[Xen-changelog] [xen-3.1-testing] libxc: Remove permute() function from xc_domain_save().

["Xen patchbot-3.1-testing" <patchbot-3.1-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1206016031 0
# Node ID b0a5b418d4a2e5a9a6cfd35b5fc522512770113e
# Parent  7ef2eb7341ed18e7770d5b948b8b366bc73c96ae
libxc: Remove permute() function from xc_domain_save().
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
xen-unstable changeset:   17250:d1e91aba27584bbefd3650ac8e5174d63b8e5b33
xen-unstable date:        Wed Mar 19 12:41:48 2008 +0000
---
 tools/libxc/xc_domain_save.c |   40 +---------------------------------------
 1 files changed, 1 insertion(+), 39 deletions(-)

diff -r 7ef2eb7341ed -r b0a5b418d4a2 tools/libxc/xc_domain_save.c
--- a/tools/libxc/xc_domain_save.c      Thu Mar 20 12:25:35 2008 +0000
+++ b/tools/libxc/xc_domain_save.c      Thu Mar 20 12:27:11 2008 +0000
@@ -126,36 +126,6 @@ static inline int count_bits ( int nr, v
     for ( i = 0; i < (nr / (sizeof(unsigned long)*8)); i++, p++ )
         count += hweight32(*p);
     return count;
-}
-
-static inline int permute( int i, int nr, int order_nr  )
-{
-    /* Need a simple permutation function so that we scan pages in a
-       pseudo random order, enabling us to get a better estimate of
-       the domain's page dirtying rate as we go (there are often
-       contiguous ranges of pfns that have similar behaviour, and we
-       want to mix them up. */
-
-    /* e.g. nr->oder 15->4 16->4 17->5 */
-    /* 512MB domain, 128k pages, order 17 */
-
-    /*
-      QPONMLKJIHGFEDCBA
-             QPONMLKJIH
-      GFEDCBA
-     */
-
-    /*
-      QPONMLKJIHGFEDCBA
-                  EDCBA
-             QPONM
-      LKJIHGF
-      */
-
-    do { i = ((i>>(order_nr-10)) | ( i<<10 ) ) & ((1<<order_nr)-1); }
-    while ( i >= nr ); /* this won't ever loop if nr is a power of 2 */
-
-    return i;
 }
 
 static uint64_t tv_to_us(struct timeval *new)
@@ -813,9 +783,6 @@ int xc_domain_save(int xc_handle, int io
     /* base of the region in which domain memory is mapped */
     unsigned char *region_base = NULL;
 
-    /* power of 2 order of p2m_size */
-    int order_nr;
-
     /* bitmap of pages:
        - that should be sent this iteration (unless later marked as skip);
        - to skip this iteration because already dirty;
@@ -917,11 +884,6 @@ int xc_domain_save(int xc_handle, int io
 
     /* pretend we sent all the pages last iteration */
     sent_last_iter = p2m_size;
-
-    /* calculate the power of 2 order of p2m_size, e.g.
-       15->4 16->4 17->5 */
-    for ( i = p2m_size-1, order_nr = 0; i ; i >>= 1, order_nr++ )
-        continue;
 
     /* Setup to_send / to_fix and to_skip bitmaps */
     to_send = malloc(BITMAP_SIZE);
@@ -1075,7 +1037,7 @@ int xc_domain_save(int xc_handle, int io
                    (batch < MAX_BATCH_SIZE) && (N < p2m_size);
                    N++ )
             {
-                int n = permute(N, p2m_size, order_nr);
+                int n = N;
 
                 if ( debug )
                     DPRINTF("%d pfn= %08lx mfn= %08lx %d  [mfn]= %08lx\n",

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