linux-kernel - [patch 0/3] per-CPU vmstat thresholds and vmstat worker disablement (v2)

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Message-Id: <20170503184007.174707977@redhat.com>
Date:   Wed, 03 May 2017 15:40:07 -0300
From:   Marcelo Tosatti <mtosatti@...hat.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     Luiz Capitulino <lcapitulino@...hat.com>,
        Rik van Riel <riel@...hat.com>,
        Linux RT Users <linux-rt-users@...r.kernel.org>
Subject: [patch 0/3] per-CPU vmstat thresholds and vmstat worker disablement (v2)

The per-CPU vmstat worker is a problem on -RT workloads (because
ideally the CPU is entirely reserved for the -RT app, without
interference). The worker transfers accumulated per-CPU
vmstat counters to global counters.

To resolve the problem, create two tunables:

* Userspace configurable per-CPU vmstat threshold: by default the
VM code calculates the size of the per-CPU vmstat arrays. This
tunable allows userspace to configure the values.

* Userspace configurable per-CPU vmstat worker: allow disabling
the per-CPU vmstat worker.

v2:
- Improve documentation (Rik/Luiz).
- Split patch in two (Luiz).
- Fix comparison to include equal, in the helpers for
stats accounting.