From 17536301d65df52b603040094a8bc71f27d2462a Mon Sep 17 00:00:00 2001
From: Carsten Grohmann <mail@carstengrohmann.de>
Date: Sat, 14 Jan 2023 22:14:03 +0100
Subject: [PATCH] Extract and store memory watermark information

---
 OOMAnalyser.py | 51 +++++++++++++++++++++++++++++++++++++++++++++++++-
 test.py        | 42 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+), 1 deletion(-)

diff --git a/OOMAnalyser.py b/OOMAnalyser.py
index 71134d5..1b92fe4 100644
--- a/OOMAnalyser.py
+++ b/OOMAnalyser.py
@@ -520,6 +520,13 @@ class BaseKernelConfig:
     rec_oom_end = re.compile(r"^Killed process \d+", re.MULTILINE)
     """RE to match the last line of an OOM block"""
 
+    watermark_start = "Node 0 DMA free:"
+    """
+    Pattern to find the start of the memory watermark information
+
+    :type: str
+     """
+
     zoneinfo_start = "Node 0 DMA: "
     """
     Pattern to find the start of the memory chunk information (buddyinfo)
@@ -2702,7 +2709,17 @@ class OOMAnalyser:
     REC_FREE_MEMORY_CHUNKS = re.compile(
         "Node (?P<node>\d+) (?P<zone>DMA|DMA32|Normal): (?P<zone_usage>.*) = (?P<total_free_kb_per_node>\d+)kB"
     )
-    """RE to extract free memory chunks in a zone"""
+    """RE to extract free memory chunks of a memor zone"""
+
+    REC_WATERMARK = re.compile(
+        "Node (?P<node>\d+) (?P<zone>DMA|DMA32|Normal) "
+        "free:(?P<free>\d+)kB "
+        "min:(?P<min>\d+)kB "
+        "low:(?P<low>\d+)kB "
+        "high:(?P<high>\d+)kB "
+        ".*"
+    )
+    """RE to extract watermark information in a memory zone"""
 
     def __init__(self, oom):
         self.oom_entity = oom
@@ -2913,6 +2930,7 @@ class OOMAnalyser:
         self._extract_pstable()
         self._extract_gpf_mask()
         self._extract_buddyinfo()
+        self._extract_watermarks()
 
     def _extract_pstable(self):
         """Extract process table"""
@@ -2991,6 +3009,37 @@ class OOMAnalyser:
                     size = size[:-2]  # strip "kB"
                     self.oom_result.details["_buddyinfo_pagesize_kb"] = int(size)
 
+    def _extract_watermarks(self):
+        """
+        Extract memory watermark information from all zones
+
+        This function fills:
+        * OOMResult.details["_watermarks"] with [<zone>][<node>][(free|min|low|high)] = <XXX>
+        """
+        self.oom_result.details["_watermarks"] = {}
+        watermark_info = self.oom_result.details["_watermarks"]
+        self.oom_entity.find_text(self.oom_result.kconfig.watermark_start)
+
+        # Currently omm_entity point to the first line of the watermark information.
+        # The iterator protocol uses the next() call. However, this will cause the
+        # current line to be skipped.
+        # Therefore, we reset the counter by one line.
+        self.oom_entity.back()
+
+        for line in self.oom_entity:
+            match = self.REC_WATERMARK.match(line)
+            if not match:
+                continue
+
+            node = int(match.group("node"))
+            zone = match.group("zone")
+            if zone not in watermark_info:
+                watermark_info[zone] = {}
+            if node not in watermark_info[zone]:
+                watermark_info[zone][node] = {}
+            for i in ["free", "min", "low", "high"]:
+                watermark_info[zone][node][i] = int(match.group(i))
+
     def _gfp_hex2flags(self, hexvalue):
         """\
         Convert the hexadecimal value into flags specified by definition
diff --git a/test.py b/test.py
index dcea9ca..35ae1bd 100755
--- a/test.py
+++ b/test.py
@@ -896,6 +896,48 @@ Hardware name: HP ProLiant DL385 G7, BIOS A18 12/08/2012
                 % (order, zone, node, count, except_count),
             )
 
+    def test_010_extract_zoneinfo(self):
+        """Test extracting watermark information"""
+        oom = OOMAnalyser.OOMEntity(OOMAnalyser.OOMDisplay.example_rhel7)
+        analyser = OOMAnalyser.OOMAnalyser(oom)
+        success = analyser.analyse()
+        self.assertTrue(success, "OOM analysis failed")
+
+        self.assertEqual(
+            analyser.oom_result.kconfig.release,
+            (3, 10, ".el7."),
+            "Wrong KernelConfig release",
+        )
+        watermarks = analyser.oom_result.details["_watermarks"]
+        for zone, node, level, except_level in [
+            ("Normal", 0, "free", 36692),
+            ("Normal", 0, "min", 36784),
+            ("Normal", 1, "low", 56804),
+            ("Normal", 1, "high", 68164),
+            ("DMA", 0, "free", 15872),
+            ("DMA", 0, "high", 60),
+            ("DMA32", 0, "free", 59728),
+            ("DMA32", 0, "low", 9788),
+        ]:
+            self.assertTrue(
+                zone in watermarks,
+                "Missing details for zone %s in memory watermarks" % zone,
+            )
+            self.assertTrue(
+                node in watermarks[zone],
+                'Missing details for node "%s" in memory watermarks' % node,
+            )
+            self.assertTrue(
+                level in watermarks[zone][node],
+                'Missing details for level "%s" in memory watermarks' % level,
+            )
+            level = watermarks[zone][node][level]
+            self.assertTrue(
+                level == except_level,
+                'Wrong watermark level for node %s in zone "%s" (got: %d, expect %d)'
+                % (node, zone, level, except_level),
+            )
+
 
 if __name__ == "__main__":
     unittest.main(verbosity=2)