[PATCH v22 0/8] support dirty restraint on vCPU

[PATCH v22 0/8] support dirty restraint on vCPU

[huangy81]

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

This is v22 of dirtylimit series. 
The following is the history of the patchset, since v22 kind of different from
the original version, i made abstracts of changelog:

RFC and v1: https://lore.kernel.org/qemu-devel/cover.1637214721.git.huangy81@chinatelecom.cn/
v2: https://lore.kernel.org/qemu-devel/cover.1637256224.git.huangy81@chinatelecom.cn/
v1->v2 changelog: 
- rename some function and variables. refactor the original algo of dirtylimit. Thanks for
  the comments given by Juan Quintela.
v3: https://lore.kernel.org/qemu-devel/cover.1637403404.git.huangy81@chinatelecom.cn/
v4: https://lore.kernel.org/qemu-devel/cover.1637653303.git.huangy81@chinatelecom.cn/
v5: https://lore.kernel.org/qemu-devel/cover.1637759139.git.huangy81@chinatelecom.cn/
v6: https://lore.kernel.org/qemu-devel/cover.1637856472.git.huangy81@chinatelecom.cn/
v7: https://lore.kernel.org/qemu-devel/cover.1638202004.git.huangy81@chinatelecom.cn/
v2->v7 changelog:
- refactor the docs, annotation and fix bugs of the original algo of dirtylimit.
  Thanks for the review given by Markus Armbruster. 
v8: https://lore.kernel.org/qemu-devel/cover.1638463260.git.huangy81@chinatelecom.cn/
v9: https://lore.kernel.org/qemu-devel/cover.1638495274.git.huangy81@chinatelecom.cn/
v10: https://lore.kernel.org/qemu-devel/cover.1639479557.git.huangy81@chinatelecom.cn/
v7->v10 changelog:
- introduce a simpler but more efficient algo of dirtylimit inspired by Peter Xu.
- keep polishing the annotation suggested by Markus Armbruster.
v11: https://lore.kernel.org/qemu-devel/cover.1641315745.git.huangy81@chinatelecom.cn/
v12: https://lore.kernel.org/qemu-devel/cover.1642774952.git.huangy81@chinatelecom.cn/
v13: https://lore.kernel.org/qemu-devel/cover.1644506963.git.huangy81@chinatelecom.cn/
v10->v13 changelog:
- handle the hotplug/unplug scenario.
- refactor the new algo, split the commit and make the code more clean.
v14: https://lore.kernel.org/qemu-devel/cover.1644509582.git.huangy81@chinatelecom.cn/
v13->v14 changelog:
- sent by accident.
v15: https://lore.kernel.org/qemu-devel/cover.1644976045.git.huangy81@chinatelecom.cn/ 
v16: https://lore.kernel.org/qemu-devel/cover.1645067452.git.huangy81@chinatelecom.cn/ 
v17: https://lore.kernel.org/qemu-devel/cover.1646243252.git.huangy81@chinatelecom.cn/
v14->v17 changelog: 
- do some code clean and fix test bug reported by Dr. David Alan Gilbert.
v18: https://lore.kernel.org/qemu-devel/cover.1646247968.git.huangy81@chinatelecom.cn/
v19: https://lore.kernel.org/qemu-devel/cover.1647390160.git.huangy81@chinatelecom.cn/
v20: https://lore.kernel.org/qemu-devel/cover.1647396907.git.huangy81@chinatelecom.cn/
v21: https://lore.kernel.org/qemu-devel/cover.1647435820.git.huangy81@chinatelecom.cn/
v17->v21 changelog:
- add qtest, fix bug and do code clean. 
v21->v22 changelog:
- move the vcpu dirty limit test into migration-test and do some modification suggested
  by Peter.

Please review.

Yong.

Abstract
========

This patchset introduce a mechanism to impose dirty restraint
on vCPU, aiming to keep the vCPU running in a certain dirtyrate
given by user. dirty restraint on vCPU maybe an alternative
method to implement convergence logic for live migration,
which could improve guest memory performance during migration
compared with traditional method in theory.

For the current live migration implementation, the convergence
logic throttles all vCPUs of the VM, which has some side effects.
-'read processes' on vCPU will be unnecessarily penalized
- throttle increase percentage step by step, which seems
  struggling to find the optimal throttle percentage when
  dirtyrate is high.
- hard to predict the remaining time of migration if the
  throttling percentage reachs 99%

to a certain extent, the dirty restraint machnism can fix these
effects by throttling at vCPU granularity during migration.

the implementation is rather straightforward, we calculate
vCPU dirtyrate via the Dirty Ring mechanism periodically
as the commit 0e21bf246 "implement dirty-ring dirtyrate calculation"
does, for vCPU that be specified to impose dirty restraint,
we throttle it periodically as the auto-converge does, once after
throttling, we compare the quota dirtyrate with current dirtyrate,
if current dirtyrate is not under the quota, increase the throttling
percentage until current dirtyrate is under the quota.

this patchset is the basis of implmenting a new auto-converge method
for live migration, we introduce two qmp commands for impose/cancel
the dirty restraint on specified vCPU, so it also can be an independent
api to supply the upper app such as libvirt, which can use it to
implement the convergence logic during live migration, supplemented
with the qmp 'calc-dirty-rate' command or whatever.

we post this patchset for RFC and any corrections and suggetions about
the implementation, api, throttleing algorithm or whatever are very
appreciated!

Please review, thanks !

Best Regards !

Hyman Huang (8):
  accel/kvm/kvm-all: Refactor per-vcpu dirty ring reaping
  cpus: Introduce cpu_list_generation_id
  migration/dirtyrate: Refactor dirty page rate calculation
  softmmu/dirtylimit: Implement vCPU dirtyrate calculation periodically
  accel/kvm/kvm-all: Introduce kvm_dirty_ring_size function
  softmmu/dirtylimit: Implement virtual CPU throttle
  softmmu/dirtylimit: Implement dirty page rate limit
  tests: Add dirty page rate limit test

 accel/kvm/kvm-all.c             |  46 ++-
 accel/stubs/kvm-stub.c          |   6 +
 cpus-common.c                   |   8 +
 hmp-commands-info.hx            |  13 +
 hmp-commands.hx                 |  32 +++
 include/exec/cpu-common.h       |   1 +
 include/exec/memory.h           |   5 +-
 include/hw/core/cpu.h           |   6 +
 include/monitor/hmp.h           |   3 +
 include/sysemu/dirtylimit.h     |  37 +++
 include/sysemu/dirtyrate.h      |  28 ++
 include/sysemu/kvm.h            |   2 +
 migration/dirtyrate.c           | 227 +++++++++------
 migration/dirtyrate.h           |   7 +-
 qapi/migration.json             |  80 ++++++
 softmmu/dirtylimit.c            | 602 ++++++++++++++++++++++++++++++++++++++++
 softmmu/meson.build             |   1 +
 softmmu/trace-events            |   7 +
 tests/qtest/migration-helpers.c |  22 ++
 tests/qtest/migration-helpers.h |   2 +
 tests/qtest/migration-test.c    | 255 +++++++++++++++++
 tests/qtest/qmp-cmd-test.c      |   2 +
 22 files changed, 1293 insertions(+), 99 deletions(-)
 create mode 100644 include/sysemu/dirtylimit.h
 create mode 100644 include/sysemu/dirtyrate.h
 create mode 100644 softmmu/dirtylimit.c

-- 
1.8.3.1

[PATCH v22 1/8] accel/kvm/kvm-all: Refactor per-vcpu dirty ring reaping

[huangy81]

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

Add a non-required argument 'CPUState' to kvm_dirty_ring_reap so
that it can cover single vcpu dirty-ring-reaping scenario.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Reviewed-by: Peter Xu <peterx@redhat.com>
---
 accel/kvm/kvm-all.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 5f1377c..c30870ae 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -756,17 +756,20 @@ static uint32_t kvm_dirty_ring_reap_one(KVMState *s, CPUState *cpu)
 }
 
 /* Must be with slots_lock held */
-static uint64_t kvm_dirty_ring_reap_locked(KVMState *s)
+static uint64_t kvm_dirty_ring_reap_locked(KVMState *s, CPUState* cpu)
 {
     int ret;
-    CPUState *cpu;
     uint64_t total = 0;
     int64_t stamp;
 
     stamp = get_clock();
 
-    CPU_FOREACH(cpu) {
-        total += kvm_dirty_ring_reap_one(s, cpu);
+    if (cpu) {
+        total = kvm_dirty_ring_reap_one(s, cpu);
+    } else {
+        CPU_FOREACH(cpu) {
+            total += kvm_dirty_ring_reap_one(s, cpu);
+        }
     }
 
     if (total) {
@@ -787,7 +790,7 @@ static uint64_t kvm_dirty_ring_reap_locked(KVMState *s)
  * Currently for simplicity, we must hold BQL before calling this.  We can
  * consider to drop the BQL if we're clear with all the race conditions.
  */
-static uint64_t kvm_dirty_ring_reap(KVMState *s)
+static uint64_t kvm_dirty_ring_reap(KVMState *s, CPUState *cpu)
 {
     uint64_t total;
 
@@ -807,7 +810,7 @@ static uint64_t kvm_dirty_ring_reap(KVMState *s)
      *     reset below.
      */
     kvm_slots_lock();
-    total = kvm_dirty_ring_reap_locked(s);
+    total = kvm_dirty_ring_reap_locked(s, cpu);
     kvm_slots_unlock();
 
     return total;
@@ -854,7 +857,7 @@ static void kvm_dirty_ring_flush(void)
      * vcpus out in a synchronous way.
      */
     kvm_cpu_synchronize_kick_all();
-    kvm_dirty_ring_reap(kvm_state);
+    kvm_dirty_ring_reap(kvm_state, NULL);
     trace_kvm_dirty_ring_flush(1);
 }
 
