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

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

Introduce qmp commands set-dirty-limit/cancel-dirty-limit to
set/cancel dirty limit on vCPU.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
---
 cpus-common.c         | 41 +++++++++++++++++++++++++++++++++++++++++
 include/hw/core/cpu.h |  9 +++++++++
 qapi/migration.json   | 43 +++++++++++++++++++++++++++++++++++++++++++
 softmmu/vl.c          |  1 +
 4 files changed, 94 insertions(+)

diff --git a/cpus-common.c b/cpus-common.c
index 6e73d3e..43b0078 100644
--- a/cpus-common.c
+++ b/cpus-common.c
@@ -23,6 +23,11 @@
 #include "hw/core/cpu.h"
 #include "sysemu/cpus.h"
 #include "qemu/lockable.h"
+#include "sysemu/dirtylimit.h"
+#include "sysemu/cpu-throttle.h"
+#include "sysemu/kvm.h"
+#include "qapi/error.h"
+#include "qapi/qapi-commands-migration.h"
 
 static QemuMutex qemu_cpu_list_lock;
 static QemuCond exclusive_cond;
@@ -352,3 +357,39 @@ void process_queued_cpu_work(CPUState *cpu)
     qemu_mutex_unlock(&cpu->work_mutex);
     qemu_cond_broadcast(&qemu_work_cond);
 }
+
+void qmp_set_dirty_limit(int64_t idx,
+                         uint64_t dirtyrate,
+                         Error **errp)
+{
+    if (!kvm_dirty_ring_enabled()) {
+        error_setg(errp, "dirty ring not enable, needed by dirty restraint!");
+        return;
+    }
+
+    dirtylimit_calc();
+    dirtylimit_vcpu(idx, dirtyrate);
+}
+
+void qmp_cancel_dirty_limit(int64_t idx,
+                            Error **errp)
+{
+    if (!kvm_dirty_ring_enabled()) {
+        error_setg(errp, "dirty ring not enable, needed by dirty restraint!");
+        return;
+    }
+
+    if (unlikely(!dirtylimit_cancel_vcpu(idx))) {
+        dirtylimit_calc_quit();
+    }
+}
+
+void dirtylimit_setup(int max_cpus)
+{
+    if (!kvm_dirty_ring_enabled()) {
+        return;
+    }
+
+    dirtylimit_calc_state_init(max_cpus);
+    dirtylimit_state_init(max_cpus);
+}
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index e948e81..11df012 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -881,6 +881,15 @@ void end_exclusive(void);
  */
 void qemu_init_vcpu(CPUState *cpu);
 
+/**
+ * dirtylimit_setup:
+ *
+ * Initializes the global state of dirtylimit calculation and
+ * dirtylimit itself. This is prepared for vCPU dirtylimit which
+ * could be triggered during vm lifecycle.
+ */
+void dirtylimit_setup(int max_cpus);
+
 #define SSTEP_ENABLE  0x1  /* Enable simulated HW single stepping */
 #define SSTEP_NOIRQ   0x2  /* Do not use IRQ while single stepping */
 #define SSTEP_NOTIMER 0x4  /* Do not Timers while single stepping */
diff --git a/qapi/migration.json b/qapi/migration.json
index bbfd48c..42b260e 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -1850,6 +1850,49 @@
 { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' }
 
 ##
+# @set-dirty-limit:
+#
+# Set the upper limit of dirty page rate for the interested vCPU.
+#
+# This command could be used to cap the vCPU memory load, which is also
+# refered as "dirty page rate". Users can use set-dirty-limit unconditionally,
+# but if one want to know which vCPU is in high memory load and which vCPU
+# should be limited, "calc-dirty-rate" with "dirty-ring" mode maybe an
+# availiable method.
+#
+# @idx: vCPU index to set dirtylimit.
+#
+# @dirtyrate: upper limit for the specified vCPU's dirty page rate (MB/s)
+#
+# Since: 6.3
+#
+# Example:
+#   {"execute": "set-dirty-limit"}
+#    "arguments": { "idx": 0,
+#                   "dirtyrate": 200 } }
+#
+##
+{ 'command': 'set-dirty-limit',
+  'data': { 'idx': 'int', 'dirtyrate': 'uint64' } }
+
+##
+# @cancel-dirty-limit:
+#
+# Cancel the dirtylimit for the vCPU which has been set with set-dirty-limit.
+#
+# @idx: vCPU index to canceled the dirtylimit
+#
+# Since: 6.3
+#
+# Example:
+#   {"execute": "cancel-dirty-limit"}
+#    "arguments": { "idx": 0 } }
+#
+##
+{ 'command': 'cancel-dirty-limit',
+  'data': { 'idx': 'int' } }
+
+##
 # @snapshot-save:
 #
 # Save a VM snapshot
diff --git a/softmmu/vl.c b/softmmu/vl.c
index 620a1f1..0f83ce3 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -3777,5 +3777,6 @@ void qemu_init(int argc, char **argv, char **envp)
     qemu_init_displays();
     accel_setup_post(current_machine);
     os_setup_post();
+    dirtylimit_setup(current_machine->smp.max_cpus);
     resume_mux_open();
 }
-- 
1.8.3.1

huangy81@chinatelecom.cn writes:

> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
>
> Implement dirtyrate calculation periodically basing on
> dirty-ring and throttle vCPU until it reachs the quota
> dirtyrate given by user.
>
> Introduce qmp commands set-dirty-limit/cancel-dirty-limit to
> set/cancel dirty limit on vCPU.
>
> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
> ---
>  cpus-common.c         | 41 +++++++++++++++++++++++++++++++++++++++++
>  include/hw/core/cpu.h |  9 +++++++++
>  qapi/migration.json   | 43 +++++++++++++++++++++++++++++++++++++++++++
>  softmmu/vl.c          |  1 +
>  4 files changed, 94 insertions(+)
>
> diff --git a/cpus-common.c b/cpus-common.c
> index 6e73d3e..43b0078 100644
> --- a/cpus-common.c
> +++ b/cpus-common.c
> @@ -23,6 +23,11 @@
>  #include "hw/core/cpu.h"
>  #include "sysemu/cpus.h"
>  #include "qemu/lockable.h"
> +#include "sysemu/dirtylimit.h"
> +#include "sysemu/cpu-throttle.h"
> +#include "sysemu/kvm.h"
> +#include "qapi/error.h"
> +#include "qapi/qapi-commands-migration.h"
>  
>  static QemuMutex qemu_cpu_list_lock;
>  static QemuCond exclusive_cond;
> @@ -352,3 +357,39 @@ void process_queued_cpu_work(CPUState *cpu)
>      qemu_mutex_unlock(&cpu->work_mutex);
>      qemu_cond_broadcast(&qemu_work_cond);
>  }
> +
> +void qmp_set_dirty_limit(int64_t idx,
> +                         uint64_t dirtyrate,
> +                         Error **errp)
> +{
> +    if (!kvm_dirty_ring_enabled()) {
> +        error_setg(errp, "dirty ring not enable, needed by dirty restraint!");

"not enabled"

What is a "dirty restraint"?

Drop the exclamation point, please.  See error.h:

 * The resulting message should be a single phrase, with no newline or
 * trailing punctuation.

What about "setting a dirty page limit requires ...".

> +        return;
> +    }
> +
> +    dirtylimit_calc();
> +    dirtylimit_vcpu(idx, dirtyrate);
> +}
> +
> +void qmp_cancel_dirty_limit(int64_t idx,
> +                            Error **errp)
> +{
> +    if (!kvm_dirty_ring_enabled()) {
> +        error_setg(errp, "dirty ring not enable, needed by dirty restraint!");
> +        return;
> +    }
> +
> +    if (unlikely(!dirtylimit_cancel_vcpu(idx))) {
> +        dirtylimit_calc_quit();
> +    }
> +}
> +
> +void dirtylimit_setup(int max_cpus)
> +{
> +    if (!kvm_dirty_ring_enabled()) {

This crashes unless the accelerator is kvm.  Reproducer:

    $ qemu-system-x86_64 -display none -accel tcg
    Segmentation fault (core dumped)

> +        return;
> +    }
> +
> +    dirtylimit_calc_state_init(max_cpus);
> +    dirtylimit_state_init(max_cpus);
> +}
> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
> index e948e81..11df012 100644
> --- a/include/hw/core/cpu.h
> +++ b/include/hw/core/cpu.h
> @@ -881,6 +881,15 @@ void end_exclusive(void);
>   */
>  void qemu_init_vcpu(CPUState *cpu);
>  
> +/**
> + * dirtylimit_setup:
> + *
> + * Initializes the global state of dirtylimit calculation and
> + * dirtylimit itself. This is prepared for vCPU dirtylimit which
> + * could be triggered during vm lifecycle.
> + */
> +void dirtylimit_setup(int max_cpus);
> +
>  #define SSTEP_ENABLE  0x1  /* Enable simulated HW single stepping */
>  #define SSTEP_NOIRQ   0x2  /* Do not use IRQ while single stepping */
>  #define SSTEP_NOTIMER 0x4  /* Do not Timers while single stepping */
> diff --git a/qapi/migration.json b/qapi/migration.json
> index bbfd48c..42b260e 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -1850,6 +1850,49 @@
>  { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' }
>  
>  ##
> +# @set-dirty-limit:
> +#
> +# Set the upper limit of dirty page rate for the interested vCPU.

"for a vCPU"

> +#
> +# This command could be used to cap the vCPU memory load, which is also
> +# refered as "dirty page rate". Users can use set-dirty-limit unconditionally,
> +# but if one want to know which vCPU is in high memory load and which vCPU
> +# should be limited, "calc-dirty-rate" with "dirty-ring" mode maybe an
> +# availiable method.

I think you should mention that the command fails unless dirty ring is
enabled, and a pointer to its documentation.

> +#
> +# @idx: vCPU index to set dirtylimit.

Please rename to @cpu-index for consistency with query-cpus-fast.  Same
for cancel-dirty-limit below.

> +#
> +# @dirtyrate: upper limit for the specified vCPU's dirty page rate (MB/s)

In QMP, we separate words with hyphens, like @dirty-rate.  Please
rename.

> +#
> +# Since: 6.3

7.0

> +#
> +# Example:
> +#   {"execute": "set-dirty-limit"}
> +#    "arguments": { "idx": 0,
> +#                   "dirtyrate": 200 } }
> +#
> +##
> +{ 'command': 'set-dirty-limit',
> +  'data': { 'idx': 'int', 'dirtyrate': 'uint64' } }
> +
> +##
> +# @cancel-dirty-limit:
> +#
> +# Cancel the dirtylimit for the vCPU which has been set with set-dirty-limit.

"the dirty page limit"

> +#
> +# @idx: vCPU index to canceled the dirtylimit
> +#
> +# Since: 6.3

7.0

> +#
> +# Example:
> +#   {"execute": "cancel-dirty-limit"}
> +#    "arguments": { "idx": 0 } }
> +#
> +##
> +{ 'command': 'cancel-dirty-limit',
> +  'data': { 'idx': 'int' } }
> +
> +##
>  # @snapshot-save:
>  #
>  # Save a VM snapshot
> diff --git a/softmmu/vl.c b/softmmu/vl.c
> index 620a1f1..0f83ce3 100644
> --- a/softmmu/vl.c
> +++ b/softmmu/vl.c
> @@ -3777,5 +3777,6 @@ void qemu_init(int argc, char **argv, char **envp)
>      qemu_init_displays();
>      accel_setup_post(current_machine);
>      os_setup_post();
> +    dirtylimit_setup(current_machine->smp.max_cpus);
>      resume_mux_open();
>  }

在 2021/11/24 23:33, Markus Armbruster 写道:
> huangy81@chinatelecom.cn writes:
> 
>> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
>>
>> Implement dirtyrate calculation periodically basing on
>> dirty-ring and throttle vCPU until it reachs the quota
>> dirtyrate given by user.
>>
>> Introduce qmp commands set-dirty-limit/cancel-dirty-limit to
>> set/cancel dirty limit on vCPU.
>>
>> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
>> ---
>>   cpus-common.c         | 41 +++++++++++++++++++++++++++++++++++++++++
>>   include/hw/core/cpu.h |  9 +++++++++
>>   qapi/migration.json   | 43 +++++++++++++++++++++++++++++++++++++++++++
>>   softmmu/vl.c          |  1 +
>>   4 files changed, 94 insertions(+)
>>
>> diff --git a/cpus-common.c b/cpus-common.c
>> index 6e73d3e..43b0078 100644
>> --- a/cpus-common.c
>> +++ b/cpus-common.c
>> @@ -23,6 +23,11 @@
>>   #include "hw/core/cpu.h"
>>   #include "sysemu/cpus.h"
>>   #include "qemu/lockable.h"
>> +#include "sysemu/dirtylimit.h"
>> +#include "sysemu/cpu-throttle.h"
>> +#include "sysemu/kvm.h"
>> +#include "qapi/error.h"
>> +#include "qapi/qapi-commands-migration.h"
>>   
>>   static QemuMutex qemu_cpu_list_lock;
>>   static QemuCond exclusive_cond;
>> @@ -352,3 +357,39 @@ void process_queued_cpu_work(CPUState *cpu)
>>       qemu_mutex_unlock(&cpu->work_mutex);
>>       qemu_cond_broadcast(&qemu_work_cond);
>>   }
>> +
>> +void qmp_set_dirty_limit(int64_t idx,
>> +                         uint64_t dirtyrate,
>> +                         Error **errp)
>> +{
>> +    if (!kvm_dirty_ring_enabled()) {
>> +        error_setg(errp, "dirty ring not enable, needed by dirty restraint!");
> 
> "not enabled"
> 
> What is a "dirty restraint"?
> 
> Drop the exclamation point, please.  See error.h:
> 
>   * The resulting message should be a single phrase, with no newline or
>   * trailing punctuation.
> 
> What about "setting a dirty page limit requires ...".
Ok, sound good
> 
>> +        return;
>> +    }
>> +
>> +    dirtylimit_calc();
>> +    dirtylimit_vcpu(idx, dirtyrate);
>> +}
>> +
>> +void qmp_cancel_dirty_limit(int64_t idx,
>> +                            Error **errp)
>> +{
>> +    if (!kvm_dirty_ring_enabled()) {
>> +        error_setg(errp, "dirty ring not enable, needed by dirty restraint!");
>> +        return;
>> +    }
>> +
>> +    if (unlikely(!dirtylimit_cancel_vcpu(idx))) {
>> +        dirtylimit_calc_quit();
>> +    }
>> +}
>> +
>> +void dirtylimit_setup(int max_cpus)
>> +{
>> +    if (!kvm_dirty_ring_enabled()) {
> 
> This crashes unless the accelerator is kvm.  Reproducer:
> 
>      $ qemu-system-x86_64 -display none -accel tcg
>      Segmentation fault (core dumped)
>
Thanks very much for finding this issue, i'll fix it next version

>> +        return;
>> +    }
>> +
>> +    dirtylimit_calc_state_init(max_cpus);
>> +    dirtylimit_state_init(max_cpus);
>> +}
>> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
>> index e948e81..11df012 100644
>> --- a/include/hw/core/cpu.h
>> +++ b/include/hw/core/cpu.h
>> @@ -881,6 +881,15 @@ void end_exclusive(void);
>>    */
>>   void qemu_init_vcpu(CPUState *cpu);
>>   
>> +/**
>> + * dirtylimit_setup:
>> + *
>> + * Initializes the global state of dirtylimit calculation and
>> + * dirtylimit itself. This is prepared for vCPU dirtylimit which
>> + * could be triggered during vm lifecycle.
>> + */
>> +void dirtylimit_setup(int max_cpus);
>> +
>>   #define SSTEP_ENABLE  0x1  /* Enable simulated HW single stepping */
>>   #define SSTEP_NOIRQ   0x2  /* Do not use IRQ while single stepping */
>>   #define SSTEP_NOTIMER 0x4  /* Do not Timers while single stepping */
>> diff --git a/qapi/migration.json b/qapi/migration.json
>> index bbfd48c..42b260e 100644
>> --- a/qapi/migration.json
>> +++ b/qapi/migration.json
>> @@ -1850,6 +1850,49 @@
>>   { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' }
>>   
>>   ##
>> +# @set-dirty-limit:
>> +#
>> +# Set the upper limit of dirty page rate for the interested vCPU.
> 
> "for a vCPU"
> 
>> +#
>> +# This command could be used to cap the vCPU memory load, which is also
>> +# refered as "dirty page rate". Users can use set-dirty-limit unconditionally,
>> +# but if one want to know which vCPU is in high memory load and which vCPU
>> +# should be limited, "calc-dirty-rate" with "dirty-ring" mode maybe an
>> +# availiable method.
> 
> I think you should mention that the command fails unless dirty ring is
> enabled, and a pointer to its documentation.
> 
Emm, it seems that there's no documentation about dirty ring in qemu，
should i metion the commit b4420f19 "KVM: Dirty ring support" for 
dirty-ring?
>> +#
>> +# @idx: vCPU index to set dirtylimit.
> 
> Please rename to @cpu-index for consistency with query-cpus-fast.  Same
> for cancel-dirty-limit below.
> 
>> +#
>> +# @dirtyrate: upper limit for the specified vCPU's dirty page rate (MB/s)
> 
> In QMP, we separate words with hyphens, like @dirty-rate.  Please
> rename.
> 
>> +#
>> +# Since: 6.3
> 
> 7.0
> 
>> +#
>> +# Example:
>> +#   {"execute": "set-dirty-limit"}
>> +#    "arguments": { "idx": 0,
>> +#                   "dirtyrate": 200 } }
>> +#
>> +##
>> +{ 'command': 'set-dirty-limit',
>> +  'data': { 'idx': 'int', 'dirtyrate': 'uint64' } }
>> +
>> +##
>> +# @cancel-dirty-limit:
>> +#
>> +# Cancel the dirtylimit for the vCPU which has been set with set-dirty-limit.
> 
> "the dirty page limit"
> 
>> +#
>> +# @idx: vCPU index to canceled the dirtylimit
>> +#
>> +# Since: 6.3
> 
> 7.0
> 
>> +#
>> +# Example:
>> +#   {"execute": "cancel-dirty-limit"}
>> +#    "arguments": { "idx": 0 } }
>> +#
>> +##
>> +{ 'command': 'cancel-dirty-limit',
>> +  'data': { 'idx': 'int' } }
>> +
>> +##
>>   # @snapshot-save:
>>   #
>>   # Save a VM snapshot
>> diff --git a/softmmu/vl.c b/softmmu/vl.c
>> index 620a1f1..0f83ce3 100644
>> --- a/softmmu/vl.c
>> +++ b/softmmu/vl.c
>> @@ -3777,5 +3777,6 @@ void qemu_init(int argc, char **argv, char **envp)
>>       qemu_init_displays();
>>       accel_setup_post(current_machine);
>>       os_setup_post();
>> +    dirtylimit_setup(current_machine->smp.max_cpus);
>>       resume_mux_open();
>>   }
> 

-- 
Best regard

Hyman Huang(黄勇)

Hyman Huang <huangy81@chinatelecom.cn> writes:

> 在 2021/11/24 23:33, Markus Armbruster 写道:
>> huangy81@chinatelecom.cn writes:
>> 
>>> From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
>>>
>>> Implement dirtyrate calculation periodically basing on
>>> dirty-ring and throttle vCPU until it reachs the quota
>>> dirtyrate given by user.
>>>
>>> Introduce qmp commands set-dirty-limit/cancel-dirty-limit to
>>> set/cancel dirty limit on vCPU.
>>>
>>> Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>

[...]

>>> diff --git a/qapi/migration.json b/qapi/migration.json
>>> index bbfd48c..42b260e 100644
>>> --- a/qapi/migration.json
>>> +++ b/qapi/migration.json
>>> @@ -1850,6 +1850,49 @@
>>>   { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' }
>>>     ##
>>> +# @set-dirty-limit:
>>> +#
>>> +# Set the upper limit of dirty page rate for the interested vCPU.
>> "for a vCPU"
>> 
>>> +#
>>> +# This command could be used to cap the vCPU memory load, which is also
>>> +# refered as "dirty page rate". Users can use set-dirty-limit unconditionally,
>>> +# but if one want to know which vCPU is in high memory load and which vCPU
>>> +# should be limited, "calc-dirty-rate" with "dirty-ring" mode maybe an
>>> +# availiable method.
>> I think you should mention that the command fails unless dirty ring
>> is
>> enabled, and a pointer to its documentation.
>> 
> Emm, it seems that there's no documentation about dirty ring in qemu，
> should i metion the commit b4420f19 "KVM: Dirty ring support" for
> dirty-ring?

I think the best you can do then is something like 'Property
"dirty-ring-size" of accelerator object "kvm" must be set.'

[...]