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bcachefs: track_event_change()

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This introduces a new helper for connecting time_stats to state changes,
i.e. when taking journal reservations is blocked for some reason.

We use this to track separately the different reasons the journal might
be blocked - i.e. space in the journal full, or the journal pin fifo
full.

Also do some cleanup and improvements on the time stats code.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2023-11-09 22:07:42 -05:00
parent 3eedfe1af9
commit 066a26460b
8 changed files with 141 additions and 93 deletions
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4
fs/bcachefs/bcachefs.h
View File

@ -401,7 +401,9 @@ BCH_DEBUG_PARAMS_DEBUG()
x(journal_flush_write) \
x(journal_noflush_write) \
x(journal_flush_seq) \
x(blocked_journal) \
x(blocked_journal_low_on_space) \
x(blocked_journal_low_on_pin) \
x(blocked_journal_max_in_flight) \
x(blocked_allocate) \
x(blocked_allocate_open_bucket) \
x(nocow_lock_contended)

16
fs/bcachefs/journal.c
View File

@ -363,11 +363,6 @@ static int journal_entry_open(struct journal *j)
} while ((v = atomic64_cmpxchg(&j->reservations.counter,
old.v, new.v)) != old.v);
if (j->res_get_blocked_start)
bch2_time_stats_update(j->blocked_time,
j->res_get_blocked_start);
j->res_get_blocked_start = 0;
mod_delayed_work(c->io_complete_wq,
&j->write_work,
msecs_to_jiffies(c->opts.journal_flush_delay));
@ -467,15 +462,12 @@ retry:
__journal_entry_close(j, JOURNAL_ENTRY_CLOSED_VAL);
ret = journal_entry_open(j);
if (ret == JOURNAL_ERR_max_in_flight)
if (ret == JOURNAL_ERR_max_in_flight) {
track_event_change(&c->times[BCH_TIME_blocked_journal_max_in_flight],
&j->max_in_flight_start, true);
trace_and_count(c, journal_entry_full, c);
unlock:
if ((ret && ret != JOURNAL_ERR_insufficient_devices) &&
!j->res_get_blocked_start) {
j->res_get_blocked_start = local_clock() ?: 1;
trace_and_count(c, journal_full, c);
}
unlock:
can_discard = j->can_discard;
spin_unlock(&j->lock);

3
fs/bcachefs/journal_io.c
View File

@ -1604,6 +1604,9 @@ static CLOSURE_CALLBACK(journal_write_done)
bch2_journal_reclaim_fast(j);
bch2_journal_space_available(j);
track_event_change(&c->times[BCH_TIME_blocked_journal_max_in_flight],
&j->max_in_flight_start, false);
closure_wake_up(&w->wait);
journal_wake(j);

25
fs/bcachefs/journal_reclaim.c
View File

@ -50,17 +50,21 @@ unsigned bch2_journal_dev_buckets_available(struct journal *j,
return available;
}
static inline void journal_set_watermark(struct journal *j, bool low_on_space)
static inline void journal_set_watermark(struct journal *j)
{
unsigned watermark = BCH_WATERMARK_stripe;
struct bch_fs *c = container_of(j, struct bch_fs, journal);
bool low_on_space = j->space[journal_space_clean].total * 4 <=
j->space[journal_space_total].total;
bool low_on_pin = fifo_free(&j->pin) < j->pin.size / 4;
unsigned watermark = low_on_space || low_on_pin
? BCH_WATERMARK_reclaim
: BCH_WATERMARK_stripe;
if (low_on_space)
watermark = max_t(unsigned, watermark, BCH_WATERMARK_reclaim);
if (fifo_free(&j->pin) < j->pin.size / 4)
watermark = max_t(unsigned, watermark, BCH_WATERMARK_reclaim);
if (watermark == j->watermark)
return;
if (track_event_change(&c->times[BCH_TIME_blocked_journal_low_on_space],
&j->low_on_space_start, low_on_space) ||
track_event_change(&c->times[BCH_TIME_blocked_journal_low_on_pin],
&j->low_on_pin_start, low_on_pin))
trace_and_count(c, journal_full, c);
swap(watermark, j->watermark);
if (watermark > j->watermark)
@ -226,7 +230,7 @@ void bch2_journal_space_available(struct journal *j)
else
clear_bit(JOURNAL_MAY_SKIP_FLUSH, &j->flags);
journal_set_watermark(j, clean * 4 <= total);
journal_set_watermark(j);
out:
j->cur_entry_sectors = !ret ? j->space[journal_space_discarded].next_entry : 0;
j->cur_entry_error = ret;
@ -833,6 +837,7 @@ static int journal_flush_done(struct journal *j, u64 seq_to_flush,
bool bch2_journal_flush_pins(struct journal *j, u64 seq_to_flush)
{
/* time_stats this */
bool did_work = false;
if (!test_bit(JOURNAL_STARTED, &j->flags))

