[Xen-devel] [PATCH 5/6] xenpaging: start xenpaging via config option

[Olaf Hering <olaf@xxxxxxxxx>]

Start xenpaging via config option.

TODO: add config option for different pagefile directory
TODO: add libxl support
TODO: parse config values like 42K, 42M, 42G, 42%

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>

---
v3:
  move debug for stopping xenpaging to destroyXenPaging
v2:
  unlink logfile instead of truncating it.
  allows hardlinking for further inspection

 tools/examples/xmexample.hvm            |    3 +
 tools/python/README.XendConfig          |    1 
 tools/python/README.sxpcfg              |    1 
 tools/python/xen/xend/XendConfig.py     |    3 +
 tools/python/xen/xend/XendDomainInfo.py |    5 +
 tools/python/xen/xend/image.py          |   87 ++++++++++++++++++++++++++++++++
 tools/python/xen/xm/create.py           |    5 +
 tools/python/xen/xm/xenapi_create.py    |    1 
 8 files changed, 106 insertions(+)

--- xen-unstable.hg-4.1.22746.orig/tools/examples/xmexample.hvm
+++ xen-unstable.hg-4.1.22746/tools/examples/xmexample.hvm
@@ -127,6 +127,9 @@ disk = [ 'file:/var/images/min-el3-i386.
 # Device Model to be used
 device_model = 'qemu-dm'
 
+# xenpaging, number of pages, or -1 for entire guest memory range
+xenpaging = 42
+
 #-----------------------------------------------------------------------------
 # boot on floppy (a), hard disk (c), Network (n) or CD-ROM (d) 
 # default: hard disk, cd-rom, floppy
--- xen-unstable.hg-4.1.22746.orig/tools/python/README.XendConfig
+++ xen-unstable.hg-4.1.22746/tools/python/README.XendConfig
@@ -120,6 +120,7 @@ otherConfig
                                 image.vncdisplay
                                 image.vncunused
                                 image.hvm.device_model
+                                image.hvm.xenpaging
                                 image.hvm.display
                                 image.hvm.xauthority
                                 image.hvm.vncconsole
--- xen-unstable.hg-4.1.22746.orig/tools/python/README.sxpcfg
+++ xen-unstable.hg-4.1.22746/tools/python/README.sxpcfg
@@ -51,6 +51,7 @@ image
   - vncunused
   (HVM)
   - device_model
+  - xenpaging
   - display
   - xauthority
   - vncconsole
--- xen-unstable.hg-4.1.22746.orig/tools/python/xen/xend/XendConfig.py
+++ xen-unstable.hg-4.1.22746/tools/python/xen/xend/XendConfig.py
@@ -147,6 +147,7 @@ XENAPI_PLATFORM_CFG_TYPES = {
     'apic': int,
     'boot': str,
     'device_model': str,
+    'xenpaging': int,
     'loader': str,
     'display' : str,
     'fda': str,
@@ -512,6 +513,8 @@ class XendConfig(dict):
             self['platform']['nomigrate'] = 0
 
         if self.is_hvm():
+            if 'xenpaging' not in self['platform']:
+                self['platform']['xenpaging'] = None
             if 'timer_mode' not in self['platform']:
                 self['platform']['timer_mode'] = 1
             if 'viridian' not in self['platform']:
--- xen-unstable.hg-4.1.22746.orig/tools/python/xen/xend/XendDomainInfo.py
+++ xen-unstable.hg-4.1.22746/tools/python/xen/xend/XendDomainInfo.py
@@ -2390,6 +2390,7 @@ class XendDomainInfo:
 
         if self.image:
             self.image.createDeviceModel()
+            self.image.createXenPaging()
 
         #if have pass-through devs, need the virtual pci slots info from qemu
         self.pci_device_configure_boot()
@@ -2402,6 +2403,10 @@ class XendDomainInfo:
                 self.image.destroyDeviceModel()
             except Exception, e:
                 log.exception("Device model destroy failed %s" % str(e))
+            try:
+                self.image.destroyXenPaging()
+            except Exception, e:
+                log.exception("stopping xenpaging failed %s" % str(e))
         else:
             log.debug("No device model")
 
--- xen-unstable.hg-4.1.22746.orig/tools/python/xen/xend/image.py
+++ xen-unstable.hg-4.1.22746/tools/python/xen/xend/image.py
@@ -122,12 +122,16 @@ class ImageHandler:
         self.vm.permissionsVm("image/cmdline", { 'dom': self.vm.getDomid(), 
'read': True } )
 
         self.device_model = vmConfig['platform'].get('device_model')
+        self.xenpaging = vmConfig['platform'].get('xenpaging')
+        if self.xenpaging == 0:
+            self.xenpaging = None
 
         self.display = vmConfig['platform'].get('display')
         self.xauthority = vmConfig['platform'].get('xauthority')
         self.vncconsole = int(vmConfig['platform'].get('vncconsole', 0))
         self.dmargs = self.parseDeviceModelArgs(vmConfig)
         self.pid = None
+        self.xenpaging_pid = None
         rtc_timeoffset = int(vmConfig['platform'].get('rtc_timeoffset', 0))
         if int(vmConfig['platform'].get('localtime', 0)):
             if time.localtime(time.time())[8]:
@@ -392,6 +396,89 @@ class ImageHandler:
         sentinel_fifos_inuse[sentinel_path_fifo] = 1
         self.sentinel_path_fifo = sentinel_path_fifo
 
