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Date:   Sun, 28 Feb 2021 16:38:46 -0800
From:   Roman Gushchin <guro@fb.com>
To:     Hugh Dickins <hughd@google.com>
CC:     Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Vlastimil Babka <vbabka@suse.cz>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/4] mm: no more EINVAL from /proc/sys/vm/stat_refresh
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On Thu, Feb 25, 2021 at 03:12:10PM -0800, Hugh Dickins wrote:
> EINVAL was good for drawing the refresher's attention to a warning in
> dmesg, but became very tiresome when running test suites scripted with
> "set -e": an underflow from a bug in one feature would cause unrelated
> tests much later to fail, just because their /proc/sys/vm/stat_refresh
> touch failed with that error. Stop doing that.

Totally agree!

> 
> Signed-off-by: Hugh Dickins <hughd@google.com>

Acked-by: Roman Gushchin <guro@fb.com>

> ---
> 
>  mm/vmstat.c |    5 -----
>  1 file changed, 5 deletions(-)
> 
> --- vmstat1/mm/vmstat.c	2021-02-25 11:50:36.000000000 -0800
> +++ vmstat2/mm/vmstat.c	2021-02-25 11:56:18.000000000 -0800
> @@ -1844,7 +1844,6 @@ int vmstat_refresh(struct ctl_table *tab
>  		if (val < 0) {
>  			pr_warn("%s: %s %ld\n",
>  				__func__, zone_stat_name(i), val);
> -			err = -EINVAL;
>  		}
>  	}
>  #ifdef CONFIG_NUMA
> @@ -1853,7 +1852,6 @@ int vmstat_refresh(struct ctl_table *tab
>  		if (val < 0) {
>  			pr_warn("%s: %s %ld\n",
>  				__func__, numa_stat_name(i), val);
> -			err = -EINVAL;
>  		}
>  	}
>  #endif
> @@ -1862,11 +1860,8 @@ int vmstat_refresh(struct ctl_table *tab
>  		if (val < 0) {
>  			pr_warn("%s: %s %ld\n",
>  				__func__, node_stat_name(i), val);
> -			err = -EINVAL;
>  		}
>  	}
> -	if (err)
> -		return err;
>  	if (write)
>  		*ppos += *lenp;
>  	else