[Xen-changelog] [xen-unstable] tools: Save superpages in the same batch, to make detection easier

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User George Dunlap <george.dunlap@xxxxxxxxxxxxx>
# Date 1306420052 -3600
# Node ID ad174b1cfddda8b5e89418a47a38ae722c6ba078
# Parent  ef06afaeb159f17ccaa113f18450605232c5397c
tools: Save superpages in the same batch, to make detection easier

On the first time through (when pfns are mostly allocated on
the receiving side), try to keep superpages together in the same
batch by ending a batch early if we see the first page of a
potential superpage and there isn't enough room in the batch
for a full superpage.

Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
---


diff -r ef06afaeb159 -r ad174b1cfddd tools/libxc/xc_domain_save.c
--- a/tools/libxc/xc_domain_save.c      Thu May 26 15:13:52 2011 +0100
+++ b/tools/libxc/xc_domain_save.c      Thu May 26 15:27:32 2011 +0100
@@ -83,6 +83,11 @@
      ((mfn_to_pfn(_mfn) < (dinfo->p2m_size)) &&   \
       (pfn_to_mfn(mfn_to_pfn(_mfn)) == (_mfn))))
 
+#define SUPERPAGE_PFN_SHIFT  9
+#define SUPERPAGE_NR_PFNS    (1UL << SUPERPAGE_PFN_SHIFT)
+
+#define SUPER_PAGE_START(pfn)    (((pfn) & (SUPERPAGE_NR_PFNS-1)) == 0 )
+
 /*
 ** During (live) save/migrate, we maintain a number of bitmaps to track
 ** which pages we have to send, to fixup, and to skip.
@@ -808,6 +813,7 @@
     int rc = 1, frc, i, j, last_iter = 0, iter = 0;
     int live  = (flags & XCFLAGS_LIVE);
     int debug = (flags & XCFLAGS_DEBUG);
+    int superpages = !!hvm;
     int race = 0, sent_last_iter, skip_this_iter = 0;
     unsigned int sent_this_iter = 0;
     int tmem_saved = 0;
@@ -1159,6 +1165,12 @@
                            (test_bit(n, to_fix)  && last_iter)) )
                         continue;
 
+                    /* First time through, try to keep superpages in the same 
batch */
+                    if ( superpages && iter == 1
+                         && SUPER_PAGE_START(n)
+                         && batch + SUPERPAGE_NR_PFNS > MAX_BATCH_SIZE )
+                        break;
+
                     /*
                     ** we get here if:
                     **  1. page is marked to_send & hasn't already been 
re-dirtied

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog