File xen.sr-abort_if_busy.patch of Package xen
From: Olaf Hering <olaf@aepfle.de>
Date: Thu, 7 Jan 2021 20:25:28 +0100
Subject: sr abort_if_busy
tools: add --abort_if_busy to libxl_domain_suspend
Provide a knob to the host admin to abort the live migration of a
running domU if the downtime during final transit will be too long
for the workload within domU.
Adjust error reporting. Add ERROR_MIGRATION_ABORTED to allow callers of
libxl_domain_suspend to distinguish between errors and the requested
constraint.
Adjust precopy_policy to simplify reporting of remaining dirty pages.
The loop in send_memory_live populates ->dirty_count in a different
place than ->iteration. Let it proceeed one more time to provide the
desired information before leaving the loop.
This patch adjusts xl(1) and the libxl API.
External users check LIBXL_HAVE_DOMAIN_SUSPEND_PROPS for the availibility
of the new .abort_if_busy property.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
docs/man/xl.1.pod.in | 8 +++
tools/include/libxl.h | 1 +
tools/libs/light/libxl_dom_save.c | 7 +-
tools/libs/light/libxl_domain.c | 1 +
tools/libs/light/libxl_internal.h | 2 +
tools/libs/light/libxl_stream_write.c | 9 ++-
tools/libs/light/libxl_types.idl | 1 +
tools/xl/xl_cmdtable.c | 6 +-
tools/xl/xl_migrate.c | 30 +++++++--
9 files changed, 55 insertions(+), 10 deletions(-)
--- a/docs/man/xl.1.pod.in
+++ b/docs/man/xl.1.pod.in
@@ -498,24 +498,32 @@ possible to use this option for a 'localhost' migration.
=item B<--max_iters> I<iterations>
Number of copy iterations before final suspend+move (default: 5)
=item B<--min_remaing> I<pages>
Number of remaining dirty pages. If the number of dirty pages drops that
low, the guest is suspended and the domU will finally be moved to I<host>.
This allows the host admin to control for how long the domU will likely
be suspended during transit.
+=item B<--abort_if_busy>
+
+Abort migration instead of doing final suspend/move/resume if the
+guest produced more than I<min_remaining> dirty pages during th number
+of I<max_iters> iterations.
+This avoids long periods of time where the guest is suspended, which
+may confuse the workload within domU.
+
=back
=item B<remus> [I<OPTIONS>] I<domain-id> I<host>
Enable Remus HA or COLO HA for domain. By default B<xl> relies on ssh as a
transport mechanism between the two hosts.
B<NOTES>
=over 4
Remus support in xl is still in experimental (proof-of-concept) phase.
--- a/tools/include/libxl.h
+++ b/tools/include/libxl.h
@@ -1791,24 +1791,25 @@ static inline int libxl_retrieve_domain_configuration_0x041200(
* LIBXL_HAVE_DOMAIN_SUSPEND_PROPS indicates that the
* libxl_domain_suspend_props() function takes a props struct.
*/
#define LIBXL_HAVE_DOMAIN_SUSPEND_PROPS 1
typedef struct {
uint32_t flags; /* LIBXL_SUSPEND_* */
uint32_t max_iters;
uint32_t min_remaining;
} libxl_domain_suspend_props;
#define LIBXL_SUSPEND_DEBUG 1
#define LIBXL_SUSPEND_LIVE 2
+#define LIBXL_SUSPEND_ABORT_IF_BUSY 4
int libxl_domain_suspend(libxl_ctx *ctx, uint32_t domid, int fd,
libxl_domain_suspend_props *props,
const libxl_asyncop_how *ao_how)
LIBXL_EXTERNAL_CALLERS_ONLY;
#if defined(LIBXL_API_VERSION) && LIBXL_API_VERSION < 0x041600
static inline int libxl_domain_suspend_0x041500(libxl_ctx *ctx, uint32_t domid,
int fd, int flags, /* LIBXL_SUSPEND_* */
const libxl_asyncop_how *ao_how)
{
libxl_domain_suspend_props props = { .flags = flags, };
