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From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Alexey Dobriyan <adobriyan@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Kees Cook <keescook@chromium.org>,
	Matthew Wilcox <willy@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: [RFC] process /proc/PID/smaps vs /proc/PID/smaps_rollup
Date: Tue, 29 Sep 2020 11:05:20 +0900	[thread overview]
Message-ID: <20200929020520.GC871730@jagdpanzerIV.localdomain> (raw)

Hello,

One of our unprivileged daemon process needs process PSS info. That
info is usually available in /proc/PID/smaps on per-vma basis, on
in /proc/PID/smaps_rollup as a bunch of accumulated per-vma values.
The latter one is much faster and simpler to get, but, unlike smaps,
smaps_rollup requires PTRACE_MODE_READ, which we don't want to
grant to our unprivileged daemon.

So the question is - can we get, somehow, accumulated PSS info from
a non-privileged process? (Iterating through all process' smaps
vma-s consumes quite a bit of CPU time). This is related to another
question - why do smaps and smaps_rollup have different permission
requirements?

	-ss

             reply	other threads:[~2020-09-29  2:05 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-29  2:05 Sergey Senozhatsky [this message]
2020-09-29  2:40 ` Sergey Senozhatsky
2022-09-08  9:42   ` Vincent Whitchurch

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