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 06/12] NFSv4/flexfiles: pair the in-flight count with the layoutstats updates
Date: Thu, 5 Nov 2026 19:12:43 -0500 [thread overview]
Message-ID: <20261106001251.73472-7-snitzer@kernel.org> (raw)
In-Reply-To: <20261106001251.73472-1-snitzer@kernel.org>
From: Mike Snitzer <snitzer@hammerspace.com>
The in-flight count of the busy timer and the requested-side statistics
are two halves of one count, but the callers update them through two
helpers. A new path could update one and not the other.
Fold nfs4_ff_layout_stat_io_update_requested() into
nfs4_ff_layoutstat_start_io(), and rename
nfs4_ff_layout_stat_io_update_completed() to
nfs4_ff_layoutstat_end_io(). Rename n_ops to ops_in_flight, which is
what it counts.
Both helpers now take the stripe, so they can assert the lock that
protects ops_in_flight.
No functional change.
Signed-off-by: Mike Snitzer <snitzer@hammerspace.com>
---
fs/nfs/flexfilelayout/flexfilelayout.c | 96 +++++++++++++-------------
fs/nfs/flexfilelayout/flexfilelayout.h | 2 +-
2 files changed, 50 insertions(+), 48 deletions(-)
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index f5591d4451ab3..db8aa2bb92406 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -711,7 +711,7 @@ static void
nfs4_ff_start_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
{
/* first IO request? */
- if (++timer->n_ops == 1)
+ if (++timer->ops_in_flight == 1)
timer->start_time = now;
}
@@ -720,7 +720,7 @@ nfs4_ff_end_busy_timer(struct nfs4_ff_busy_timer *timer, ktime_t now)
{
ktime_t start;
- WARN_ON_ONCE(--timer->n_ops < 0);
+ WARN_ON_ONCE(--timer->ops_in_flight < 0);
start = timer->start_time;
timer->start_time = now;
@@ -738,18 +738,27 @@ nfs4_ff_layoutstat_set_start_time(struct nfs4_ff_layout_ds_stripe *dss_info,
try_cmpxchg64(&dss_info->start_time, &unset, now);
}
+/*
+ * Account for an I/O about to be sent to this stripe, and return true if a
+ * LAYOUTSTATS report is due.
+ */
static bool
-nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_mirror *mirror,
- u32 dss_id,
+nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_ds_stripe *dss_info,
struct nfs4_ff_layoutstat *layoutstat,
- ktime_t now)
+ __u64 requested, ktime_t now)
{
- s64 report_interval = FF_LAYOUTSTATS_REPORT_INTERVAL;
+ struct nfs4_ff_layout_mirror *mirror = dss_info->mirror;
struct nfs4_flexfile_layout *ffl = FF_LAYOUT_FROM_HDR(mirror->layout);
+ s64 report_interval = FF_LAYOUTSTATS_REPORT_INTERVAL;
ktime_t last_report;
+ lockdep_assert_held(&dss_info->lock);
+
nfs4_ff_start_busy_timer(&layoutstat->busy_timer, now);
- nfs4_ff_layoutstat_set_start_time(&mirror->dss[dss_id], now);
+ layoutstat->io_stat.ops_requested++;
+ layoutstat->io_stat.bytes_requested += requested;
+
+ nfs4_ff_layoutstat_set_start_time(dss_info, now);
if (mirror->report_interval != 0)
report_interval = (s64)mirror->report_interval * 1000LL;
else if (layoutstats_timer != 0)
@@ -763,27 +772,21 @@ nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_mirror *mirror,
return try_cmpxchg64(&ffl->last_report_time, &last_report, now);
}
+/* Account for an I/O that has completed on this stripe. */
static void
-nfs4_ff_layout_stat_io_update_requested(struct nfs4_ff_layoutstat *layoutstat,
- __u64 requested)
-{
- struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
-
- iostat->ops_requested++;
- iostat->bytes_requested += requested;
-}
-
-static void
-nfs4_ff_layout_stat_io_update_completed(struct nfs4_ff_layoutstat *layoutstat,
- __u64 requested,
- __u64 completed,
- ktime_t time_completed,
- ktime_t time_started)
+nfs4_ff_layoutstat_end_io(struct nfs4_ff_layout_ds_stripe *dss_info,
+ struct nfs4_ff_layoutstat *layoutstat,
+ __u64 requested,
+ __u64 completed,
+ ktime_t time_completed,
+ ktime_t time_started)
{
struct nfs4_ff_io_stat *iostat = &layoutstat->io_stat;
