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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 04/15] libxl: domain save: API changes for asynchrony
Change the internal and external APIs for domain save (suspend) to be
capable of asynchronous operation. The implementation remains
synchronous. The interfaces surrounding device model saving are still
synchronous.
Public API changes:
* libxl_domain_save takes an ao_how.
* libxl_domain_remus_start takes an ao_how. If the
libxl_domain_remus_info is NULL, we abort rather than returning an
error.
* The `suspend_callback' function passed to libxl_domain_save is
never called by the existing implementation in libxl. Abolish it.
* libxl_domain_save takes its flags parameter as an argument.
Thus libxl_domain_suspend_info is abolished.
* XL_SUSPEND_* flags renamed to LIBXL_SAVE_*.
* Callers in xl updated.
Internal code restructuring:
* libxl__domain_suspend_state member types and names rationalised.
* libxl__domain_suspend renamed from libxl__domain_suspend_common.
(_common here actually meant "internal function").
* libxl__domain_suspend takes a libxl__domain_suspend_state, which
where the parameters to the operation are filled in by the caller.
* xc_domain_save is now called via libxl__xc_domain_save which can
itself become asynchronous.
* Consequently, libxl__domain_suspend is split into two functions at
the callback boundary; the second half is
libxl__xc_domain_save_done.
* libxl__domain_save_device_model is now called by the actual
implementation rather than by the public wrapper. It is already in
its proper place in the domain save execution sequence. So
officially make it part of that execution sequence, renaming it to
domain_save_device_model.
* Effectively, rewrite the public wrapper functions
libxl_domain_suspend and libxl_domain_remus_start.
* Remove a needless #include <xenctrl.h>
* libxl__domain_suspend aborts on unexpected domain types rather
than mysteriously returning EINVAL.
* struct save_callbacks moved from the stack to the dss.
Signed-off-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Changes in v2:
* Move save_callbacks too.
* Merge with Remus changes.
* Improvements to commit message.
* Do not rename libxl_domain_suspend any more.
---
tools/libxl/libxl.c | 89 +++++++++++++++++++--------
tools/libxl/libxl.h | 22 ++++----
tools/libxl/libxl_dom.c | 122 ++++++++++++++++++++++++++-----------
tools/libxl/libxl_internal.h | 45 ++++++++++++---
tools/libxl/libxl_save_callout.c | 12 ++++
tools/libxl/xl_cmdimpl.c | 9 +--
6 files changed, 212 insertions(+), 87 deletions(-)
diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 8a18fdf..53626ae 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -619,27 +619,44 @@ libxl_vminfo * libxl_list_vm(libxl_ctx *ctx, int *nb_vm)
return ptr;
}
+static void remus_crashed_cb(libxl__egc *egc,
+ libxl__domain_suspend_state *dss, int rc);
+
/* TODO: Explicit Checkpoint acknowledgements via recv_fd. */
int libxl_domain_remus_start(libxl_ctx *ctx, libxl_domain_remus_info *info,
- uint32_t domid, int send_fd, int recv_fd)
+ uint32_t domid, int send_fd, int recv_fd,
+ const libxl_asyncop_how *ao_how)
{
- GC_INIT(ctx);
+ AO_CREATE(ctx, domid, ao_how);
+ libxl__domain_suspend_state *dss;
+
libxl_domain_type type = libxl__domain_type(gc, domid);
- int rc = 0;
+ /* TODO: check error return from libxl__domain_type */
- if (info == NULL) {
- LIBXL__LOG(ctx, LIBXL__LOG_ERROR,
- "No remus_info structure supplied for domain %d", domid);
- rc = ERROR_INVAL;
- goto remus_fail;
- }
+ GCNEW(dss);
+ dss->ao = ao;
+ dss->callback = remus_crashed_cb;
+ dss->domid = domid;
+ dss->fd = send_fd;
+ /* TODO do something with recv_fd */
+ dss->type = type;
+ dss->live = 1;
+ dss->debug = 0;
+ dss->remus = info;
+
+ assert(info);
/* TBD: Remus setup - i.e. attach qdisc, enable disk buffering, etc */
/* Point of no return */
- rc = libxl__domain_suspend_common(gc, domid, send_fd, type, /* live */ 1,
- /* debug */ 0, info);
+ libxl__domain_suspend(egc, dss);
+ return AO_INPROGRESS;
+}
+static void remus_crashed_cb(libxl__egc *egc,
+ libxl__domain_suspend_state *dss, int rc)
+{
+ STATE_AO_GC(dss->ao);
/*
* With Remus, if we reach this point, it means either
* backup died or some network error occurred preventing us
@@ -649,27 +666,47 @@ int libxl_domain_remus_start(libxl_ctx *ctx,
libxl_domain_remus_info *info,
/* TBD: Remus cleanup - i.e. detach qdisc, release other
* resources.
*/
- remus_fail:
- GC_FREE;
- return rc;
+ libxl__ao_complete(egc, ao, rc);
}
-int libxl_domain_suspend(libxl_ctx *ctx, libxl_domain_suspend_info *info,
- uint32_t domid, int fd)
+static void domain_suspend_cb(libxl__egc *egc,
+ libxl__domain_suspend_state *dss, int rc)
{
- GC_INIT(ctx);
+ STATE_AO_GC(dss->ao);
+ libxl__ao_complete(egc,ao,rc);
+
+}
+
+int libxl_domain_suspend(libxl_ctx *ctx, uint32_t domid, int fd, int flags,
+ const libxl_asyncop_how *ao_how)
+{
+ AO_CREATE(ctx, domid, ao_how);
+ int rc;
+
libxl_domain_type type = libxl__domain_type(gc, domid);
- int live = info != NULL && info->flags & XL_SUSPEND_LIVE;
- int debug = info != NULL && info->flags & XL_SUSPEND_DEBUG;
- int rc = 0;
+ if (type < 0) {
+ LOG(ERROR,"domain %"PRIu32": unable to determine domain type", domid);
+ rc = ERROR_FAIL;
+ goto out_err;
+ }
- rc = libxl__domain_suspend_common(gc, domid, fd, type, live, debug,
- /* No Remus */ NULL);
+ libxl__domain_suspend_state *dss;
+ GCNEW(dss);
- if (!rc && type == LIBXL_DOMAIN_TYPE_HVM)
- rc = libxl__domain_save_device_model(gc, domid, fd);
- GC_FREE;
- return rc;
+ dss->ao = ao;
+ dss->callback = domain_suspend_cb;
+
+ dss->domid = domid;
+ dss->fd = fd;
+ dss->type = type;
+ dss->live = flags & LIBXL_SUSPEND_LIVE;
+ dss->debug = flags & LIBXL_SUSPEND_DEBUG;
+
+ libxl__domain_suspend(egc, dss);
+ return AO_INPROGRESS;
+
+ out_err:
+ return AO_ABORT(rc);
}
int libxl_domain_pause(libxl_ctx *ctx, uint32_t domid)
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 3a0d71d..4f1f4fd 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -347,13 +347,6 @@ typedef struct libxl__ctx libxl_ctx;
const libxl_version_info* libxl_get_version_info(libxl_ctx *ctx);
-typedef struct {
-#define XL_SUSPEND_DEBUG 1
-#define XL_SUSPEND_LIVE 2
- int flags;
- int (*suspend_callback)(void *, int);
-} libxl_domain_suspend_info;
-
enum {
ERROR_NONSPECIFIC = -1,
ERROR_VERSION = -2,
@@ -514,16 +507,23 @@ int libxl_domain_create_restore(libxl_ctx *ctx,
libxl_domain_config *d_config,
void libxl_domain_config_init(libxl_domain_config *d_config);
void libxl_domain_config_dispose(libxl_domain_config *d_config);
-int libxl_domain_remus_start(libxl_ctx *ctx, libxl_domain_remus_info *info,
- uint32_t domid, int send_fd, int recv_fd);
-int libxl_domain_suspend(libxl_ctx *ctx, libxl_domain_suspend_info *info,
- uint32_t domid, int fd);
+
+int libxl_domain_suspend(libxl_ctx *ctx, uint32_t domid, int fd,
+ int flags, /* LIBXL_SUSPEND_* */
+ const libxl_asyncop_how *ao_how);
+#define LIBXL_SUSPEND_DEBUG 1
+#define LIBXL_SUSPEND_LIVE 2
/* @param suspend_cancel [from xenctrl.h:xc_domain_resume( @param fast )]
* If this parameter is true, use co-operative resume. The guest
* must support this.
*/
int libxl_domain_resume(libxl_ctx *ctx, uint32_t domid, int suspend_cancel);
+
+int libxl_domain_remus_start(libxl_ctx *ctx, libxl_domain_remus_info *info,
+ uint32_t domid, int send_fd, int recv_fd,
+ const libxl_asyncop_how *ao_how);
+
int libxl_domain_shutdown(libxl_ctx *ctx, uint32_t domid);
int libxl_domain_reboot(libxl_ctx *ctx, uint32_t domid);
int libxl_domain_destroy(libxl_ctx *ctx, uint32_t domid);
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index 3bd1cb9..8cac6d5 100644
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -17,13 +17,11 @@
#include <glob.h>
-#include <xenctrl.h>
-#include <xc_dom.h>
+#include "libxl_internal.h"
+#include <xc_dom.h>
#include <xen/hvm/hvm_info_table.h>
-#include "libxl_internal.h"
-
libxl_domain_type libxl__domain_type(libxl__gc *gc, uint32_t domid)
{
libxl_ctx *ctx = libxl__gc_owner(gc);
@@ -519,11 +517,18 @@ int libxl__toolstack_restore(uint32_t domid, const
uint8_t *buf,
return 0;
}
-static int libxl__domain_suspend_common_switch_qemu_logdirty
+/*==================== Domain suspend (save) ====================*/
+
+static void domain_suspend_done(libxl__egc *egc,
+ libxl__domain_suspend_state *dss, int rc);
+
+/*----- callbacks, called by xc_domain_save -----*/
+
+int libxl__domain_suspend_common_switch_qemu_logdirty
(int domid, unsigned int enable, void *data)
{
libxl__domain_suspend_state *dss = data;
- libxl__gc *gc = dss->gc;
+ STATE_AO_GC(dss->ao);
char *path;
bool rc;
@@ -588,10 +593,10 @@ int libxl__domain_resume_device_model(libxl__gc *gc,
uint32_t domid)
return 0;
}
-static int libxl__domain_suspend_common_callback(void *data)
+int libxl__domain_suspend_common_callback(void *data)
{
libxl__domain_suspend_state *dss = data;
- libxl__gc *gc = dss->gc;
+ STATE_AO_GC(dss->ao);
unsigned long hvm_s_state = 0, hvm_pvdrv = 0;
int ret;
char *state = "suspend";
@@ -712,7 +717,7 @@ static int libxl__domain_suspend_common_callback(void *data)
guest_suspended:
if (dss->hvm) {
- ret = libxl__domain_suspend_device_model(dss->gc, dss->domid);
+ ret = libxl__domain_suspend_device_model(gc, dss->domid);
if (ret) {
LOG(ERROR, "libxl__domain_suspend_device_model failed ret=%d",
ret);
return 0;
@@ -729,11 +734,11 @@ static inline char *save_helper(libxl__gc *gc, uint32_t
domid,
domid, phys_offset, node);
}
-static int libxl__toolstack_save(uint32_t domid, uint8_t **buf,
+int libxl__toolstack_save(uint32_t domid, uint8_t **buf,
uint32_t *len, void *data)
{
libxl__domain_suspend_state *dss = data;
- libxl__gc *gc = dss->gc;
+ STATE_AO_GC(dss->ao);
int i = 0;
char *start_addr = NULL, *size = NULL, *phys_offset = NULL, *name = NULL;
unsigned int num = 0;
@@ -804,6 +809,8 @@ static int libxl__toolstack_save(uint32_t domid, uint8_t
**buf,
return 0;
}
+/*----- remus callbacks -----*/
+
static int libxl__remus_domain_suspend_callback(void *data)
{
/* TODO: Issue disk and network checkpoint reqs. */
@@ -813,7 +820,7 @@ static int libxl__remus_domain_suspend_callback(void *data)
static int libxl__remus_domain_resume_callback(void *data)
