[PATCH v7 1/3] migration/dirtyrate: implement vCPU dirtyrate calculation periodically

[huangy81]

From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>

Introduce the third method GLOBAL_DIRTY_LIMIT of dirty
tracking for calculate dirtyrate periodly for dirty restraint.

Implement thread for calculate dirtyrate periodly, which will
be used for dirty restraint.

Add dirtylimit.h to introduce the util function for dirty
limit implementation.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
---
 include/exec/memory.h       |   5 +-
 include/sysemu/dirtylimit.h |  44 ++++++++++++++
 migration/dirtyrate.c       | 139 ++++++++++++++++++++++++++++++++++++++++----
 migration/dirtyrate.h       |   2 +
 4 files changed, 179 insertions(+), 11 deletions(-)
 create mode 100644 include/sysemu/dirtylimit.h

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 20f1b27..606bec8 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -69,7 +69,10 @@ static inline void fuzz_dma_read_cb(size_t addr,
 /* Dirty tracking enabled because measuring dirty rate */
 #define GLOBAL_DIRTY_DIRTY_RATE (1U << 1)
 
-#define GLOBAL_DIRTY_MASK  (0x3)
+/* Dirty tracking enabled because dirty limit */
+#define GLOBAL_DIRTY_LIMIT      (1U << 2)
+
+#define GLOBAL_DIRTY_MASK  (0x7)
 
 extern unsigned int global_dirty_tracking;
 
diff --git a/include/sysemu/dirtylimit.h b/include/sysemu/dirtylimit.h
new file mode 100644
index 0000000..49298a2
--- /dev/null
+++ b/include/sysemu/dirtylimit.h
@@ -0,0 +1,44 @@
+/*
+ * dirty limit helper functions
+ *
+ * Copyright (c) 2021 CHINA TELECOM CO.,LTD.
+ *
+ * Authors:
+ *  Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#ifndef QEMU_DIRTYRLIMIT_H
+#define QEMU_DIRTYRLIMIT_H
+
+#define DIRTYLIMIT_CALC_PERIOD_TIME_S   15      /* 15s */
+
+/**
+ * dirtylimit_calc_current:
+ *
+ * get current dirty page rate for specified vCPU.
+ */
+int64_t dirtylimit_calc_current(int cpu_index);
+
+/**
+ * dirtylimit_calc:
+ *
+ * start dirty page rate calculation thread.
+ */
+void dirtylimit_calc(void);
+
+/**
+ * dirtylimit_calc_quit:
+ *
+ * quit dirty page rate calculation thread.
+ */
+void dirtylimit_calc_quit(void);
+
+/**
+ * dirtylimit_calc_state_init:
+ *
+ * initialize dirty page rate calculation state.
+ */
+void dirtylimit_calc_state_init(int max_cpus);
+#endif
diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index d65e744..d370a21 100644
--- a/migration/dirtyrate.c
+++ b/migration/dirtyrate.c
@@ -27,6 +27,7 @@
 #include "qapi/qmp/qdict.h"
 #include "sysemu/kvm.h"
 #include "sysemu/runstate.h"
+#include "sysemu/dirtylimit.h"
 #include "exec/memory.h"
 
 /*
@@ -46,6 +47,134 @@ static struct DirtyRateStat DirtyStat;
 static DirtyRateMeasureMode dirtyrate_mode =
                 DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
 
+#define DIRTYLIMIT_CALC_TIME_MS         1000    /* 1000ms */
+
+struct {
+    DirtyRatesData data;
+    int64_t period;
+    bool quit;
+} *dirtylimit_calc_state;
+
+static void dirtylimit_global_dirty_log_start(void)
+{
+    qemu_mutex_lock_iothread();
+    memory_global_dirty_log_start(GLOBAL_DIRTY_LIMIT);
+    qemu_mutex_unlock_iothread();
+}
+
+static void dirtylimit_global_dirty_log_stop(void)
+{
+    qemu_mutex_lock_iothread();
+    memory_global_dirty_log_sync();
+    memory_global_dirty_log_stop(GLOBAL_DIRTY_LIMIT);
+    qemu_mutex_unlock_iothread();
+}
+
+static inline void record_dirtypages(DirtyPageRecord *dirty_pages,
+                                     CPUState *cpu, bool start)
+{
+    if (start) {
+        dirty_pages[cpu->cpu_index].start_pages = cpu->dirty_pages;
+    } else {
+        dirty_pages[cpu->cpu_index].end_pages = cpu->dirty_pages;
+    }
+}
+
+static void dirtylimit_calc_func(void)
+{
+    CPUState *cpu;
+    DirtyPageRecord *dirty_pages;
+    int64_t start_time, end_time, calc_time;
+    DirtyRateVcpu rate;
+    int i = 0;
+
+    dirty_pages = g_malloc0(sizeof(*dirty_pages) *
+        dirtylimit_calc_state->data.nvcpu);
+
+    dirtylimit_global_dirty_log_start();
+
+    CPU_FOREACH(cpu) {
+        record_dirtypages(dirty_pages, cpu, true);
+    }
+
+    start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+    g_usleep(DIRTYLIMIT_CALC_TIME_MS * 1000);
+    end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+    calc_time = end_time - start_time;
+
+    dirtylimit_global_dirty_log_stop();
+
+    CPU_FOREACH(cpu) {
+        record_dirtypages(dirty_pages, cpu, false);
+    }
+
+    for (i = 0; i < dirtylimit_calc_state->data.nvcpu; i++) {
+        uint64_t increased_dirty_pages =
+            dirty_pages[i].end_pages - dirty_pages[i].start_pages;
+        uint64_t memory_size_MB =
+            (increased_dirty_pages * TARGET_PAGE_SIZE) >> 20;
+        int64_t dirtyrate = (memory_size_MB * 1000) / calc_time;
+
+        rate.id = i;
+        rate.dirty_rate  = dirtyrate;
+        dirtylimit_calc_state->data.rates[i] = rate;
+
+        trace_dirtyrate_do_calculate_vcpu(i,
+            dirtylimit_calc_state->data.rates[i].dirty_rate);
+    }
+}
+
+static void *dirtylimit_calc_thread(void *opaque)
+{
+    rcu_register_thread();
+
+    while (!qatomic_read(&dirtylimit_calc_state->quit)) {
+        dirtylimit_calc_func();
+        sleep(dirtylimit_calc_state->period);
+    }
+
+    rcu_unregister_thread();
+    return NULL;
+}
+
+int64_t dirtylimit_calc_current(int cpu_index)
+{
+    DirtyRateVcpu *rates = dirtylimit_calc_state->data.rates;
+
+    return qatomic_read(&rates[cpu_index].dirty_rate);
+}
+
+void dirtylimit_calc(void)
+{
+    if (unlikely(qatomic_read(&dirtylimit_calc_state->quit))) {
+        qatomic_set(&dirtylimit_calc_state->quit, 0);
+        QemuThread thread;
+        qemu_thread_create(&thread, "dirtylimit-calc",
+            dirtylimit_calc_thread,
+            NULL, QEMU_THREAD_DETACHED);
+    }
+}
+
+void dirtylimit_calc_quit(void)
+{
+    qatomic_set(&dirtylimit_calc_state->quit, 1);
+}
+
+void dirtylimit_calc_state_init(int max_cpus)
+{
+    dirtylimit_calc_state =
+        g_malloc0(sizeof(*dirtylimit_calc_state));
+
+    dirtylimit_calc_state->data.nvcpu = max_cpus;
+    dirtylimit_calc_state->data.rates =
+        g_malloc0(sizeof(DirtyRateVcpu) * max_cpus);
+
+    dirtylimit_calc_state->period =
+        DIRTYLIMIT_CALC_PERIOD_TIME_S;
+
+    dirtylimit_calc_state->quit = true;
+}
+
 static int64_t set_sample_page_period(int64_t msec, int64_t initial_time)
 {
     int64_t current_time;
@@ -396,16 +525,6 @@ static bool compare_page_hash_info(struct 
RamblockDirtyInfo *info,
     return true;
 }
 
-static inline void record_dirtypages(DirtyPageRecord *dirty_pages,
-                                     CPUState *cpu, bool start)
-{
-    if (start) {
-        dirty_pages[cpu->cpu_index].start_pages = cpu->dirty_pages;
-    } else {
-        dirty_pages[cpu->cpu_index].end_pages = cpu->dirty_pages;
-    }
-}
-
 static void dirtyrate_global_dirty_log_start(void)
 {
     qemu_mutex_lock_iothread();
diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
index 69d4c5b..e96acdc 100644
--- a/migration/dirtyrate.h
+++ b/migration/dirtyrate.h
@@ -70,6 +70,8 @@ typedef struct VcpuStat {
     DirtyRateVcpu *rates; /* array of dirty rate for each vcpu */
 } VcpuStat;
 
+typedef struct VcpuStat DirtyRatesData;
+
 /*
  * Store calculation statistics for each measure.
  */
-- 
1.8.3.1