16ee597 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.h
+++ b/fs/nfs/flexfilelayout/flexfilelayout.h
@@ -64,9 +64,10 @@ struct nfs4_ff_io_stat {
ktime_t aggregate_completion_time;
};
+/* Both members are protected by the enclosing stripe's lock */
struct nfs4_ff_busy_timer {
ktime_t start_time;
- atomic_t n_ops;
+ int n_ops;
};
struct nfs4_ff_layoutstat {
--
2.52.0
next prev parent reply other threads:[~2026-11-06 0:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-06 0:12 [PATCH v2 00/12] NFSv4/flexfiles: scale layoutstats for striped layouts Mike Snitzer
2026-11-06 0:12 ` [PATCH v2 01/12] NFSv4/flexfiles: move layoutstats accounting to a per-stripe lock Mike Snitzer
2026-11-06 12:28 ` kernel test robot
2026-11-06 0:12 ` [PATCH v2 02/12] NFSv4/flexfiles: drop the now-unused per-mirror lock Mike Snitzer
2026-11-06 0:12 ` [PATCH v2 03/12] NFSv4/flexfiles: cacheline align the per-stripe layoutstats Mike Snitzer
2026-11-06 0:12 ` [PATCH v2 04/12] NFSv4/flexfiles: make dss_info->start_time write-once Mike Snitzer
2026-11-06 0:12 ` Mike Snitzer [this message]
2026-11-06 0:12 ` [PATCH v2 06/12] NFSv4/flexfiles: pair the in-flight count with the layoutstats updates Mike Snitzer
2026-11-06 0:12 ` [PATCH v2 07/12] NFSv4/flexfiles: derive ffil_ops_requested rather than storing it Mike Snitzer
2026-11-06 0:12 ` [PATCH v2 08/12] NFSv4/flexfiles: give each direction its own lock and cacheline Mike Snitzer
2026-11-06 0:12 ` [PATCH v2 09/12] NFSv4/flexfiles: drop NFS4_FF_MIRROR_STAT_AVAIL Mike Snitzer
2026-11-06 0:12 ` [PATCH v2 10/12] NFSv4/flexfiles: rotate LAYOUTSTATS reporting across a mirror's stripes Mike Snitzer
2026-11-06 0:12 ` [PATCH v2 11/12] NFSv4/flexfiles: take the report decision out of the critical section Mike Snitzer
2026-11-06 0:12 ` [PATCH v2 12/12] NFSv4/flexfiles: share one helper for the start of a read and a write Mike Snitzer
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