#!/usr/bin/python
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"""
**buddyinfo.py**
Linux uses buddy allocator for memory management. Pages
are allocated in each NUMA node and zones within each
node. Within each zones, pages are allocated as
contiguous groups of 1, 2, 3, 4, and so on order
pages where 1 means 4K pages. Number of free pages in
each bucket is exposed through /proc/buddyinfo
When this number goes below a threshold in any bucket,
kswapd (slowpath for finding free pages) kicks in. It
then scans for free pages in all order levels until
all of them reach above min limit. This process can take
long time and may cause issues for GC latencies.
Typical contents of /proc/buddyinfo:
- Node 0, zone Normal 1490 4026 12224 8508 4493 1929 849 301 101 45 5257
- Node 1, zone DMA 1 1 1 1 1 0 1 0 1 1 3
- Node 1, zone DMA32 15 3 2 5 8 7 4 4 7 8 681
- Node 1, zone Normal 6061 13681 20887 15188 9097 4546 1948 731 273 125 3976
Here are the fields interpretation in each row:
1. NUMA node (such as 0 or 1)
2. Zone name (Normal, DMA32, DMA, etc.)
3. Col. 3 to end: page order or buckets on contiguous memory sizes: 4K, 8K, 16K, 32K, 64K, 128K, 256K, 512K, 1024K, and 2048K
"""
import collectd
import platform
import os
import socket
import time
import re
os_name = platform.system()
BUDDY_FNAME = '/proc/buddyinfo'
METRIC_PLUGIN = 'buddyinfo'
METRIC_TYPE = 'gauge'
buddy_fields = ['numa_node',
'zone_name',
'bucket_free_pages'
]
buddy_metrics = ['bucket_free_pages_per_sec',
'total_free_pages_per_sec',
'pct_fragment_per_sec'
]
white_list = []
node_list = []
zone_list = []
stats_cache = {}
stats_current = {}
re_buddyinfo=re.compile(r'^\s*Node\s+(?P<node>\d+)'
r',\s+zone\s+(?P<zone>\S+)\s+(?P<pages>.*)$')
def init_stats_cache():
global white_list
if os.path.exists(BUDDY_FNAME):
num_buckets = 0
with open(BUDDY_FNAME) as f:
for line in f:
match = re_buddyinfo.search(line)
if not match:
collectd.error('buddyinfo: unknown line pattern: %s' % (line))
continue;
node = match.group('node')
zone = match.group('zone')
free_pages = match.group('pages').strip().split()
num_buckets = len(free_pages)
if node not in node_list:
node_list.append(node)
if zone not in zone_list:
zone_list.append(zone)
stats_cache[(node, zone, 'val')] = free_pages
stats_cache[(node, zone, 'ts')] = time.time()
f.close()
for i in range(0, num_buckets):
white_list.append('free_pages_' + str(4*2**i) + 'K')
collectd.info('buddyinfo: node_list : %s' % (node_list))
collectd.info('buddyinfo: zone_list : %s' % (zone_list))
collectd.info('buddyinfo: white_list: %s' % (white_list))
else:
collectd.info('buddyinfo: init_stats_cache: path: %s does not exist'
% (BUDDY_FNAME))
def collect_buddyinfo():
if os.path.exists(BUDDY_FNAME):
with open(BUDDY_FNAME) as f:
for line in f:
match = re_buddyinfo.search(line)
if not match:
continue;
node = match.group('node')
zone = match.group('zone')
free_pages = match.group('pages').strip().split()
stats_current[(node, zone, 'val')] = free_pages
stats_current[(node, zone, 'ts')] = time.time()
key_val = dict(zip(white_list, free_pages))
metric = collectd.Values()
metric.plugin = METRIC_PLUGIN
metric.plugin_instance = node
metric.type = METRIC_TYPE
for k in range(0, len(white_list)):
metric.type_instance = 'node_'+ node + '_zone_' + zone + '.'
metric.type_instance += white_list[k]
metric.values = [free_pages[k]]
metric.dispatch()
f.close()
else:
collectd.error('buddyinfo: procfs path: %s does not exist'
% (BUDDY_FNAME))
def swap_current_cache():
stats_cache = stats_current.copy()
def configer(ObjConfiguration):
collectd.info('buddyinfo plugin: configuring host' )
def initer():
collectd.info('buddyinfo initer: white list: %s' % (white_list))
init_stats_cache()
collectd.info('buddyinfo init: stats_cache: %s' % (stats_cache))
def reader(input_data=None):
collect_buddyinfo()
swap_current_cache()
def writer(metric, data=None):
for i in metric.values:
collectd.debug('%s (%s): %f' % (metric.plugin, metric.type, i))
def shutdown():
collectd.info('buddyinfo plugin shutting down')
#== Callbacks ==#
if (os_name == 'Linux'):
collectd.register_config(configer)
collectd.register_init(initer)
collectd.register_read(reader)
collectd.register_write(writer)
collectd.register_shutdown(shutdown)
else:
collectd.warning('buddyinfo plugin currently works for Linux only')