pakfire: Sync with upstream.

[ipfire-3.x.git] / pakfire / patches / 0005-builder-Use-cgroups-if-the-system-supports-it.patch

diff --git a/pakfire/patches/0005-builder-Use-cgroups-if-the-system-supports-it.patch b/pakfire/patches/0005-builder-Use-cgroups-if-the-system-supports-it.patch
new file mode 100644 (file)
index 0000000..dbd3232
--- /dev/null
+++ b/pakfire/patches/0005-builder-Use-cgroups-if-the-system-supports-it.patch
@@ -0,0 +1,153 @@
+From 904c8f1136b683a90a08cd4cf671a26f24e45f03 Mon Sep 17 00:00:00 2001
+From: Michael Tremer <michael.tremer@ipfire.org>
+Date: Fri, 8 Mar 2013 16:08:16 +0100
+Subject: [PATCH 05/19] builder: Use cgroups if the system supports it.
+
+A systemd-based system is required right now.
+---
+ python/pakfire/builder.py | 12 ++++++--
+ python/pakfire/cgroup.py  | 73 ++++++++++++++++++++++++++++-------------------
+ 2 files changed, 52 insertions(+), 33 deletions(-)
+
+diff --git a/python/pakfire/builder.py b/python/pakfire/builder.py
+index 5cb00aa..7427a8c 100644
+--- a/python/pakfire/builder.py
++++ b/python/pakfire/builder.py
+@@ -309,10 +309,16 @@ class BuildEnviron(object):
+                       self.cgroup = None
+                       return
+ 
+-              self.cgroup = cgroup.CGroup("pakfire/builder/%s" % self.build_id)
++              # Search for the cgroup this process is currently running in.
++              parent_cgroup = cgroup.find_by_pid(os.getpid())
++              if not parent_cgroup:
++                      return
++
++              # Create our own cgroup inside the parent cgroup.
++              self.cgroup = parent_cgroup.create_child_cgroup("pakfire/builder/%s" % self.build_id)
+ 
+-              # Attach the pakfire-builder process to the parent group.
+-              self.cgroup.parent.attach()
++              # Attach the pakfire-builder process to the group.
++              self.cgroup.attach()
+ 
+       def init_logging(self, logfile):
+               if logfile:
+diff --git a/python/pakfire/cgroup.py b/python/pakfire/cgroup.py
+index f372a6c..6c85937 100644
+--- a/python/pakfire/cgroup.py
++++ b/python/pakfire/cgroup.py
+@@ -8,40 +8,14 @@ import time
+ import logging
+ log = logging.getLogger("pakfire.cgroups")
+ 
+-CGROUP_PATH_CANDIDATES = (
+-      "/sys/fs/cgroup",
+-)
+-
+-def find_cgroup_path():
+-      """
+-              This function tries to find the right place
+-              where to put the cgroups.
+-      """
+-      for path in CGROUP_PATH_CANDIDATES:
+-              check_path = os.path.join(path, "tasks")
+-              if not os.path.exists(check_path):
+-                      continue
+-
+-              return path
+-
+-CGROUP_PATH = find_cgroup_path()
+-
+-def supported():
+-      """
+-              Returns True or False depending on
+-              whether cgroups are supported or not.
+-      """
+-      if CGROUP_PATH is None:
+-              return False
+-
+-      return True
++CGROUP_MOUNTPOINT = "/sys/fs/cgroup/systemd"
+ 
+ class CGroup(object):
+       def __init__(self, name):
+               assert supported(), "cgroups are not supported by this kernel"
+ 
+               self.name = name
+-              self.path = os.path.join(CGROUP_PATH, name)
++              self.path = os.path.join(CGROUP_MOUNTPOINT, name)
+               self.path = os.path.abspath(self.path)
+ 
+               # The parent cgroup.
+@@ -58,6 +32,31 @@ class CGroup(object):
+       def __cmp__(self, other):
+               return cmp(self.path, other.path)
+ 
++      @classmethod
++      def find_by_pid(cls, pid):
++              """
++                      Returns the cgroup of the process with the given PID.
++
++                      If no cgroup can be found, None is returned.
++              """
++              if not cls.supported:
++                      return
++
++              for d, subdirs, files in os.walk(CGROUP_MOUNTPOINT):
++                      if not "tasks" in files:
++                              continue
++
++                      cgroup = cls(d)
++                      if pid in cgroup.tasks:
++                              return cgroup
++
++      @staticmethod
++      def supported():
++              """
++                      Returns true, if this hosts supports cgroups.
++              """
++              return os.path.ismount(CGROUP_MOUNTPOINT)
++
+       def create(self):
+               """
+                       Creates the filesystem structure for
+@@ -69,6 +68,13 @@ class CGroup(object):
+               log.debug("cgroup '%s' has been created." % self.name)
+               os.makedirs(self.path)
+ 
++      def create_child_cgroup(self, name):
++              """
++                      Create a child cgroup with name relative to the
++                      parent cgroup.
++              """
++              return self.__class__(os.path.join(self.name, name))
++
+       def attach(self):
+               """
+                       Attaches this task to the cgroup.
+@@ -152,8 +158,8 @@ class CGroup(object):
+ 
+       @property
+       def parent(self):
+-              # Cannot go above CGROUP_PATH.
+-              if self.path == CGROUP_PATH:
++              # Cannot go above CGROUP_MOUNTPOINT.
++              if self.path == CGROUP_MOUNTPOINT:
+                       return
+ 
+               if self._parent is None:
+@@ -317,3 +323,10 @@ class CGroup(object):
+                       time.sleep(0.2)
+ 
+               return self.is_empty()
++
++
++# Alias for simple access to check if this host supports cgroups.
++supported = CGroup.supported
++
++# Alias for simple access to find the cgroup of a certain process.
++find_by_pid = CGroup.find_by_pid
+-- 
+1.8.1.4
+