在 2021/11/24 23:33, Markus Armbruster 写道:
huang...@chinatelecom.cn writes:

From: Hyman Huang(黄勇) <huang...@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) <huang...@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)

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