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Date:   Mon, 24 May 2021 11:54:11 +0200
From:   Jan Kara <jack@suse.cz>
To:     Zhang Yi <yi.zhang@huawei.com>
Cc:     linux-ext4@vger.kernel.org, tytso@mit.edu,
        adilger.kernel@dilger.ca, jack@suse.cz, yukuai3@huawei.com
Subject: Re: [PATCH 2/2] ext4: correct the cache_nr in tracepoint
 ext4_es_shrink_exit
Message-ID: <20210524095411.GH32705@quack2.suse.cz>
References: <20210522103045.690103-1-yi.zhang@huawei.com>
 <20210522103045.690103-3-yi.zhang@huawei.com>
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On Sat 22-05-21 18:30:45, Zhang Yi wrote:
> The cache_cnt parameter of tracepoint ext4_es_shrink_exit means the
> remaining cache count after shrink, but now it is the cache count before
> shrink, fix it by read sbi->s_extent_cache_cnt again.
> 
> Fixes: 1ab6c4997e04 ("fs: convert fs shrinkers to new scan/count API")
> Cc: stable@vger.kernel.org # 3.12+
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>

Yeah, probably it is better this way. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ext4/extents_status.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
> index db3cd70a72e4..9a3a8996aacf 100644
> --- a/fs/ext4/extents_status.c
> +++ b/fs/ext4/extents_status.c
> @@ -1576,6 +1576,7 @@ static unsigned long ext4_es_scan(struct shrinker *shrink,
>  
>  	nr_shrunk = __es_shrink(sbi, nr_to_scan, NULL);
>  
> +	ret = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
>  	trace_ext4_es_shrink_scan_exit(sbi->s_sb, nr_shrunk, ret);
>  	return nr_shrunk;
>  }
> -- 
> 2.25.4
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR