[PATCH 5/5] iocost: add iocg_forgive_debt tracepoint

Tejun Heo
2020-09-18T00:45:15Z

block/blk-iocost.c | 12 ++++++++++
include/trace/events/iocost.h | 41 +++++++++++++++++++++++++++++++++++
2 files changed, 53 insertions(+)

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 9b1f94499432..328ae805e85f 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2046,12 +2046,24 @@ static void ioc_forgive_debts(struct ioc *ioc, u64 usage_us_sum, int nr_debtors,
ioc->dfgv_period_rem = do_div(nr_cycles, DFGV_PERIOD);

list_for_each_entry(iocg, &ioc->active_iocgs, active_list) {
+ u64 __maybe_unused old_debt, __maybe_unused old_delay;
+
if (!iocg->abs_vdebt)
continue;
+
spin_lock(&iocg->waitq.lock);
+
+ old_debt = iocg->abs_vdebt;
+ old_delay = iocg->delay;
+
iocg->abs_vdebt >>= nr_cycles;
iocg->delay = 0; /* kick_waitq will recalc */
iocg_kick_waitq(iocg, true, now);
+
+ TRACE_IOCG_PATH(iocg_forgive_debt, iocg, now, usage_pct,
+ old_debt, iocg->abs_vdebt,
+ old_delay, iocg->delay);
+
spin_unlock(&iocg->waitq.lock);
}
}
diff --git a/include/trace/events/iocost.h b/include/trace/events/iocost.h
index b350860d2e71..0b6869980ba2 100644
--- a/include/trace/events/iocost.h
+++ b/include/trace/events/iocost.h
@@ -164,6 +164,47 @@ TRACE_EVENT(iocost_ioc_vrate_adj,
)
);

+TRACE_EVENT(iocost_iocg_forgive_debt,
+
+ TP_PROTO(struct ioc_gq *iocg, const char *path, struct ioc_now *now,
+ u32 usage_pct, u64 old_debt, u64 new_debt,
+ u64 old_delay, u64 new_delay),
+
+ TP_ARGS(iocg, path, now, usage_pct,
+ old_debt, new_debt, old_delay, new_delay),
+
+ TP_STRUCT__entry (
+ __string(devname, ioc_name(iocg->ioc))
+ __string(cgroup, path)
+ __field(u64, now)
+ __field(u64, vnow)
+ __field(u32, usage_pct)
+ __field(u64, old_debt)
+ __field(u64, new_debt)
+ __field(u64, old_delay)
+ __field(u64, new_delay)
+ ),
+
+ TP_fast_assign(
+ __assign_str(devname, ioc_name(iocg->ioc));
+ __assign_str(cgroup, path);
+ __entry->now = now->now;
+ __entry->vnow = now->vnow;
+ __entry->usage_pct = usage_pct;
+ __entry->old_debt = old_debt;
+ __entry->new_debt = new_debt;
+ __entry->old_delay = old_delay;
+ __entry->new_delay = new_delay;
+ ),
+
+ TP_printk("[%s:%s] now=%llu:%llu usage=%u debt=%llu->%llu delay=%llu->%llu",
+ __get_str(devname), __get_str(cgroup),
+ __entry->now, __entry->vnow, __entry->usage_pct,
+ __entry->old_debt, __entry->new_debt,
+ __entry->old_delay, __entry->new_delay
+ )
+);
+
#endif /* _TRACE_BLK_IOCOST_H */

/* This part must be outside protection */
--
2.26.2