[Xen-devel] [PATCH 4 of 5] tools/libxl: Control network buffering in remus callbacks

[rshriram@xxxxxxxxx]

# HG changeset patch
# User Shriram Rajagopalan <rshriram@xxxxxxxxx>
# Date 1377473611 25200
# Node ID c6804ccfe660cb9c373c5f53a8996d0443316684
# Parent  4b23104828c09218aa7f9fbde1578bb6706e13d6
tools/libxl: Control network buffering in remus callbacks

This patch constitutes the core network buffering logic.
and does the following:
 a) create a new network buffer when the domain is suspended
    (remus_domain_suspend_callback)
 b) release the previous network buffer pertaining to the
    committed checkpoint (remus_domain_checkpoint_dm_saved)

Signed-off-by: Shriram Rajagopalan <rshriram@xxxxxxxxx>

diff -r 4b23104828c0 -r c6804ccfe660 tools/libxl/libxl_dom.c
--- a/tools/libxl/libxl_dom.c   Sun Aug 25 16:33:29 2013 -0700
+++ b/tools/libxl/libxl_dom.c   Sun Aug 25 16:33:31 2013 -0700
@@ -1213,12 +1213,28 @@ int libxl__toolstack_save(uint32_t domid
 
 /*----- remus callbacks -----*/
 
+/* REMUS TODO: Issue disk checkpoint reqs. */
 static int libxl__remus_domain_suspend_callback(void *data)
 {
-    /* REMUS TODO: Issue disk and network checkpoint reqs. */
-    return libxl__domain_suspend_common_callback(data);
+    libxl__save_helper_state *shs = data;
+    libxl__domain_suspend_state *dss = CONTAINER_OF(shs, *dss, shs);
+    libxl__remus_ctx *remus_ctx = dss->remus_ctx;
+    int is_suspended = 0;
+    STATE_AO_GC(dss->ao);
+
+    is_suspended = libxl__domain_suspend_common_callback(data);
+    if (!remus_ctx->netbuf_ctx) return is_suspended;
+
+    if (is_suspended) {
+        if (libxl__remus_netbuf_start_new_epoch(gc, dss->domid,
+                                                remus_ctx))
+            return !is_suspended;
+    }
+
+    return is_suspended;
 }
 
+/* REMUS TODO: Deal with disk. */
 static int libxl__remus_domain_resume_callback(void *data)
 {
     libxl__save_helper_state *shs = data;
@@ -1229,7 +1245,6 @@ static int libxl__remus_domain_resume_ca
     if (libxl__domain_resume(gc, dss->domid, /* Fast Suspend */1))
         return 0;
 
-    /* REMUS TODO: Deal with disk. Start a new network output buffer */
     return 1;
 }
 
@@ -1256,10 +1271,34 @@ static void libxl__remus_domain_checkpoi
 static void remus_checkpoint_dm_saved(libxl__egc *egc,
                                       libxl__domain_suspend_state *dss, int rc)
 {
-    /* REMUS TODO: Wait for disk and memory ack, release network buffer */
-    /* REMUS TODO: make this asynchronous */
-    assert(!rc); /* REMUS TODO handle this error properly */
-    usleep(dss->remus_ctx->interval * 1000);
+    /* REMUS TODO: Wait for disk and explicit memory ack (through restore
+       callback from remote) before releasing network buffer. */
+    libxl__remus_ctx *remus_ctx = dss->remus_ctx;
+    struct timespec epoch;
+    int ret;
+    STATE_AO_GC(dss->ao);
+
+    if (rc) {
+        LOG(ERROR, "Failed to save device model. Terminating Remus..");
+        libxl__xc_domain_saverestore_async_callback_done(egc,
+                                                         &dss->shs, rc);
+        return;
+    }
+
+    if (remus_ctx->netbuf_ctx) {
+        ret = libxl__remus_netbuf_release_prev_epoch(gc, dss->domid,
+                                                     remus_ctx);
+        if (ret) {
+            libxl__xc_domain_saverestore_async_callback_done(egc,
+                                                             &dss->shs,
+                                                             ret);
+            return;
+        }
+    }
+
+    epoch.tv_sec = remus_ctx->interval / 1000; /* interval is in ms */
+    epoch.tv_nsec = remus_ctx->interval * 1000L * 1000L;
+    nanosleep(&epoch, 0);
     libxl__xc_domain_saverestore_async_callback_done(egc, &dss->shs, 1);
 }
 

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