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Re: [Qemu-devel] [PATCH v4] Add interface to traverse the qmp command li
From: |
Michael Roth |
Subject: |
Re: [Qemu-devel] [PATCH v4] Add interface to traverse the qmp command list by QmpCommand |
Date: |
Wed, 09 Oct 2013 12:19:09 -0500 |
User-agent: |
alot/0.3.4 |
Quoting Mark Wu (2013-10-08 22:25:07)
> In the original code, qmp_get_command_list is used to construct
> a list of all commands' name. To get the information of all qga
> commands, it traverses the name list and search the command info
> with its name. So it can cause O(n^2) in the number of commands.
>
> This patch adds an interface to traverse the qmp command list by
> QmpCommand to replace qmp_get_command_list. It can decrease the
> complexity from O(n^2) to O(n).
>
> Signed-off-by: Mark Wu <address@hidden>
Thanks, applied to qga tree:
https://github.com/mdroth/qemu/commits/qga
> ---
> v4:
> Add the missing change from cmd->namd to qmp_command_name(cmd)
> v3:
> Add an accessor for cmd->name to avoid exposing internals of QmpCommand
> v2:
> 1. Keep the signature of qmp_command_is_enabled (per Eric and Michael)
> 2. Remove the unnecessary pointer castings (per Eric)
> include/qapi/qmp/dispatch.h | 6 ++--
> qapi/qmp-registry.c | 30 +++++-------------
> qga/commands.c | 38 +++++++++--------------
> qga/main.c | 75
> ++++++++++++++++++---------------------------
> 4 files changed, 57 insertions(+), 92 deletions(-)
>
> diff --git a/include/qapi/qmp/dispatch.h b/include/qapi/qmp/dispatch.h
> index 1ce11f5..7d759ef 100644
> --- a/include/qapi/qmp/dispatch.h
> +++ b/include/qapi/qmp/dispatch.h
> @@ -47,9 +47,11 @@ QmpCommand *qmp_find_command(const char *name);
> QObject *qmp_dispatch(QObject *request);
> void qmp_disable_command(const char *name);
> void qmp_enable_command(const char *name);
> -bool qmp_command_is_enabled(const char *name);
> -char **qmp_get_command_list(void);
> +bool qmp_command_is_enabled(const QmpCommand *cmd);
> +const char *qmp_command_name(const QmpCommand *cmd);
> QObject *qmp_build_error_object(Error *errp);
> +typedef void (*qmp_cmd_callback_fn)(QmpCommand *cmd, void *opaque);
> +void qmp_for_each_command(qmp_cmd_callback_fn fn, void *opaque);
>
> #endif
>
> diff --git a/qapi/qmp-registry.c b/qapi/qmp-registry.c
> index 28bbbe8..5e26710 100644
> --- a/qapi/qmp-registry.c
> +++ b/qapi/qmp-registry.c
> @@ -66,35 +66,21 @@ void qmp_enable_command(const char *name)
> qmp_toggle_command(name, true);
> }
>
> -bool qmp_command_is_enabled(const char *name)
> +bool qmp_command_is_enabled(const QmpCommand *cmd)
> {
> - QmpCommand *cmd;
> -
> - QTAILQ_FOREACH(cmd, &qmp_commands, node) {
> - if (strcmp(cmd->name, name) == 0) {
> - return cmd->enabled;
> - }
> - }
> + return cmd->enabled;
> +}
>
> - return false;
> +const char *qmp_command_name(const QmpCommand *cmd)
> +{
> + return cmd->name;
> }
>
> -char **qmp_get_command_list(void)
> +void qmp_for_each_command(qmp_cmd_callback_fn fn, void *opaque)
> {
> QmpCommand *cmd;
> - int count = 1;
> - char **list_head, **list;
> -
> - QTAILQ_FOREACH(cmd, &qmp_commands, node) {
> - count++;
> - }
> -
> - list_head = list = g_malloc0(count * sizeof(char *));
>
> QTAILQ_FOREACH(cmd, &qmp_commands, node) {
> - *list = g_strdup(cmd->name);
> - list++;
> + fn(cmd, opaque);
> }
> -
> - return list_head;
> }
> diff --git a/qga/commands.c b/qga/commands.c
> index 528b082..e87cbf8 100644
> --- a/qga/commands.c
> +++ b/qga/commands.c
> @@ -45,35 +45,27 @@ void qmp_guest_ping(Error **err)
> slog("guest-ping called");
> }
>
> -struct GuestAgentInfo *qmp_guest_info(Error **err)
> +static void qmp_command_info(QmpCommand *cmd, void *opaque)
> {
> - GuestAgentInfo *info = g_malloc0(sizeof(GuestAgentInfo));
> + GuestAgentInfo *info = opaque;
> GuestAgentCommandInfo *cmd_info;
> GuestAgentCommandInfoList *cmd_info_list;
> - char **cmd_list_head, **cmd_list;
> -
> - info->version = g_strdup(QEMU_VERSION);
> -
> - cmd_list_head = cmd_list = qmp_get_command_list();
> - if (*cmd_list_head == NULL) {
> - goto out;
> - }
>
> - while (*cmd_list) {
> - cmd_info = g_malloc0(sizeof(GuestAgentCommandInfo));
> - cmd_info->name = g_strdup(*cmd_list);
> - cmd_info->enabled = qmp_command_is_enabled(cmd_info->name);
> + cmd_info = g_malloc0(sizeof(GuestAgentCommandInfo));
> + cmd_info->name = g_strdup(qmp_command_name(cmd));
> + cmd_info->enabled = qmp_command_is_enabled(cmd);
>
> - cmd_info_list = g_malloc0(sizeof(GuestAgentCommandInfoList));
> - cmd_info_list->value = cmd_info;
> - cmd_info_list->next = info->supported_commands;
> - info->supported_commands = cmd_info_list;
> + cmd_info_list = g_malloc0(sizeof(GuestAgentCommandInfoList));
> + cmd_info_list->value = cmd_info;
> + cmd_info_list->next = info->supported_commands;
> + info->supported_commands = cmd_info_list;
> +}
>
> - g_free(*cmd_list);
> - cmd_list++;
> - }
> +struct GuestAgentInfo *qmp_guest_info(Error **err)
> +{
> + GuestAgentInfo *info = g_malloc0(sizeof(GuestAgentInfo));
>
> -out:
> - g_free(cmd_list_head);
> + info->version = g_strdup(QEMU_VERSION);
> + qmp_for_each_command(qmp_command_info, info);
> return info;
> }
> diff --git a/qga/main.c b/qga/main.c
> index 6c746c8..c58b26a 100644
> --- a/qga/main.c
> +++ b/qga/main.c
> @@ -347,48 +347,35 @@ static gint ga_strcmp(gconstpointer str1, gconstpointer
> str2)
> }
>
> /* disable commands that aren't safe for fsfreeze */
> -static void ga_disable_non_whitelisted(void)
> +static void ga_disable_non_whitelisted(QmpCommand *cmd, void *opaque)
> {
> - char **list_head, **list;
> - bool whitelisted;
> - int i;
> -
> - list_head = list = qmp_get_command_list();
> - while (*list != NULL) {
> - whitelisted = false;
> - i = 0;
> - while (ga_freeze_whitelist[i] != NULL) {
> - if (strcmp(*list, ga_freeze_whitelist[i]) == 0) {
> - whitelisted = true;
> - }
> - i++;
> - }
> - if (!whitelisted) {
> - g_debug("disabling command: %s", *list);
> - qmp_disable_command(*list);
> + bool whitelisted = false;
> + int i = 0;
> + const char *name = qmp_command_name(cmd);
> +
> + while (ga_freeze_whitelist[i] != NULL) {
> + if (strcmp(name, ga_freeze_whitelist[i]) == 0) {
> + whitelisted = true;
> }
> - g_free(*list);
> - list++;
> + i++;
> + }
> + if (!whitelisted) {
> + g_debug("disabling command: %s", name);
> + qmp_disable_command(name);
> }
> - g_free(list_head);
> }
>
> /* [re-]enable all commands, except those explicitly blacklisted by user */
> -static void ga_enable_non_blacklisted(GList *blacklist)
> +static void ga_enable_non_blacklisted(QmpCommand *cmd, void *opaque)
> {
> - char **list_head, **list;
> -
> - list_head = list = qmp_get_command_list();
> - while (*list != NULL) {
> - if (g_list_find_custom(blacklist, *list, ga_strcmp) == NULL &&
> - !qmp_command_is_enabled(*list)) {
> - g_debug("enabling command: %s", *list);
> - qmp_enable_command(*list);
> - }
> - g_free(*list);
> - list++;
> + GList *blacklist = opaque;
> + const char *name = qmp_command_name(cmd);
> +
> + if (g_list_find_custom(blacklist, name, ga_strcmp) == NULL &&
> + !qmp_command_is_enabled(cmd)) {
> + g_debug("enabling command: %s", name);
> + qmp_enable_command(name);
> }
> - g_free(list_head);
> }
>
> static bool ga_create_file(const char *path)
> @@ -424,7 +411,7 @@ void ga_set_frozen(GAState *s)
> return;
> }
> /* disable all non-whitelisted (for frozen state) commands */
> - ga_disable_non_whitelisted();
> + qmp_for_each_command(ga_disable_non_whitelisted, NULL);
> g_warning("disabling logging due to filesystem freeze");
> ga_disable_logging(s);
> s->frozen = true;
> @@ -460,7 +447,7 @@ void ga_unset_frozen(GAState *s)
> }
>
> /* enable all disabled, non-blacklisted commands */
> - ga_enable_non_blacklisted(s->blacklist);
> + qmp_for_each_command(ga_enable_non_blacklisted, s->blacklist);
> s->frozen = false;
> if (!ga_delete_file(s->state_filepath_isfrozen)) {
> g_warning("unable to delete %s, fsfreeze may not function properly",
> @@ -920,6 +907,11 @@ int64_t ga_get_fd_handle(GAState *s, Error **errp)
> return handle;
> }
>
> +static void ga_print_cmd(QmpCommand *cmd, void *opaque)
> +{
> + printf("%s\n", qmp_command_name(cmd));
> +}
> +
> int main(int argc, char **argv)
> {
> const char *sopt = "hVvdm:p:l:f:F::b:s:t:";
> @@ -996,15 +988,8 @@ int main(int argc, char **argv)
> daemonize = 1;
> break;
> case 'b': {
> - char **list_head, **list;
> if (is_help_option(optarg)) {
> - list_head = list = qmp_get_command_list();
> - while (*list != NULL) {
> - printf("%s\n", *list);
> - g_free(*list);
> - list++;
> - }
> - g_free(list_head);
> + qmp_for_each_command(ga_print_cmd, NULL);
> return 0;
> }
> for (j = 0, i = 0, len = strlen(optarg); i < len; i++) {
> @@ -1126,7 +1111,7 @@ int main(int argc, char **argv)
> s->deferred_options.log_filepath = log_filepath;
> }
> ga_disable_logging(s);
> - ga_disable_non_whitelisted();
> + qmp_for_each_command(ga_disable_non_whitelisted, NULL);
> } else {
> if (daemonize) {
> become_daemon(pid_filepath);
> --
> 1.8.3.1