tests: Add dirty page rate limit test

Add dirty page rate limit test if kernel support dirty ring,

The following qmp commands are covered by this test case:
"calc-dirty-rate", "query-dirty-rate", "set-vcpu-dirty-limit",
"cancel-vcpu-dirty-limit" and "query-vcpu-dirty-limit".

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Acked-by: Peter Xu <peterx@redhat.com>
Message-Id: <eed5b847a6ef0a9c02a36383dbdd7db367dd1e7e.1656177590.git.huangy81@chinatelecom.cn>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

tests/qtest/migration-helpers.c

@@ -83,6 +83,28 @@ QDict *wait_command(QTestState *who, const char *command, ...)
     return ret;
 }
 
+/*
+ * Execute the qmp command only
+ */
+QDict *qmp_command(QTestState *who, const char *command, ...)
+{
+    va_list ap;
+    QDict *resp, *ret;
+
+    va_start(ap, command);
+    resp = qtest_vqmp(who, command, ap);
+    va_end(ap);
+
+    g_assert(!qdict_haskey(resp, "error"));
+    g_assert(qdict_haskey(resp, "return"));
+
+    ret = qdict_get_qdict(resp, "return");
+    qobject_ref(ret);
+    qobject_unref(resp);
+
+    return ret;
+}
+
 /*
  * Send QMP command "migrate".
  * Arguments are built from @fmt... (formatted like

tests/qtest/migration-helpers.h

@@ -23,6 +23,8 @@ QDict *wait_command_fd(QTestState *who, int fd, const char *command, ...);
 G_GNUC_PRINTF(2, 3)
 QDict *wait_command(QTestState *who, const char *command, ...);
 
+QDict *qmp_command(QTestState *who, const char *command, ...);
+
 G_GNUC_PRINTF(3, 4)
 void migrate_qmp(QTestState *who, const char *uri, const char *fmt, ...);
 

tests/qtest/migration-test.c

@@ -24,6 +24,7 @@
 #include "qapi/qobject-input-visitor.h"
 #include "qapi/qobject-output-visitor.h"
 #include "crypto/tlscredspsk.h"
+#include "qapi/qmp/qlist.h"
 
 #include "migration-helpers.h"
 #include "tests/migration/migration-test.h"
@@ -46,6 +47,12 @@ unsigned start_address;
 unsigned end_address;
 static bool uffd_feature_thread_id;
 
+/*
+ * Dirtylimit stop working if dirty page rate error
+ * value less than DIRTYLIMIT_TOLERANCE_RANGE
+ */
+#define DIRTYLIMIT_TOLERANCE_RANGE  25  /* MB/s */
+
 #if defined(__linux__)
 #include <sys/syscall.h>
 #include <sys/vfs.h>
@@ -2059,6 +2066,253 @@ static void test_multifd_tcp_cancel(void)
     test_migrate_end(from, to2, true);
 }
 
