WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] [PATCH] don't save Xen heap pages during domain save

To: <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] [PATCH] don't save Xen heap pages during domain save
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: Tue, 15 Jun 2010 12:45:31 +0100
Delivery-date: Tue, 15 Jun 2010 04:46:19 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
As discussed in the thread starting at
http://lists.xensource.com/archives/html/xen-devel/2010-05/msg01383.html,
don't save Xen heap pages in order to avoid overallocation when the
domain gets restored, as those pages would get (temporarily) backed
with normal RAM pages by the restore code.

This requires making DOMCTL_getpageframeinfo{2,3} usable for HVM guests,
meaning that the input to these must be treated as GMFNs.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- 2010-06-15.orig/tools/libxc/xc_domain_save.c        2010-06-01 
13:39:57.000000000 +0200
+++ 2010-06-15/tools/libxc/xc_domain_save.c     2010-06-15 09:32:42.000000000 
+0200
@@ -1288,58 +1288,64 @@ int xc_domain_save(xc_interface *xch, in
                 goto out;
             }
 
-            if ( hvm )
+            /* Get page types */
+            if ( xc_get_pfn_type_batch(xch, dom, batch, pfn_type) )
             {
-                /* Look for and skip completely empty batches. */
-                for ( j = 0; j < batch; j++ )
-                {
-                    if ( !pfn_err[j] )
-                        break;
-                    pfn_type[j] |= XEN_DOMCTL_PFINFO_XTAB;
-                }
-                if ( j == batch )
-                {
-                    munmap(region_base, batch*PAGE_SIZE);
-                    continue; /* bail on this batch: no valid pages */
-                }
-                for ( ; j < batch; j++ )
-                    if ( pfn_err[j] )
-                        pfn_type[j] |= XEN_DOMCTL_PFINFO_XTAB;
+                PERROR("get_pfn_type_batch failed");
+                goto out;
             }
-            else
+
+            for ( run = j = 0; j < batch; j++ )
             {
-                /* Get page types */
-                if ( xc_get_pfn_type_batch(xch, dom, batch, pfn_type) )
-                {
-                    PERROR("get_pfn_type_batch failed");
-                    goto out;
-                }
+                unsigned long gmfn = pfn_batch[j];
 
-                for ( j = 0; j < batch; j++ )
+                if ( !hvm )
+                    gmfn = pfn_to_mfn(gmfn);
+
+                if ( pfn_err[j] )
                 {
-                    unsigned long mfn = pfn_to_mfn(pfn_batch[j]);
-                    
                     if ( pfn_type[j] == XEN_DOMCTL_PFINFO_XTAB )
-                    {
-                        DPRINTF("type fail: page %i mfn %08lx\n", 
-                                j, mfn);
                         continue;
-                    }
-                    
-                    if ( debug )
+                    DPRINTF("map fail: page %i mfn %08lx err %d\n",
+                            j, gmfn, pfn_err[j]);
+                    pfn_type[j] = XEN_DOMCTL_PFINFO_XTAB;
+                    continue;
+                }
+
+                if ( pfn_type[j] == XEN_DOMCTL_PFINFO_XTAB )
+                {
+                    DPRINTF("type fail: page %i mfn %08lx\n", j, gmfn);
+                    continue;
+                }
+
+                /* canonicalise mfn->pfn */
+                pfn_type[j] |= pfn_batch[j];
+                ++run;
+
+                if ( debug )
+                {
+                    if ( hvm )
+                        DPRINTF("%d pfn=%08lx sum=%08lx\n",
+                                iter,
+                                pfn_type[j],
+                                csum_page(region_base + (PAGE_SIZE*j)));
+                    else
                         DPRINTF("%d pfn= %08lx mfn= %08lx [mfn]= %08lx"
                                 " sum= %08lx\n",
                                 iter,
-                                pfn_type[j] | pfn_batch[j],
-                                mfn,
-                                mfn_to_pfn(mfn),
+                                pfn_type[j],
+                                gmfn,
+                                mfn_to_pfn(gmfn),
                                 csum_page(region_base + (PAGE_SIZE*j)));
-                    
-                    /* canonicalise mfn->pfn */
-                    pfn_type[j] |= pfn_batch[j];
                 }
             }
 
+            if ( !run )
+            {
+                munmap(region_base, batch*PAGE_SIZE);
+                continue; /* bail on this batch: no valid pages */
+            }
+
             if ( wrexact(io_fd, &batch, sizeof(unsigned int)) )
             {
                 PERROR("Error when writing to state file (2)");
--- 2010-06-15.orig/xen/arch/x86/domctl.c       2010-03-02 09:11:28.000000000 
+0100
+++ 2010-06-15/xen/arch/x86/domctl.c    2010-06-15 09:32:42.000000000 +0200
@@ -207,11 +207,12 @@ long arch_do_domctl(
 
                 for ( j = 0; j < k; j++ )
                 {
-                    unsigned long type = 0, mfn = arr[j];
+                    unsigned long type = 0, mfn = gmfn_to_mfn(d, arr[j]);
 
                     page = mfn_to_page(mfn);
 
-                    if ( unlikely(!mfn_valid(mfn)) )
+                    if ( unlikely(!mfn_valid(mfn)) ||
+                         unlikely(is_xen_heap_mfn(mfn)) )
                         type = XEN_DOMCTL_PFINFO_XTAB;
                     else if ( xsm_getpageframeinfo(page) != 0 )
                         ;
@@ -306,14 +307,15 @@ long arch_do_domctl(
             for ( j = 0; j < k; j++ )
             {      
                 struct page_info *page;
-                unsigned long mfn = arr32[j];
+                unsigned long mfn = gmfn_to_mfn(d, arr32[j]);
 
                 page = mfn_to_page(mfn);
 
                 if ( domctl->cmd == XEN_DOMCTL_getpageframeinfo3)
                     arr32[j] = 0;
 
-                if ( unlikely(!mfn_valid(mfn)) )
+                if ( unlikely(!mfn_valid(mfn)) ||
+                     unlikely(is_xen_heap_mfn(mfn)) )
                     arr32[j] |= XEN_DOMCTL_PFINFO_XTAB;
                 else if ( xsm_getpageframeinfo(page) != 0 )
                     continue;


Attachment: dont-save-xen-heap-pages.patch
Description: Text document

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
<Prev in Thread] Current Thread [Next in Thread>