[PATCH 5.17 0223/1126] blk-cgroup: set blkg iostat after percpu stat aggregation

Greg Kroah-Hartman
2022-04-05T08:07:46Z

From: Chengming Zhou <zhouchengming@bytedance.com>

[ Upstream commit f122d103b564e5fb7c82de902c6f8f6cbdf50ec9 ]

Don't need to do blkg_iostat_set for top blkg iostat on each CPU,
so move it after percpu stat aggregation.

Fixes: ef45fe470e1e ("blk-cgroup: show global disk stats in root cgroup io.stat")
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220213085902.88884-1-zhouchengming@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/blk-cgroup.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 650f7e27989f..87a1c0c3fa40 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -857,11 +857,11 @@ static void blkcg_fill_root_iostats(void)
blk_queue_root_blkg(bdev_get_queue(bdev));
struct blkg_iostat tmp;
int cpu;
+ unsigned long flags;

memset(&tmp, 0, sizeof(tmp));
for_each_possible_cpu(cpu) {
struct disk_stats *cpu_dkstats;
- unsigned long flags;

cpu_dkstats = per_cpu_ptr(bdev->bd_stats, cpu);
tmp.ios[BLKG_IOSTAT_READ] +=
@@ -877,11 +877,11 @@ static void blkcg_fill_root_iostats(void)
cpu_dkstats->sectors[STAT_WRITE] << 9;
tmp.bytes[BLKG_IOSTAT_DISCARD] +=
cpu_dkstats->sectors[STAT_DISCARD] << 9;
-
- flags = u64_stats_update_begin_irqsave(&blkg->iostat.sync);
- blkg_iostat_set(&blkg->iostat.cur, &tmp);
- u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags);
}
+
+ flags = u64_stats_update_begin_irqsave(&blkg->iostat.sync);
+ blkg_iostat_set(&blkg->iostat.cur, &tmp);
+ u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags);
}
}

--
2.34.1