+static void calc_dirty_rate(QTestState *who, uint64_t calc_time)
+{
+    qobject_unref(qmp_command(who,
+                  "{ 'execute': 'calc-dirty-rate',"
+                  "'arguments': { "
+                  "'calc-time': %ld,"
+                  "'mode': 'dirty-ring' }}",
+                  calc_time));
+}
+
+static QDict *query_dirty_rate(QTestState *who)
+{
+    return qmp_command(who, "{ 'execute': 'query-dirty-rate' }");
+}
+
+static void dirtylimit_set_all(QTestState *who, uint64_t dirtyrate)
+{
+    qobject_unref(qmp_command(who,
+                  "{ 'execute': 'set-vcpu-dirty-limit',"
+                  "'arguments': { "
+                  "'dirty-rate': %ld } }",
+                  dirtyrate));
+}
+
+static void cancel_vcpu_dirty_limit(QTestState *who)
+{
+    qobject_unref(qmp_command(who,
+                  "{ 'execute': 'cancel-vcpu-dirty-limit' }"));
+}
+
+static QDict *query_vcpu_dirty_limit(QTestState *who)
+{
+    QDict *rsp;
+
+    rsp = qtest_qmp(who, "{ 'execute': 'query-vcpu-dirty-limit' }");
+    g_assert(!qdict_haskey(rsp, "error"));
+    g_assert(qdict_haskey(rsp, "return"));
+
+    return rsp;
+}
+
+static bool calc_dirtyrate_ready(QTestState *who)
+{
+    QDict *rsp_return;
+    gchar *status;
+
+    rsp_return = query_dirty_rate(who);
+    g_assert(rsp_return);
+
+    status = g_strdup(qdict_get_str(rsp_return, "status"));
+    g_assert(status);
+
+    return g_strcmp0(status, "measuring");
+}
+
+static void wait_for_calc_dirtyrate_complete(QTestState *who,
+                                             int64_t time_s)
+{
+    int max_try_count = 10000;
+    usleep(time_s * 1000000);
+
+    while (!calc_dirtyrate_ready(who) && max_try_count--) {
+        usleep(1000);
+    }
+
+    /*
+     * Set the timeout with 10 s(max_try_count * 1000us),
+     * if dirtyrate measurement not complete, fail test.
+     */
+    g_assert_cmpint(max_try_count, !=, 0);
+}
+
+static int64_t get_dirty_rate(QTestState *who)
+{
+    QDict *rsp_return;
+    gchar *status;
+    QList *rates;
+    const QListEntry *entry;
+    QDict *rate;
+    int64_t dirtyrate;
+
+    rsp_return = query_dirty_rate(who);
+    g_assert(rsp_return);
+
+    status = g_strdup(qdict_get_str(rsp_return, "status"));
+    g_assert(status);
+    g_assert_cmpstr(status, ==, "measured");
+
+    rates = qdict_get_qlist(rsp_return, "vcpu-dirty-rate");
+    g_assert(rates && !qlist_empty(rates));
+
+    entry = qlist_first(rates);
+    g_assert(entry);
+
+    rate = qobject_to(QDict, qlist_entry_obj(entry));
+    g_assert(rate);
+
+    dirtyrate = qdict_get_try_int(rate, "dirty-rate", -1);
+
+    qobject_unref(rsp_return);
+    return dirtyrate;
+}
+
+static int64_t get_limit_rate(QTestState *who)
+{
+    QDict *rsp_return;
+    QList *rates;
+    const QListEntry *entry;
+    QDict *rate;
+    int64_t dirtyrate;
+
+    rsp_return = query_vcpu_dirty_limit(who);
+    g_assert(rsp_return);
+
+    rates = qdict_get_qlist(rsp_return, "return");
+    g_assert(rates && !qlist_empty(rates));
+
+    entry = qlist_first(rates);
+    g_assert(entry);
+
+    rate = qobject_to(QDict, qlist_entry_obj(entry));
+    g_assert(rate);
+
+    dirtyrate = qdict_get_try_int(rate, "limit-rate", -1);
+
+    qobject_unref(rsp_return);
+    return dirtyrate;
+}
+
+static QTestState *dirtylimit_start_vm(void)
+{
+    QTestState *vm = NULL;
+    g_autofree gchar *cmd = NULL;
+    const char *arch = qtest_get_arch();
+    g_autofree char *bootpath = NULL;
+
+    assert((strcmp(arch, "x86_64") == 0));
+    bootpath = g_strdup_printf("%s/bootsect", tmpfs);
+    assert(sizeof(x86_bootsect) == 512);
+    init_bootfile(bootpath, x86_bootsect, sizeof(x86_bootsect));
+
+    cmd = g_strdup_printf("-accel kvm,dirty-ring-size=4096 "
+                          "-name dirtylimit-test,debug-threads=on "
+                          "-m 150M -smp 1 "
+                          "-serial file:%s/vm_serial "
+                          "-drive file=%s,format=raw ",
+                          tmpfs, bootpath);
+
+    vm = qtest_init(cmd);
+    return vm;
+}
+
+static void dirtylimit_stop_vm(QTestState *vm)
+{
+    qtest_quit(vm);
+    cleanup("bootsect");
+    cleanup("vm_serial");
+}
+
+static void test_vcpu_dirty_limit(void)
+{
+    QTestState *vm;
+    int64_t origin_rate;
+    int64_t quota_rate;
+    int64_t rate ;
+    int max_try_count = 20;
+    int hit = 0;
+
+    /* Start vm for vcpu dirtylimit test */
+    vm = dirtylimit_start_vm();
+
+    /* Wait for the first serial output from the vm*/
+    wait_for_serial("vm_serial");
+
+    /* Do dirtyrate measurement with calc time equals 1s */
+    calc_dirty_rate(vm, 1);
+
+    /* Sleep calc time and wait for calc dirtyrate complete */
+    wait_for_calc_dirtyrate_complete(vm, 1);
+
+    /* Query original dirty page rate */
+    origin_rate = get_dirty_rate(vm);
+
+    /* VM booted from bootsect should dirty memory steadily */
+    assert(origin_rate != 0);
+
+    /* Setup quota dirty page rate at half of origin */
+    quota_rate = origin_rate / 2;
+
+    /* Set dirtylimit */
+    dirtylimit_set_all(vm, quota_rate);
+
+    /*
+     * Check if set-vcpu-dirty-limit and query-vcpu-dirty-limit
+     * works literally
+     */
+    g_assert_cmpint(quota_rate, ==, get_limit_rate(vm));
+
+    /* Sleep a bit to check if it take effect */
+    usleep(2000000);
+
+    /*
+     * Check if dirtylimit take effect realistically, set the
+     * timeout with 20 s(max_try_count * 1s), if dirtylimit
+     * doesn't take effect, fail test.
+     */
+    while (--max_try_count) {
+        calc_dirty_rate(vm, 1);
+        wait_for_calc_dirtyrate_complete(vm, 1);
+        rate = get_dirty_rate(vm);
+
+        /*
+         * Assume hitting if current rate is less
+         * than quota rate (within accepting error)
+         */
+        if (rate < (quota_rate + DIRTYLIMIT_TOLERANCE_RANGE)) {
+            hit = 1;
+            break;
+        }
+    }
+
+    g_assert_cmpint(hit, ==, 1);
+
+    hit = 0;
+    max_try_count = 20;
+
+    /* Check if dirtylimit cancellation take effect */
+    cancel_vcpu_dirty_limit(vm);
+    while (--max_try_count) {
+        calc_dirty_rate(vm, 1);
+        wait_for_calc_dirtyrate_complete(vm, 1);
+        rate = get_dirty_rate(vm);
+
+        /*
+         * Assume dirtylimit be canceled if current rate is
+         * greater than quota rate (within accepting error)
+         */
+        if (rate > (quota_rate + DIRTYLIMIT_TOLERANCE_RANGE)) {
+            hit = 1;
+            break;
+        }
+    }
+
+    g_assert_cmpint(hit, ==, 1);
+    dirtylimit_stop_vm(vm);
+}
+
 static bool kvm_dirty_ring_supported(void)
 {
 #if defined(__linux__) && defined(HOST_X86_64)
@@ -2204,6 +2458,8 @@ int main(int argc, char **argv)
     if (kvm_dirty_ring_supported()) {
         qtest_add_func("/migration/dirty_ring",
                        test_precopy_unix_dirty_ring);
+        qtest_add_func("/migration/vcpu_dirty_limit",
+                       test_vcpu_dirty_limit);
     }
 
     ret = g_test_run();