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block: only calculate part_in_flight() once 

We first check if we have inflight IO, then retrieve that
same number again. Usually this isn't that costly since the
chance of having the data dirtied in between is small, but
there's no reason for calling part_in_flight() twice.

Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Jens Axboe 2014-05-09 15:48:23 -06:00
parent cf4b50afc2
commit 7276d02e24
1 changed files with 5 additions and 2 deletions
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7
block/blk-core.c
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@ -1233,12 +1233,15 @@ static void add_acct_request(struct request_queue *q, struct request *rq,
static void part_round_stats_single(int cpu, struct hd_struct *part, static void part_round_stats_single(int cpu, struct hd_struct *part,
unsigned long now) unsigned long now)
{ {
int inflight;
if (now == part->stamp) if (now == part->stamp)
return; return;
if (part_in_flight(part)) { inflight = part_in_flight(part);
if (inflight) {
__part_stat_add(cpu, part, time_in_queue, __part_stat_add(cpu, part, time_in_queue,
part_in_flight(part) * (now - part->stamp)); inflight * (now - part->stamp));
__part_stat_add(cpu, part, io_ticks, (now - part->stamp)); __part_stat_add(cpu, part, io_ticks, (now - part->stamp));
} }
part->stamp = now; part->stamp = now;