[PATCH] libxc: use correct macro when unmapping memory after save operation

From: Jim Fehlig <jfehlig@novell.com>
To: xen-devel <xen-devel@lists.xensource.com>
Cc: Olaf Hering <olaf@aepfle.de>
Subject: [PATCH] libxc: use correct macro when unmapping memory after save operation
Date: Fri, 20 May 2011 16:04:41 -0600	[thread overview]
Message-ID: <4DD6E579.7060304@novell.com> (raw)

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With some help from Olaf, I've finally got to the bottom of an issue I
came across while trying to implement save/restore in the libvirt
libxenlight driver.  After issuing the save operation, the saved domain
was not being cleaned up properly and left in this state from xl's
perspective

xen33:# xl list
Name                   ID   Mem VCPUs      State   Time(s)
Domain-0                0  6821     8     r-----     122.5
(null)                  2     2     2     --pssd      10.8

Checking the libvirtd /proc/$pid/maps I found this

7f3798984000-7f3798b86000 r--s 00002000 00:03 4026532097 /proc/xen/privcmd

So not all all pages belonging to the domain were unmapped from
libvirtd.  In tools/libxc/xc_domain_save.c we found that P2M_FL_ENTRIES
were being mapped but only P2M_FLL_ENTRIES were being unmapped.  The
attached patch changes the unmapping to use the same P2M_FL_ENTRIES
macro.  I'm not too familiar with this code though so posting here for
review.

I suspect this was not noticed before since most (all?) processes doing
save terminate after the save and are not long-running like libvirtd.

Regards,
Jim


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diff -r 5fb4c607049d tools/libxc/xc_domain_save.c

--- a/tools/libxc/xc_domain_save.c	Fri May 20 09:44:41 2011 +0100
+++ b/tools/libxc/xc_domain_save.c	Fri May 20 16:02:28 2011 -0600
@@ -1955,7 +1955,7 @@ int xc_domain_save(xc_interface *xch, in
         munmap(live_shinfo, PAGE_SIZE);
 
     if ( ctx->live_p2m )
-        munmap(ctx->live_p2m, P2M_FLL_ENTRIES * PAGE_SIZE);
+        munmap(ctx->live_p2m, P2M_FL_ENTRIES * PAGE_SIZE);
 
     if ( ctx->live_m2p )
         munmap(ctx->live_m2p, M2P_SIZE(ctx->max_mfn));

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