Add the hmp and qmp interface to drop vm's page cache, users
can control the type of cache they want vm to drop.
Signed-off-by: Liang Li <liang.z.li@xxxxxxxxx>
---
balloon.c | 19 +++++++++++++++++++
hmp-commands.hx | 15 +++++++++++++++
hmp.c | 22 ++++++++++++++++++++++
hmp.h | 3 +++
monitor.c | 18 ++++++++++++++++++
qapi-schema.json | 35 +++++++++++++++++++++++++++++++++++
qmp-commands.hx | 23 +++++++++++++++++++++++
7 files changed, 135 insertions(+)
diff --git a/balloon.c b/balloon.c
index 0fb34bf..3d96111 100644
--- a/balloon.c
+++ b/balloon.c
@@ -122,3 +122,22 @@ void qmp_balloon(int64_t target, Error **errp)
trace_balloon_event(balloon_opaque, target);
balloon_event_fn(balloon_opaque, target);
}
+
+void qmp_balloon_drop_cache(DropCacheType type, Error **errp)
+{
+ if (!have_balloon(errp)) {
+ return;
+ }
+
+ if (!balloon_drop_cache_fn) {
+ error_setg(errp, QERR_UNSUPPORTED);
+ return;
+ }
+ if (type < 0 && type >= DROP_CACHE_TYPE__MAX) {
+ error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "type",
+ "a value in range[0, 3]");
+ return;
+ }
+
+ balloon_drop_cache_fn(balloon_opaque, type);
+}
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 98b4b1a..c73572c 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1378,6 +1378,21 @@ Request VM to change its memory allocation to @var{value} (in MB).
ETEXI
{
+ .name = "balloon_drop_cache",
+ .args_type = "type:s",
+ .params = "type",
+ .help = "request VM to drop its page caches",
+ .mhandler.cmd = hmp_balloon_drop_cache,
+ .command_completion = balloon_drop_cache_completion
+ },
+
+STEXI
+@item balloon_drop_cache @var{type}
+@findex balloon_drop_cache
+Request VM to dorp its page caches.
+ETEXI
+
+ {
.name = "set_link",
.args_type = "name:s,up:b",
.params = "name on|off",
diff --git a/hmp.c b/hmp.c
index a4b1d3d..3aa1062 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1061,6 +1061,28 @@ void hmp_balloon(Monitor *mon, const QDict *qdict)
}
}
+void hmp_balloon_drop_cache(Monitor *mon, const QDict *qdict)
+{
+ const char *type = qdict_get_str(qdict, "type");
+ Error *err = NULL;
+ int i;
+
+ for (i = 0; i < DROP_CACHE_TYPE__MAX; i++) {
+ if (strcmp(type, DropCacheType_lookup[i]) == 0) {
+ qmp_balloon_drop_cache(1 + i, &err);
+ break;
+ }
+ }
+
+ if (i == DROP_CACHE_TYPE__MAX) {
+ error_setg(&err, QERR_INVALID_PARAMETER, type);
+ }
+
+ if (err) {
+ error_report_err(err);
+ }
+}
+
void hmp_block_resize(Monitor *mon, const QDict *qdict)
{
const char *device = qdict_get_str(qdict, "device");
diff --git a/hmp.h b/hmp.h
index 093d65f..6bb6499 100644
--- a/hmp.h
+++ b/hmp.h
@@ -55,6 +55,7 @@ void hmp_nmi(Monitor *mon, const QDict *qdict);
void hmp_set_link(Monitor *mon, const QDict *qdict);
void hmp_block_passwd(Monitor *mon, const QDict *qdict);
void hmp_balloon(Monitor *mon, const QDict *qdict);
+void hmp_balloon_drop_cache(Monitor *mon, const QDict *qdict);
void hmp_block_resize(Monitor *mon, const QDict *qdict);
void hmp_snapshot_blkdev(Monitor *mon, const QDict *qdict);
void hmp_snapshot_blkdev_internal(Monitor *mon, const QDict *qdict);
@@ -120,6 +121,8 @@ void watchdog_action_completion(ReadLineState *rs, int nb_args,
const char *str);
void migrate_set_capability_completion(ReadLineState *rs, int nb_args,
const char *str);
+void balloon_drop_cache_completion(ReadLineState *rs, int nb_args,
+ const char *str);
void migrate_set_parameter_completion(ReadLineState *rs, int nb_args,
const char *str);
void host_net_add_completion(ReadLineState *rs, int nb_args, const char *str);
diff --git a/monitor.c b/monitor.c
index a27e115..eefdf3d 100644
--- a/monitor.c
+++ b/monitor.c
@@ -3367,6 +3367,24 @@ void migrate_set_parameter_completion(ReadLineState *rs, int nb_args,
}
}
+void balloon_drop_cache_completion(ReadLineState *rs, int nb_args,
+ const char *str)
+{
+ size_t len;
+
+ len = strlen(str);
+ readline_set_completion_index(rs, len);
+ if (nb_args == 2) {
+ int i;
+ for (i = 0; i < DROP_CACHE_TYPE__MAX; i++) {
+ const char *name = DropCacheType_lookup[i];
+ if (!strncmp(str, name, len)) {
+ readline_add_completion(rs, name);
+ }
+ }
+ }
+}
+
void host_net_add_completion(ReadLineState *rs, int nb_args, const char *str)
{
int i;
diff --git a/qapi-schema.json b/qapi-schema.json
index 8483bdf..117f70a 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1655,6 +1655,41 @@
{ 'command': 'balloon', 'data': {'value': 'int'} }
##
+# @DropCacheType
+#
+# Cache types enumeration
+#
+# @clean: Drop the clean page cache.
+#
+# @slab: Drop the slab cache.
+#
+# @all: Drop both the clean and the slab cache.
+#
+# Since: 2.7
+##
+{ 'enum': 'DropCacheType', 'data': ['clean', 'slab', 'all'] }
+
+##
+# @balloon_drop_cache:
+#
+# Request the vm to drop its cache.
+#
+# @value: the type of cache want vm to drop
+#
+# Returns: Nothing on success
+# If the balloon driver is enabled but not functional because the KVM
+# kernel module cannot support it, KvmMissingCap
+# If no balloon device is present, DeviceNotActive
+#
+# Notes: This command just issues a request to the guest. When it returns,
+# the drop cache operation may not have completed. A guest can drop its
+# cache independent of this command.
+#
+# Since: 2.7.0
+##
+{ 'command': 'balloon_drop_cache', 'data': {'value': 'DropCacheType'} }
+
+##
# @Abort
#
# This action can be used to test transaction failure.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 28801a2..6650ba0 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1802,6 +1802,29 @@ Example:
EQMP
{
+ .name = "balloon_drop_cache",
+ .args_type = "value:i",
+ .mhandler.cmd_new = qmp_marshal_balloon_drop_cache,
+ },
+
+SQMP
+balloon_drop_cache
+-------
+
+Request VM to drop its cache.
+
+Arguments:
+
+- "value": cache type to drop (json-int)
+
+Example:
+
+-> { "execute": "balloon_drop_cache", "arguments": { "value": 1 } }
+<- { "return": {} }
+
+EQMP
+
+ {
.name = "set_link",
.args_type = "name:s,up:b",
.mhandler.cmd_new = qmp_marshal_set_link,
--
1.9.1
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