Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
Message-ID: <trinity-fd67cbaa-5164-40ca-b198-ded5998d2578-1546544963406@3c-app-mailcom-bs01>
From:   "Hussam Al-Tayeb" <hussam.altayeb@gmx.com>
To:     linux-kernel@vger.kernel.org
Subject: Excessive swapping under Linux 4.14.91 (no issues in 4.14.90).
Content-Type: text/plain; charset=UTF-8
Date:   Thu, 3 Jan 2019 20:49:23 +0100
Importance: normal
Sensitivity: Normal
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hello. My system has 16GB of ram. Before kernel 4.14.91, it would use about 700KBytes to 1MB of the swap if the memory usage was 4 to 5GB in use out of 16GB (15.6 actually).

After upgrading to 4.14.91, I am seeing 500 to 700MB of swap usage even under low memory pressure situations. For example, 3.5GB used out of 16GB.

I downgraded to 4.14.90 and the excessive swapping stopped. I upgraded to 4.14.91 and the heavy swapping came back.

Any idea how I can gather information to tell what is happening?

The machine always has the same services and applications running so I am sure this is a kernel issue. It hasn't received any non-kernel updates in months. This narrows the issue down to the kernel.

Thank you.