{
libxl__domain_suspend_state *dss = data;
- libxl__gc *gc = dss->gc;
+ STATE_AO_GC(dss->ao);
/* Resumes the domain and the device model */
if (libxl_domain_resume(CTX, dss->domid, /* Fast Suspend */1))
@@ -826,10 +833,11 @@ static int libxl__remus_domain_resume_callback(void *data)
static int libxl__remus_domain_checkpoint_callback(void *data)
{
libxl__domain_suspend_state *dss = data;
+ STATE_AO_GC(dss->ao);
/* This would go into tailbuf. */
if (dss->hvm &&
- libxl__domain_save_device_model(dss->gc, dss->domid, dss->save_fd))
+ libxl__domain_save_device_model(gc, dss->domid, dss->fd))
return 0;
/* TODO: Wait for disk and memory ack, release network buffer */
@@ -837,18 +845,24 @@ static int libxl__remus_domain_checkpoint_callback(void
*data)
return 1;
}
-int libxl__domain_suspend_common(libxl__gc *gc, uint32_t domid, int fd,
- libxl_domain_type type,
- int live, int debug,
- const libxl_domain_remus_info *r_info)
+/*----- main code for suspending, in order of execution -----*/
+
+void libxl__domain_suspend(libxl__egc *egc, libxl__domain_suspend_state *dss)
{
+ STATE_AO_GC(dss->ao);
int xcflags;
int port;
- struct save_callbacks callbacks[1];
- libxl__domain_suspend_state dss[1];
int hvm, rc = ERROR_FAIL;
unsigned long vm_generationid_addr;
+ /* 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;
+ const libxl_domain_remus_info *const r_info = dss->remus;
+ struct save_callbacks *const callbacks = &dss->callbacks;
+
switch (type) {
case LIBXL_DOMAIN_TYPE_HVM: {
char *path;
@@ -867,17 +881,14 @@ int libxl__domain_suspend_common(libxl__gc *gc, uint32_t
domid, int fd,
hvm = 0;
break;
default:
- return ERROR_INVAL;
+ abort();
}
xcflags = (live) ? XCFLAGS_LIVE : 0
| (debug) ? XCFLAGS_DEBUG : 0
| (hvm) ? XCFLAGS_HVM : 0;
- dss->domid = domid;
- dss->xcflags = xcflags;
dss->hvm = hvm;
- dss->gc = gc;
dss->suspend_eventchn = -1;
dss->guest_responded = 0;
@@ -885,10 +896,7 @@ int libxl__domain_suspend_common(libxl__gc *gc, uint32_t
domid, int fd,
dss->interval = r_info->interval;
if (r_info->compression)
xcflags |= XCFLAGS_CHECKPOINT_COMPRESS;
- dss->save_fd = fd;
}
- else
- dss->save_fd = -1;
dss->xce = xc_evtchn_open(NULL, 0);
if (dss->xce == NULL)
@@ -918,10 +926,28 @@ int libxl__domain_suspend_common(libxl__gc *gc, uint32_t
domid, int fd,
callbacks->toolstack_save = libxl__toolstack_save;
callbacks->data = dss;
- rc = xc_domain_save(CTX->xch, fd, domid, 0, 0, xcflags, callbacks,
- hvm, vm_generationid_addr);
- if ( rc ) {
- LOGE(ERROR, "saving domain: %s",
+ libxl__xc_domain_save(egc, dss, xcflags, hvm, vm_generationid_addr);
+ return;
+
+ out:
+ domain_suspend_done(egc, dss, rc);
+}
+
+void libxl__xc_domain_save_done(libxl__egc *egc,
+ libxl__domain_suspend_state *dss,
+ int rc, int retval, int errnoval)
+{
+ STATE_AO_GC(dss->ao);
+
+ /* Convenience aliases */
+ const libxl_domain_type type = dss->type;
+ const uint32_t domid = dss->domid;
+
+ if (rc)
+ goto out;
+
+ if (retval) {
+ LOGEV(ERROR, errnoval, "saving domain: %s",
dss->guest_responded ?
