[Xen-devel] [PATCH: Lazy Restore] xl restore: Add a new "-l" lazy switch.

[Dushyant Behl <myselfdushyantbehl@xxxxxxxxx>]

Add a new "-l" option to xl restore which implies use of lazy restore.
Plumb the lazy argument from libxl to libxc. Currently libxc just prints
a debug message and continue with the conventional process.

Please note that the lazy restore is to be enabled only for HVM guests.
If "-l" is passed as an argument to non HVM guest then the process will
exit with error.

Signed-off-by: Dushyant Behl <myselfdushyantbehl@xxxxxxxxx>
---
 tools/libxc/xc_domain_restore.c  | 11 ++++++++++-
 tools/libxc/xenguest.h           |  2 +-
 tools/libxl/libxl_create.c       | 14 +++++++++-----
 tools/libxl/libxl_internal.h     |  1 +
 tools/libxl/libxl_save_callout.c |  2 +-
 tools/libxl/libxl_save_helper.c  |  3 ++-
 tools/libxl/libxl_types.idl      |  1 +
 tools/libxl/xl_cmdimpl.c         | 16 ++++++++++++++--
 tools/libxl/xl_cmdtable.c        |  1 +
 9 files changed, 40 insertions(+), 11 deletions(-)

diff --git a/tools/libxc/xc_domain_restore.c b/tools/libxc/xc_domain_restore.c
index bcb0ae0..f9c506c 100644
--- a/tools/libxc/xc_domain_restore.c
+++ b/tools/libxc/xc_domain_restore.c
@@ -1409,7 +1409,7 @@ int xc_domain_restore(xc_interface *xch, int io_fd, 
uint32_t dom,
                       unsigned long *console_mfn, domid_t console_domid,
                       unsigned int hvm, unsigned int pae, int superpages,
                       int no_incr_generationid, int checkpointed_stream,
-                      unsigned long *vm_generationid_addr,
+                      int lazy, unsigned long *vm_generationid_addr,
                       struct restore_callbacks *callbacks)
 {
     DECLARE_DOMCTL;
@@ -1470,6 +1470,15 @@ int xc_domain_restore(xc_interface *xch, int io_fd, 
uint32_t dom,
 
     DPRINTF("%s: starting restore of new domid %u", __func__, dom);
 
+    if ( lazy ) {
+        DPRINTF("xc: lazy switch enabled for restore\n");
+
+        if ( !hvm ) {
+            PERROR("xc: lazy restore called for non HVM guest");
+            return 1;
+        }
+    }
+
     pagebuf_init(&pagebuf);
     memset(&tailbuf, 0, sizeof(tailbuf));
     tailbuf.ishvm = hvm;
diff --git a/tools/libxc/xenguest.h b/tools/libxc/xenguest.h
index 1f216cd..269275a 100644
--- a/tools/libxc/xenguest.h
+++ b/tools/libxc/xenguest.h
@@ -126,7 +126,7 @@ int xc_domain_restore(xc_interface *xch, int io_fd, 
uint32_t dom,
                       unsigned long *console_mfn, domid_t console_domid,
                       unsigned int hvm, unsigned int pae, int superpages,
                       int no_incr_generationid, int checkpointed_stream,
-                      unsigned long *vm_generationid_addr,
+                      int lazy, unsigned long *vm_generationid_addr,
                       struct restore_callbacks *callbacks);
 /**
  * xc_domain_restore writes a file to disk that contains the device
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index d015cf4..f599280 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -1348,8 +1348,8 @@ static void domain_create_cb(libxl__egc *egc,
                              int rc, uint32_t domid);
 
 static int do_domain_create(libxl_ctx *ctx, libxl_domain_config *d_config,
-                            uint32_t *domid,
-                            int restore_fd, int checkpointed_stream,
+                            uint32_t *domid, int restore_fd,
+                            const libxl_domain_restore_params *restore_params,
                             const libxl_asyncop_how *ao_how,
                             const libxl_asyncprogress_how *aop_console_how)
 {
@@ -1361,10 +1361,14 @@ static int do_domain_create(libxl_ctx *ctx, 
libxl_domain_config *d_config,
     cdcs->dcs.guest_config = d_config;
     cdcs->dcs.restore_fd = restore_fd;
     cdcs->dcs.callback = domain_create_cb;
-    cdcs->dcs.checkpointed_stream = checkpointed_stream;
     libxl__ao_progress_gethow(&cdcs->dcs.aop_console_how, aop_console_how);
     cdcs->domid_out = domid;
 
