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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 3 of 4 RFC] xl/remus: Control network buffering in remus callbacks
This patch constitutes the core network buffering logic.
Libxl would receive a list of IFB devices that collectively act as
network buffering devices, for a given guest. Also, libxl expects that
every ifb device in the list supplied by a toolstack (netbuf_iflist)
should have a plug qdisc installed.
This patch does the following:
a) establish a dedicated remus context containing libnl related
state (netlink sockets, qdisc caches, etc.,)
b) Obtain handles to plug qdiscs installed on the supplied list of
IFB devices
c) add a new network buffer (i.e., create a new one) when the domain is
suspended (remus_domain_suspend_callback)
d) release the network buffer pertaining to the acknowledged checkpoint
in remus_domain_checkpoint_dm_saved, which is invoked for both PV & HVM.
Signed-off-by: Shriram Rajagopalan <rshriram@xxxxxxxxx>
diff -r 3cd67f6ff63a -r bef729fc4336 tools/libxl/libxl_dom.c
--- a/tools/libxl/libxl_dom.c Thu Jul 25 00:02:19 2013 -0700
+++ b/tools/libxl/libxl_dom.c Thu Jul 25 00:02:22 2013 -0700
@@ -20,6 +20,7 @@
#include "libxl_internal.h"
#include "libxl_arch.h"
+#include <netlink/route/qdisc/plug.h>
#include <xc_dom.h>
#include <xen/hvm/hvm_info_table.h>
#include <xen/hvm/hvm_xs_strings.h>
@@ -1212,12 +1213,36 @@ 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);
+ STATE_AO_GC(dss->ao);
+
+ int is_suspended = 0, i, ret;
+ libxl__remus_ctx *remus_ctx = dss->remus_ctx;
+ is_suspended = libxl__domain_suspend_common_callback(data);
+ if (!remus_ctx->num_netbufs) return is_suspended;
+
+ if (is_suspended) {
+ for (i = 0; i < remus_ctx->num_netbufs; ++i) {
+ ret = rtnl_qdisc_plug_buffer(remus_ctx->netbuf_qdisc_list[i]);
+ if (!ret)
+ ret = rtnl_qdisc_add(remus_ctx->nlsock,
remus_ctx->netbuf_qdisc_list[i],
+ NLM_F_REQUEST);
+ if (ret) {
+ LOG(ERROR, "Cannot create new buffer on %s:%s",
+ dss->remus->netbuf_iflist[i], nl_geterror(ret));
+ return 0;
+ }
+ }
+ }
+
+ return is_suspended;
}
+/* REMUS TODO: Deal with disk. */
static int libxl__remus_domain_resume_callback(void *data)
{
libxl__save_helper_state *shs = data;
@@ -1228,7 +1253,6 @@ 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;
}
@@ -1255,13 +1279,104 @@ 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->interval * 1000);
+ /* REMUS TODO: Wait for disk and explicit memory ack (through restore
+ callback from remote) before release network buffer. */
+ int i, ret;
+ libxl__remus_ctx *remus_ctx = dss->remus_ctx;
+ STATE_AO_GC(dss->ao);
+
+ assert(!rc);
+
+ if (remus_ctx->num_netbufs > 0) {
+ for (i = 0; i < remus_ctx->num_netbufs; ++i) {
+ ret = rtnl_qdisc_plug_release_one(remus_ctx->netbuf_qdisc_list[i]);
+ if (!ret)
+ ret = rtnl_qdisc_add(remus_ctx->nlsock,
remus_ctx->netbuf_qdisc_list[i],
+ NLM_F_REQUEST);
+ if (ret) {
+ LOG(ERROR, "Cannot release buffer from %s:%s",
+ dss->remus->netbuf_iflist[i], nl_geterror(ret));
+ ret= 0;
+ break;
+ }
+ }
+ }
+
+ usleep(dss->remus_ctx->interval * 1000);
libxl__xc_domain_saverestore_async_callback_done(egc, &dss->shs, 1);
}
+static libxl__remus_ctx *setup_remus_ctx(libxl__gc *gc,
+ const libxl_domain_remus_info *r_info)
+{
+ libxl__remus_ctx *remus_ctx = NULL;
+ int num_netbufs = 0, i;
+ struct nl_cache *qdisc_cache = NULL;
+ struct rtnl_link *ifb = NULL;
+ struct nl_sock *nlsock = NULL;
+ struct rtnl_qdisc *qdisc = NULL;
+ libxl_string_list l;
+ int ifindex;
+
