Re: [PATCH 4.19 071/114] kernel: sysctl: make drop_caches write-only

[Pavel Machek]

Hi!

> From: Johannes Weiner <hannes@xxxxxxxxxxx>
> 
> [ Upstream commit 204cb79ad42f015312a5bbd7012d09c93d9b46fb ]
> 
> 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.

I have no problem with that, but is it good idea for stable?

Plus, I seem to recall that drop_caches was somehow dangerous,
debugging-only stuff, one should not use on production system. Did
that get fixed in the meantime?

Best regards,
								Pavel
								
> @@ -1411,7 +1411,7 @@ 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		= &one,
>  		.extra2		= &four,

-- 
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