From 0a4abd532ebb3425ec86d53a470cac0f43ebb313 Mon Sep 17 00:00:00 2001
From: Doug Szumski <doug@stackhpc.com>
Date: Wed, 6 Nov 2019 10:49:30 +0000
Subject: [PATCH] Add support for gathering Slab memory usage

This is useful, for example when monitoring Slab memory leaks. To support
gathering this metric a minimum version of psutil 5.4.4 is required
(released on Apr 13th 2018).

Story: 2006815
Task: 37375
Change-Id: Ibe8def9e2a7c967a34236889aa03b287065abcdc
---
 docs/Plugins.md                                            | 1 +
 monasca_agent/collector/checks_d/memory.py                 | 7 +++++++
 .../notes/add-slab-usage-metric-e7504c57e4b3ba16.yaml      | 3 +++
 3 files changed, 11 insertions(+)
 create mode 100644 releasenotes/notes/add-slab-usage-metric-e7504c57e4b3ba16.yaml

diff --git a/docs/Plugins.md b/docs/Plugins.md
index 71c7783c..be8be26a 100644
--- a/docs/Plugins.md
+++ b/docs/Plugins.md
@@ -459,6 +459,7 @@ instances:
 | mem.used_cached |  | Mbytes of memory used for the page cache
 | mem.used_shared  |  | Mbytes of memory shared between separate processes and typically used for inter-process communication
 | mem.used_real_mb |  | Mbytes of memory currently in use less mem.used_buffers and mem.used_cached
+| mem.used_slab_mb  |  | Mbytes of memory currently allocated to slab. Requires psutil >=5.4.4.
 
 ### Disk
 | Metric Name | Dimensions | Semantics |
diff --git a/monasca_agent/collector/checks_d/memory.py b/monasca_agent/collector/checks_d/memory.py
index 9179cc00..da5bb01c 100644
--- a/monasca_agent/collector/checks_d/memory.py
+++ b/monasca_agent/collector/checks_d/memory.py
@@ -97,4 +97,11 @@ class Memory(checks.AgentCheck):
                        dimensions=dimensions)
             count += 1
 
+        # The slab metric was added in psutil 5.4.4
+        if hasattr(mem_info, 'slab') and mem_info.slab:
+            self.gauge('mem.used_slab_mb',
+                       int(mem_info.slab / 1048576),
+                       dimensions=dimensions)
+            count += 1
+
         log.debug('Collected {0} memory metrics'.format(count))
diff --git a/releasenotes/notes/add-slab-usage-metric-e7504c57e4b3ba16.yaml b/releasenotes/notes/add-slab-usage-metric-e7504c57e4b3ba16.yaml
new file mode 100644
index 00000000..44060a62
--- /dev/null
+++ b/releasenotes/notes/add-slab-usage-metric-e7504c57e4b3ba16.yaml
@@ -0,0 +1,3 @@
+---
+features:
+  - Adds support for monitoring slab memory usage.