#!/usr/bin/python """ Copyright 2014 Domas Mituzas, Facebook Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. """ # This script deals with buddy allocation starving # on larger page allocations. # It detects if 16k+ pages are less than 10% of # available memory and recompacts via procfs # import os def buddy_zones(): """Returns buddy zone information""" for line in open("/proc/buddyinfo"): zone = {} line = line.strip().split() zone["type"] = line[3] k = os.sysconf("SC_PAGESIZE") / 1024 for count in line[4:]: zone[k] = int(count) k *= 2 yield zone def total_size(zone, min=0, max=1048576): """Calculates total size in kilobytes per zone of specied slab sizes (min and max are in k) """ total = 0 for k, v in zone.items(): if k == "type": continue if k < min or k > max: continue total += (k * v) return total / 4 def maybe_compact(): need_compaction = False for z in buddy_zones(): if z["type"] != "Normal": continue if total_size(z, 4, 8) / total_size(z, 16) >= 10: need_compaction = True if need_compaction: try: open("/proc/sys/vm/compact_memory", "w").write("1") except IOError: pass if __name__ == "__main__": maybe_compact()