return libxl_domain_suspend(ctx, domid, fd, &props, ao_how);
--- a/tools/libs/light/libxl_dom_save.c
+++ b/tools/libs/light/libxl_dom_save.c
@@ -374,29 +374,34 @@ int libxl__save_emulator_xenstore_data(libxl__domain_save_state *dss,
}
static int libxl__domain_save_precopy_policy(struct precopy_stats stats, void *user)
{
libxl__save_helper_state *shs = user;
libxl__domain_save_state *dss = shs->caller_state;
STATE_AO_GC(dss->ao);
LOGD(DEBUG, shs->domid, "iteration %u dirty_count %ld total_written %lu",
stats.iteration, stats.dirty_count, stats.total_written);
if (stats.dirty_count >= 0 && stats.dirty_count < dss->min_remaining)
goto stop_copy;
- if (stats.iteration >= dss->max_iters)
+ if (stats.dirty_count >= 0 && stats.iteration >= dss->max_iters)
goto stop_copy;
return XGS_POLICY_CONTINUE_PRECOPY;
stop_copy:
+ if (dss->abort_if_busy)
+ {
+ dss->remaining_dirty_pages = stats.dirty_count;
+ return XGS_POLICY_ABORT;
+ }
return XGS_POLICY_STOP_AND_COPY;
}
/*----- main code for saving, in order of execution -----*/
void libxl__domain_save(libxl__egc *egc, libxl__domain_save_state *dss)
{
STATE_AO_GC(dss->ao);
int rc, ret;
/* Convenience aliases */
const uint32_t domid = dss->domid;
--- a/tools/libs/light/libxl_domain.c
+++ b/tools/libs/light/libxl_domain.c
@@ -517,24 +517,25 @@ int libxl_domain_suspend(libxl_ctx *ctx, uint32_t domid, int fd,
libxl__domain_save_state *dss;
GCNEW(dss);
dss->ao = ao;
dss->callback = domain_suspend_cb;
dss->domid = domid;
dss->fd = fd;
dss->type = type;
dss->max_iters = props->max_iters ?: LIBXL_XGS_POLICY_MAX_ITERATIONS;
dss->min_remaining = props->min_remaining ?: LIBXL_XGS_POLICY_TARGET_DIRTY_COUNT;
+ dss->abort_if_busy = props->flags & LIBXL_SUSPEND_ABORT_IF_BUSY;
dss->live = props->flags & LIBXL_SUSPEND_LIVE;
dss->debug = props->flags & LIBXL_SUSPEND_DEBUG;
dss->checkpointed_stream = LIBXL_CHECKPOINTED_STREAM_NONE;
rc = libxl__fd_flags_modify_save(gc, dss->fd,
~(O_NONBLOCK|O_NDELAY), 0,
&dss->fdfl);
if (rc < 0) goto out_err;
libxl__domain_save(egc, dss);
return AO_INPROGRESS;
--- a/tools/libs/light/libxl_internal.h
+++ b/tools/libs/light/libxl_internal.h
@@ -3647,27 +3647,29 @@ _hidden void libxl__qmp_suspend_save(libxl__egc *egc,
struct libxl__domain_save_state {
/* set by caller of libxl__domain_save */
libxl__ao *ao;
libxl__domain_save_cb *callback;
uint32_t domid;
int fd;
int fdfl; /* original flags on fd */
int recv_fd;
libxl_domain_type type;
int live;
int debug;
+ int abort_if_busy;
int checkpointed_stream;
uint32_t max_iters;
uint32_t min_remaining;
+ long remaining_dirty_pages;
const libxl_domain_remus_info *remus;
/* private */
int rc;
int xcflags;
libxl__domain_suspend_state dsps;
union {
/* for Remus */
libxl__remus_state rs;
/* for COLO */
libxl__colo_save_state css;
};
libxl__checkpoint_devices_state cds;
--- a/tools/libs/light/libxl_stream_write.c
+++ b/tools/libs/light/libxl_stream_write.c
@@ -335,29 +335,36 @@ static void libxc_header_done(libxl__egc *egc,
void libxl__xc_domain_save_done(libxl__egc *egc, void *dss_void,
int rc, int retval, int errnoval)
{
libxl__domain_save_state *dss = dss_void;
libxl__stream_write_state *stream = &dss->sws;
STATE_AO_GC(dss->ao);
if (rc)
goto err;
if (retval) {
+ if (dss->remaining_dirty_pages) {
+ LOGD(NOTICE, dss->domid, "saving domain: aborted,"
+ " %ld remaining dirty pages.", dss->remaining_dirty_pages);
+ } else {
LOGEVD(ERROR, errnoval, dss->domid, "saving domain: %s",
dss->dsps.guest_responded ?
"domain responded to suspend request" :
"domain did not respond to suspend request");
- if (!dss->dsps.guest_responded)
+ }
+ if (dss->remaining_dirty_pages)
+ rc = ERROR_MIGRATION_ABORTED;
+ else if(!dss->dsps.guest_responded)
rc = ERROR_GUEST_TIMEDOUT;
else if (dss->rc)
rc = dss->rc;
else
rc = ERROR_FAIL;
goto err;
}
err:
check_all_finished(egc, stream, rc);
/*
--- a/tools/libs/light/libxl_types.idl
+++ b/tools/libs/light/libxl_types.idl
@@ -67,24 +67,25 @@ libxl_error = Enumeration("error", [
(-21, "DOMAIN_NOTFOUND"),
(-22, "ABORTED"),
(-23, "NOTFOUND"),
(-24, "DOMAIN_DESTROYED"), # Target domain ceased to exist during op
(-25, "FEATURE_REMOVED"), # For functionality that has been removed
(-26, "PROTOCOL_ERROR_QMP"),
(-27, "UNKNOWN_QMP_ERROR"),
(-28, "QMP_GENERIC_ERROR"), # unspecified qmp error
(-29, "QMP_COMMAND_NOT_FOUND"), # the requested command has not been found
(-30, "QMP_DEVICE_NOT_ACTIVE"), # a device has failed to be become active
(-31, "QMP_DEVICE_NOT_FOUND"), # the requested device has not been found
(-32, "QEMU_API"), # QEMU's replies don't contains expected members
+ (-33, "MIGRATION_ABORTED"),
], value_namespace = "")
libxl_domain_type = Enumeration("domain_type", [
(-1, "INVALID"),
(1, "HVM"),
(2, "PV"),
(3, "PVH"),
], init_val = "LIBXL_DOMAIN_TYPE_INVALID")
libxl_rdm_reserve_strategy = Enumeration("rdm_reserve_strategy", [
(0, "ignore"),
(1, "host"),
--- a/tools/xl/xl_cmdtable.c
+++ b/tools/xl/xl_cmdtable.c
@@ -167,25 +167,29 @@ const struct cmd_spec cmd_table[] = {
"[options] <Domain> <host>",
"-h Print this help.\n"
"-C <config> Send <config> instead of config file from creation.\n"
"-s <sshcommand> Use <sshcommand> instead of ssh. String will be passed\n"
" to sh. If empty, run <host> instead of ssh <host> xl\n"
" migrate-receive [-d -e]\n"
"-e Do not wait in the background (on <host>) for the death\n"
" of the domain.\n"
"--debug Enable verification mode.\n"
"-p Do not unpause domain after migrating it.\n"
"-D Preserve the domain id\n"
"--max_iters N Number of copy iterations before final stop+move\n"
- "--min_remaining N Number of remaining dirty pages before final stop+move"
+ "--min_remaining N Number of remaining dirty pages before final stop+move\n"
+ "--abort_if_busy Abort migration instead of doing final stop+move,\n"
+ " if the number of dirty pages is higher than <min_remaining>\n"
+ " after <max_iters> iterations. Otherwise the amount of memory\n"
+ " to be transfered would exceed maximum allowed domU downtime."
},
{ "restore",
&main_restore, 0, 1,
"Restore a domain from a saved state",
"[options] [<ConfigFile>] <CheckpointFile>",
"-h Print this help.\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"
"-V, --vncviewer Connect to the VNC display after the domain is created.\n"
"-A, --vncviewer-autopass Pass VNC password to viewer via stdin."
},
--- a/tools/xl/xl_migrate.c
+++ b/tools/xl/xl_migrate.c
@@ -168,25 +168,25 @@ static void migrate_do_preamble(int send_fd, int recv_fd, pid_t child,
if (rc) {
close(send_fd);
migration_child_report(recv_fd);
exit(EXIT_FAILURE);
}
save_domain_core_writeconfig(send_fd, "migration stream",
config_data, config_len);
}
static void migrate_domain(uint32_t domid, int preserve_domid,
- const char *rune, int debug,
+ const char *rune, int debug, int abort_if_busy,
uint32_t max_iters,
uint32_t min_remaining,
const char *override_config_file)
{
pid_t child = -1;
int rc;
int send_fd = -1, recv_fd = -1;
char *away_domname;
char rc_buf;
uint8_t *config_data;
int config_len;
libxl_domain_suspend_props props = {
@@ -204,32 +204,38 @@ static void migrate_domain(uint32_t domid, int preserve_domid,
exit(EXIT_FAILURE);
}
child = create_migration_child(rune, &send_fd, &recv_fd);
migrate_do_preamble(send_fd, recv_fd, child, config_data, config_len,
rune);
xtl_stdiostream_adjust_flags(logger, XTL_STDIOSTREAM_HIDE_PROGRESS, 0);
if (debug)
props.flags |= LIBXL_SUSPEND_DEBUG;
+ if (abort_if_busy)
+ props.flags |= LIBXL_SUSPEND_ABORT_IF_BUSY;
rc = libxl_domain_suspend(ctx, domid, send_fd, &props, NULL);
if (rc) {
fprintf(stderr, "migration sender: libxl_domain_suspend failed"
" (rc=%d)\n", rc);
- if (rc == ERROR_GUEST_TIMEDOUT)
- goto failed_suspend;
- else
- goto failed_resume;
+ switch (rc) {
+ case ERROR_GUEST_TIMEDOUT:
+ goto failed_suspend;
+ case ERROR_MIGRATION_ABORTED:
+ goto failed_busy;
+ default:
+ goto failed_resume;
+ }
}
//fprintf(stderr, "migration sender: Transfer complete.\n");
// Should only be printed when debugging as it's a bit messy with
// progress indication.