ktime_t completion_time = ktime_sub(time_completed, time_started);
ktime_t timer;
+ lockdep_assert_held(&dss_info->lock);
+
iostat->ops_completed++;
iostat->bytes_completed += completed;
iostat->bytes_not_delivered += requested - completed;
@@ -802,14 +805,13 @@ nfs4_ff_layout_stat_io_start_read(struct inode *inode,
u32 dss_id,
__u64 requested, ktime_t now)
{
+ struct nfs4_ff_layout_ds_stripe *dss_info = &mirror->dss[dss_id];
bool report;
- spin_lock(&mirror->dss[dss_id].lock);
- report = nfs4_ff_layoutstat_start_io(
- mirror, dss_id, &mirror->dss[dss_id].read_stat, now);
- nfs4_ff_layout_stat_io_update_requested(
- &mirror->dss[dss_id].read_stat, requested);
- spin_unlock(&mirror->dss[dss_id].lock);
+ spin_lock(&dss_info->lock);
+ report = nfs4_ff_layoutstat_start_io(dss_info, &dss_info->read_stat,
+ requested, now);
+ spin_unlock(&dss_info->lock);
set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
if (report)
@@ -823,11 +825,13 @@ nfs4_ff_layout_stat_io_end_read(struct rpc_task *task,
__u64 requested,
__u64 completed)
{
- spin_lock(&mirror->dss[dss_id].lock);
- nfs4_ff_layout_stat_io_update_completed(&mirror->dss[dss_id].read_stat,
- requested, completed,
- ktime_get(), task->tk_start);
- spin_unlock(&mirror->dss[dss_id].lock);
+ struct nfs4_ff_layout_ds_stripe *dss_info = &mirror->dss[dss_id];
+
+ spin_lock(&dss_info->lock);
+ nfs4_ff_layoutstat_end_io(dss_info, &dss_info->read_stat,
+ requested, completed,
+ ktime_get(), task->tk_start);
+ spin_unlock(&dss_info->lock);
set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
}
@@ -837,18 +841,13 @@ nfs4_ff_layout_stat_io_start_write(struct inode *inode,
u32 dss_id,
__u64 requested, ktime_t now)
{
+ struct nfs4_ff_layout_ds_stripe *dss_info = &mirror->dss[dss_id];
bool report;
- spin_lock(&mirror->dss[dss_id].lock);
- report = nfs4_ff_layoutstat_start_io(
- mirror,
- dss_id,
- &mirror->dss[dss_id].write_stat,
- now);
- nfs4_ff_layout_stat_io_update_requested(
- &mirror->dss[dss_id].write_stat,
- requested);
- spin_unlock(&mirror->dss[dss_id].lock);
+ spin_lock(&dss_info->lock);
+ report = nfs4_ff_layoutstat_start_io(dss_info, &dss_info->write_stat,
+ requested, now);
+ spin_unlock(&dss_info->lock);
set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
if (report)
@@ -863,13 +862,16 @@ nfs4_ff_layout_stat_io_end_write(struct rpc_task *task,
__u64 completed,
enum nfs3_stable_how committed)
{
+ struct nfs4_ff_layout_ds_stripe *dss_info = &mirror->dss[dss_id];
+
if (committed == NFS_UNSTABLE)
requested = completed = 0;
- spin_lock(&mirror->dss[dss_id].lock);
- nfs4_ff_layout_stat_io_update_completed(&mirror->dss[dss_id].write_stat,
- requested, completed, ktime_get(), task->tk_start);
- spin_unlock(&mirror->dss[dss_id].lock);
+ spin_lock(&dss_info->lock);
+ nfs4_ff_layoutstat_end_io(dss_info, &dss_info->write_stat,
+ requested, completed,
+ ktime_get(), task->tk_start);
+ spin_unlock(&dss_info->lock);
set_bit(NFS4_FF_MIRROR_STAT_AVAIL, &mirror->flags);
}
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h
index 4b2aaa16ee597..8d24f94263b3a 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.h
+++ b/fs/nfs/flexfilelayout/flexfilelayout.h
@@ -67,7 +67,7 @@ struct nfs4_ff_io_stat {
/* Both members are protected by the enclosing stripe's lock */
struct nfs4_ff_busy_timer {
ktime_t start_time;
- int n_ops;
+ int ops_in_flight;
};
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 ` [PATCH v2 05/12] NFSv4/flexfiles: drop the redundant atomic from the busy timer Mike Snitzer
2026-11-06 0:12 ` Mike Snitzer [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20261106001251.73472-7-snitzer@kernel.org \
--to=snitzer@kernel.org \
--cc=anna@kernel.org \
--cc=jonathan.flynn@hammerspace.com \
--cc=linux-nfs@vger.kernel.org \
--cc=snitzer@hammerspace.com \
--cc=trondmy@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox