migration: Move rate_limit_max and rate_limit_used to migration_stats

These way we can make them atomic and use this functions from any
place.  I also moved all functions that use rate_limit to
migration-stats.

Functions got renamed, they are not qemu_file anymore.

qemu_file_rate_limit -> migration_rate_exceeded
qemu_file_set_rate_limit -> migration_rate_set
qemu_file_get_rate_limit -> migration_rate_get
qemu_file_reset_rate_limit -> migration_rate_reset
qemu_file_acct_rate_limit -> migration_rate_account.

Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515195709.63843-6-quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

hw/ppc/spapr.c

@@ -2166,7 +2166,7 @@ static void htab_save_first_pass(QEMUFile *f, SpaprMachineState *spapr,
                 break;
             }
         }
-    } while ((index < htabslots) && !qemu_file_rate_limit(f));
+    } while ((index < htabslots) && !migration_rate_exceeded(f));
 
     if (index >= htabslots) {
         assert(index == htabslots);
@@ -2237,7 +2237,7 @@ static int htab_save_later_pass(QEMUFile *f, SpaprMachineState *spapr,
             assert(index == htabslots);
             index = 0;
         }
-    } while ((examined < htabslots) && (!qemu_file_rate_limit(f) || final));
+    } while ((examined < htabslots) && (!migration_rate_exceeded(f) || final));
 
     if (index >= htabslots) {
         assert(index == htabslots);

hw/s390x/s390-stattrib.c

@@ -209,7 +209,7 @@ static int cmma_save(QEMUFile *f, void *opaque, int final)
         return -ENOMEM;
     }
 
-    while (final ? 1 : qemu_file_rate_limit(f) == 0) {
+    while (final ? 1 : migration_rate_exceeded(f) == 0) {
         reallen = sac->get_stattr(sas, &start_gfn, buflen, buf);
         if (reallen < 0) {
             g_free(buf);

include/migration/qemu-file-types.h

@@ -165,6 +165,16 @@ size_t coroutine_mixed_fn qemu_get_counted_string(QEMUFile *f, char buf[256]);
 
 void qemu_put_counted_string(QEMUFile *f, const char *name);
 
-int qemu_file_rate_limit(QEMUFile *f);
+/**
+ * migration_rate_exceeded: Check if we have exceeded rate for this interval
+ *
+ * Checks if we have already transferred more data that we are allowed
+ * in the current interval.
+ *
+ * @f: QEMUFile used for main migration channel
+ *
+ * Returns if we should stop sending data for this interval.
+ */
+bool migration_rate_exceeded(QEMUFile *f);
 
 #endif

migration/block-dirty-bitmap.c

@@ -706,7 +706,7 @@ static void bulk_phase(QEMUFile *f, DBMSaveState *s, bool limit)
     QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {
         while (!dbms->bulk_completed) {
             bulk_phase_send_chunk(f, s, dbms);
-            if (limit && qemu_file_rate_limit(f)) {
+            if (limit && migration_rate_exceeded(f)) {
                 return;
             }
         }

migration/block.c

@@ -23,6 +23,7 @@
 #include "block/dirty-bitmap.h"
 #include "migration/misc.h"
 #include "migration.h"
+#include "migration-stats.h"
 #include "migration/register.h"
 #include "qemu-file.h"
 #include "migration/vmstate.h"
@@ -625,7 +626,7 @@ static int flush_blks(QEMUFile *f)
 
     blk_mig_lock();
     while ((blk = QSIMPLEQ_FIRST(&block_mig_state.blk_list)) != NULL) {
-        if (qemu_file_rate_limit(f)) {
+        if (migration_rate_exceeded(f)) {
             break;
         }
         if (blk->ret < 0) {
@@ -762,7 +763,7 @@ static int block_save_iterate(QEMUFile *f, void *opaque)
     /* control the rate of transfer */
     blk_mig_lock();
     while (block_mig_state.read_done * BLK_MIG_BLOCK_SIZE <
-           qemu_file_get_rate_limit(f) &&
+           migration_rate_get() &&
            block_mig_state.submitted < MAX_PARALLEL_IO &&
            (block_mig_state.submitted + block_mig_state.read_done) <
            MAX_IO_BUFFERS) {

migration/meson.build

@@ -1,5 +1,6 @@
 # Files needed by unit tests
 migration_files = files(
+  'migration-stats.c',
   'page_cache.c',
   'xbzrle.c',
   'vmstate-types.c',
@@ -18,7 +19,6 @@ softmmu_ss.add(files(
   'fd.c',
   'global_state.c',
   'migration-hmp-cmds.c',
-  'migration-stats.c',
   'migration.c',
   'multifd.c',
   'multifd-zlib.c',

migration/migration-stats.c

@@ -12,6 +12,50 @@
 
 #include "qemu/osdep.h"
 #include "qemu/stats64.h"
+#include "qemu-file.h"
 #include "migration-stats.h"
 
