[Xen-changelog] Enable 'live' migration from a tools pov; prior to this the 'live' flag was

[Xen patchbot -unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User shand@xxxxxxxxxxxxxxxxxxxxxxxxxxx
# Node ID a1de77c1486c5f35884e9f578b7f33b6bd75c362
# Parent  0c0d929e787c0848ba26168cd0fbebb6dad2aaf2
Enable 'live' migration from a tools pov; prior to this the 'live' flag was 
being ignored by xend/xc_linux_save.

Signed-off-by: Steven Hand <steven@xxxxxxxxxxxxx>

diff -r 0c0d929e787c -r a1de77c1486c tools/libxc/xc_linux_save.c
--- a/tools/libxc/xc_linux_save.c       Fri Sep  2 17:55:24 2005
+++ b/tools/libxc/xc_linux_save.c       Sat Sep  3 01:36:29 2005
@@ -20,6 +20,24 @@
 #define BATCH_SIZE 1024   /* 1024 pages (4MB) at a time */
 
 #define MAX_MBIT_RATE 500
+
+
+/*
+** Default values for important tuning parameters. Can override by passing
+** non-zero replacement values to xc_linux_save().  
+**
+** XXX SMH: should consider if want to be able to override MAX_MBIT_RATE too. 
+** 
+*/
+#define DEF_MAX_ITERS   29   /* limit us to 30 times round loop */ 
+#define DEF_MAX_FACTOR   3   /* never send more than 3x nr_pfns */
+
+
+
+/* Flags to control behaviour of xc_linux_save */
+#define XCFLAGS_LIVE      1
+#define XCFLAGS_DEBUG     2
+
 
 #define DEBUG 0
 
@@ -320,18 +338,18 @@
                              xc_dominfo_t *info,
                              vcpu_guest_context_t *ctxt)
 {
-    int i=0;
+    int i = 0;
     char ans[30];
 
     printf("suspend\n");
     fflush(stdout);
     if (fgets(ans, sizeof(ans), stdin) == NULL) {
-       ERR("failed reading suspend reply");
-       return -1;
+        ERR("failed reading suspend reply");
+        return -1;
     }
     if (strncmp(ans, "done\n", 5)) {
-       ERR("suspend reply incorrect: %s", ans);
-       return -1;
+        ERR("suspend reply incorrect: %s", ans);
+        return -1;
     }
 
 retry:
@@ -377,19 +395,16 @@
     return -1;
 }
 
-int xc_linux_save(int xc_handle, int io_fd, u32 dom)
+int xc_linux_save(int xc_handle, int io_fd, u32 dom, u32 max_iters, 
+                  u32 max_factor, u32 flags)
 {
     xc_dominfo_t info;
 
     int rc = 1, i, j, k, last_iter, iter = 0;
     unsigned long mfn;
-    int live =  0; // (ioctxt->flags & XCFLAGS_LIVE);
-    int debug = 0; // (ioctxt->flags & XCFLAGS_DEBUG);
+    int live  = (flags & XCFLAGS_LIVE); 
+    int debug = (flags & XCFLAGS_DEBUG); 
     int sent_last_iter, skip_this_iter;
-
-    /* Important tuning parameters */
-    int max_iters  = 29; /* limit us to 30 times round loop */
-    int max_factor = 3;  /* never send more than 3x nr_pfns */
 
     /* The new domain's shared-info frame number. */
     unsigned long shared_info_frame;
@@ -442,8 +457,16 @@
 
     MBIT_RATE = START_MBIT_RATE;
 
-    DPRINTF("xc_linux_save start %d\n", dom);
-    
+
+    /* If no explicit control parameters given, use defaults */
+    if(!max_iters) 
+        max_iters = DEF_MAX_ITERS; 
+    if(!max_factor) 
+        max_factor = DEF_MAX_FACTOR; 
+
+
+    DPRINTF("xc_linux_save start DOM%u live=%s\n", dom, live?"true":"false"); 
+
     if (mlock(&ctxt, sizeof(ctxt))) {
         ERR("Unable to mlock ctxt");
         return 1;
diff -r 0c0d929e787c -r a1de77c1486c tools/libxc/xenguest.h
--- a/tools/libxc/xenguest.h    Fri Sep  2 17:55:24 2005
+++ b/tools/libxc/xenguest.h    Sat Sep  3 01:36:29 2005
@@ -6,13 +6,12 @@
  * Copyright (c) 2003-2004, K A Fraser.
  */
 
-#ifndef XENBUILD_H
-#define XENBUILD_H
+#ifndef XENGUEST_H
+#define XENGUEST_H
 
-#define XCFLAGS_VERBOSE   1
-#define XCFLAGS_LIVE      2
-#define XCFLAGS_DEBUG     4
-#define XCFLAGS_CONFIGURE 8
+#define XCFLAGS_LIVE      1
+#define XCFLAGS_DEBUG     2
+
 
