Return path: Source handling of return path

Open a return path, and handle messages that are received upon it.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert 2015-11-05 18:10:49 +00:00 committed by Juan Quintela
parent f6844b99ce
commit 70b2047774
3 changed files with 175 additions and 2 deletions

View file

@ -80,6 +80,14 @@ struct MigrationState
int state;
MigrationParams params;
/* State related to return path */
struct {
QEMUFile *from_dst_file;
QemuThread rp_thread;
bool error;
} rp_state;
double mbps;
int64_t total_time;
int64_t downtime;

View file

@ -696,6 +696,11 @@ static void migrate_fd_cancel(MigrationState *s)
QEMUFile *f = migrate_get_current()->file;
trace_migrate_fd_cancel();
if (s->rp_state.from_dst_file) {
/* shutdown the rp socket, so causing the rp thread to shutdown */
qemu_file_shutdown(s->rp_state.from_dst_file);
}
do {
old_state = s->state;
if (!migration_is_setup_or_active(old_state)) {
@ -1030,6 +1035,154 @@ int64_t migrate_xbzrle_cache_size(void)
return s->xbzrle_cache_size;
}
/* migration thread support */
/*
* Something bad happened to the RP stream, mark an error
* The caller shall print or trace something to indicate why
*/
static void mark_source_rp_bad(MigrationState *s)
{
s->rp_state.error = true;
}
static struct rp_cmd_args {
ssize_t len; /* -1 = variable */
const char *name;
} rp_cmd_args[] = {
[MIG_RP_MSG_INVALID] = { .len = -1, .name = "INVALID" },
[MIG_RP_MSG_SHUT] = { .len = 4, .name = "SHUT" },
[MIG_RP_MSG_PONG] = { .len = 4, .name = "PONG" },
[MIG_RP_MSG_MAX] = { .len = -1, .name = "MAX" },
};
/*
* Handles messages sent on the return path towards the source VM
*
*/
static void *source_return_path_thread(void *opaque)
{
MigrationState *ms = opaque;
QEMUFile *rp = ms->rp_state.from_dst_file;
uint16_t header_len, header_type;
const int max_len = 512;
uint8_t buf[max_len];
uint32_t tmp32, sibling_error;
int res;
trace_source_return_path_thread_entry();
while (!ms->rp_state.error && !qemu_file_get_error(rp) &&
migration_is_setup_or_active(ms->state)) {
trace_source_return_path_thread_loop_top();
header_type = qemu_get_be16(rp);
header_len = qemu_get_be16(rp);
if (header_type >= MIG_RP_MSG_MAX ||
header_type == MIG_RP_MSG_INVALID) {
error_report("RP: Received invalid message 0x%04x length 0x%04x",
header_type, header_len);
mark_source_rp_bad(ms);
goto out;
}
if ((rp_cmd_args[header_type].len != -1 &&
header_len != rp_cmd_args[header_type].len) ||
header_len > max_len) {
error_report("RP: Received '%s' message (0x%04x) with"
"incorrect length %d expecting %zu",
rp_cmd_args[header_type].name, header_type, header_len,
(size_t)rp_cmd_args[header_type].len);
mark_source_rp_bad(ms);
goto out;
}
/* We know we've got a valid header by this point */
res = qemu_get_buffer(rp, buf, header_len);
if (res != header_len) {
error_report("RP: Failed reading data for message 0x%04x"
" read %d expected %d",
header_type, res, header_len);
mark_source_rp_bad(ms);
goto out;
}
/* OK, we have the message and the data */
switch (header_type) {
case MIG_RP_MSG_SHUT:
sibling_error = be32_to_cpup((uint32_t *)buf);
trace_source_return_path_thread_shut(sibling_error);
if (sibling_error) {
error_report("RP: Sibling indicated error %d", sibling_error);
mark_source_rp_bad(ms);
}
/*
* We'll let the main thread deal with closing the RP
* we could do a shutdown(2) on it, but we're the only user
* anyway, so there's nothing gained.
*/
goto out;
case MIG_RP_MSG_PONG:
tmp32 = be32_to_cpup((uint32_t *)buf);
trace_source_return_path_thread_pong(tmp32);
break;
default:
break;
}
}
if (rp && qemu_file_get_error(rp)) {
trace_source_return_path_thread_bad_end();
mark_source_rp_bad(ms);
}
trace_source_return_path_thread_end();
out:
ms->rp_state.from_dst_file = NULL;
qemu_fclose(rp);
return NULL;
}
__attribute__ (( unused )) /* Until later in patch series */
static int open_return_path_on_source(MigrationState *ms)
{
ms->rp_state.from_dst_file = qemu_file_get_return_path(ms->file);
if (!ms->rp_state.from_dst_file) {
return -1;
}
trace_open_return_path_on_source();
qemu_thread_create(&ms->rp_state.rp_thread, "return path",
source_return_path_thread, ms, QEMU_THREAD_JOINABLE);
trace_open_return_path_on_source_continue();
return 0;
}
__attribute__ (( unused )) /* Until later in patch series */
/* Returns 0 if the RP was ok, otherwise there was an error on the RP */
static int await_return_path_close_on_source(MigrationState *ms)
{
/*
* If this is a normal exit then the destination will send a SHUT and the
* rp_thread will exit, however if there's an error we need to cause
* it to exit.
*/
if (qemu_file_get_error(ms->file) && ms->rp_state.from_dst_file) {
/*
* shutdown(2), if we have it, will cause it to unblock if it's stuck
* waiting for the destination.
*/
qemu_file_shutdown(ms->rp_state.from_dst_file);
mark_source_rp_bad(ms);
}
trace_await_return_path_close_on_source_joining();
qemu_thread_join(&ms->rp_state.rp_thread);
trace_await_return_path_close_on_source_close();
return ms->rp_state.error;
}
/**
* migration_completion: Used by migration_thread when there's not much left.
* The caller 'breaks' the loop when this returns.
@ -1074,8 +1227,10 @@ fail:
migrate_set_state(s, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_FAILED);
}
/* migration thread support */
/*
* Master migration thread on the source VM.
* It drives the migration and pumps the data down the outgoing channel.
*/
static void *migration_thread(void *opaque)
{
MigrationState *s = opaque;

View file

@ -1426,12 +1426,22 @@ flic_no_device_api(int err) "flic: no Device Contral API support %d"
flic_reset_failed(int err) "flic: reset failed %d"
# migration.c
await_return_path_close_on_source_close(void) ""
await_return_path_close_on_source_joining(void) ""
migrate_set_state(int new_state) "new state %d"
migrate_fd_cleanup(void) ""
migrate_fd_error(void) ""
migrate_fd_cancel(void) ""
migrate_pending(uint64_t size, uint64_t max) "pending size %" PRIu64 " max %" PRIu64
migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d"
open_return_path_on_source(void) ""
open_return_path_on_source_continue(void) ""
source_return_path_thread_bad_end(void) ""
source_return_path_thread_end(void) ""
source_return_path_thread_entry(void) ""
source_return_path_thread_loop_top(void) ""
source_return_path_thread_pong(uint32_t val) "%x"
source_return_path_thread_shut(uint32_t val) "%x"
migrate_transferred(uint64_t tranferred, uint64_t time_spent, double bandwidth, uint64_t size) "transferred %" PRIu64 " time_spent %" PRIu64 " bandwidth %g max_size %" PRId64
migrate_state_too_big(void) ""
migrate_global_state_post_load(const char *state) "loaded state: %s"