From: Vlastimil Babka <vbabka@suse.cz>
To: Johannes Weiner <hannes@cmpxchg.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH] kernel: sysctl: make drop_caches write-only
Date: Mon, 4 Nov 2019 14:25:54 +0100 [thread overview]
Message-ID: <e8b6cbe6-2a38-1c72-2f22-fe3b6819e75c@suse.cz> (raw)
In-Reply-To: <20191031221602.9375-1-hannes@cmpxchg.org>
On 10/31/19 11:16 PM, Johannes Weiner wrote:
> Currently, the drop_caches proc file and sysctl read back the last
> value written, suggesting this is somehow a stateful setting instead
> of a one-time command. Make it write-only, like e.g. compact_memory.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Generic tools such as "sysctl -a" will be fine as they already are fine
with compact_memory being 0200, and if somebody has a specific script,
they are maybe already making wrong decisions, so at least hopefully
they will learn and adjust.
> ---
> kernel/sysctl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 31ece1120aa4..50373984a5e2 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -1474,7 +1474,7 @@ static struct ctl_table vm_table[] = {
> .procname = "drop_caches",
> .data = &sysctl_drop_caches,
> .maxlen = sizeof(int),
> - .mode = 0644,
> + .mode = 0200,
> .proc_handler = drop_caches_sysctl_handler,
> .extra1 = SYSCTL_ONE,
> .extra2 = &four,
>
next prev parent reply other threads:[~2019-11-04 13:26 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-31 22:16 [PATCH] kernel: sysctl: make drop_caches write-only Johannes Weiner
2019-10-31 23:28 ` Andrew Morton
2019-11-01 11:09 ` Chris Down
2019-11-01 11:09 ` Chris Down
2019-11-01 14:45 ` Johannes Weiner
2019-11-01 18:59 ` Andrew Morton
2019-11-01 19:24 ` Chris Down
2019-11-01 19:29 ` Andrew Morton
2019-11-01 19:35 ` Andrew Morton
2019-11-02 15:55 ` Alexey Dobriyan
2019-11-03 19:00 ` Eric W. Biederman
2019-11-01 10:58 ` Chris Down
2019-11-04 10:37 ` David Hildenbrand
2019-11-04 13:25 ` Vlastimil Babka [this message]
2019-11-05 6:20 ` Michal Hocko
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