"domain responded to suspend request" :
"domain did not respond to suspend request");
@@ -929,16 +955,21 @@ int libxl__domain_suspend_common(libxl__gc *gc, uint32_t
domid, int fd,
rc = ERROR_GUEST_TIMEDOUT;
else
rc = ERROR_FAIL;
+ goto out;
}
- if (dss->suspend_eventchn > 0)
- xc_suspend_evtchn_release(CTX->xch, dss->xce, domid,
- dss->suspend_eventchn);
- if (dss->xce != NULL)
- xc_evtchn_close(dss->xce);
+ if (type == LIBXL_DOMAIN_TYPE_HVM) {
+ rc = libxl__domain_suspend_device_model(gc, domid);
+ if (rc) goto out;
+
+ rc = libxl__domain_save_device_model(gc, domid, dss->fd);
+ if (rc) goto out;
+ }
+
+ rc = 0;
out:
- return rc;
+ domain_suspend_done(egc, dss, rc);
}
int libxl__domain_save_device_model(libxl__gc *gc, uint32_t domid, int fd)
@@ -993,6 +1024,25 @@ out:
return rc;
}
+static void domain_suspend_done(libxl__egc *egc,
+ libxl__domain_suspend_state *dss, int rc)
+{
+ STATE_AO_GC(dss->ao);
+
+ /* Convenience aliases */
+ const uint32_t domid = dss->domid;
+
+ if (dss->suspend_eventchn > 0)
+ xc_suspend_evtchn_release(CTX->xch, dss->xce, domid,
+ dss->suspend_eventchn);
+ if (dss->xce != NULL)
+ xc_evtchn_close(dss->xce);
+
+ dss->callback(egc, dss, rc);
+}
+
+/*==================== Miscellaneous ====================*/
+
char *libxl__uuid2string(libxl__gc *gc, const libxl_uuid uuid)
{
char *s = libxl__sprintf(gc, LIBXL_UUID_FMT, LIBXL_UUID_BYTES(uuid));
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index ae4b99d..63da9b0 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1778,16 +1778,27 @@ _hidden int
libxl__datacopier_start(libxl__datacopier_state *dc);
typedef struct libxl__domain_suspend_state libxl__domain_suspend_state;
+typedef void libxl__domain_suspend_cb(libxl__egc*,
+ libxl__domain_suspend_state*, int rc);
+
struct libxl__domain_suspend_state {
- libxl__gc *gc;
+ /* set by caller of libxl__domain_suspend */
+ libxl__ao *ao;
+ libxl__domain_suspend_cb *callback;
+
+ uint32_t domid;
+ int fd;
+ libxl_domain_type type;
+ int live;
+ int debug;
+ const libxl_domain_remus_info *remus;
+ /* private */
xc_evtchn *xce; /* event channel handle */
int suspend_eventchn;
- int domid;
int hvm;
- unsigned int xcflags;
int guest_responded;
- int save_fd; /* Migration stream fd (for Remus) */
int interval; /* checkpoint interval (for Remus) */
+ struct save_callbacks callbacks;
};
@@ -1904,10 +1915,28 @@ struct libxl__domain_create_state {
/*----- Domain suspend (save) functions -----*/
-_hidden int libxl__domain_suspend_common(libxl__gc *gc, uint32_t domid, int fd,
- libxl_domain_type type,
- int live, int debug,
- const libxl_domain_remus_info
*r_info);
+/* calls callback when done */
+_hidden void libxl__domain_suspend(libxl__egc *egc,
+ libxl__domain_suspend_state *dss);
+
+
+/* calls libxl__xc_domain_suspend_done when done */
+_hidden void libxl__xc_domain_save(libxl__egc*, libxl__domain_suspend_state*,
+ int xcflags, int hvm,
+ unsigned long vm_generationid_addr);
+/* If rc==0 then retval is the return value from xc_domain_save
+ * and errnoval is the errno value it provided.
+ * If rc!=0, retval and errnoval are undefined. */
+_hidden void libxl__xc_domain_save_done(libxl__egc*,
+ libxl__domain_suspend_state*,
+ int rc, int retval, int errnoval);
+
+_hidden int libxl__domain_suspend_common_callback(void *data);
+_hidden int libxl__domain_suspend_common_switch_qemu_logdirty
+ (int domid, unsigned int enable, void *data);
+_hidden int libxl__toolstack_save(uint32_t domid, uint8_t **buf,
+ uint32_t *len, void *data);
+
/* calls libxl__xc_domain_restore_done when done */
_hidden void libxl__xc_domain_restore(libxl__egc *egc,
diff --git a/tools/libxl/libxl_save_callout.c b/tools/libxl/libxl_save_callout.c
index 2f8db9f..d8defa9 100644
--- a/tools/libxl/libxl_save_callout.c
+++ b/tools/libxl/libxl_save_callout.c
@@ -35,3 +35,15 @@ void libxl__xc_domain_restore(libxl__egc *egc,
libxl__domain_create_state *dcs,
&state->vm_generationid_addr, &dcs->callbacks);
libxl__xc_domain_restore_done(egc, dcs, 0, r, errno);
}
+
+void libxl__xc_domain_save(libxl__egc *egc, libxl__domain_suspend_state *dss,
+ int xcflags, int hvm,
+ unsigned long vm_generationid_addr)
+{
+ STATE_AO_GC(dss->ao);
+ int r;
+
+ r = xc_domain_save(CTX->xch, dss->fd, dss->domid, 0, 0, xcflags,
+ &dss->callbacks, hvm, vm_generationid_addr);
+ libxl__xc_domain_save_done(egc, dss, 0, r, errno);
+}
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 040cefc..9b4a80e 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -2820,7 +2820,7 @@ static int save_domain(const char *p, const char
*filename, int checkpoint,
save_domain_core_writeconfig(fd, filename, config_data, config_len);
- CHK_ERRNO(libxl_domain_suspend(ctx, NULL, domid, fd));
+ CHK_ERRNO(libxl_domain_suspend(ctx, domid, fd, 0, NULL));
close(fd);
if (checkpoint)
@@ -2982,7 +2982,6 @@ static void migrate_domain(const char *domain_spec, const
char *rune,
pid_t child = -1;
int rc;
int send_fd = -1, recv_fd = -1;
- libxl_domain_suspend_info suspinfo;
char *away_domname;
char rc_buf;
uint8_t *config_data;
@@ -3004,9 +3003,7 @@ static void migrate_domain(const char *domain_spec, const
char *rune,
xtl_stdiostream_adjust_flags(logger, XTL_STDIOSTREAM_HIDE_PROGRESS, 0);
- memset(&suspinfo, 0, sizeof(suspinfo));
- suspinfo.flags |= XL_SUSPEND_LIVE;
- rc = libxl_domain_suspend(ctx, &suspinfo, domid, send_fd);
+ rc = libxl_domain_suspend(ctx, domid, send_fd, LIBXL_SUSPEND_LIVE, NULL);
if (rc) {
fprintf(stderr, "migration sender: libxl_domain_suspend failed"
" (rc=%d)\n", rc);
@@ -6623,7 +6620,7 @@ int main_remus(int argc, char **argv)
}
/* Point of no return */
- rc = libxl_domain_remus_start(ctx, &r_info, domid, send_fd, recv_fd);
+ rc = libxl_domain_remus_start(ctx, &r_info, domid, send_fd, recv_fd, 0);
/* If we are here, it means backup has failed/domain suspend failed.
* Try to resume the domain and exit gracefully.
--
1.7.2.5
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