+    if (restore_params) {
+        cdcs->dcs.checkpointed_stream = restore_params->checkpointed_stream;
+        cdcs->dcs.lazy = restore_params->lazy;
+    }
+    
     initiate_domain_create(egc, &cdcs->dcs);
 
     return AO_INPROGRESS;
@@ -1388,7 +1392,7 @@ int libxl_domain_create_new(libxl_ctx *ctx, 
libxl_domain_config *d_config,
                             const libxl_asyncop_how *ao_how,
                             const libxl_asyncprogress_how *aop_console_how)
 {
-    return do_domain_create(ctx, d_config, domid, -1, 0,
+    return do_domain_create(ctx, d_config, domid, -1, NULL,
                             ao_how, aop_console_how);
 }
 
@@ -1399,7 +1403,7 @@ int libxl_domain_create_restore(libxl_ctx *ctx, 
libxl_domain_config *d_config,
                                 const libxl_asyncprogress_how *aop_console_how)
 {
     return do_domain_create(ctx, d_config, domid, restore_fd,
-                            params->checkpointed_stream, ao_how, 
aop_console_how);
+                            params, ao_how, aop_console_how);
 }
 
 /*
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index c2b73c4..de8fae6 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -2718,6 +2718,7 @@ struct libxl__domain_create_state {
     /* private to domain_create */
     int guest_domid;
     int checkpointed_stream;
+    int lazy;
     libxl__domain_build_state build_state;
     libxl__bootloader_state bl;
     libxl__stub_dm_spawn_state dmss;
diff --git a/tools/libxl/libxl_save_callout.c b/tools/libxl/libxl_save_callout.c
index e3bda8f..aa8c586 100644
--- a/tools/libxl/libxl_save_callout.c
+++ b/tools/libxl/libxl_save_callout.c
@@ -60,7 +60,7 @@ void libxl__xc_domain_restore(libxl__egc *egc, 
libxl__domain_create_state *dcs,
         state->store_domid, state->console_port,
         state->console_domid,
         hvm, pae, superpages, no_incr_generationid,
-        cbflags, dcs->checkpointed_stream,
+        cbflags, dcs->checkpointed_stream, dcs->lazy,
     };
 
     dcs->shs.ao = ao;
diff --git a/tools/libxl/libxl_save_helper.c b/tools/libxl/libxl_save_helper.c
index c36314c..bd0b04a 100644
--- a/tools/libxl/libxl_save_helper.c
+++ b/tools/libxl/libxl_save_helper.c
@@ -242,6 +242,7 @@ int main(int argc, char **argv)
         int no_incr_genidad =      strtoul(NEXTARG,0,10);
         unsigned cbflags =         strtoul(NEXTARG,0,10);
         int checkpointed =         strtoul(NEXTARG,0,10);
+        int lazy =                 strtoul(NEXTARG,0,10);
         assert(!*++argv);
 
         helper_setcallbacks_restore(&helper_restore_callbacks, cbflags);
@@ -254,7 +255,7 @@ int main(int argc, char **argv)
         r = xc_domain_restore(xch, io_fd, dom, store_evtchn, &store_mfn,
                               store_domid, console_evtchn, &console_mfn,
                               console_domid, hvm, pae, superpages,
-                              no_incr_genidad, checkpointed, &genidad,
+                              no_incr_genidad, checkpointed, lazy, &genidad,
                               &helper_restore_callbacks);
         helper_stub_restore_results(store_mfn,console_mfn,genidad,0);
         complete(r);
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 52f1aa9..6c8355c 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -282,6 +282,7 @@ libxl_domain_create_info = Struct("domain_create_info",[
 
 libxl_domain_restore_params = Struct("domain_restore_params", [
     ("checkpointed_stream", integer),
+    ("lazy", integer),
     ])
 