6
fs/bcachefs/journal_types.h
View File

@ -262,16 +262,18 @@ struct journal {
unsigned long last_flush_write;
u64 res_get_blocked_start;
u64 write_start_time;
u64 nr_flush_writes;
u64 nr_noflush_writes;
u64 entry_bytes_written;
u64 low_on_space_start;
u64 low_on_pin_start;
u64 max_in_flight_start;
struct bch2_time_stats *flush_write_time;
struct bch2_time_stats *noflush_write_time;
struct bch2_time_stats *blocked_time;
struct bch2_time_stats *flush_seq_time;
#ifdef CONFIG_DEBUG_LOCK_ALLOC

3
fs/bcachefs/super.c
View File

@ -661,7 +661,9 @@ static int bch2_fs_online(struct bch_fs *c)
ret = kobject_add(&c->kobj, NULL, "%pU", c->sb.user_uuid.b) ?:
kobject_add(&c->internal, &c->kobj, "internal") ?:
kobject_add(&c->opts_dir, &c->kobj, "options") ?:
#ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
kobject_add(&c->time_stats, &c->kobj, "time_stats") ?:
#endif
kobject_add(&c->counters_kobj, &c->kobj, "counters") ?:
bch2_opts_create_sysfs_files(&c->opts_dir);
if (ret) {
@ -773,7 +775,6 @@ static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
c->journal.flush_write_time = &c->times[BCH_TIME_journal_flush_write];
c->journal.noflush_write_time = &c->times[BCH_TIME_journal_noflush_write];
c->journal.blocked_time = &c->times[BCH_TIME_blocked_journal];
c->journal.flush_seq_time = &c->times[BCH_TIME_journal_flush_seq];
bch2_fs_btree_cache_init_early(&c->btree_cache);

