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* [PATCH][RFC] to fix xm list memory reporting
@ 2006-10-11 18:24 McAfee, Tommie M
  2006-10-11 21:34 ` Anthony Liguori
  0 siblings, 1 reply; 7+ messages in thread
From: McAfee, Tommie M @ 2006-10-11 18:24 UTC (permalink / raw)
  To: xen-devel

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This patch addresses bugzilla #649, enabling `xm list' to display the actual amount of memory allocated by a guest.  This is done by checking the value that the balloon driver returns after memory requests.  As a result, I'm noticing that a guest that I've set to start with 128Mb will actually give the user 126Mb.  All other allocations perform normally, and attempting to over-allocate will simply return the amount of space that the domain was able to expand to.  

Under the premises that xm list should report actual memory values, 
 2 tests in xm-test may need to be modified to verify the amount of memory that a guest is physically using, and not rely on the value in the config file as being the amount of memory that the guest will have.

xm-test reactions to patch as of changset 11376:

REASON: Started domain with 128MB, but it got 126 MB
FAIL: 08_create_mem128_pos.test
REASON: Started domain with 256MB, but it got 254 MB
FAIL: 09_create_mem256_pos.test

Running 'free' inside of each guest shows 126, and 254 respectively, not their config file #'s. 


Signed-off-by: Tommie McAfee <tommie.mcafee@unisys.com>

Regards,
Tommie McAfee
Xen-Testing 



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diff -r 593b5623a0d2 linux-2.6-xen-sparse/drivers/xen/balloon/balloon.c
--- a/linux-2.6-xen-sparse/drivers/xen/balloon/balloon.c	Fri Sep 29 15:40:35 2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/balloon/balloon.c	Wed Oct 04 14:46:33 2006 -0400
@@ -57,6 +57,8 @@
 #include <xen/xenbus.h>
 
 #define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
+#define NOXENBUS 0
+#define XENBUSREADY 1
 
 #ifdef CONFIG_PROC_FS
 static struct proc_dir_entry *balloon_pde;
@@ -83,6 +85,9 @@ extern unsigned long totalram_pages;
 
 /* We may hit the hard limit in Xen. If we do then we remember it. */
 static unsigned long hard_limit;
+
+/* Aknowledge that xenstore is available */
+static int xenbus_status;
 
 /*
  * Drivers may alter the memory reservation independently, but they must
@@ -325,6 +330,22 @@ static int decrease_reservation(unsigned
 	return need_sleep;
 }
 
+/* write currently allocated kbs to xenstore */
+static void xenbus_write_xmtarget(void){
+
+	struct xenbus_transaction xbt;
+	unsigned int xm_current_pages;
+	
+
+	if(likely(xenbus_status==XENBUSREADY)){
+		xm_current_pages = PAGES2KB(current_pages);
+		xenbus_transaction_start(&xbt);
+		xenbus_printf(xbt,"memory", "xmtarget", "%8u",xm_current_pages);
+		xenbus_transaction_end(xbt,0);
+	}
+
+}
+
 /*
  * We avoid multiple worker processes conflicting via the balloon mutex.
  * We may of course race updates of the target counts (which are protected
@@ -355,6 +376,8 @@ static void balloon_process(void *unused
 	if (current_target() != current_pages)
 		mod_timer(&balloon_timer, jiffies + HZ);
 
+        xenbus_write_xmtarget();
+
 	up(&balloon_mutex);
 }
 
@@ -384,6 +407,8 @@ static void watch_target(struct xenbus_w
 		/* This is ok (for domain0 at least) - so just return */
 		return;
 	}
+
+        xenbus_status=XENBUSREADY;
 