@@ -1398,7 +1401,7 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
                  * Not easy.  Let's cross the fingers until it's fixed.
                  */
                 if (kvm_state->kvm_dirty_ring_size) {
-                    kvm_dirty_ring_reap_locked(kvm_state);
+                    kvm_dirty_ring_reap_locked(kvm_state, NULL);
                 } else {
                     kvm_slot_get_dirty_log(kvm_state, mem);
                 }
@@ -1470,7 +1473,7 @@ static void *kvm_dirty_ring_reaper_thread(void *data)
         r->reaper_state = KVM_DIRTY_RING_REAPER_REAPING;
 
         qemu_mutex_lock_iothread();
-        kvm_dirty_ring_reap(s);
+        kvm_dirty_ring_reap(s, NULL);
         qemu_mutex_unlock_iothread();
 
         r->reaper_iteration++;
@@ -2957,7 +2960,7 @@ int kvm_cpu_exec(CPUState *cpu)
              */
             trace_kvm_dirty_ring_full(cpu->cpu_index);
             qemu_mutex_lock_iothread();
-            kvm_dirty_ring_reap(kvm_state);
+            kvm_dirty_ring_reap(kvm_state, NULL);
             qemu_mutex_unlock_iothread();
             ret = 0;
             break;
-- 
1.8.3.1

[PATCH v22 2/8] cpus: Introduce cpu_list_generation_id

[huangy81]

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

Introduce cpu_list_generation_id to track cpu list generation so
that cpu hotplug/unplug can be detected during measurement of
dirty page rate.

cpu_list_generation_id could be used to detect changes of cpu
list, which is prepared for dirty page rate measurement.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Reviewed-by: Peter Xu <peterx@redhat.com>
---
 cpus-common.c             | 8 ++++++++
 include/exec/cpu-common.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/cpus-common.c b/cpus-common.c
index db459b4..793364d 100644
--- a/cpus-common.c
+++ b/cpus-common.c
@@ -73,6 +73,12 @@ static int cpu_get_free_index(void)
 }
 
 CPUTailQ cpus = QTAILQ_HEAD_INITIALIZER(cpus);
+static unsigned int cpu_list_generation_id;
+
+unsigned int cpu_list_generation_id_get(void)
+{
+    return cpu_list_generation_id;
+}
 
 void cpu_list_add(CPUState *cpu)
 {
@@ -84,6 +90,7 @@ void cpu_list_add(CPUState *cpu)
         assert(!cpu_index_auto_assigned);
     }
     QTAILQ_INSERT_TAIL_RCU(&cpus, cpu, node);
+    cpu_list_generation_id++;
 }
 
 void cpu_list_remove(CPUState *cpu)
@@ -96,6 +103,7 @@ void cpu_list_remove(CPUState *cpu)
 
     QTAILQ_REMOVE_RCU(&cpus, cpu, node);
     cpu->cpu_index = UNASSIGNED_CPU_INDEX;
+    cpu_list_generation_id++;
 }
 
 CPUState *qemu_get_cpu(int index)
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index 50a7d29..7cba376 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -32,6 +32,7 @@ extern intptr_t qemu_host_page_mask;
 void qemu_init_cpu_list(void);
 void cpu_list_lock(void);
 void cpu_list_unlock(void);
+unsigned int cpu_list_generation_id_get(void);
 
 void tcg_flush_softmmu_tlb(CPUState *cs);
 
-- 
1.8.3.1

[PATCH v22 3/8] migration/dirtyrate: Refactor dirty page rate calculation

[huangy81]

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

abstract out dirty log change logic into function
global_dirty_log_change.

abstract out dirty page rate calculation logic via
dirty-ring into function vcpu_calculate_dirtyrate.

abstract out mathematical dirty page rate calculation
into do_calculate_dirtyrate, decouple it from DirtyStat.

rename set_sample_page_period to dirty_stat_wait, which
is well-understood and will be reused in dirtylimit.

handle cpu hotplug/unplug scenario during measurement of
dirty page rate.

export util functions outside migration.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Reviewed-by: Peter Xu <peterx@redhat.com>
---
 include/sysemu/dirtyrate.h |  28 ++++++
 migration/dirtyrate.c      | 227 ++++++++++++++++++++++++++++-----------------
 migration/dirtyrate.h      |   7 +-
 3 files changed, 174 insertions(+), 88 deletions(-)
 create mode 100644 include/sysemu/dirtyrate.h

diff --git a/include/sysemu/dirtyrate.h b/include/sysemu/dirtyrate.h
new file mode 100644
index 0000000..4d3b9a4
--- /dev/null
+++ b/include/sysemu/dirtyrate.h
@@ -0,0 +1,28 @@
+/*
+ * dirty page rate helper functions
+ *
+ * Copyright (c) 2022 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_DIRTYRATE_H
+#define QEMU_DIRTYRATE_H
+
+typedef struct VcpuStat {
+    int nvcpu; /* number of vcpu */
+    DirtyRateVcpu *rates; /* array of dirty rate for each vcpu */
+} VcpuStat;
+
+int64_t vcpu_calculate_dirtyrate(int64_t calc_time_ms,
+                                 VcpuStat *stat,
+                                 unsigned int flag,
+                                 bool one_shot);
+
+void global_dirty_log_change(unsigned int flag,
+                             bool start);
+#endif
diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index aace12a..795fab5 100644
--- a/migration/dirtyrate.c
+++ b/migration/dirtyrate.c
@@ -46,7 +46,7 @@ static struct DirtyRateStat DirtyStat;
 static DirtyRateMeasureMode dirtyrate_mode =
                 DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
 
-static int64_t set_sample_page_period(int64_t msec, int64_t initial_time)
+static int64_t dirty_stat_wait(int64_t msec, int64_t initial_time)
 {
     int64_t current_time;
 
@@ -60,6 +60,132 @@ static int64_t set_sample_page_period(int64_t msec, int64_t initial_time)
     return msec;
 }
 
+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 int64_t do_calculate_dirtyrate(DirtyPageRecord dirty_pages,
+                                      int64_t calc_time_ms)
+{
+    uint64_t memory_size_MB;
+    uint64_t increased_dirty_pages =
+        dirty_pages.end_pages - dirty_pages.start_pages;
+
+    memory_size_MB = (increased_dirty_pages * TARGET_PAGE_SIZE) >> 20;
+
+    return memory_size_MB * 1000 / calc_time_ms;
+}
+
+void global_dirty_log_change(unsigned int flag, bool start)
+{
+    qemu_mutex_lock_iothread();
+    if (start) {
+        memory_global_dirty_log_start(flag);
+    } else {
+        memory_global_dirty_log_stop(flag);
+    }
+    qemu_mutex_unlock_iothread();
+}
+
+/*
+ * global_dirty_log_sync
+ * 1. sync dirty log from kvm
+ * 2. stop dirty tracking if needed.
+ */
+static void global_dirty_log_sync(unsigned int flag, bool one_shot)
+{
+    qemu_mutex_lock_iothread();
+    memory_global_dirty_log_sync();
+    if (one_shot) {
+        memory_global_dirty_log_stop(flag);
+    }
+    qemu_mutex_unlock_iothread();
+}
+
+static DirtyPageRecord *vcpu_dirty_stat_alloc(VcpuStat *stat)
+{
+    CPUState *cpu;
+    DirtyPageRecord *records;
+    int nvcpu = 0;
+
+    CPU_FOREACH(cpu) {
+        nvcpu++;
+    }
+
+    stat->nvcpu = nvcpu;
+    stat->rates = g_malloc0(sizeof(DirtyRateVcpu) * nvcpu);
+
+    records = g_malloc0(sizeof(DirtyPageRecord) * nvcpu);
+
+    return records;
+}
+
+static void vcpu_dirty_stat_collect(VcpuStat *stat,
+                                    DirtyPageRecord *records,
+                                    bool start)
+{
+    CPUState *cpu;
+
+    CPU_FOREACH(cpu) {
+        record_dirtypages(records, cpu, start);
+    }
+}
+
+int64_t vcpu_calculate_dirtyrate(int64_t calc_time_ms,
+                                 VcpuStat *stat,
+                                 unsigned int flag,
+                                 bool one_shot)
+{
+    DirtyPageRecord *records;
+    int64_t init_time_ms;
+    int64_t duration;
+    int64_t dirtyrate;
+    int i = 0;
+    unsigned int gen_id;
+
+retry:
+    init_time_ms = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+
+    cpu_list_lock();
+    gen_id = cpu_list_generation_id_get();
+    records = vcpu_dirty_stat_alloc(stat);
+    vcpu_dirty_stat_collect(stat, records, true);
+    cpu_list_unlock();
+
+    duration = dirty_stat_wait(calc_time_ms, init_time_ms);
+
+    global_dirty_log_sync(flag, one_shot);
+
+    cpu_list_lock();
+    if (gen_id != cpu_list_generation_id_get()) {
+        g_free(records);
+        g_free(stat->rates);
+        cpu_list_unlock();
+        goto retry;
+    }
+    vcpu_dirty_stat_collect(stat, records, false);
+    cpu_list_unlock();
+
+    for (i = 0; i < stat->nvcpu; i++) {
+        dirtyrate = do_calculate_dirtyrate(records[i], duration);
+
+        stat->rates[i].id = i;
+        stat->rates[i].dirty_rate = dirtyrate;
+
+        trace_dirtyrate_do_calculate_vcpu(i, dirtyrate);
+    }
+
+    g_free(records);
+
+    return duration;
+}
+
 static bool is_sample_period_valid(int64_t sec)
 {
     if (sec < MIN_FETCH_DIRTYRATE_TIME_SEC ||
@@ -396,44 +522,6 @@ 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();
-    memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE);
-    qemu_mutex_unlock_iothread();
-}
-
-static void dirtyrate_global_dirty_log_stop(void)
-{
-    qemu_mutex_lock_iothread();
-    memory_global_dirty_log_sync();
-    memory_global_dirty_log_stop(GLOBAL_DIRTY_DIRTY_RATE);
-    qemu_mutex_unlock_iothread();
-}
-
-static int64_t do_calculate_dirtyrate_vcpu(DirtyPageRecord dirty_pages)
-{
-    uint64_t memory_size_MB;
-    int64_t time_s;
-    uint64_t increased_dirty_pages =
-        dirty_pages.end_pages - dirty_pages.start_pages;
-
-    memory_size_MB = (increased_dirty_pages * TARGET_PAGE_SIZE) >> 20;
-    time_s = DirtyStat.calc_time;
-
-    return memory_size_MB / time_s;
-}
-
 static inline void record_dirtypages_bitmap(DirtyPageRecord *dirty_pages,
                                             bool start)
 {
@@ -444,11 +532,6 @@ static inline void record_dirtypages_bitmap(DirtyPageRecord *dirty_pages,
     }
 }
 
