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authorWaiman Long <longman@redhat.com>2020-04-21 09:07:55 -0400
committerJens Axboe <axboe@kernel.dk>2020-04-21 09:49:36 -0600
commitd6c8e949a35d6906d6c03a50e9a9cdf4e494528a (patch)
treeb3e31a1639e2409c77ed2e1ca85eed35f57d9ffb
parentb849dd84b6ccfe32622988b79b7b073861fcf9f7 (diff)
blk-iocost: Fix error on iocost_ioc_vrate_adj
Systemtap 4.2 is unable to correctly interpret the "u32 (*missed_ppm)[2]" argument of the iocost_ioc_vrate_adj trace entry defined in include/trace/events/iocost.h leading to the following error: /tmp/stapAcz0G0/stap_c89c58b83cea1724e26395efa9ed4939_6321_aux_6.c:78:8: error: expected ‘;’, ‘,’ or ‘)’ before ‘*’ token , u32[]* __tracepoint_arg_missed_ppm That argument type is indeed rather complex and hard to read. Looking at block/blk-iocost.c. It is just a 2-entry u32 array. By simplifying the argument to a simple "u32 *missed_ppm" and adjusting the trace entry accordingly, the compilation error was gone. Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--block/blk-iocost.c4
-rw-r--r--include/trace/events/iocost.h6
2 files changed, 5 insertions, 5 deletions
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index db35ee682294..3ab0c1c704b6 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -1591,7 +1591,7 @@ skip_surplus_transfers:
vrate_min, vrate_max);
}
- trace_iocost_ioc_vrate_adj(ioc, vrate, &missed_ppm, rq_wait_pct,
+ trace_iocost_ioc_vrate_adj(ioc, vrate, missed_ppm, rq_wait_pct,
nr_lagging, nr_shortages,
nr_surpluses);
@@ -1600,7 +1600,7 @@ skip_surplus_transfers:
ioc->period_us * vrate * INUSE_MARGIN_PCT, 100);
} else if (ioc->busy_level != prev_busy_level || nr_lagging) {
trace_iocost_ioc_vrate_adj(ioc, atomic64_read(&ioc->vtime_rate),
- &missed_ppm, rq_wait_pct, nr_lagging,
+ missed_ppm, rq_wait_pct, nr_lagging,
nr_shortages, nr_surpluses);
}
diff --git a/include/trace/events/iocost.h b/include/trace/events/iocost.h
index 7ecaa65b7106..c2f580fd371b 100644
--- a/include/trace/events/iocost.h
+++ b/include/trace/events/iocost.h
@@ -130,7 +130,7 @@ DEFINE_EVENT(iocg_inuse_update, iocost_inuse_reset,
TRACE_EVENT(iocost_ioc_vrate_adj,
- TP_PROTO(struct ioc *ioc, u64 new_vrate, u32 (*missed_ppm)[2],
+ TP_PROTO(struct ioc *ioc, u64 new_vrate, u32 *missed_ppm,
u32 rq_wait_pct, int nr_lagging, int nr_shortages,
int nr_surpluses),
@@ -155,8 +155,8 @@ TRACE_EVENT(iocost_ioc_vrate_adj,
__entry->old_vrate = atomic64_read(&ioc->vtime_rate);;
__entry->new_vrate = new_vrate;
__entry->busy_level = ioc->busy_level;
- __entry->read_missed_ppm = (*missed_ppm)[READ];
- __entry->write_missed_ppm = (*missed_ppm)[WRITE];
+ __entry->read_missed_ppm = missed_ppm[READ];
+ __entry->write_missed_ppm = missed_ppm[WRITE];
__entry->rq_wait_pct = rq_wait_pct;
__entry->nr_lagging = nr_lagging;
__entry->nr_shortages = nr_shortages;