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@xxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
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,
>