-static void do_calculate_dirtyrate_bitmap(DirtyPageRecord dirty_pages)
-{
-    DirtyStat.dirty_rate = do_calculate_dirtyrate_vcpu(dirty_pages);
-}
-
 static inline void dirtyrate_manual_reset_protect(void)
 {
     RAMBlock *block = NULL;
@@ -492,71 +575,49 @@ static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config)
     DirtyStat.start_time = start_time / 1000;
 
     msec = config.sample_period_seconds * 1000;
-    msec = set_sample_page_period(msec, start_time);
+    msec = dirty_stat_wait(msec, start_time);
     DirtyStat.calc_time = msec / 1000;
 
     /*
-     * dirtyrate_global_dirty_log_stop do two things.
+     * do two things.
      * 1. fetch dirty bitmap from kvm
      * 2. stop dirty tracking
      */
-    dirtyrate_global_dirty_log_stop();
+    global_dirty_log_sync(GLOBAL_DIRTY_DIRTY_RATE, true);
 
     record_dirtypages_bitmap(&dirty_pages, false);
 
-    do_calculate_dirtyrate_bitmap(dirty_pages);
+    DirtyStat.dirty_rate = do_calculate_dirtyrate(dirty_pages, msec);
 }
 
 static void calculate_dirtyrate_dirty_ring(struct DirtyRateConfig config)
 {
-    CPUState *cpu;
-    int64_t msec = 0;
-    int64_t start_time;
+    int64_t duration;
     uint64_t dirtyrate = 0;
     uint64_t dirtyrate_sum = 0;
-    DirtyPageRecord *dirty_pages;
-    int nvcpu = 0;
     int i = 0;
 
-    CPU_FOREACH(cpu) {
-        nvcpu++;
-    }
-
-    dirty_pages = malloc(sizeof(*dirty_pages) * nvcpu);
-
-    DirtyStat.dirty_ring.nvcpu = nvcpu;
-    DirtyStat.dirty_ring.rates = malloc(sizeof(DirtyRateVcpu) * nvcpu);
-
-    dirtyrate_global_dirty_log_start();
-
-    CPU_FOREACH(cpu) {
-        record_dirtypages(dirty_pages, cpu, true);
-    }
-
-    start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
-    DirtyStat.start_time = start_time / 1000;
+    /* start log sync */
+    global_dirty_log_change(GLOBAL_DIRTY_DIRTY_RATE, true);
 
-    msec = config.sample_period_seconds * 1000;
-    msec = set_sample_page_period(msec, start_time);
-    DirtyStat.calc_time = msec / 1000;
+    DirtyStat.start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
 
-    dirtyrate_global_dirty_log_stop();
+    /* calculate vcpu dirtyrate */
+    duration = vcpu_calculate_dirtyrate(config.sample_period_seconds * 1000,
+                                        &DirtyStat.dirty_ring,
+                                        GLOBAL_DIRTY_DIRTY_RATE,
+                                        true);
 
-    CPU_FOREACH(cpu) {
-        record_dirtypages(dirty_pages, cpu, false);
-    }
+    DirtyStat.calc_time = duration / 1000;
 
+    /* calculate vm dirtyrate */
     for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
-        dirtyrate = do_calculate_dirtyrate_vcpu(dirty_pages[i]);
-        trace_dirtyrate_do_calculate_vcpu(i, dirtyrate);
-
-        DirtyStat.dirty_ring.rates[i].id = i;
+        dirtyrate = DirtyStat.dirty_ring.rates[i].dirty_rate;
         DirtyStat.dirty_ring.rates[i].dirty_rate = dirtyrate;
         dirtyrate_sum += dirtyrate;
     }
 
     DirtyStat.dirty_rate = dirtyrate_sum;
-    free(dirty_pages);
 }
 
 static void calculate_dirtyrate_sample_vm(struct DirtyRateConfig config)
@@ -574,7 +635,7 @@ static void calculate_dirtyrate_sample_vm(struct DirtyRateConfig config)
     rcu_read_unlock();
 
     msec = config.sample_period_seconds * 1000;
-    msec = set_sample_page_period(msec, initial_time);
+    msec = dirty_stat_wait(msec, initial_time);
     DirtyStat.start_time = initial_time / 1000;
     DirtyStat.calc_time = msec / 1000;
 
diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
index 69d4c5b..594a5c0 100644
--- a/migration/dirtyrate.h
+++ b/migration/dirtyrate.h
@@ -13,6 +13,8 @@
 #ifndef QEMU_MIGRATION_DIRTYRATE_H
 #define QEMU_MIGRATION_DIRTYRATE_H
 
+#include "sysemu/dirtyrate.h"
+
 /*
  * Sample 512 pages per GB as default.
  */
@@ -65,11 +67,6 @@ typedef struct SampleVMStat {
     uint64_t total_block_mem_MB; /* size of total sampled pages in MB */
 } SampleVMStat;
 
-typedef struct VcpuStat {
-    int nvcpu; /* number of vcpu */
-    DirtyRateVcpu *rates; /* array of dirty rate for each vcpu */
-} VcpuStat;
-
 /*
  * Store calculation statistics for each measure.
  */
-- 
1.8.3.1

[PATCH v22 4/8] softmmu/dirtylimit: 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 page
rate limit.

Add dirtylimit.c to implement dirtyrate calculation periodly,
which will be used for dirty page rate limit.

Add dirtylimit.h to export util functions for dirty page rate
limit implementation.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Reviewed-by: Peter Xu <peterx@redhat.com>
---
 include/exec/memory.h       |   5 +-
 include/sysemu/dirtylimit.h |  22 +++++++++
 softmmu/dirtylimit.c        | 116 ++++++++++++++++++++++++++++++++++++++++++++
 softmmu/meson.build         |   1 +
 4 files changed, 143 insertions(+), 1 deletion(-)
 create mode 100644 include/sysemu/dirtylimit.h
 create mode 100644 softmmu/dirtylimit.c

