File libxc-sr-min_remaining.patch of Package xen
From: Olaf Hering <olaf@aepfle.de>
Date: Thu, 7 Jan 2021 19:39:28 +0100
Subject: libxc sr min_remaining
tools: add --min_remaining to libxl_domain_suspend
The decision to stop+move a domU to the new host must be based on two factors:
- the available network bandwidth for the migration stream
- the maximum time a workload within a domU can be savely suspended
Both values define how many dirty pages a workload may produce prior the
final stop+move.
The default value of 50 pages is much too low with todays network bandwidths.
On an idle 1GiB link these 200K will be transferred within ~2ms.
Give the admin a knob to adjust the point when the final stop+move will
be done, so he can base this decision on his own needs.
This patch adjusts xl(1) and the libxl API.
External users check LIBXL_HAVE_DOMAIN_SUSPEND_PROPS for the availibility
of the new .min_remaining 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 | 2 +-
tools/libs/light/libxl_domain.c | 1 +
tools/libs/light/libxl_internal.h | 1 +
tools/xl/xl_cmdtable.c | 23 ++++++++++++-----------
tools/xl/xl_migrate.c | 9 ++++++++-
7 files changed, 32 insertions(+), 13 deletions(-)
--- a/docs/man/xl.1.pod.in
+++ b/docs/man/xl.1.pod.in
@@ -505,6 +505,14 @@ possible to use this option for a 'local
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.
+
=back
=item B<remus> [I<OPTIONS>] I<domain-id> I<host>
--- a/tools/include/libxl.h
+++ b/tools/include/libxl.h
@@ -1820,6 +1820,7 @@ static inline int libxl_retrieve_domain_
typedef struct {
uint32_t flags; /* LIBXL_SUSPEND_* */
uint32_t max_iters;
+ uint32_t min_remaining;
} libxl_domain_suspend_suse_properties;
#define LIBXL_SUSPEND_DEBUG 1
#define LIBXL_SUSPEND_LIVE 2
--- a/tools/libs/light/libxl_dom_save.c
+++ b/tools/libs/light/libxl_dom_save.c
@@ -381,7 +381,7 @@ static int libxl__domain_save_precopy_po
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 < LIBXL_XGS_POLICY_TARGET_DIRTY_COUNT)
+ if (stats.dirty_count >= 0 && stats.dirty_count < dss->min_remaining)
goto stop_copy;
if (stats.iteration >= dss->max_iters)
goto stop_copy;
--- a/tools/libs/light/libxl_domain.c
+++ b/tools/libs/light/libxl_domain.c
@@ -525,6 +525,7 @@ static int do_libxl_domain_suspend(libxl
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->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
@@ -3657,6 +3657,7 @@ struct libxl__domain_save_state {
int debug;
int checkpointed_stream;
uint32_t max_iters;
+ uint32_t min_remaining;
const libxl_domain_remus_info *remus;
/* private */
int rc;
--- a/tools/xl/xl_cmdtable.c
+++ b/tools/xl/xl_cmdtable.c
@@ -166,17 +166,18 @@ const struct cmd_spec cmd_table[] = {
&main_migrate, 0, 1,
"Migrate a domain to another host",
"[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"
+ "-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"
},
{ "restore",
&main_restore, 0, 1,
--- a/tools/xl/xl_migrate.c
+++ b/tools/xl/xl_migrate.c
@@ -179,6 +179,7 @@ static void migrate_do_preamble(int send
static void migrate_domain(uint32_t domid, int preserve_domid,
const char *rune, int debug,
uint32_t max_iters,
+ uint32_t min_remaining,
const char *override_config_file)
{
pid_t child = -1;
@@ -191,6 +192,7 @@ static void migrate_domain(uint32_t domi
libxl_domain_suspend_suse_properties props = {
.flags = LIBXL_SUSPEND_LIVE,
.max_iters = max_iters,
+ .min_remaining = min_remaining,
};
save_domain_core_begin(domid, preserve_domid, override_config_file,
@@ -545,9 +547,11 @@ int main_migrate(int argc, char **argv)
int opt, daemonize = 1, monitor = 1, debug = 0, pause_after_migration = 0;
int preserve_domid = 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},
{"live", 0, 0, 0x200},
COMMON_LONG_OPTS
};
@@ -578,6 +582,9 @@ int main_migrate(int argc, char **argv)
case 0x101: /* --max_iters */
max_iters = atoi(optarg);
break;
+ case 0x102: /* --min_remaining */
+ min_remaining = atoi(optarg);
+ break;
case 0x200: /* --live */
/* ignored for compatibility with xm */
break;
@@ -613,7 +620,7 @@ int main_migrate(int argc, char **argv)
}
migrate_domain(domid, preserve_domid, rune, debug,
- max_iters, config_filename);
+ max_iters, min_remaining, config_filename);
return EXIT_SUCCESS;
}
