[lttng-dev] [PATCH lttng-tools v2 4/6] Allow regenerating the statedump of a running session
Jérémie Galarneau
jeremie.galarneau at efficios.com
Mon Jul 4 20:33:41 UTC 2016
On Mon, Jul 4, 2016 at 11:13 AM, Julien Desfossez
<jdesfossez at efficios.com> wrote:
> The "lttng regenerate statedump" command can be used to regenerate the
> statedump of a running session whenever needed. This is particularly
> useful in snapshot and trace-file rotation modes where the original
> statedump may be lost.
>
> Signed-off-by: Julien Desfossez <jdesfossez at efficios.com>
> ---
> include/lttng/lttng-error.h | 1 +
> include/lttng/lttng.h | 9 +++++
> src/bin/lttng-sessiond/cmd.c | 44 +++++++++++++++++++++
> src/bin/lttng-sessiond/cmd.h | 1 +
> src/bin/lttng-sessiond/main.c | 6 +++
> src/bin/lttng-sessiond/ust-app.c | 66 ++++++++++++++++++++++++++++++++
> src/bin/lttng-sessiond/ust-app.h | 6 +++
> src/bin/lttng/commands/regenerate.c | 19 +++++++++
> src/common/error.c | 1 +
> src/common/kernel-ctl/kernel-ctl.c | 5 +++
> src/common/kernel-ctl/kernel-ctl.h | 1 +
> src/common/sessiond-comm/sessiond-comm.h | 1 +
> src/lib/lttng-ctl/lttng-ctl.c | 30 +++++++++++++++
> 13 files changed, 190 insertions(+)
>
> diff --git a/include/lttng/lttng-error.h b/include/lttng/lttng-error.h
> index 72194ef..52ce333 100644
> --- a/include/lttng/lttng-error.h
> +++ b/include/lttng/lttng-error.h
> @@ -142,6 +142,7 @@ enum lttng_error_code {
> LTTNG_ERR_LIVE_SESSION = 119, /* Live session unsupported */
> LTTNG_ERR_PER_PID_SESSION = 120, /* Per-PID sessions unsupported */
> LTTNG_ERR_KERN_CONTEXT_UNAVAILABLE = 121, /* Context unavailable on this kernel */
> + LTTNG_ERR_REGEN_STATEDUMP_FAIL = 122, /* Failed to regenerate the statdump */
statdump -> statedump
>
> /* MUST be last element */
> LTTNG_ERR_NR, /* Last element */
> diff --git a/include/lttng/lttng.h b/include/lttng/lttng.h
> index 09aa969..b81a01c 100644
> --- a/include/lttng/lttng.h
> +++ b/include/lttng/lttng.h
> @@ -173,6 +173,15 @@ extern int lttng_metadata_regenerate(const char *session_name);
> */
> extern int lttng_regenerate_metadata(const char *session_name);
>
> +/*
> + * Trigger the regeneration of the statedump for a session. The new statedump
> + * information is appended to the currently active trace, the session needs to
> + * be started.
needs to be active
> + *
> + * Return 0 on success, a negative LTTng error code on error.
> + */
> +extern int lttng_regenerate_statedump(const char *session_name);
> +
> #ifdef __cplusplus
> }
> #endif
> diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
> index bd63389..480333d 100644
> --- a/src/bin/lttng-sessiond/cmd.c
> +++ b/src/bin/lttng-sessiond/cmd.c
> @@ -3540,6 +3540,50 @@ end:
> }
>
> /*
> + * Command LTTNG_REGENERATE_STATEDUMP from the lttng-ctl library.
> + *
> + * Ask the tracer to regenerate a new statedump.
> + *
> + * Return 0 on success or else a LTTNG_ERR code.
> + */
> +int cmd_regenerate_statedump(struct ltt_session *session)
> +{
> + int ret;
> +
> + assert(session);
> +
> + if (!session->active) {
> + ret = LTTNG_ERR_SESSION_NOT_STARTED;
> + goto end;
> + }
> + ret = 0;
> +
> + if (session->kernel_session) {
> + ret = kernctl_session_regenerate_statedump(
> + session->kernel_session->fd);
> + if (ret < 0) {
> + ret = LTTNG_ERR_REGEN_STATEDUMP_FAIL;
Does kernctl_session_regenerate_statedump() return a more precise error code?
I see that this can fail if the session is not active (handled
before). Are there other reasons?
> + ERR("Failed to regenerate the kernel statedump");
> + goto end;
> + }
> + }
> +
> + if (session->ust_session) {
> + ret = ust_app_regenerate_statedump_all(session->ust_session);
Same applies here.
> + if (ret < 0) {
> + ret = LTTNG_ERR_REGEN_STATEDUMP_FAIL;
> + ERR("Failed to regenerate the UST statedump");
> + goto end;
> + }
> + }
> + DBG("Cmd regenerate statedump for session %s", session->name);
> + ret = LTTNG_OK;
> +
> +end:
> + return ret;
> +}
> +
> +/*
> * Send relayd sockets from snapshot output to consumer. Ignore request if the
> * snapshot output is *not* set with a remote destination.
> *
> diff --git a/src/bin/lttng-sessiond/cmd.h b/src/bin/lttng-sessiond/cmd.h
> index 320d717..975a7f1 100644
> --- a/src/bin/lttng-sessiond/cmd.h
> +++ b/src/bin/lttng-sessiond/cmd.h
> @@ -111,5 +111,6 @@ int cmd_snapshot_record(struct ltt_session *session,
> int cmd_set_session_shm_path(struct ltt_session *session,
> const char *shm_path);
> int cmd_regenerate_metadata(struct ltt_session *session);
> +int cmd_regenerate_statedump(struct ltt_session *session);
>
> #endif /* CMD_H */
> diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
> index 3623e5d..8309c3f 100644
> --- a/src/bin/lttng-sessiond/main.c
> +++ b/src/bin/lttng-sessiond/main.c
> @@ -3004,6 +3004,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
> case LTTNG_SAVE_SESSION:
> case LTTNG_SET_SESSION_SHM_PATH:
> case LTTNG_REGENERATE_METADATA:
> + case LTTNG_REGENERATE_STATEDUMP:
> need_domain = 0;
> break;
> default:
> @@ -4119,6 +4120,11 @@ error_add_context:
> ret = cmd_regenerate_metadata(cmd_ctx->session);
> break;
> }
> + case LTTNG_REGENERATE_STATEDUMP:
> + {
> + ret = cmd_regenerate_statedump(cmd_ctx->session);
> + break;
> + }
> default:
> ret = LTTNG_ERR_UND;
> break;
> diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c
> index f30df20..3474082 100644
> --- a/src/bin/lttng-sessiond/ust-app.c
> +++ b/src/bin/lttng-sessiond/ust-app.c
> @@ -6148,3 +6148,69 @@ end:
> rcu_read_unlock();
> return ret;
> }
> +
> +static
> +int ust_app_regenerate_statedump(struct ltt_ust_session *usess,
> + struct ust_app *app)
> +{
> + int ret = 0;
> + struct ust_app_session *ua_sess;
> +
> + DBG("Regenerating the metadata for ust app pid %d", app->pid);
> +
> + rcu_read_lock();
> +
> + ua_sess = lookup_session_by_app(usess, app);
> + if (ua_sess == NULL) {
> + /* The session is in teardown process. Ignore and continue. */
> + goto end;
> + }
> +
> + pthread_mutex_lock(&ua_sess->lock);
> +
> + if (ua_sess->deleted) {
> + pthread_mutex_unlock(&ua_sess->lock);
Remove this pthread_mutex_unlock() and goto end_unlock;
> + goto end;
> + }
> +
> + pthread_mutex_lock(&app->sock_lock);
> + ret = ustctl_regenerate_statedump(app->sock, ua_sess->handle);
> + pthread_mutex_unlock(&app->sock_lock);
Add
end_unlock:
> + pthread_mutex_unlock(&ua_sess->lock);
> +
> +end:
> + rcu_read_unlock();
> + health_code_update();
> + return ret;
> +}
> +
> +/*
> + * Regenerate the statedump for each app in the session.
> + */
> +int ust_app_regenerate_statedump_all(struct ltt_ust_session *usess)
> +{
> + int ret = 0;
> + struct lttng_ht_iter iter;
> + struct ust_app *app;
> +
> + DBG("Regenerating the metadata for all UST apps");
> +
> + rcu_read_lock();
> +
> + cds_lfht_for_each_entry(ust_app_ht->ht, &iter.iter, app, pid_n.node) {
> + if (!app->compatible) {
> + continue;
> + }
> +
> + ret = ust_app_regenerate_statedump(usess, app);
> + if (ret < 0) {
> + /* Continue to next apps even on error */
to next app
> + continue;
> + }
> + }
> +
> + rcu_read_unlock();
> +
> + return 0;
> +}
> +
Remove blank line here.
> diff --git a/src/bin/lttng-sessiond/ust-app.h b/src/bin/lttng-sessiond/ust-app.h
> index d02f353..8369d14 100644
> --- a/src/bin/lttng-sessiond/ust-app.h
> +++ b/src/bin/lttng-sessiond/ust-app.h
> @@ -352,6 +352,7 @@ int ust_app_pid_get_channel_runtime_stats(struct ltt_ust_session *usess,
> struct ltt_ust_channel *uchan,
> struct consumer_output *consumer,
> int overwrite, uint64_t *discarded, uint64_t *lost);
> +int ust_app_regenerate_statedump_all(struct ltt_ust_session *usess);
>
> static inline
> int ust_app_supported(void)
> @@ -583,6 +584,11 @@ int ust_app_pid_get_channel_runtime_stats(struct ltt_ust_session *usess,
> {
> return 0;
> }
> +static inline
> +int ust_app_regenerate_metadata_all(struct ltt_ust_session *usess)
> +{
> + return 0;
> +}
>
> #endif /* HAVE_LIBLTTNG_UST_CTL */
>
> diff --git a/src/bin/lttng/commands/regenerate.c b/src/bin/lttng/commands/regenerate.c
> index c64d8fe..f111d06 100644
> --- a/src/bin/lttng/commands/regenerate.c
> +++ b/src/bin/lttng/commands/regenerate.c
> @@ -32,6 +32,7 @@ static char *opt_session_name;
> static char *session_name = NULL;
>
> static int regenerate_metadata(int argc, const char **argv);
> +static int regenerate_statedump(int argc, const char **argv);
>
> enum {
> OPT_HELP = 1,
> @@ -52,6 +53,7 @@ static struct poptOption long_options[] = {
>
> static struct cmd_struct actions[] = {
> { "metadata", regenerate_metadata },
> + { "statedump", regenerate_statedump },
> { NULL, NULL } /* Array closure */
> };
>
> @@ -88,6 +90,23 @@ end:
> return ret;
> }
>
> +static int regenerate_statedump(int argc, const char **argv)
> +{
> + int ret;
> +
> + if (argc > 1) {
> + ret = -LTTNG_ERR_INVALID;
> + goto end;
> + }
> + ret = lttng_regenerate_statedump(session_name);
> + if (ret == 0) {
> + MSG("Statedump successfully regenerated for session %s", session_name);
Please use "State dump" in two words in human-readable messages.
> + }
> +
> +end:
> + return ret;
> +}
> +
> static int handle_command(const char **argv)
> {
> struct cmd_struct *cmd;
> diff --git a/src/common/error.c b/src/common/error.c
> index bc42577..6730e14 100644
> --- a/src/common/error.c
> +++ b/src/common/error.c
> @@ -183,6 +183,7 @@ static const char *error_string_array[] = {
> [ ERROR_INDEX(LTTNG_ERR_LIVE_SESSION) ] = "Live sessions are not supported",
> [ ERROR_INDEX(LTTNG_ERR_PER_PID_SESSION) ] = "Per-PID tracing sessions are not supported",
> [ ERROR_INDEX(LTTNG_ERR_KERN_CONTEXT_UNAVAILABLE) ] = "Context unavailable on this kernel",
> + [ ERROR_INDEX(LTTNG_ERR_REGEN_STATEDUMP_FAIL) ] = "Statedump regeneration failed",
"State dump"
>
> /* Last element */
> [ ERROR_INDEX(LTTNG_ERR_NR) ] = "Unknown error code"
> diff --git a/src/common/kernel-ctl/kernel-ctl.c b/src/common/kernel-ctl/kernel-ctl.c
> index e1de0e7..1c2ab61 100644
> --- a/src/common/kernel-ctl/kernel-ctl.c
> +++ b/src/common/kernel-ctl/kernel-ctl.c
> @@ -230,6 +230,11 @@ int kernctl_session_regenerate_metadata(int fd)
> return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_METADATA_REGEN);
> }
>
> +int kernctl_session_regenerate_statedump(int fd)
> +{
> + return LTTNG_IOCTL_CHECK(fd, LTTNG_KERNEL_SESSION_STATEDUMP);
> +}
> +
> int kernctl_create_stream(int fd)
> {
> return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_STREAM,
> diff --git a/src/common/kernel-ctl/kernel-ctl.h b/src/common/kernel-ctl/kernel-ctl.h
> index f30e6f3..7c25a17 100644
> --- a/src/common/kernel-ctl/kernel-ctl.h
> +++ b/src/common/kernel-ctl/kernel-ctl.h
> @@ -66,6 +66,7 @@ int kernctl_untrack_pid(int fd, int pid);
> int kernctl_list_tracker_pids(int fd);
>
> int kernctl_session_regenerate_metadata(int fd);
> +int kernctl_session_regenerate_statedump(int fd);
>
> /* Buffer operations */
>
> diff --git a/src/common/sessiond-comm/sessiond-comm.h b/src/common/sessiond-comm/sessiond-comm.h
> index 29740c1..628b1ea 100644
> --- a/src/common/sessiond-comm/sessiond-comm.h
> +++ b/src/common/sessiond-comm/sessiond-comm.h
> @@ -95,6 +95,7 @@ enum lttcomm_sessiond_command {
> LTTNG_LIST_TRACKER_PIDS = 34,
> LTTNG_SET_SESSION_SHM_PATH = 40,
> LTTNG_REGENERATE_METADATA = 41,
> + LTTNG_REGENERATE_STATEDUMP = 42,
> };
>
> enum lttcomm_relayd_command {
> diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
> index 8c78e1c..bcd59f0 100644
> --- a/src/lib/lttng-ctl/lttng-ctl.c
> +++ b/src/lib/lttng-ctl/lttng-ctl.c
> @@ -2419,6 +2419,36 @@ int lttng_metadata_regenerate(const char *session_name)
> }
>
> /*
> + * Regenerate the statedump of a session.
> + * Return 0 on success, a negative error code on error.
> + */
> +int lttng_regenerate_statedump(const char *session_name)
> +{
> + int ret;
> + struct lttcomm_session_msg lsm;
> +
> + if (!session_name) {
> + ret = -LTTNG_ERR_INVALID;
> + goto end;
> + }
> +
> + memset(&lsm, 0, sizeof(lsm));
> + lsm.cmd_type = LTTNG_REGENERATE_STATEDUMP;
> +
> + lttng_ctl_copy_string(lsm.session.name, session_name,
> + sizeof(lsm.session.name));
> +
> + ret = lttng_ctl_ask_sessiond(&lsm, NULL);
> + if (ret < 0) {
> + goto end;
> + }
> +
> + ret = 0;
> +end:
> + return ret;
> +}
> +
> +/*
> * lib constructor.
> */
> static void __attribute__((constructor)) init(void)
> --
> 1.9.1
>
--
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com
More information about the lttng-dev
mailing list