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 4d5997e..88ca510 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..da459f0
--- /dev/null
+++ b/include/sysemu/dirtylimit.h
@@ -0,0 +1,22 @@
+/*
+ * Dirty page rate limit common functions
+ *
+ * Copyright (c) 2022 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_TIME_MS         1000    /* 1000ms */
+
+int64_t vcpu_dirty_rate_get(int cpu_index);
+void vcpu_dirty_rate_stat_start(void);
+void vcpu_dirty_rate_stat_stop(void);
+void vcpu_dirty_rate_stat_initialize(void);
+void vcpu_dirty_rate_stat_finalize(void);
+#endif
diff --git a/softmmu/dirtylimit.c b/softmmu/dirtylimit.c
new file mode 100644
index 0000000..6102e8c
--- /dev/null
+++ b/softmmu/dirtylimit.c
@@ -0,0 +1,116 @@
+/*
+ * Dirty page rate limit implementation code
+ *
+ * Copyright (c) 2022 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.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu/main-loop.h"
+#include "qapi/qapi-commands-migration.h"
+#include "sysemu/dirtyrate.h"
+#include "sysemu/dirtylimit.h"
+#include "exec/memory.h"
+#include "hw/boards.h"
+
+struct {
+    VcpuStat stat;
+    bool running;
+    QemuThread thread;
+} *vcpu_dirty_rate_stat;
+
+static void vcpu_dirty_rate_stat_collect(void)
+{
+    VcpuStat stat;
+    int i = 0;
+
+    /* calculate vcpu dirtyrate */
+    vcpu_calculate_dirtyrate(DIRTYLIMIT_CALC_TIME_MS,
+                             &stat,
+                             GLOBAL_DIRTY_LIMIT,
+                             false);
+
+    for (i = 0; i < stat.nvcpu; i++) {
+        vcpu_dirty_rate_stat->stat.rates[i].id = i;
+        vcpu_dirty_rate_stat->stat.rates[i].dirty_rate =
+            stat.rates[i].dirty_rate;
+    }
+
+    free(stat.rates);
+}
+
+static void *vcpu_dirty_rate_stat_thread(void *opaque)
+{
+    rcu_register_thread();
+
+    /* start log sync */
+    global_dirty_log_change(GLOBAL_DIRTY_LIMIT, true);
+
+    while (qatomic_read(&vcpu_dirty_rate_stat->running)) {
+        vcpu_dirty_rate_stat_collect();
+    }
+
+    /* stop log sync */
+    global_dirty_log_change(GLOBAL_DIRTY_LIMIT, false);
+
+    rcu_unregister_thread();
+    return NULL;
+}
+
+int64_t vcpu_dirty_rate_get(int cpu_index)
+{
+    DirtyRateVcpu *rates = vcpu_dirty_rate_stat->stat.rates;
+    return qatomic_read(&rates[cpu_index].dirty_rate);
+}
+
+void vcpu_dirty_rate_stat_start(void)
+{
+    if (qatomic_read(&vcpu_dirty_rate_stat->running)) {
+        return;
+    }
+
+    qatomic_set(&vcpu_dirty_rate_stat->running, 1);
+    qemu_thread_create(&vcpu_dirty_rate_stat->thread,
+                       "dirtyrate-stat",
+                       vcpu_dirty_rate_stat_thread,
+                       NULL,
+                       QEMU_THREAD_JOINABLE);
+}
+
+void vcpu_dirty_rate_stat_stop(void)
+{
+    qatomic_set(&vcpu_dirty_rate_stat->running, 0);
+    qemu_mutex_unlock_iothread();
+    qemu_thread_join(&vcpu_dirty_rate_stat->thread);
+    qemu_mutex_lock_iothread();
+}
+
+void vcpu_dirty_rate_stat_initialize(void)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+    int max_cpus = ms->smp.max_cpus;
+
+    vcpu_dirty_rate_stat =
+        g_malloc0(sizeof(*vcpu_dirty_rate_stat));
+
+    vcpu_dirty_rate_stat->stat.nvcpu = max_cpus;
+    vcpu_dirty_rate_stat->stat.rates =
+        g_malloc0(sizeof(DirtyRateVcpu) * max_cpus);
+
+    vcpu_dirty_rate_stat->running = false;
+}
+
+void vcpu_dirty_rate_stat_finalize(void)
+{
+    free(vcpu_dirty_rate_stat->stat.rates);
+    vcpu_dirty_rate_stat->stat.rates = NULL;
+
+    free(vcpu_dirty_rate_stat);
+    vcpu_dirty_rate_stat = NULL;
+}
diff --git a/softmmu/meson.build b/softmmu/meson.build
index 8138248..3272af1 100644
--- a/softmmu/meson.build
+++ b/softmmu/meson.build
@@ -4,6 +4,7 @@ specific_ss.add(when: 'CONFIG_SOFTMMU', if_true: [files(
   'memory.c',
   'physmem.c',
   'qtest.c',
+  'dirtylimit.c',
 )])
 
 specific_ss.add(when: ['CONFIG_SOFTMMU', 'CONFIG_TCG'], if_true: [files(
-- 
1.8.3.1

[PATCH v22 5/8] accel/kvm/kvm-all: Introduce kvm_dirty_ring_size function

[huangy81]

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

Introduce kvm_dirty_ring_size util function to help calculate
dirty ring ful time.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Acked-by: Peter Xu <peterx@redhat.com>
---
 accel/kvm/kvm-all.c    | 5 +++++
 accel/stubs/kvm-stub.c | 6 ++++++
 include/sysemu/kvm.h   | 2 ++
 3 files changed, 13 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index c30870ae..95deab9 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2313,6 +2313,11 @@ bool kvm_dirty_ring_enabled(void)
     return kvm_state->kvm_dirty_ring_size ? true : false;
 }
 
+uint32_t kvm_dirty_ring_size(void)
+{
+    return kvm_state->kvm_dirty_ring_size;
+}
+
 static int kvm_init(MachineState *ms)
 {
     MachineClass *mc = MACHINE_GET_CLASS(ms);
diff --git a/accel/stubs/kvm-stub.c b/accel/stubs/kvm-stub.c
index 3345882..c5aafaa 100644
--- a/accel/stubs/kvm-stub.c
+++ b/accel/stubs/kvm-stub.c
@@ -148,3 +148,9 @@ bool kvm_dirty_ring_enabled(void)
 {
     return false;
 }
+
+uint32_t kvm_dirty_ring_size(void)
+{
+    return 0;
+}
+#endif
diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
index a783c78..efd6dee 100644
--- a/include/sysemu/kvm.h
+++ b/include/sysemu/kvm.h
@@ -582,4 +582,6 @@ bool kvm_cpu_check_are_resettable(void);
 bool kvm_arch_cpu_check_are_resettable(void);
 
 bool kvm_dirty_ring_enabled(void);
+
+uint32_t kvm_dirty_ring_size(void);
 #endif
-- 
1.8.3.1

[PATCH v22 6/8] softmmu/dirtylimit: Implement virtual CPU throttle

[huangy81]

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

Setup a negative feedback system when vCPU thread
handling KVM_EXIT_DIRTY_RING_FULL exit by introducing
throttle_us_per_full field in struct CPUState. Sleep
throttle_us_per_full microseconds to throttle vCPU
if dirtylimit is in service.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Reviewed-by: Peter Xu <peterx@redhat.com>
---
 accel/kvm/kvm-all.c         |  20 ++-
 include/hw/core/cpu.h       |   6 +
 include/sysemu/dirtylimit.h |  15 +++
 softmmu/dirtylimit.c        | 291 ++++++++++++++++++++++++++++++++++++++++++++
 softmmu/trace-events        |   7 ++
 5 files changed, 338 insertions(+), 1 deletion(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 95deab9..6cbeca0 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -45,6 +45,7 @@
 #include "qemu/guest-random.h"
 #include "sysemu/hw_accel.h"
 #include "kvm-cpus.h"
+#include "sysemu/dirtylimit.h"
 
 #include "hw/boards.h"
 
@@ -476,6 +477,7 @@ int kvm_init_vcpu(CPUState *cpu, Error **errp)
     cpu->kvm_state = s;
     cpu->vcpu_dirty = true;
     cpu->dirty_pages = 0;
+    cpu->throttle_us_per_full = 0;
 
     mmap_size = kvm_ioctl(s, KVM_GET_VCPU_MMAP_SIZE, 0);
     if (mmap_size < 0) {
@@ -1469,6 +1471,11 @@ static void *kvm_dirty_ring_reaper_thread(void *data)
          */
         sleep(1);
 
+        /* keep sleeping so that dirtylimit not be interfered by reaper */
+        if (dirtylimit_in_service()) {
+            continue;
+        }
+
         trace_kvm_dirty_ring_reaper("wakeup");
         r->reaper_state = KVM_DIRTY_RING_REAPER_REAPING;
 
@@ -2965,8 +2972,19 @@ int kvm_cpu_exec(CPUState *cpu)
              */
             trace_kvm_dirty_ring_full(cpu->cpu_index);
             qemu_mutex_lock_iothread();
-            kvm_dirty_ring_reap(kvm_state, NULL);
+            /*
+             * We throttle vCPU by making it sleep once it exit from kernel
+             * due to dirty ring full. In the dirtylimit scenario, reaping
+             * all vCPUs after a single vCPU dirty ring get full result in
+             * the miss of sleep, so just reap the ring-fulled vCPU.
+             */
+            if (dirtylimit_in_service()) {
+                kvm_dirty_ring_reap(kvm_state, cpu);
+            } else {
+                kvm_dirty_ring_reap(kvm_state, NULL);
+            }
             qemu_mutex_unlock_iothread();
+            dirtylimit_vcpu_execute(cpu);
             ret = 0;
             break;
         case KVM_EXIT_SYSTEM_EVENT:
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 1369736..2380001 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -418,6 +418,12 @@ struct CPUState {
      */
     bool throttle_thread_scheduled;
 
+    /*
+     * Sleep throttle_us_per_full microseconds once dirty ring is full
+     * if dirty page rate limit is enabled.
+     */
+    int64_t throttle_us_per_full;
+
     bool ignore_memory_transaction_failures;
 
     /* Used for user-only emulation of prctl(PR_SET_UNALIGN). */
diff --git a/include/sysemu/dirtylimit.h b/include/sysemu/dirtylimit.h
index da459f0..8d2c1f3 100644
--- a/include/sysemu/dirtylimit.h
+++ b/include/sysemu/dirtylimit.h
@@ -19,4 +19,19 @@ void vcpu_dirty_rate_stat_start(void);
 void vcpu_dirty_rate_stat_stop(void);
 void vcpu_dirty_rate_stat_initialize(void);
 void vcpu_dirty_rate_stat_finalize(void);
+
+void dirtylimit_state_lock(void);
+void dirtylimit_state_unlock(void);
+void dirtylimit_state_initialize(void);
+void dirtylimit_state_finalize(void);
+bool dirtylimit_in_service(void);
+bool dirtylimit_vcpu_index_valid(int cpu_index);
+void dirtylimit_process(void);
+void dirtylimit_change(bool start);
+void dirtylimit_set_vcpu(int cpu_index,
+                         uint64_t quota,
+                         bool enable);
+void dirtylimit_set_all(uint64_t quota,
+                        bool enable);
+void dirtylimit_vcpu_execute(CPUState *cpu);
 #endif
diff --git a/softmmu/dirtylimit.c b/softmmu/dirtylimit.c
index 6102e8c..76d0b44 100644
--- a/softmmu/dirtylimit.c
+++ b/softmmu/dirtylimit.c
@@ -18,6 +18,26 @@
 #include "sysemu/dirtylimit.h"
 #include "exec/memory.h"
 #include "hw/boards.h"
+#include "sysemu/kvm.h"
+#include "trace.h"
+
+/*
+ * Dirtylimit stop working if dirty page rate error
+ * value less than DIRTYLIMIT_TOLERANCE_RANGE
+ */
+#define DIRTYLIMIT_TOLERANCE_RANGE  25  /* MB/s */
+/*
+ * Plus or minus vcpu sleep time linearly if dirty
+ * page rate error value percentage over
+ * DIRTYLIMIT_LINEAR_ADJUSTMENT_PCT.
+ * Otherwise, plus or minus a fixed vcpu sleep time.
+ */
+#define DIRTYLIMIT_LINEAR_ADJUSTMENT_PCT     50
+/*
+ * Max vcpu sleep time percentage during a cycle
+ * composed of dirty ring full and sleep time.
+ */
+#define DIRTYLIMIT_THROTTLE_PCT_MAX 99
 
 struct {
     VcpuStat stat;
@@ -25,6 +45,30 @@ struct {
     QemuThread thread;
 } *vcpu_dirty_rate_stat;
 
+typedef struct VcpuDirtyLimitState {
+    int cpu_index;
+    bool enabled;
+    /*
+     * Quota dirty page rate, unit is MB/s
+     * zero if not enabled.
+     */
+    uint64_t quota;
+} VcpuDirtyLimitState;
+
+struct {
+    VcpuDirtyLimitState *states;
+    /* Max cpus number configured by user */
+    int max_cpus;
+    /* Number of vcpu under dirtylimit */
+    int limited_nvcpu;
+} *dirtylimit_state;
+
+/* protect dirtylimit_state */
+static QemuMutex dirtylimit_mutex;
+
+/* dirtylimit thread quit if dirtylimit_quit is true */
+static bool dirtylimit_quit;
+
 static void vcpu_dirty_rate_stat_collect(void)
 {
     VcpuStat stat;
@@ -54,6 +98,9 @@ static void *vcpu_dirty_rate_stat_thread(void *opaque)
 
     while (qatomic_read(&vcpu_dirty_rate_stat->running)) {
         vcpu_dirty_rate_stat_collect();
+        if (dirtylimit_in_service()) {
+            dirtylimit_process();
+        }
     }
 
     /* stop log sync */
@@ -86,9 +133,11 @@ void vcpu_dirty_rate_stat_start(void)
 void vcpu_dirty_rate_stat_stop(void)
 {
     qatomic_set(&vcpu_dirty_rate_stat->running, 0);
+    dirtylimit_state_unlock();
     qemu_mutex_unlock_iothread();
     qemu_thread_join(&vcpu_dirty_rate_stat->thread);
     qemu_mutex_lock_iothread();
+    dirtylimit_state_lock();
 }
 
 void vcpu_dirty_rate_stat_initialize(void)
@@ -114,3 +163,245 @@ void vcpu_dirty_rate_stat_finalize(void)
     free(vcpu_dirty_rate_stat);
     vcpu_dirty_rate_stat = NULL;
 }
+
+void dirtylimit_state_lock(void)
+{
+    qemu_mutex_lock(&dirtylimit_mutex);
+}
+
+void dirtylimit_state_unlock(void)
+{
+    qemu_mutex_unlock(&dirtylimit_mutex);
+}
+
+static void
+__attribute__((__constructor__)) dirtylimit_mutex_init(void)
+{
+    qemu_mutex_init(&dirtylimit_mutex);
+}
+
+static inline VcpuDirtyLimitState *dirtylimit_vcpu_get_state(int cpu_index)
+{
+    return &dirtylimit_state->states[cpu_index];
+}
+
+void dirtylimit_state_initialize(void)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+    int max_cpus = ms->smp.max_cpus;
+    int i;
+
+    dirtylimit_state = g_malloc0(sizeof(*dirtylimit_state));
+
+    dirtylimit_state->states =
+            g_malloc0(sizeof(VcpuDirtyLimitState) * max_cpus);
+
+    for (i = 0; i < max_cpus; i++) {
+        dirtylimit_state->states[i].cpu_index = i;
+    }
+
+    dirtylimit_state->max_cpus = max_cpus;
+    trace_dirtylimit_state_initialize(max_cpus);
+}
+
+void dirtylimit_state_finalize(void)
+{
+    free(dirtylimit_state->states);
+    dirtylimit_state->states = NULL;
+
+    free(dirtylimit_state);
+    dirtylimit_state = NULL;
+
+    trace_dirtylimit_state_finalize();
+}
+
+bool dirtylimit_in_service(void)
+{
+    return !!dirtylimit_state;
+}
+
+bool dirtylimit_vcpu_index_valid(int cpu_index)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+
+    return !(cpu_index < 0 ||
+             cpu_index >= ms->smp.max_cpus);
+}
+
+static inline int64_t dirtylimit_dirty_ring_full_time(uint64_t dirtyrate)
+{
+    static uint64_t max_dirtyrate;
+    uint32_t dirty_ring_size = kvm_dirty_ring_size();
+    uint64_t dirty_ring_size_meory_MB =
+        dirty_ring_size * TARGET_PAGE_SIZE >> 20;
+
+    if (max_dirtyrate < dirtyrate) {
+        max_dirtyrate = dirtyrate;
+    }
+
+    return dirty_ring_size_meory_MB * 1000000 / max_dirtyrate;
+}
+
+static inline bool dirtylimit_done(uint64_t quota,
+                                   uint64_t current)
+{
+    uint64_t min, max;
+
+    min = MIN(quota, current);
+    max = MAX(quota, current);
+
+    return ((max - min) <= DIRTYLIMIT_TOLERANCE_RANGE) ? true : false;
+}
+
+static inline bool
+dirtylimit_need_linear_adjustment(uint64_t quota,
+                                  uint64_t current)
+{
+    uint64_t min, max;
+
+    min = MIN(quota, current);
+    max = MAX(quota, current);
+
+    return ((max - min) * 100 / max) > DIRTYLIMIT_LINEAR_ADJUSTMENT_PCT;
+}
+
+static void dirtylimit_set_throttle(CPUState *cpu,
+                                    uint64_t quota,
+                                    uint64_t current)
+{
+    int64_t ring_full_time_us = 0;
+    uint64_t sleep_pct = 0;
+    uint64_t throttle_us = 0;
+
+    if (current == 0) {
+        cpu->throttle_us_per_full = 0;
+        return;
+    }
+
+    ring_full_time_us = dirtylimit_dirty_ring_full_time(current);
+
+    if (dirtylimit_need_linear_adjustment(quota, current)) {
+        if (quota < current) {
+            sleep_pct = (current - quota) * 100 / current;
+            throttle_us =
+                ring_full_time_us * sleep_pct / (double)(100 - sleep_pct);
+            cpu->throttle_us_per_full += throttle_us;
+        } else {
+            sleep_pct = (quota - current) * 100 / quota;
+            throttle_us =
+                ring_full_time_us * sleep_pct / (double)(100 - sleep_pct);
+            cpu->throttle_us_per_full -= throttle_us;
+        }
+
+        trace_dirtylimit_throttle_pct(cpu->cpu_index,
+                                      sleep_pct,
+                                      throttle_us);
+    } else {
+        if (quota < current) {
+            cpu->throttle_us_per_full += ring_full_time_us / 10;
+        } else {
+            cpu->throttle_us_per_full -= ring_full_time_us / 10;
+        }
+    }
+
+    /*
+     * TODO: in the big kvm_dirty_ring_size case (eg: 65536, or other scenario),
+     *       current dirty page rate may never reach the quota, we should stop
+     *       increasing sleep time?
+     */
+    cpu->throttle_us_per_full = MIN(cpu->throttle_us_per_full,
+        ring_full_time_us * DIRTYLIMIT_THROTTLE_PCT_MAX);
+
+    cpu->throttle_us_per_full = MAX(cpu->throttle_us_per_full, 0);
+}
+
+static void dirtylimit_adjust_throttle(CPUState *cpu)
+{
+    uint64_t quota = 0;
+    uint64_t current = 0;
+    int cpu_index = cpu->cpu_index;
+
+    quota = dirtylimit_vcpu_get_state(cpu_index)->quota;
+    current = vcpu_dirty_rate_get(cpu_index);
+
+    if (!dirtylimit_done(quota, current)) {
+        dirtylimit_set_throttle(cpu, quota, current);
+    }
+
+    return;
+}
+
+void dirtylimit_process(void)
+{
+    CPUState *cpu;
+
+    if (!qatomic_read(&dirtylimit_quit)) {
+        dirtylimit_state_lock();
+
+        if (!dirtylimit_in_service()) {
+            dirtylimit_state_unlock();
+            return;
+        }
+
+        CPU_FOREACH(cpu) {
+            if (!dirtylimit_vcpu_get_state(cpu->cpu_index)->enabled) {
+                continue;
+            }
+            dirtylimit_adjust_throttle(cpu);
+        }
+        dirtylimit_state_unlock();
+    }
+}
+
+void dirtylimit_change(bool start)
+{
+    if (start) {
+        qatomic_set(&dirtylimit_quit, 0);
+    } else {
+        qatomic_set(&dirtylimit_quit, 1);
+    }
+}
+
+void dirtylimit_set_vcpu(int cpu_index,
+                         uint64_t quota,
+                         bool enable)
+{
+    trace_dirtylimit_set_vcpu(cpu_index, quota);
+
+    if (enable) {
+        dirtylimit_state->states[cpu_index].quota = quota;
+        if (!dirtylimit_vcpu_get_state(cpu_index)->enabled) {
+            dirtylimit_state->limited_nvcpu++;
+        }
+    } else {
+        dirtylimit_state->states[cpu_index].quota = 0;
+        if (dirtylimit_state->states[cpu_index].enabled) {
+            dirtylimit_state->limited_nvcpu--;
+        }
+    }
+
+    dirtylimit_state->states[cpu_index].enabled = enable;
+}
+
+void dirtylimit_set_all(uint64_t quota,
+                        bool enable)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+    int max_cpus = ms->smp.max_cpus;
+    int i;
+
+    for (i = 0; i < max_cpus; i++) {
+        dirtylimit_set_vcpu(i, quota, enable);
+    }
+}
+
+void dirtylimit_vcpu_execute(CPUState *cpu)
+{
+    if (dirtylimit_in_service() &&
+        dirtylimit_vcpu_get_state(cpu->cpu_index)->enabled &&
+        cpu->throttle_us_per_full) {
+        trace_dirtylimit_vcpu_execute(cpu->cpu_index,
+                cpu->throttle_us_per_full);
+        usleep(cpu->throttle_us_per_full);
+    }
+}
diff --git a/softmmu/trace-events b/softmmu/trace-events
index 9c88887..22606dc 100644
--- a/softmmu/trace-events
+++ b/softmmu/trace-events
@@ -31,3 +31,10 @@ runstate_set(int current_state, const char *current_state_str, int new_state, co
 system_wakeup_request(int reason) "reason=%d"
 qemu_system_shutdown_request(int reason) "reason=%d"
 qemu_system_powerdown_request(void) ""
+
+#dirtylimit.c
+dirtylimit_state_initialize(int max_cpus) "dirtylimit state initialize: max cpus %d"
+dirtylimit_state_finalize(void)
+dirtylimit_throttle_pct(int cpu_index, uint64_t pct, int64_t time_us) "CPU[%d] throttle percent: %" PRIu64 ", throttle adjust time %"PRIi64 " us"
+dirtylimit_set_vcpu(int cpu_index, uint64_t quota) "CPU[%d] set dirty page rate limit %"PRIu64
+dirtylimit_vcpu_execute(int cpu_index, int64_t sleep_time_us) "CPU[%d] sleep %"PRIi64 " us"
-- 
1.8.3.1

[PATCH v22 7/8] softmmu/dirtylimit: Implement dirty page rate limit

[huangy81]

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

Implement dirtyrate calculation periodically basing on
dirty-ring and throttle virtual CPU until it reachs the quota
dirty page rate given by user.

Introduce qmp commands "set-vcpu-dirty-limit",
"cancel-vcpu-dirty-limit", "query-vcpu-dirty-limit"
to enable, disable, query dirty page limit for virtual CPU.

Meanwhile, introduce corresponding hmp commands
"set_vcpu_dirty_limit", "cancel_vcpu_dirty_limit",
"info vcpu_dirty_limit" so the feature can be more usable.

"query-vcpu-dirty-limit" success depends on enabling dirty
page rate limit, so just add it to the list of skipped
command to ensure qmp-cmd-test run successfully.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
---
 hmp-commands-info.hx       |  13 +++
 hmp-commands.hx            |  32 ++++++++
 include/monitor/hmp.h      |   3 +
 qapi/migration.json        |  80 +++++++++++++++++++
 softmmu/dirtylimit.c       | 195 +++++++++++++++++++++++++++++++++++++++++++++
 tests/qtest/qmp-cmd-test.c |   2 +
 6 files changed, 325 insertions(+)

diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index adfa085..016717d 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -865,6 +865,19 @@ SRST
     Display the vcpu dirty rate information.
 ERST
 
+    {
+        .name       = "vcpu_dirty_limit",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show dirty page limit information of all vCPU",
+        .cmd        = hmp_info_vcpu_dirty_limit,
+    },
+
+SRST
+  ``info vcpu_dirty_limit``
+    Display the vcpu dirty page limit information.
+ERST
+
 #if defined(TARGET_I386)
     {
         .name       = "sgx",
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 8476277..82ab75f 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -1746,3 +1746,35 @@ ERST
                       "\n\t\t\t -b to specify dirty bitmap as method of calculation)",
         .cmd        = hmp_calc_dirty_rate,
     },
+
+SRST
+``set_vcpu_dirty_limit``
+  Set dirty page rate limit on virtual CPU, the information about all the
+  virtual CPU dirty limit status can be observed with ``info vcpu_dirty_limit``
+  command.
+ERST
+
+    {
+        .name       = "set_vcpu_dirty_limit",
+        .args_type  = "dirty_rate:l,cpu_index:l?",
+        .params     = "dirty_rate [cpu_index]",
+        .help       = "set dirty page rate limit, use cpu_index to set limit"
+                      "\n\t\t\t\t\t on a specified virtual cpu",
+        .cmd        = hmp_set_vcpu_dirty_limit,
+    },
+
+SRST
+``cancel_vcpu_dirty_limit``
+  Cancel dirty page rate limit on virtual CPU, the information about all the
+  virtual CPU dirty limit status can be observed with ``info vcpu_dirty_limit``
+  command.
+ERST
+
+    {
+        .name       = "cancel_vcpu_dirty_limit",
+        .args_type  = "cpu_index:l?",
+        .params     = "[cpu_index]",
+        .help       = "cancel dirty page rate limit, use cpu_index to cancel"
+                      "\n\t\t\t\t\t limit on a specified virtual cpu",
+        .cmd        = hmp_cancel_vcpu_dirty_limit,
+    },
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index 96d0148..478820e 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -131,6 +131,9 @@ void hmp_replay_delete_break(Monitor *mon, const QDict *qdict);
 void hmp_replay_seek(Monitor *mon, const QDict *qdict);
 void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict);
 void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict);
+void hmp_set_vcpu_dirty_limit(Monitor *mon, const QDict *qdict);
+void hmp_cancel_vcpu_dirty_limit(Monitor *mon, const QDict *qdict);
+void hmp_info_vcpu_dirty_limit(Monitor *mon, const QDict *qdict);
 void hmp_human_readable_text_helper(Monitor *mon,
                                     HumanReadableText *(*qmp_handler)(Error **));
 
diff --git a/qapi/migration.json b/qapi/migration.json
index 092a633..6a21027 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -1863,6 +1863,86 @@
 { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' }
 
 ##
+# @DirtyLimitInfo:
+#
+# Dirty page rate limit information of a virtual CPU.
+#
+# @cpu-index: index of a virtual CPU.
+#
+# @limit-rate: upper limit of dirty page rate (MB/s) for a virtual
+#              CPU, 0 means unlimited.
+#
+# @current-rate: current dirty page rate (MB/s) for a virtual CPU.
+#
+# Since: 7.0
+#
+##
+{ 'struct': 'DirtyLimitInfo',
+  'data': { 'cpu-index': 'int',
+            'limit-rate': 'uint64',
+            'current-rate': 'uint64' } }
+
+##
+# @set-vcpu-dirty-limit:
+#
+# Set the upper limit of dirty page rate for virtual CPUs.
+#
+# Requires KVM with accelerator property "dirty-ring-size" set.
+# A virtual CPU's dirty page rate is a measure of its memory load.
+# To observe dirty page rates, use @calc-dirty-rate.
+#
+# @cpu-index: index of a virtual CPU, default is all.
+#
+# @dirty-rate: upper limit of dirty page rate (MB/s) for virtual CPUs.
+#
+# Since: 7.0
+#
+# Example:
+#   {"execute": "set-vcpu-dirty-limit"}
+#    "arguments": { "dirty-rate": 200,
+#                   "cpu-index": 1 } }
+#
+##
+{ 'command': 'set-vcpu-dirty-limit',
+  'data': { '*cpu-index': 'int',
+            'dirty-rate': 'uint64' } }
+
+##
+# @cancel-vcpu-dirty-limit:
+#
+# Cancel the upper limit of dirty page rate for virtual CPUs.
+#
+# Cancel the dirty page limit for the vCPU which has been set with
+# set-vcpu-dirty-limit command. Note that this command requires
+# support from dirty ring, same as the "set-vcpu-dirty-limit".
+#
+# @cpu-index: index of a virtual CPU, default is all.
+#
+# Since: 7.0
+#
+# Example:
+#   {"execute": "cancel-vcpu-dirty-limit"}
+#    "arguments": { "cpu-index": 1 } }
+#
+##
+{ 'command': 'cancel-vcpu-dirty-limit',
+  'data': { '*cpu-index': 'int'} }
+
+##
+# @query-vcpu-dirty-limit:
+#
+# Returns information about virtual CPU dirty page rate limits, if any.
+#
+# Since: 7.0
+#
+# Example:
+#   {"execute": "query-vcpu-dirty-limit"}
+#
+##
+{ 'command': 'query-vcpu-dirty-limit',
+  'returns': [ 'DirtyLimitInfo' ] }
+
+##
 # @snapshot-save:
 #
 # Save a VM snapshot
diff --git a/softmmu/dirtylimit.c b/softmmu/dirtylimit.c
index 76d0b44..365bd43 100644
--- a/softmmu/dirtylimit.c
+++ b/softmmu/dirtylimit.c
@@ -14,8 +14,12 @@
 #include "qapi/error.h"
 #include "qemu/main-loop.h"
 #include "qapi/qapi-commands-migration.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/error.h"
 #include "sysemu/dirtyrate.h"
 #include "sysemu/dirtylimit.h"
+#include "monitor/hmp.h"
+#include "monitor/monitor.h"
 #include "exec/memory.h"
 #include "hw/boards.h"
 #include "sysemu/kvm.h"
@@ -405,3 +409,194 @@ void dirtylimit_vcpu_execute(CPUState *cpu)
         usleep(cpu->throttle_us_per_full);
     }
 }
+
+static void dirtylimit_init(void)
+{
+    dirtylimit_state_initialize();
+    dirtylimit_change(true);
+    vcpu_dirty_rate_stat_initialize();
+    vcpu_dirty_rate_stat_start();
+}
+
+static void dirtylimit_cleanup(void)
+{
+    vcpu_dirty_rate_stat_stop();
+    vcpu_dirty_rate_stat_finalize();
+    dirtylimit_change(false);
+    dirtylimit_state_finalize();
+}
+
+void qmp_cancel_vcpu_dirty_limit(bool has_cpu_index,
+                                 int64_t cpu_index,
+                                 Error **errp)
+{
+    if (!kvm_enabled() || !kvm_dirty_ring_enabled()) {
+        return;
+    }
+
+    if (has_cpu_index && !dirtylimit_vcpu_index_valid(cpu_index)) {
+        error_setg(errp, "incorrect cpu index specified");
+        return;
+    }
+
+    if (!dirtylimit_in_service()) {
+        return;
+    }
+
+    dirtylimit_state_lock();
+
+    if (has_cpu_index) {
+        dirtylimit_set_vcpu(cpu_index, 0, false);
+    } else {
+        dirtylimit_set_all(0, false);
+    }
+
+    if (!dirtylimit_state->limited_nvcpu) {
+        dirtylimit_cleanup();
+    }
+
+    dirtylimit_state_unlock();
+}
+
+void hmp_cancel_vcpu_dirty_limit(Monitor *mon, const QDict *qdict)
+{
+    int64_t cpu_index = qdict_get_try_int(qdict, "cpu_index", -1);
+    Error *err = NULL;
+
+    qmp_cancel_vcpu_dirty_limit(!!(cpu_index != -1), cpu_index, &err);
+    if (err) {
+        hmp_handle_error(mon, err);
+        return;
+    }
+
+    monitor_printf(mon, "[Please use 'info vcpu_dirty_limit' to query "
+                   "dirty limit for virtual CPU]\n");
+}
+
+void qmp_set_vcpu_dirty_limit(bool has_cpu_index,
+                              int64_t cpu_index,
+                              uint64_t dirty_rate,
+                              Error **errp)
+{
+    if (!kvm_enabled() || !kvm_dirty_ring_enabled()) {
+        error_setg(errp, "dirty page limit feature requires KVM with"
+                   " accelerator property 'dirty-ring-size' set'");
+        return;
+    }
+
+    if (has_cpu_index && !dirtylimit_vcpu_index_valid(cpu_index)) {
+        error_setg(errp, "incorrect cpu index specified");
+        return;
+    }
+
+    if (!dirty_rate) {
+        qmp_cancel_vcpu_dirty_limit(has_cpu_index, cpu_index, errp);
+        return;
+    }
+
+    dirtylimit_state_lock();
+
+    if (!dirtylimit_in_service()) {
+        dirtylimit_init();
+    }
+
+    if (has_cpu_index) {
+        dirtylimit_set_vcpu(cpu_index, dirty_rate, true);
+    } else {
+        dirtylimit_set_all(dirty_rate, true);
+    }
+
+    dirtylimit_state_unlock();
+}
+
+void hmp_set_vcpu_dirty_limit(Monitor *mon, const QDict *qdict)
+{
+    int64_t dirty_rate = qdict_get_int(qdict, "dirty_rate");
+    int64_t cpu_index = qdict_get_try_int(qdict, "cpu_index", -1);
+    Error *err = NULL;
+
+    qmp_set_vcpu_dirty_limit(!!(cpu_index != -1), cpu_index, dirty_rate, &err);
+    if (err) {
+        hmp_handle_error(mon, err);
+        return;
+    }
+
+    monitor_printf(mon, "[Please use 'info vcpu_dirty_limit' to query "
+                   "dirty limit for virtual CPU]\n");
+}
+
+static struct DirtyLimitInfo *dirtylimit_query_vcpu(int cpu_index)
+{
+    DirtyLimitInfo *info = NULL;
+
+    info = g_malloc0(sizeof(*info));
+    info->cpu_index = cpu_index;
+    info->limit_rate = dirtylimit_vcpu_get_state(cpu_index)->quota;
+    info->current_rate = vcpu_dirty_rate_get(cpu_index);
+
+    return info;
+}
+
+static struct DirtyLimitInfoList *dirtylimit_query_all(void)
+{
+    int i, index;
+    DirtyLimitInfo *info = NULL;
+    DirtyLimitInfoList *head = NULL, **tail = &head;
+
+    dirtylimit_state_lock();
+
+    if (!dirtylimit_in_service()) {
+        dirtylimit_state_unlock();
+        return NULL;
+    }
+
+    for (i = 0; i < dirtylimit_state->max_cpus; i++) {
+        index = dirtylimit_state->states[i].cpu_index;
+        if (dirtylimit_vcpu_get_state(index)->enabled) {
+            info = dirtylimit_query_vcpu(index);
+            QAPI_LIST_APPEND(tail, info);
+        }
+    }
+
+    dirtylimit_state_unlock();
+
+    return head;
+}
+
+struct DirtyLimitInfoList *qmp_query_vcpu_dirty_limit(Error **errp)
+{
+    if (!dirtylimit_in_service()) {
+        error_setg(errp, "dirty page limit not enabled");
+        return NULL;
+    }
+
+    return dirtylimit_query_all();
+}
+
+void hmp_info_vcpu_dirty_limit(Monitor *mon, const QDict *qdict)
+{
+    DirtyLimitInfoList *limit, *head, *info = NULL;
+    Error *err = NULL;
+
+    if (!dirtylimit_in_service()) {
+        monitor_printf(mon, "Dirty page limit not enabled!\n");
+        return;
+    }
+
+    info = qmp_query_vcpu_dirty_limit(&err);
+    if (err) {
+        hmp_handle_error(mon, err);
+        return;
+    }
+
+    head = info;
+    for (limit = head; limit != NULL; limit = limit->next) {
+        monitor_printf(mon, "vcpu[%"PRIi64"], limit rate %"PRIi64 " (MB/s),"
+                            " current rate %"PRIi64 " (MB/s)\n",
+                            limit->value->cpu_index,
+                            limit->value->limit_rate,
+                            limit->value->current_rate);
+    }
+
+    g_free(info);
+}
diff --git a/tests/qtest/qmp-cmd-test.c b/tests/qtest/qmp-cmd-test.c
index 7f103ea..4b216a0 100644
--- a/tests/qtest/qmp-cmd-test.c
+++ b/tests/qtest/qmp-cmd-test.c
@@ -110,6 +110,8 @@ static bool query_is_ignored(const char *cmd)
         "query-sev-capabilities",
         "query-sgx",
         "query-sgx-capabilities",
+        /* Success depends on enabling dirty page rate limit */
+        "query-vcpu-dirty-limit",
         NULL
     };
     int i;
-- 
1.8.3.1

[PATCH v22 8/8] tests: Add dirty page rate limit test

[huangy81]

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

Add dirty page rate limit test if kernel support dirty ring,
create a standalone file to implement the test case.

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>
---
 tests/qtest/migration-helpers.c |  22 ++++
 tests/qtest/migration-helpers.h |   2 +
 tests/qtest/migration-test.c    | 255 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 279 insertions(+)

diff --git a/tests/qtest/migration-helpers.c b/tests/qtest/migration-helpers.c
index 4ee2601..1e594f9 100644
--- a/tests/qtest/migration-helpers.c
+++ b/tests/qtest/migration-helpers.c
@@ -76,6 +76,28 @@ QDict *wait_command(QTestState *who, const char *command, ...)
 }
 
 /*
+ * 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
  * qobject_from_jsonf_nofail()) with "uri": @uri spliced in.
diff --git a/tests/qtest/migration-helpers.h b/tests/qtest/migration-helpers.h
index 555adaf..04939fa 100644
--- a/tests/qtest/migration-helpers.h
+++ b/tests/qtest/migration-helpers.h
@@ -22,6 +22,8 @@ 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, ...);
 
diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
index 0870656..40f2873 100644
--- a/tests/qtest/migration-test.c
+++ b/tests/qtest/migration-test.c
@@ -23,6 +23,7 @@
 #include "qapi/qapi-visit-sockets.h"
 #include "qapi/qobject-input-visitor.h"
 #include "qapi/qobject-output-visitor.h"
+#include "qapi/qmp/qlist.h"
 
 #include "migration-helpers.h"
 #include "tests/migration/migration-test.h"
@@ -51,6 +52,11 @@ static bool uffd_feature_thread_id;
 #include <sys/eventfd.h>
 #include <sys/ioctl.h>
 #include <linux/userfaultfd.h>
+/*
+ * Dirtylimit stop working if dirty page rate error
+ * value less than DIRTYLIMIT_TOLERANCE_RANGE
+ */
+#define DIRTYLIMIT_TOLERANCE_RANGE  25  /* MB/s */
 
 static bool ufd_version_check(void)
 {
@@ -1397,6 +1403,253 @@ 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)
@@ -1486,6 +1739,8 @@ 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();
-- 
1.8.3.1

Re: [PATCH v22 8/8] tests: Add dirty page rate limit test

[Peter Xu]

On Fri, Apr 01, 2022 at 01:49:24AM +0800, huangy81@chinatelecom.cn wrote:
> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> 
> Add dirty page rate limit test if kernel support dirty ring,
> create a standalone file to implement the test case.
> 
> 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>

Thanks,

-- 
Peter Xu

Re: [PATCH v22 0/8] support dirty restraint on vCPU

[Hyman]

Ping.
  Hi, David and Peter, how do you think this patchset?
  Is it suitable for queueing ? or is there still something need to be 
done ?

Yong

在 2022/4/1 1:49, huangy81@chinatelecom.cn 写道:
> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> 
> This is v22 of dirtylimit series.
> The following is the history of the patchset, since v22 kind of different from
> the original version, i made abstracts of changelog:
> 
> RFC and v1: https://lore.kernel.org/qemu-devel/cover.1637214721.git.huangy81@chinatelecom.cn/
> v2: https://lore.kernel.org/qemu-devel/cover.1637256224.git.huangy81@chinatelecom.cn/
> v1->v2 changelog:
> - rename some function and variables. refactor the original algo of dirtylimit. Thanks for
>    the comments given by Juan Quintela.
> v3: https://lore.kernel.org/qemu-devel/cover.1637403404.git.huangy81@chinatelecom.cn/
> v4: https://lore.kernel.org/qemu-devel/cover.1637653303.git.huangy81@chinatelecom.cn/
> v5: https://lore.kernel.org/qemu-devel/cover.1637759139.git.huangy81@chinatelecom.cn/
> v6: https://lore.kernel.org/qemu-devel/cover.1637856472.git.huangy81@chinatelecom.cn/
> v7: https://lore.kernel.org/qemu-devel/cover.1638202004.git.huangy81@chinatelecom.cn/
> v2->v7 changelog:
> - refactor the docs, annotation and fix bugs of the original algo of dirtylimit.
>    Thanks for the review given by Markus Armbruster.
> v8: https://lore.kernel.org/qemu-devel/cover.1638463260.git.huangy81@chinatelecom.cn/
> v9: https://lore.kernel.org/qemu-devel/cover.1638495274.git.huangy81@chinatelecom.cn/
> v10: https://lore.kernel.org/qemu-devel/cover.1639479557.git.huangy81@chinatelecom.cn/
> v7->v10 changelog:
> - introduce a simpler but more efficient algo of dirtylimit inspired by Peter Xu.
> - keep polishing the annotation suggested by Markus Armbruster.
> v11: https://lore.kernel.org/qemu-devel/cover.1641315745.git.huangy81@chinatelecom.cn/
> v12: https://lore.kernel.org/qemu-devel/cover.1642774952.git.huangy81@chinatelecom.cn/
> v13: https://lore.kernel.org/qemu-devel/cover.1644506963.git.huangy81@chinatelecom.cn/
> v10->v13 changelog:
> - handle the hotplug/unplug scenario.
> - refactor the new algo, split the commit and make the code more clean.
> v14: https://lore.kernel.org/qemu-devel/cover.1644509582.git.huangy81@chinatelecom.cn/
> v13->v14 changelog:
> - sent by accident.
> v15: https://lore.kernel.org/qemu-devel/cover.1644976045.git.huangy81@chinatelecom.cn/
> v16: https://lore.kernel.org/qemu-devel/cover.1645067452.git.huangy81@chinatelecom.cn/
> v17: https://lore.kernel.org/qemu-devel/cover.1646243252.git.huangy81@chinatelecom.cn/
> v14->v17 changelog:
> - do some code clean and fix test bug reported by Dr. David Alan Gilbert.
> v18: https://lore.kernel.org/qemu-devel/cover.1646247968.git.huangy81@chinatelecom.cn/
> v19: https://lore.kernel.org/qemu-devel/cover.1647390160.git.huangy81@chinatelecom.cn/
> v20: https://lore.kernel.org/qemu-devel/cover.1647396907.git.huangy81@chinatelecom.cn/
> v21: https://lore.kernel.org/qemu-devel/cover.1647435820.git.huangy81@chinatelecom.cn/
> v17->v21 changelog:
> - add qtest, fix bug and do code clean.
> v21->v22 changelog:
> - move the vcpu dirty limit test into migration-test and do some modification suggested
>    by Peter.
> 
> Please review.
> 
> Yong.
> 
> Abstract
> ========
> 
> This patchset introduce a mechanism to impose dirty restraint
> on vCPU, aiming to keep the vCPU running in a certain dirtyrate
> given by user. dirty restraint on vCPU maybe an alternative
> method to implement convergence logic for live migration,
> which could improve guest memory performance during migration
> compared with traditional method in theory.
> 
> For the current live migration implementation, the convergence
> logic throttles all vCPUs of the VM, which has some side effects.
> -'read processes' on vCPU will be unnecessarily penalized
> - throttle increase percentage step by step, which seems
>    struggling to find the optimal throttle percentage when
>    dirtyrate is high.
> - hard to predict the remaining time of migration if the
>    throttling percentage reachs 99%
> 
> to a certain extent, the dirty restraint machnism can fix these
> effects by throttling at vCPU granularity during migration.
> 
> the implementation is rather straightforward, we calculate
> vCPU dirtyrate via the Dirty Ring mechanism periodically
> as the commit 0e21bf246 "implement dirty-ring dirtyrate calculation"
> does, for vCPU that be specified to impose dirty restraint,
> we throttle it periodically as the auto-converge does, once after
> throttling, we compare the quota dirtyrate with current dirtyrate,
> if current dirtyrate is not under the quota, increase the throttling
> percentage until current dirtyrate is under the quota.
> 
> this patchset is the basis of implmenting a new auto-converge method
> for live migration, we introduce two qmp commands for impose/cancel
> the dirty restraint on specified vCPU, so it also can be an independent
> api to supply the upper app such as libvirt, which can use it to
> implement the convergence logic during live migration, supplemented
> with the qmp 'calc-dirty-rate' command or whatever.
> 
> we post this patchset for RFC and any corrections and suggetions about
> the implementation, api, throttleing algorithm or whatever are very
> appreciated!
> 
> Please review, thanks !
> 
> Best Regards !
> 
> Hyman Huang (8):
>    accel/kvm/kvm-all: Refactor per-vcpu dirty ring reaping
>    cpus: Introduce cpu_list_generation_id
>    migration/dirtyrate: Refactor dirty page rate calculation
>    softmmu/dirtylimit: Implement vCPU dirtyrate calculation periodically
>    accel/kvm/kvm-all: Introduce kvm_dirty_ring_size function
>    softmmu/dirtylimit: Implement virtual CPU throttle
>    softmmu/dirtylimit: Implement dirty page rate limit
>    tests: Add dirty page rate limit test
> 
>   accel/kvm/kvm-all.c             |  46 ++-
>   accel/stubs/kvm-stub.c          |   6 +
>   cpus-common.c                   |   8 +
>   hmp-commands-info.hx            |  13 +
>   hmp-commands.hx                 |  32 +++
>   include/exec/cpu-common.h       |   1 +
>   include/exec/memory.h           |   5 +-
>   include/hw/core/cpu.h           |   6 +
>   include/monitor/hmp.h           |   3 +
>   include/sysemu/dirtylimit.h     |  37 +++
>   include/sysemu/dirtyrate.h      |  28 ++
>   include/sysemu/kvm.h            |   2 +
>   migration/dirtyrate.c           | 227 +++++++++------
>   migration/dirtyrate.h           |   7 +-
>   qapi/migration.json             |  80 ++++++
>   softmmu/dirtylimit.c            | 602 ++++++++++++++++++++++++++++++++++++++++
>   softmmu/meson.build             |   1 +
>   softmmu/trace-events            |   7 +
>   tests/qtest/migration-helpers.c |  22 ++
>   tests/qtest/migration-helpers.h |   2 +
>   tests/qtest/migration-test.c    | 255 +++++++++++++++++
>   tests/qtest/qmp-cmd-test.c      |   2 +
>   22 files changed, 1293 insertions(+), 99 deletions(-)
>   create mode 100644 include/sysemu/dirtylimit.h
>   create mode 100644 include/sysemu/dirtyrate.h
>   create mode 100644 softmmu/dirtylimit.c
> 

Re: [PATCH v22 0/8] support dirty restraint on vCPU

[Peter Xu]

Hi, Yong,

On Mon, Apr 25, 2022 at 12:52:45AM +0800, Hyman wrote:
> Ping.
>  Hi, David and Peter, how do you think this patchset?
>  Is it suitable for queueing ? or is there still something need to be done ?

It keeps looking good to me in general, let's see whether the maintainers
have any comments.  Thanks,

-- 
Peter Xu

Re: [PATCH v22 0/8] support dirty restraint on vCPU

[Markus Armbruster]

Peter Xu <peterx@redhat.com> writes:

> Hi, Yong,
>
> On Mon, Apr 25, 2022 at 12:52:45AM +0800, Hyman wrote:
>> Ping.
>>  Hi, David and Peter, how do you think this patchset?
>>  Is it suitable for queueing ? or is there still something need to be done ?
>
> It keeps looking good to me in general, let's see whether the maintainers
> have any comments.  Thanks,

Whose review is still needed?  Or is this ready?