tools: add parallel parameter to virsh save command

Signed-off-by: Claudio Fontana <cfontana@suse.de>
Signed-off-by: Jim Fehlig <jfehlig@suse.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

diff --git a/docs/manpages/virsh.rst b/docs/manpages/virsh.rst
index a8966994482259945ad587f4ad9d25d5f3438924..38f3967ed81feb5894bfcec287c6e0643125d325 100644 (file)
--- a/docs/manpages/virsh.rst
+++ b/docs/manpages/virsh.rst
@@ -4174,6 +4174,7 @@ save
 ::
 
    save domain state-file [--bypass-cache] [--xml file]
+      [--parallel] [--parallel-channels channels]
       [{--running | --paused}] [--verbose]
 
 Saves a running domain (RAM, but not disk state) to a state file so that
@@ -4181,8 +4182,11 @@ it can be restored
 later.  Once saved, the domain will no longer be running on the
 system, thus the memory allocated for the domain will be free for
 other domains to use.  ``virsh restore`` restores from this state file.
+
 If *--bypass-cache* is specified, the save will avoid the file system
-cache, although this may slow down the operation.
+cache. Depending on the specific scenario this may slow down or speed up
+the operation.
+
 
 The progress may be monitored using ``domjobinfo`` virsh command and canceled
 with ``domjobabort`` command (sent by another virsh instance). Another option
@@ -4204,6 +4208,12 @@ based on the state the domain was in when the save was done; passing
 either the *--running* or *--paused* flag will allow overriding which
 state the ``restore`` should use.
 
+*--parallel* option will cause the save data to be written to file
+over multiple parallel IO channels. The number of channels can be
+specified using *--parallel-channels*. Using parallel IO channels
+requires the use of ``sparse`` image save format. Parallel save may
+significantly reduce the time required to save large memory domains.
+
 Domain saved state files assume that disk images will be unchanged
 between the creation and restore point.  For a more complete system
 restore point, where the disk state is saved alongside the memory

diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index f07260f21740ce3b0b37b0a9bbb28bffa24d3e78..fd56400f6a0ab73415aaf69858c0672d60f73e53 100644 (file)
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -4530,6 +4530,14 @@ static const vshCmdOptDef opts_save[] = {
      .type = VSH_OT_BOOL,
      .help = N_("avoid file system cache when saving")
     },
+    {.name = "parallel",
+     .type = VSH_OT_BOOL,
+     .help = N_("enable parallel save")
+    },
+    {.name = "parallel-channels",
+     .type = VSH_OT_INT,
+     .help = N_("number of extra IO channels to use for parallel save")
+    },
     {.name = "xml",
      .type = VSH_OT_STRING,
      .unwanted_positional = true,
@@ -4560,6 +4568,11 @@ doSave(void *opaque)
     g_autoptr(virshDomain) dom = NULL;
     const char *name = NULL;
     const char *to = NULL;
+    virTypedParameterPtr params = NULL;
+    int nparams = 0;
+    int maxparams = 0;
+    int nchannels = 1;
+    int rv = -1;
     unsigned int flags = 0;
     const char *xmlfile = NULL;
     g_autofree char *xml = NULL;
@@ -4573,15 +4586,30 @@ doSave(void *opaque)
         goto out_sig;
 #endif /* !WIN32 */
 
-    if (vshCommandOptString(ctl, cmd, "file", &to) < 0)
-        goto out;
-
     if (vshCommandOptBool(cmd, "bypass-cache"))
         flags |= VIR_DOMAIN_SAVE_BYPASS_CACHE;
     if (vshCommandOptBool(cmd, "running"))
         flags |= VIR_DOMAIN_SAVE_RUNNING;
     if (vshCommandOptBool(cmd, "paused"))
         flags |= VIR_DOMAIN_SAVE_PAUSED;
+    if (vshCommandOptBool(cmd, "parallel"))
+        flags |= VIR_DOMAIN_SAVE_PARALLEL;
+
+    if (vshCommandOptString(ctl, cmd, "file", &to) < 0)
+        goto out;
+    if (to &&
+        virTypedParamsAddString(&params, &nparams, &maxparams,
+                                VIR_DOMAIN_SAVE_PARAM_FILE, to) < 0)
+        goto out;
+
+    if (flags & VIR_DOMAIN_SAVE_PARALLEL) {
+        if ((rv = vshCommandOptInt(ctl, cmd, "parallel-channels", &nchannels)) < 0)
+            goto out;
+
+        if (virTypedParamsAddInt(&params, &nparams, &maxparams,
+                                 VIR_DOMAIN_SAVE_PARAM_PARALLEL_CHANNELS, nchannels) < 0)
+            goto out;
+    }
 
     if (vshCommandOptString(ctl, cmd, "xml", &xmlfile) < 0)
         goto out;
@@ -4594,9 +4622,13 @@ doSave(void *opaque)
         vshReportError(ctl);
         goto out;
     }
+    if (xml &&
+        virTypedParamsAddString(&params, &nparams, &maxparams,
+                                VIR_DOMAIN_SAVE_PARAM_DXML, xml) < 0)
+        goto out;
 
     if (flags || xml) {
-        rc = virDomainSaveFlags(dom, to, xml, flags);
+        rc = virDomainSaveParams(dom, params, nparams, flags);
     } else {
         rc = virDomainSave(dom, to);
     }
@@ -4609,6 +4641,8 @@ doSave(void *opaque)
     data->ret = 0;
 
  out:
+    virTypedParamsFree(params, nparams);
+
 #ifndef WIN32
     pthread_sigmask(SIG_SETMASK, &oldsigmask, NULL);
  out_sig: