File libxc-sr-abort_if_busy.patch of Package xen.35687
From: Olaf Hering <olaf@aepfle.de>
Date: Thu, 7 Jan 2021 20:25:28 +0100
Subject: libxc 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
@@ -513,6 +513,14 @@ low, the guest is suspended and the domU
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>
--- a/tools/include/libxl.h
+++ b/tools/include/libxl.h
@@ -1824,6 +1824,7 @@ typedef struct {
} libxl_domain_suspend_suse_properties;
#define LIBXL_SUSPEND_DEBUG 1
#define LIBXL_SUSPEND_LIVE 2
+#define LIBXL_SUSPEND_ABORT_IF_BUSY 4
#define LIBXL_HAVE_DOMAIN_SUSPEND_SUSE
int libxl_domain_suspend_suse(libxl_ctx *ctx, uint32_t domid, int fd,
--- a/tools/libs/light/libxl_dom_save.c
+++ b/tools/libs/light/libxl_dom_save.c
@@ -383,11 +383,16 @@ static int libxl__domain_save_precopy_po
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;
}
--- a/tools/libs/light/libxl_domain.c
+++ b/tools/libs/light/libxl_domain.c
@@ -526,6 +526,7 @@ static int do_libxl_domain_suspend(libxl
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;
--- a/tools/libs/light/libxl_internal.h
+++ b/tools/libs/light/libxl_internal.h
@@ -3655,9 +3655,11 @@ struct libxl__domain_save_state {
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;
--- a/tools/libs/light/libxl_stream_write.c
+++ b/tools/libs/light/libxl_stream_write.c
@@ -344,11 +344,18 @@ void libxl__xc_domain_save_done(libxl__e
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;
--- a/tools/libs/light/libxl_types.idl
+++ b/tools/libs/light/libxl_types.idl
@@ -76,6 +76,7 @@ libxl_error = Enumeration("error", [
(-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", [
--- a/tools/xl/xl_cmdtable.c
+++ b/tools/xl/xl_cmdtable.c
@@ -177,7 +177,11 @@ const struct cmd_spec cmd_table[] = {
"-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,
--- a/tools/xl/xl_migrate.c
+++ b/tools/xl/xl_migrate.c
@@ -177,7 +177,7 @@ static void migrate_do_preamble(int send
}
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)
@@ -213,14 +213,20 @@ static void migrate_domain(uint32_t domi
if (debug)
props.flags |= LIBXL_SUSPEND_DEBUG;
+ if (abort_if_busy)
+ props.flags |= LIBXL_SUSPEND_ABORT_IF_BUSY;
rc = libxl_domain_suspend_suse(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");
@@ -302,6 +308,12 @@ static void migrate_domain(uint32_t domi
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);
@@ -545,13 +557,14 @@ int main_migrate(int argc, char **argv)
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
};
@@ -585,6 +598,9 @@ int main_migrate(int argc, char **argv)
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;
@@ -619,7 +635,7 @@ int main_migrate(int argc, char **argv)
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;
}