 	/* The given memory/target value is in KiB, so it needs converting to
 	 * pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
@@ -462,6 +487,8 @@ static int __init balloon_init(void)
 {
 	unsigned long pfn;
 	struct page *page;
+
+	xenbus_status=NOXENBUS;
 
 	if (!is_running_on_xen())
 		return -ENODEV;
diff -r 593b5623a0d2 tools/python/xen/xend/XendDomainInfo.py
--- a/tools/python/xen/xend/XendDomainInfo.py	Fri Sep 29 15:40:35 2006 +0100
+++ b/tools/python/xen/xend/XendDomainInfo.py	Wed Oct 04 14:46:33 2006 -0400
@@ -459,6 +459,7 @@ class XendDomainInfo:
         self.console_mfn = None
 
         self.vmWatch = None
+        self.memWatch = None
         self.shutdownWatch = None
 
         self.shutdownStartTime = None
@@ -487,6 +488,14 @@ class XendDomainInfo:
             return []
 
 
+    def xsMemoryChanged(self, _):
+        """Get the memory target from xenstore of this domain.
+        """
+        xs_memory=int(self.readDom('memory/xmtarget'))/1024
+        self.info['memory']=xs_memory
+        self.storeVm("memory", xs_memory)
+	return 1
+      
     def storeChanged(self, _):
         log.trace("XendDomainInfo.storeChanged");
 
@@ -775,6 +784,9 @@ class XendDomainInfo:
         self.vmWatch = xswatch(self.vmpath, self.storeChanged)
         self.shutdownWatch = xswatch(self.dompath + '/control/shutdown',
                                      self.handleShutdownWatch)
+        self.memWatch = xswatch(self.dompath + '/memory/xmtarget',
+                                     self.xsMemoryChanged)
+
 
 
     def getDomid(self):
@@ -1015,6 +1027,7 @@ class XendDomainInfo:
         
         self.info['memory'] = target
         self.storeVm("memory", target)
+        self.storeDom('memory/xmtarget', target << 10)
         self.storeDom("memory/target", target << 10)
 
 
@@ -1372,6 +1385,7 @@ class XendDomainInfo:
         self.refresh_shutdown_lock.acquire()
         try:
             self.unwatchShutdown()
+            self.unwatchMemory()
 
             self.release_devices()
 
@@ -1439,6 +1453,18 @@ class XendDomainInfo:
                 self.shutdownWatch = None
         except:
             log.exception("Unwatching control/shutdown failed.")
+
+
+    def unwatchMemory(self):
+	"""Remove the watch on the domain's control/shutdown node, if any."""
+	try:
+            try:
+                if self.memWatch:
+                    self.memWatch.unwatch()
+            finally:
+                self.memWatch= None
+        except:
+            log.exception("Unwatching memory/xmtarget failed.")
 
 
     ## public:
diff -r 593b5623a0d2 tools/python/xen/xend/image.py
--- a/tools/python/xen/xend/image.py	Fri Sep 29 15:40:35 2006 +0100
+++ b/tools/python/xen/xend/image.py	Wed Oct 04 14:46:33 2006 -0400
@@ -382,6 +382,7 @@ class HVMImageHandler(ImageHandler):
 
     def destroy(self):
         self.unregister_shutdown_watch();
+        self.unregister_memory_watch();
         import signal
         if not self.pid:
             return
@@ -406,6 +407,18 @@ class HVMImageHandler(ImageHandler):
             log.exception("Unwatching hvm shutdown watch failed.")
         self.shutdownWatch = None
         log.debug("hvm shutdown watch unregistered")
+	
+    def unregister_memory_watch(self):
+        """Remove the watch on the target/xmtarget, if any. Nothrow
+        guarantee."""
+        try:
+           if self.memWatch:
+                self.memWatch.unwatch()
+        except:
+            log.exception("Unwatching memory/xmtarget failed.")
+        self.memWatch = None
+        log.debug("hvm memory watch unregistered")
+
 
     def hvm_shutdown(self, _):
         """ watch call back on node control/shutdown,

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^ permalink raw reply	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2006-10-18 14:53 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2006-10-11 18:24 [PATCH][RFC] to fix xm list memory reporting McAfee, Tommie M
2006-10-11 21:34 ` Anthony Liguori
2006-10-11 21:58   ` Keir Fraser
2006-10-16 19:55     ` McAfee, Tommie M
2006-10-18 14:53       ` [RESEND][PATCH][RFC] " McAfee, Tommie M
2006-10-11 22:27   ` [PATCH][RFC] " McAfee, Tommie M
2006-10-11 23:12     ` Anthony Liguori

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