144
fs/bcachefs/util.c
View File

@ -315,6 +315,57 @@ int bch2_prt_task_backtrace(struct printbuf *out, struct task_struct *task)
return ret;
}
#ifndef __KERNEL__
#include <time.h>
void bch2_prt_datetime(struct printbuf *out, time64_t sec)
{
time_t t = sec;
char buf[64];
ctime_r(&t, buf);
prt_str(out, buf);
}
#else
void bch2_prt_datetime(struct printbuf *out, time64_t sec)
{
char buf[64];
snprintf(buf, sizeof(buf), "%ptT", &sec);
prt_u64(out, sec);
}
#endif
static const struct time_unit {
const char *name;
u64 nsecs;
} time_units[] = {
{ "ns", 1 },
{ "us", NSEC_PER_USEC },
{ "ms", NSEC_PER_MSEC },
{ "s", NSEC_PER_SEC },
{ "m", (u64) NSEC_PER_SEC * 60},
{ "h", (u64) NSEC_PER_SEC * 3600},
{ "eon", U64_MAX },
};
static const struct time_unit *pick_time_units(u64 ns)
{
const struct time_unit *u;
for (u = time_units;
u + 1 < time_units + ARRAY_SIZE(time_units) &&
ns >= u[1].nsecs << 1;
u++)
;
return u;
}
void bch2_pr_time_units(struct printbuf *out, u64 ns)
{
const struct time_unit *u = pick_time_units(ns);
prt_printf(out, "%llu %s", div_u64(ns, u->nsecs), u->name);
}
/* time stats: */
#ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
@ -359,6 +410,7 @@ static inline void bch2_time_stats_update_one(struct bch2_time_stats *stats,
mean_and_variance_weighted_update(&stats->duration_stats_weighted, duration);
stats->max_duration = max(stats->max_duration, duration);
stats->min_duration = min(stats->min_duration, duration);
stats->total_duration += duration;
bch2_quantiles_update(&stats->quantiles, duration);
}
@ -372,22 +424,26 @@ static inline void bch2_time_stats_update_one(struct bch2_time_stats *stats,
}
}
static noinline void bch2_time_stats_clear_buffer(struct bch2_time_stats *stats,
struct bch2_time_stat_buffer *b)
static void __bch2_time_stats_clear_buffer(struct bch2_time_stats *stats,
struct bch2_time_stat_buffer *b)
{
struct bch2_time_stat_buffer_entry *i;
unsigned long flags;
spin_lock_irqsave(&stats->lock, flags);
for (i = b->entries;
for (struct bch2_time_stat_buffer_entry *i = b->entries;
i < b->entries + ARRAY_SIZE(b->entries);
i++)
bch2_time_stats_update_one(stats, i->start, i->end);
spin_unlock_irqrestore(&stats->lock, flags);
b->nr = 0;
}
static noinline void bch2_time_stats_clear_buffer(struct bch2_time_stats *stats,
struct bch2_time_stat_buffer *b)
{
unsigned long flags;
spin_lock_irqsave(&stats->lock, flags);
__bch2_time_stats_clear_buffer(stats, b);
spin_unlock_irqrestore(&stats->lock, flags);
}
void __bch2_time_stats_update(struct bch2_time_stats *stats, u64 start, u64 end)
{
unsigned long flags;
@ -423,40 +479,6 @@ void __bch2_time_stats_update(struct bch2_time_stats *stats, u64 start, u64 end)
preempt_enable();
}
}
#endif
static const struct time_unit {
const char *name;
u64 nsecs;
} time_units[] = {
{ "ns", 1 },
{ "us", NSEC_PER_USEC },
{ "ms", NSEC_PER_MSEC },
{ "s", NSEC_PER_SEC },
{ "m", (u64) NSEC_PER_SEC * 60},
{ "h", (u64) NSEC_PER_SEC * 3600},
{ "eon", U64_MAX },
};
static const struct time_unit *pick_time_units(u64 ns)
{
const struct time_unit *u;
for (u = time_units;
u + 1 < time_units + ARRAY_SIZE(time_units) &&
ns >= u[1].nsecs << 1;
u++)
;
return u;
}
void bch2_pr_time_units(struct printbuf *out, u64 ns)
{
const struct time_unit *u = pick_time_units(ns);
prt_printf(out, "%llu %s", div_u64(ns, u->nsecs), u->name);
}
static void bch2_pr_time_units_aligned(struct printbuf *out, u64 ns)
{
@ -467,26 +489,6 @@ static void bch2_pr_time_units_aligned(struct printbuf *out, u64 ns)
prt_printf(out, "%s", u->name);
}
#ifndef __KERNEL__
#include <time.h>
void bch2_prt_datetime(struct printbuf *out, time64_t sec)
{
time_t t = sec;
char buf[64];
ctime_r(&t, buf);
prt_str(out, buf);
}
#else
void bch2_prt_datetime(struct printbuf *out, time64_t sec)
{
char buf[64];
snprintf(buf, sizeof(buf), "%ptT", &sec);
prt_u64(out, sec);
}
#endif
#define TABSTOP_SIZE 12
static inline void pr_name_and_units(struct printbuf *out, const char *name, u64 ns)
{
prt_str(out, name);
@ -495,12 +497,24 @@ static inline void pr_name_and_units(struct printbuf *out, const char *name, u64
prt_newline(out);
}
#define TABSTOP_SIZE 12
void bch2_time_stats_to_text(struct printbuf *out, struct bch2_time_stats *stats)
{
const struct time_unit *u;
s64 f_mean = 0, d_mean = 0;
u64 q, last_q = 0, f_stddev = 0, d_stddev = 0;
int i;
if (stats->buffer) {
int cpu;
spin_lock_irq(&stats->lock);
for_each_possible_cpu(cpu)
__bch2_time_stats_clear_buffer(stats, per_cpu_ptr(stats->buffer, cpu));
spin_unlock_irq(&stats->lock);
}
/*
* avoid divide by zero
*/
@ -546,6 +560,7 @@ void bch2_time_stats_to_text(struct printbuf *out, struct bch2_time_stats *stats
pr_name_and_units(out, "min:", stats->min_duration);
pr_name_and_units(out, "max:", stats->max_duration);
pr_name_and_units(out, "total:", stats->total_duration);
prt_printf(out, "mean:");
prt_tab(out);
@ -603,6 +618,9 @@ void bch2_time_stats_to_text(struct printbuf *out, struct bch2_time_stats *stats
last_q = q;
}
}
#else
void bch2_time_stats_to_text(struct printbuf *out, struct bch2_time_stats *stats) {}
#endif
void bch2_time_stats_exit(struct bch2_time_stats *stats)
{

33
fs/bcachefs/util.h
View File

@ -374,8 +374,9 @@ struct bch2_time_stat_buffer {
struct bch2_time_stats {
spinlock_t lock;
/* all fields are in nanoseconds */
u64 max_duration;
u64 min_duration;
u64 max_duration;
u64 total_duration;
u64 max_freq;
u64 min_freq;
u64 last_event;
@ -390,15 +391,39 @@ struct bch2_time_stats {
#ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
void __bch2_time_stats_update(struct bch2_time_stats *stats, u64, u64);
#else
static inline void __bch2_time_stats_update(struct bch2_time_stats *stats, u64 start, u64 end) {}
#endif
static inline void bch2_time_stats_update(struct bch2_time_stats *stats, u64 start)
{
__bch2_time_stats_update(stats, start, local_clock());
}
static inline bool track_event_change(struct bch2_time_stats *stats,
u64 *start, bool v)
{
if (v != !!*start) {
if (!v) {
bch2_time_stats_update(stats, *start);
*start = 0;
} else {
*start = local_clock() ?: 1;
return true;
}
}
return false;
}
#else
static inline void __bch2_time_stats_update(struct bch2_time_stats *stats, u64 start, u64 end) {}
static inline void bch2_time_stats_update(struct bch2_time_stats *stats, u64 start) {}
static inline bool track_event_change(struct bch2_time_stats *stats,
u64 *start, bool v)
{
bool ret = v && !*start;
*start = v;
return ret;
}
#endif
void bch2_time_stats_to_text(struct printbuf *, struct bch2_time_stats *);
void bch2_time_stats_exit(struct bch2_time_stats *);