rc = migrate_read_fixedmessage(recv_fd, migrate_receiver_ready,
sizeof(migrate_receiver_ready),
"ready message", rune);
if (rc) goto failed_resume;
xtl_stdiostream_adjust_flags(logger, 0, XTL_STDIOSTREAM_HIDE_PROGRESS);
@@ -293,24 +299,30 @@ static void migrate_domain(uint32_t domid, int preserve_domid,
fprintf(stderr, "migration sender: Target reports successful startup.\n");
libxl_domain_destroy(ctx, domid, 0); /* bang! */
fprintf(stderr, "Migration successful.\n");
exit(EXIT_SUCCESS);
failed_suspend:
close(send_fd);
migration_child_report(recv_fd);
fprintf(stderr, "Migration failed, failed to suspend at sender.\n");
exit(EXIT_FAILURE);
+ failed_busy:
+ close(send_fd);
+ migration_child_report(recv_fd);
+ fprintf(stderr, "Migration aborted as requested, domain is too busy.\n");
+ exit(EXIT_FAILURE);
+
failed_resume:
close(send_fd);
migration_child_report(recv_fd);
fprintf(stderr, "Migration failed, resuming at sender.\n");
libxl_domain_resume(ctx, domid, 1, 0);
exit(EXIT_FAILURE);
failed_badly:
fprintf(stderr,
"** Migration failed during final handshake **\n"
"Domain state is now undefined !\n"
"Please CHECK AT BOTH ENDS for running instances, before renaming and\n"
@@ -536,31 +548,32 @@ int main_migrate_receive(int argc, char **argv)
return EXIT_SUCCESS;
}
int main_migrate(int argc, char **argv)
{
uint32_t domid;
const char *config_filename = NULL;
const char *ssh_command = "ssh";
char *rune = NULL;
char *host;
int opt, daemonize = 1, monitor = 1, debug = 0, pause_after_migration = 0;
- int preserve_domid = 0;
+ int preserve_domid = 0, abort_if_busy = 0;
uint32_t max_iters = 0;
uint32_t min_remaining = 0;
static struct option opts[] = {
{"debug", 0, 0, 0x100},
{"max_iters", 1, 0, 0x101},
{"min_remaining", 1, 0, 0x102},
+ {"abort_if_busy", 0, 0, 0x103},
{"live", 0, 0, 0x200},
COMMON_LONG_OPTS
};
SWITCH_FOREACH_OPT(opt, "FC:s:epD", opts, "migrate", 2) {
case 'C':
config_filename = optarg;
break;
case 's':
ssh_command = optarg;
break;
case 'F':
@@ -576,24 +589,27 @@ int main_migrate(int argc, char **argv)
case 'D':
preserve_domid = 1;
break;
case 0x100: /* --debug */
debug = 1;
break;
case 0x101: /* --max_iters */
max_iters = atoi(optarg);
break;
case 0x102: /* --min_remaining */
min_remaining = atoi(optarg);
break;
+ case 0x103: /* --abort_if_busy */
+ abort_if_busy = 1;
+ break;
case 0x200: /* --live */
/* ignored for compatibility with xm */
break;
}
domid = find_domain(argv[optind]);
host = argv[optind + 1];
bool pass_tty_arg = progress_use_cr || (isatty(2) > 0);
if (!ssh_command[0]) {
rune= host;
@@ -610,25 +626,25 @@ int main_migrate(int argc, char **argv)
verbose_len = (minmsglevel_default - minmsglevel) + 2;
}
xasprintf(&rune, "exec %s %s xl%s%s%.*s migrate-receive%s%s%s",
ssh_command, host,
pass_tty_arg ? " -t" : "",
timestamps ? " -T" : "",
verbose_len, verbose_buf,
daemonize ? "" : " -e",
debug ? " -d" : "",
pause_after_migration ? " -p" : "");
}
- migrate_domain(domid, preserve_domid, rune, debug,
+ migrate_domain(domid, preserve_domid, rune, debug, abort_if_busy,
max_iters, min_remaining, config_filename);
return EXIT_SUCCESS;
}
int main_remus(int argc, char **argv)
{
uint32_t domid;
int opt, rc, daemonize = 1;
const char *ssh_command = "ssh";
char *host = NULL, *rune = NULL;
libxl_domain_remus_info r_info;
int send_fd = -1, recv_fd = -1;