 MemKB = UInt(64, init_val = "LIBXL_MEMKB_DEFAULT")
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 5195914..2a10193 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -146,6 +146,7 @@ struct domain_create {
     int paused;
     int dryrun;
     int quiet;
+    int lazy;
     int vnc;
     int vncautopass;
     int console_autoconnect;
@@ -2045,6 +2046,7 @@ static uint32_t create_domain(struct domain_create 
*dom_info)
     int daemonize = dom_info->daemonize;
     int monitor = dom_info->monitor;
     int paused = dom_info->paused;
+    int lazy = dom_info->lazy;
     int vncautopass = dom_info->vncautopass;
     const char *config_file = dom_info->config_file;
     const char *extra_config = dom_info->extra_config;
@@ -2237,7 +2239,14 @@ start:
 
     if ( restoring ) {
         libxl_domain_restore_params params;
+        libxl_domain_create_info *c_info = &d_config.c_info;
+        if ( lazy && (c_info->type != LIBXL_DOMAIN_TYPE_HVM) ) {
+            fprintf(stderr, "lazy restore should be called for HVM guest 
only");
+            ret = ERROR_INVAL;
+            goto error_out;
+        }
         params.checkpointed_stream = dom_info->checkpointed_stream;
+        params.lazy = lazy;        
         ret = libxl_domain_create_restore(ctx, &d_config,
                                           &domid, restore_fd,
                                           &params,
@@ -3925,7 +3934,7 @@ int main_restore(int argc, char **argv)
     const char *config_file = NULL;
     struct domain_create dom_info;
     int paused = 0, debug = 0, daemonize = 1, monitor = 1,
-        console_autoconnect = 0, vnc = 0, vncautopass = 0;
+        console_autoconnect = 0, vnc = 0, vncautopass = 0, lazy = 0;
     int opt, rc;
     static struct option opts[] = {
         {"vncviewer", 0, 0, 'V'},
@@ -3934,7 +3943,7 @@ int main_restore(int argc, char **argv)
         {0, 0, 0, 0}
     };
 
-    SWITCH_FOREACH_OPT(opt, "FhcpdeVA", opts, "restore", 1) {
+    SWITCH_FOREACH_OPT(opt, "FhcpdleVA", opts, "restore", 1) {
     case 'c':
         console_autoconnect = 1;
         break;
@@ -3957,6 +3966,8 @@ int main_restore(int argc, char **argv)
     case 'A':
         vnc = vncautopass = 1;
         break;
+    case 'l':
+        lazy = 1;
     }
 
     if (argc-optind == 1) {
@@ -3977,6 +3988,7 @@ int main_restore(int argc, char **argv)
     dom_info.config_file = config_file;
     dom_info.restore_file = checkpoint_file;
     dom_info.migrate_fd = -1;
+    dom_info.lazy = lazy;
     dom_info.vnc = vnc;
     dom_info.vncautopass = vncautopass;
     dom_info.console_autoconnect = console_autoconnect;
diff --git a/tools/libxl/xl_cmdtable.c b/tools/libxl/xl_cmdtable.c
index 4279b9f..0405c6e 100644
--- a/tools/libxl/xl_cmdtable.c
+++ b/tools/libxl/xl_cmdtable.c
@@ -167,6 +167,7 @@ struct cmd_spec cmd_table[] = {
       "Restore a domain from a saved state",
       "[options] [<ConfigFile>] <CheckpointFile>",
       "-h                       Print this help.\n"
+      "-l                       Enable lazy restore.\n"
       "-p                       Do not unpause domain after restoring it.\n"
       "-e                       Do not wait in the background for the death of 
the domain.\n"
       "-d                       Enable debug messages.\n"
-- 
1.9.1


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