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From: Chris Down <>
To: Andrew Morton <>
Cc: Johannes Weiner <>,,,
Subject: Re: [PATCH] kernel: sysctl: make drop_caches write-only
Date: Fri, 1 Nov 2019 11:09:01 +0000
Message-ID: <> (raw)
In-Reply-To: <>

Hm, not sure why my client didn't show this reply.

Andrew Morton writes:
>Risk: some (odd) userspace code will break.  Fixable by manually chmodding
>it back again.

The only scenario I can construct in my head is that someone has built 
something to watch drop_caches for modification, but we already have the kmsg 
output for that.

>Reward: very little.
>Is the reward worth the risk?

There is evidence that this has already caused confusion[0] for many, judging 
by the number of views and votes. I think the reward is higher than stated 
here, since it makes the intent and lack of persistent API in the API clearer, 
and less likely to cause confusion in future.


  reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-31 22:16 Johannes Weiner
2019-10-31 23:28 ` Andrew Morton
2019-11-01 11:09   ` Chris Down [this message]
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
2019-11-05  6:20 ` Michal Hocko

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