 /**
  * This function will save a domain running Linux.
@@ -22,7 +21,8 @@
  * @parm dom the id of the domain
  * @return 0 on success, -1 on failure
  */
-int xc_linux_save(int xc_handle, int fd, uint32_t dom);
+int xc_linux_save(int xc_handle, int fd, uint32_t dom, uint32_t max_iters, 
+                  uint32_t max_factor, uint32_t flags /* XCFLAGS_xxx */);
 
 /**
  * This function will restore a saved domain running Linux.
@@ -35,8 +35,9 @@
  * @parm store_mfn returned with the mfn of the store page
  * @return 0 on success, -1 on failure
  */
-int xc_linux_restore(int xc_handle, int io_fd, uint32_t dom, unsigned long 
nr_pfns,
-                    unsigned int store_evtchn, unsigned long *store_mfn);
+int xc_linux_restore(int xc_handle, int io_fd, uint32_t dom, 
+                     unsigned long nr_pfns, unsigned int store_evtchn, 
+                     unsigned long *store_mfn);
 
 int xc_linux_build(int xc_handle,
                    uint32_t domid,
@@ -65,4 +66,4 @@
                  unsigned int store_evtchn,
                  unsigned long *store_mfn);
 
-#endif
+#endif // XENGUEST_H
diff -r 0c0d929e787c -r a1de77c1486c tools/python/xen/xend/XendCheckpoint.py
--- a/tools/python/xen/xend/XendCheckpoint.py   Fri Sep  2 17:55:24 2005
+++ b/tools/python/xen/xend/XendCheckpoint.py   Sat Sep  3 01:36:29 2005
@@ -34,7 +34,7 @@
         raise XendError(errmsg)
     return buf
 
-def save(xd, fd, dominfo):
+def save(xd, fd, dominfo, live):
     write_exact(fd, SIGNATURE, "could not write guest state file: signature")
 
     config = sxp.to_string(dominfo.sxpr())
@@ -42,8 +42,13 @@
                 "could not write guest state file: config len")
     write_exact(fd, config, "could not write guest state file: config")
 
+    # xc_save takes three customization parameters: maxit, max_f, and flags
+    # the last controls whether or not save is 'live', while the first two
+    # further customize behaviour when 'live' save is enabled. Passing "0"
+    # simply uses the defaults compiled into libxenguest; see the comments 
+    # and/or code in xc_linux_save() for more information. 
     cmd = [PATH_XC_SAVE, str(xc.handle()), str(fd),
-           str(dominfo.id)]
+           str(dominfo.id), "0", "0", str(live) ]
     log.info("[xc_save] " + join(cmd))
     child = xPopen3(cmd, True, -1, [fd, xc.handle()])
     
diff -r 0c0d929e787c -r a1de77c1486c tools/python/xen/xend/XendDomain.py
--- a/tools/python/xen/xend/XendDomain.py       Fri Sep  2 17:55:24 2005
+++ b/tools/python/xen/xend/XendDomain.py       Sat Sep  3 01:36:29 2005
@@ -542,7 +542,7 @@
             dominfo.name = "tmp-" + dominfo.name
 
         try:
-            XendCheckpoint.save(self, sock.fileno(), dominfo)
+            XendCheckpoint.save(self, sock.fileno(), dominfo, live)
         except:
             if dst == "localhost":
                 dominfo.name = string.replace(dominfo.name, "tmp-", "", 1)
@@ -563,7 +563,8 @@
 
             fd = os.open(dst, os.O_WRONLY | os.O_CREAT | os.O_TRUNC)
 
-            return XendCheckpoint.save(self, fd, dominfo)
+            # For now we don't support 'live checkpoint' 
+            return XendCheckpoint.save(self, fd, dominfo, False)
 
         except OSError, ex:
             raise XendError("can't write guest state file %s: %s" %
diff -r 0c0d929e787c -r a1de77c1486c tools/xcutils/xc_save.c
--- a/tools/xcutils/xc_save.c   Fri Sep  2 17:55:24 2005
+++ b/tools/xcutils/xc_save.c   Sat Sep  3 01:36:29 2005
@@ -17,14 +17,17 @@
 int
 main(int argc, char **argv)
 {
-    unsigned int xc_fd, io_fd, domid;
+    unsigned int xc_fd, io_fd, domid, maxit, max_f, flags; 
 
-    if (argc != 4)
-       errx(1, "usage: %s xcfd iofd domid", argv[0]);
+    if (argc != 7)
+       errx(1, "usage: %s xcfd iofd domid maxit maxf flags", argv[0]);
 
     xc_fd = atoi(argv[1]);
     io_fd = atoi(argv[2]);
     domid = atoi(argv[3]);
+    maxit = atoi(argv[4]);
+    max_f = atoi(argv[5]);
+    flags = atoi(argv[6]);
 
-    return xc_linux_save(xc_fd, io_fd, domid);
+    return xc_linux_save(xc_fd, io_fd, domid, maxit, max_f, flags);
 }

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