+ remus_ctx = libxl__zalloc(gc, sizeof(libxl__remus_ctx));
+ remus_ctx->interval = r_info->interval;
+
+ l = r_info->netbuf_iflist;
+ num_netbufs = libxl_string_list_length(&l);
+ if (!num_netbufs) return remus_ctx;
+
+ nlsock = nl_socket_alloc();
+ if (!nlsock) {
+ LOG(ERROR, "setup_remus_ctx: cannot allocate nl socket");
+ return NULL;
+ }
+
+ nl_connect(nlsock, NETLINK_ROUTE);
+
+ if (rtnl_qdisc_alloc_cache(nlsock, &qdisc_cache) < 0) {
+ LOG(ERROR, "setup_remus_ctx: failed to allocate qdisc cache");
+ goto end;
+ }
+
+ remus_ctx->netbuf_qdisc_list = libxl__calloc(gc, num_netbufs + 1,
+ sizeof(struct rtnl_qdisc *));
+ remus_ctx->num_netbufs = num_netbufs;
+ remus_ctx->nlsock = nlsock;
+ remus_ctx->qdisc_cache = qdisc_cache;
+ ifb = rtnl_link_alloc();
+
+ for (i = 0; i < num_netbufs; ++i) {
+
+ if (rtnl_link_get_kernel(nlsock, 0, l[i], &ifb) < 0) {
+ LOG(ERROR, "setup_remus_ctx: cannot obtain handle for %s", l[i]);
+ goto end;
+ }
+
+ ifindex = rtnl_link_get_ifindex(ifb);
+ if (!ifindex) {
+ LOG(ERROR, "setup_remus_ctx: invalid interface %s", l[i]);
+ goto end;
+ }
+
+ qdisc = rtnl_qdisc_get_by_parent(qdisc_cache, ifindex, TC_H_ROOT);
+ if (!qdisc || strcmp(rtnl_tc_get_kind(TC_CAST(qdisc)), "plug")) {
+ LOG(ERROR, "setup_remus_ctx: plug qdisc is not installed on %s",
l[i]);
+ goto end;
+ }
+
+ remus_ctx->netbuf_qdisc_list[i] = qdisc;
+ }
+
+ rtnl_link_put(ifb);
+ return remus_ctx;
+
+ end:
+ if (ifb) rtnl_link_put(ifb);
+ if (qdisc_cache) nl_cache_free(qdisc_cache);
+ if (nlsock) nl_close(nlsock);
+ return NULL;
+}
+
/*----- main code for suspending, in order of execution -----*/
void libxl__domain_suspend(libxl__egc *egc, libxl__domain_suspend_state *dss)
@@ -1312,7 +1427,12 @@ void libxl__domain_suspend(libxl__egc *e
dss->dm_savefile = libxl__device_model_savefile(gc, domid);
if (r_info != NULL) {
- dss->interval = r_info->interval;
+ /* This suspend is for Remus. We need to get a handle on
+ * the network output buffers and setup the remus_ctx;
+ */
+ dss->remus_ctx = setup_remus_ctx(gc, r_info);
+ if (!dss->remus_ctx)
+ goto out;
if (r_info->compression)
dss->xcflags |= XCFLAGS_CHECKPOINT_COMPRESS;
}
diff -r 3cd67f6ff63a -r bef729fc4336 tools/libxl/libxl_internal.h
--- a/tools/libxl/libxl_internal.h Thu Jul 25 00:02:19 2013 -0700
+++ b/tools/libxl/libxl_internal.h Thu Jul 25 00:02:22 2013 -0700
@@ -44,6 +44,13 @@
#include <sys/wait.h>
#include <sys/socket.h>
+#include <netlink/cache.h>
+#include <netlink/socket.h>
+#include <netlink/attr.h>
+#include <netlink/route/link.h>
+#include <netlink/route/route.h>
+#include <netlink/route/qdisc.h>
+
#include <xenstore.h>
#include <xenctrl.h>
#include <xenguest.h>
@@ -2242,6 +2249,18 @@ typedef struct libxl__logdirty_switch {
libxl__ev_time timeout;
} libxl__logdirty_switch;
+typedef struct libxl__remus_ctx {
+ /* checkpoint interval */
+ int interval;
+ /* array of plug qdisc pointers, that hold
+ * network output from the guest's vifs.
+ */
+ int num_netbufs;
+ struct rtnl_qdisc **netbuf_qdisc_list;
+ struct nl_sock *nlsock;
+ struct nl_cache *qdisc_cache;
+} libxl__remus_ctx;
+
struct libxl__domain_suspend_state {
/* set by caller of libxl__domain_suspend */
libxl__ao *ao;
@@ -2260,7 +2279,7 @@ struct libxl__domain_suspend_state {
int xcflags;
int guest_responded;
const char *dm_savefile;
- int interval; /* checkpoint interval (for Remus) */
+ libxl__remus_ctx *remus_ctx;
libxl__save_helper_state shs;
libxl__logdirty_switch logdirty;
/* private for libxl__domain_save_device_model */
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