Re: [PATCH 1/2] pidmap(2)

On Tue, Sep 05, 2017 at 10:05:00PM +0300, Alexey Dobriyan wrote:

From: Tatsiana Brouka <redacted>

Implement system call for bulk retrieveing of pids in binary form.

Using /proc is slower than necessary: 3 syscalls + another 3 for each thread +
converting with atoi().

/proc may be not mounted especially in containers. Natural extension of
hidepid=2 efforts is to not mount /proc at all.

It could be used by programs like ps, top or CRIU. Speed increase will
become more drastic once combined with bulk retrieval of process statistics.

What could give a noticeable performance gain in a less ridiculous way
is an interface like task_diag, see https://lkml.org/lkml/2016/4/11/924 .


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ldv