Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Chengming Zhou <zhouchengming@bytedance.com>,
        Tejun Heo <tj@kernel.org>, Jens Axboe <axboe@kernel.dk>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 205/913] blk-cgroup: set blkg iostat after percpu stat aggregation
Date:   Tue,  5 Apr 2022 09:21:07 +0200
Message-Id: <20220405070346.004282448@linuxfoundation.org>
In-Reply-To: <20220405070339.801210740@linuxfoundation.org>
References: <20220405070339.801210740@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

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 0eec59e4df65..07a2524e6efd 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -855,11 +855,11 @@ static void blkcg_fill_root_iostats(void)
 			blk_queue_root_blkg(bdev->bd_disk->queue);
 		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] +=
@@ -875,11 +875,11 @@ 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