File xen.sr-precopy_policy.patch of Package xen
From: Olaf Hering <olaf@aepfle.de>
Date: Fri, 8 Jan 2021 18:19:49 +0100
Subject: sr precopy_policy
tools: add callback to libxl for precopy_policy and precopy_stats
This duplicates simple_precopy_policy. To recap its purpose:
- do up to 5 iterations of copying dirty domU memory to target,
including the initial copying of all domU memory, excluding
the final copying while the domU is suspended
- do fewer iterations in case the domU dirtied less than 50 pages
Take the opportunity to also move xen_pfn_t into qw().
Signed-off-by: Olaf Hering <olaf@aepfle.de>
v02:
- use plain struct precopy_stats instead of inventing
a new precopy_stats_t (anthony)
---
tools/libs/light/libxl_dom_save.c | 19 +++++++++
tools/libs/light/libxl_internal.h | 2 +
tools/libs/light/libxl_save_msgs_gen.pl | 3 +-
3 files changed, 23 insertions(+), 1 deletion(-)
--- a/tools/libs/light/libxl_dom_save.c
+++ b/tools/libs/light/libxl_dom_save.c
@@ -364,24 +364,42 @@ int libxl__save_emulator_xenstore_data(libxl__domain_save_state *dss,
rc = 0;
out:
if (!rc) {
*callee_buf = buf;
*callee_len = len;
}
return rc;
}
+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 < LIBXL_XGS_POLICY_TARGET_DIRTY_COUNT)
+ goto stop_copy;
+ if (stats.iteration >= LIBXL_XGS_POLICY_MAX_ITERATIONS)
+ goto stop_copy;
+ return XGS_POLICY_CONTINUE_PRECOPY;
+
+stop_copy:
+ 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;
const libxl_domain_type type = dss->type;
const int live = dss->live;
const int debug = dss->debug;
@@ -421,24 +439,25 @@ void libxl__domain_save(libxl__egc *egc, libxl__domain_save_state *dss)
ret = xc_domain_getvnuma(CTX->xch, domid, &nr_vnodes, &nr_vmemranges,
&nr_vcpus, NULL, NULL, NULL);
if (ret != -1 || errno != EOPNOTSUPP) {
LOGD(ERROR, domid, "Cannot save a guest with vNUMA configured");
rc = ERROR_FAIL;
goto out;
}
if (dss->checkpointed_stream == LIBXL_CHECKPOINTED_STREAM_NONE)
callbacks->suspend = libxl__domain_suspend_callback;
callbacks->switch_qemu_logdirty = libxl__domain_suspend_common_switch_qemu_logdirty;
+ callbacks->precopy_policy = libxl__domain_save_precopy_policy;
dss->sws.ao = dss->ao;
dss->sws.dss = dss;
dss->sws.fd = dss->fd;
dss->sws.back_channel = false;
dss->sws.completion_callback = stream_done;
libxl__stream_write_start(egc, &dss->sws);
return;
out:
domain_save_done(egc, dss, rc);
--- a/tools/libs/light/libxl_internal.h
+++ b/tools/libs/light/libxl_internal.h
@@ -116,24 +116,26 @@
#define QEMU_SIGNATURE "DeviceModelRecord0002"
#define STUBDOM_CONSOLE_LOGGING 0
#define STUBDOM_CONSOLE_SAVE 1
#define STUBDOM_CONSOLE_RESTORE 2
#define STUBDOM_CONSOLE_SERIAL 3
#define STUBDOM_SPECIAL_CONSOLES 3
#define LIBXL_LINUX_STUBDOM_MEM 128
#define LIBXL_STUBDOM_EMPTY_CDROM XEN_RUN_DIR "/empty-cdrom" /* .$domid */
#define TAP_DEVICE_SUFFIX "-emu"
#define DOMID_XS_PATH "domid"
#define PVSHIM_BASENAME "xen-shim"
#define PVSHIM_CMDLINE "pv-shim console=xen,pv"
+#define LIBXL_XGS_POLICY_MAX_ITERATIONS 5
+#define LIBXL_XGS_POLICY_TARGET_DIRTY_COUNT 50
#define DIV_ROUNDUP(n, d) (((n) + (d) - 1) / (d))
#define LIBXL__LOGGING_ENABLED
#ifdef LIBXL__LOGGING_ENABLED
#define LIBXL__LOG(ctx, loglevel, _f, _a...) libxl__log(ctx, loglevel, -1, __FILE__, __LINE__, __func__, INVALID_DOMID, _f, ##_a)
#define LIBXL__LOG_ERRNO(ctx, loglevel, _f, _a...) libxl__log(ctx, loglevel, errno, __FILE__, __LINE__, __func__, INVALID_DOMID, _f, ##_a)
#define LIBXL__LOG_ERRNOVAL(ctx, loglevel, errnoval, _f, _a...) libxl__log(ctx, loglevel, errnoval, __FILE__, __LINE__, __func__, INVALID_DOMID, _f, ##_a)
/* Same log functions as above, but with _d being a domain id. */
#define LIBXL__LOGD(ctx, loglevel, _d, _f, _a...) libxl__log(ctx, loglevel, -1, __FILE__, __LINE__, __func__, _d, _f, ##_a)
--- a/tools/libs/light/libxl_save_msgs_gen.pl
+++ b/tools/libs/light/libxl_save_msgs_gen.pl
@@ -14,24 +14,25 @@ our @msgs = (
# x - function pointer is in struct {save,restore}_callbacks
# and its null-ness needs to be passed through to the helper's xc
# W - needs a return value; callback is synchronous
# A - needs a return value; callback is asynchronous
[ 'sr', "log", [qw(uint32_t level
uint32_t errnoval
STRING context
STRING formatted)] ],
[ 'sr', "progress", [qw(STRING context
STRING doing_what),
'unsigned long', 'done',
'unsigned long', 'total'] ],
+ [ 'scxW', "precopy_policy", ['struct precopy_stats', 'stats'] ],
[ 'srcxA', "suspend", [] ],
[ 'srcxA', "postcopy", [] ],
[ 'srcxA', "checkpoint", [] ],
[ 'srcxA', "wait_checkpoint", [] ],
[ 'scxA', "switch_qemu_logdirty", [qw(uint32_t domid
unsigned enable)] ],
[ 'rcxW', "static_data_done", [qw(unsigned missing)] ],
[ 'rcx', "restore_results", ['xen_pfn_t', 'store_gfn',
'xen_pfn_t', 'console_gfn'] ],
[ 'srW', "complete", [qw(int retval
int errnoval)] ],
);
@@ -133,25 +134,25 @@ END
$out_body{'helper'} .= <<END;
static void bytes_put(unsigned char *const buf, int *len,
const void *value, int vlen)
{
assert(vlen < INT_MAX/2 - *len);
if (buf)
memcpy(buf + *len, value, vlen);
*len += vlen;
}
END
-foreach my $simpletype (qw(int uint16_t uint32_t unsigned), 'unsigned long', 'xen_pfn_t') {
+foreach my $simpletype (qw(int uint16_t uint32_t unsigned xen_pfn_t), 'struct precopy_stats', 'unsigned long') {
my $typeid = typeid($simpletype);
$out_body{'callout'} .= <<END;
static int ${typeid}_get(const unsigned char **msg,
const unsigned char *const endmsg,
$simpletype *result)
{
return bytes_get(msg, endmsg, result, sizeof(*result));
}
END
$out_body{'helper'} .= <<END;
static void ${typeid}_put(unsigned char *const buf, int *len,