+    def createXenPaging(self):
+        if self.xenpaging is None:
+            return
+        if self.xenpaging_pid:
+            return
+        xenpaging_bin = auxbin.pathTo("xenpaging")
+        args = [xenpaging_bin]
+        args = args + ([ "%d" % self.vm.getDomid()])
+        args = args + ([ "%s" % self.xenpaging])
+        env = dict(os.environ)
+        self.xenpaging_logfile = "/var/log/xen/xenpaging-%s.log" %  
str(self.vm.info['name_label'])
+        logfile_mode = os.O_WRONLY|os.O_CREAT|os.O_APPEND|os.O_TRUNC
+        null = os.open("/dev/null", os.O_RDONLY)
+        try:
+            os.unlink(self.xenpaging_logfile)
+        except:
+            pass
+        logfd = os.open(self.xenpaging_logfile, logfile_mode, 0644)
+        sys.stderr.flush()
+        contract = osdep.prefork("%s:%d" % (self.vm.getName(), 
self.vm.getDomid()))
+        xenpaging_pid = os.fork()
+        if xenpaging_pid == 0: #child
+            try:
+                xenpaging_dir = "/var/lib/xen/xenpaging"
+                osdep.postfork(contract)
+                os.dup2(null, 0)
+                os.dup2(logfd, 1)
+                os.dup2(logfd, 2)
+                try:
+                    os.chdir(xenpaging_dir)
+                except:
+                    log.warn("chdir %s failed" % xenpaging_dir)
+                try:
+                    log.info("starting %s" % args)
+                    os.execve(xenpaging_bin, args, env)
+                except Exception, e:
+                    print >>sys.stderr, (
+                        'failed to execute xenpaging: %s: %s' %
+                        xenpaging_bin, utils.exception_string(e))
+                    os._exit(126)
+            except Exception, e:
+                log.warn("staring xenpaging in %s failed" % xenpaging_dir)
+                os._exit(127)
+        else:
+            osdep.postfork(contract, abandon=True)
+            self.xenpaging_pid = xenpaging_pid
+            os.close(null)
+            os.close(logfd)
+
+    def destroyXenPaging(self):
+        if self.xenpaging is None:
+            return
+        log.debug("stopping xenpaging")
+        if self.xenpaging_pid:
+            try:
+                os.kill(self.xenpaging_pid, signal.SIGHUP)
+            except OSError, exn:
+                log.exception(exn)
+            for i in xrange(100):
+                try:
+                    (p, rv) = os.waitpid(self.xenpaging_pid, os.WNOHANG)
+                    if p == self.xenpaging_pid:
+                        break
+                except OSError:
+                    # This is expected if Xend has been restarted within
+                    # the life of this domain.  In this case, we can kill
+                    # the process, but we can't wait for it because it's
+                    # not our child. We continue this loop, and after it is
+                    # terminated make really sure the process is going away
+                    # (SIGKILL).
+                    pass
+                time.sleep(0.1)
+            else:
+                log.warning("xenpaging %d took more than 10s "
+                            "to terminate: sending SIGKILL" % 
self.xenpaging_pid)
+                try:
+                    os.kill(self.xenpaging_pid, signal.SIGKILL)
+                    os.waitpid(self.xenpaging_pid, 0)
+                except OSError:
+                    # This happens if the process doesn't exist.
+                    pass
+        self.xenpaging_pid = None
+
     def createDeviceModel(self, restore = False):
         if self.device_model is None:
             return
--- xen-unstable.hg-4.1.22746.orig/tools/python/xen/xm/create.py
+++ xen-unstable.hg-4.1.22746/tools/python/xen/xm/create.py
@@ -491,6 +491,10 @@ gopts.var('nfs_root', val="PATH",
           fn=set_value, default=None,
           use="Set the path of the root NFS directory.")
 
+gopts.var('xenpaging', val='NUM',
+          fn=set_int, default=None,
+          use="Number of pages to swap.")
+
 gopts.var('device_model', val='FILE',
           fn=set_value, default=None,
           use="Path to device model program.")
@@ -1076,6 +1080,7 @@ def configure_hvm(config_image, vals):
     args = [ 'acpi', 'apic',
              'boot',
              'cpuid', 'cpuid_check',
+             'xenpaging',
              'device_model', 'display',
              'fda', 'fdb',
              'gfx_passthru', 'guest_os_type',
--- xen-unstable.hg-4.1.22746.orig/tools/python/xen/xm/xenapi_create.py
+++ xen-unstable.hg-4.1.22746/tools/python/xen/xm/xenapi_create.py
@@ -1085,6 +1085,7 @@ class sxp2xml:
             'acpi',
             'apic',
             'boot',
+            'xenpaging',
             'device_model',
             'loader',
             'fda',


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