 MigrationAtomicStats mig_stats;
+
+bool migration_rate_exceeded(QEMUFile *f)
+{
+    if (qemu_file_get_error(f)) {
+        return true;
+    }
+
+    uint64_t rate_limit_used = stat64_get(&mig_stats.rate_limit_used);
+    uint64_t rate_limit_max = stat64_get(&mig_stats.rate_limit_max);
+
+    if (rate_limit_max == RATE_LIMIT_DISABLED) {
+        return false;
+    }
+    if (rate_limit_max > 0 && rate_limit_used > rate_limit_max) {
+        return true;
+    }
+    return false;
+}
+
+uint64_t migration_rate_get(void)
+{
+    return stat64_get(&mig_stats.rate_limit_max);
+}
+
+#define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
+
+void migration_rate_set(uint64_t limit)
+{
+    /*
+     * 'limit' is per second.  But we check it each BUFER_DELAY miliseconds.
+     */
+    stat64_set(&mig_stats.rate_limit_max, limit / XFER_LIMIT_RATIO);
+}
+
+void migration_rate_reset(void)
+{
+    stat64_set(&mig_stats.rate_limit_used, 0);
+}
+
+void migration_rate_account(uint64_t len)
+{
+    stat64_add(&mig_stats.rate_limit_used, len);
+}

migration/migration-stats.h

@@ -15,6 +15,12 @@
 
 #include "qemu/stats64.h"
 
+/*
+ * Amount of time to allocate to each "chunk" of bandwidth-throttled
+ * data.
+ */
+#define BUFFER_DELAY     100
+
 /*
  * If rate_limit_max is 0, there is special code to remove the rate
  * limit.
@@ -75,6 +81,14 @@ typedef struct {
      * Number of bytes sent during precopy stage.
      */
     Stat64 precopy_bytes;
+    /*
+     * Maximum amount of data we can send in a cycle.
+     */
+    Stat64 rate_limit_max;
+    /*
+     * Amount of data we have sent in the current cycle.
+     */
+    Stat64 rate_limit_used;
     /*
      * Total number of bytes transferred.
      */
@@ -87,4 +101,36 @@ typedef struct {
 
 extern MigrationAtomicStats mig_stats;
 
+/**
+ * migration_rate_account: Increase the number of bytes transferred.
+ *
+ * Report on a number of bytes the have been transferred that need to
+ * be applied to the rate limiting calcuations.
+ *
+ * @len: amount of bytes transferred
+ */
+void migration_rate_account(uint64_t len);
+
+/**
+ * migration_rate_get: Get the maximum amount that can be transferred.
+ *
+ * Returns the maximum number of bytes that can be transferred in a cycle.
+ */
+uint64_t migration_rate_get(void);
+
+/**
+ * migration_rate_reset: Reset the rate limit counter.
+ *
+ * This is called when we know we start a new transfer cycle.
+ */
+void migration_rate_reset(void);
+
+/**
+ * migration_rate_set: Set the maximum amount that can be transferred.
+ *
+ * Sets the maximum amount of bytes that can be transferred in one cycle.
+ *
+ * @new_rate: new maximum amount
+ */
+void migration_rate_set(uint64_t new_rate);
 #endif

migration/migration.c

@@ -2120,7 +2120,7 @@ static int postcopy_start(MigrationState *ms)
      * will notice we're in POSTCOPY_ACTIVE and not actually
      * wrap their state up here
      */
-    qemu_file_set_rate_limit(ms->to_dst_file, bandwidth);
+    migration_rate_set(bandwidth);
     if (migrate_postcopy_ram()) {
         /* Ping just for debugging, helps line traces up */
         qemu_savevm_send_ping(ms->to_dst_file, 2);
@@ -2304,7 +2304,7 @@ static void migration_completion(MigrationState *s)
                  * them if migration fails or is cancelled.
                  */
                 s->block_inactive = !migrate_colo();
-                qemu_file_set_rate_limit(s->to_dst_file, RATE_LIMIT_DISABLED);
+                migration_rate_set(RATE_LIMIT_DISABLED);
                 ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false,
                                                          s->block_inactive);
             }
@@ -2699,7 +2699,7 @@ static void migration_update_counters(MigrationState *s,
             stat64_get(&mig_stats.dirty_bytes_last_sync) / bandwidth;
     }
 
-    qemu_file_reset_rate_limit(s->to_dst_file);
+    migration_rate_reset();
 
     update_iteration_initial_status(s);
 
@@ -2852,7 +2852,7 @@ bool migration_rate_limit(void)
 
     bool urgent = false;
     migration_update_counters(s, now);
-    if (qemu_file_rate_limit(s->to_dst_file)) {
+    if (migration_rate_exceeded(s->to_dst_file)) {
 
         if (qemu_file_get_error(s->to_dst_file)) {
             return false;
@@ -2974,7 +2974,7 @@ static void *migration_thread(void *opaque)
     trace_migration_thread_setup_complete();
 
     while (migration_is_active(s)) {
-        if (urgent || !qemu_file_rate_limit(s->to_dst_file)) {
+        if (urgent || !migration_rate_exceeded(s->to_dst_file)) {
             MigIterateState iter_state = migration_iteration_run(s);
             if (iter_state == MIG_ITERATE_SKIP) {
                 continue;
@@ -3048,7 +3048,7 @@ static void *bg_migration_thread(void *opaque)
     rcu_register_thread();
     object_ref(OBJECT(s));
 
-    qemu_file_set_rate_limit(s->to_dst_file, RATE_LIMIT_DISABLED);
+    migration_rate_set(RATE_LIMIT_DISABLED);
 
     setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
     /*
@@ -3220,7 +3220,7 @@ void migrate_fd_connect(MigrationState *s, Error *error_in)
         notifier_list_notify(&migration_state_notifiers, s);
     }
 
-    qemu_file_set_rate_limit(s->to_dst_file, rate_limit);
+    migration_rate_set(rate_limit);
     qemu_file_set_blocking(s->to_dst_file, true);
 
     /*

migration/multifd.c

@@ -431,7 +431,7 @@ static int multifd_send_pages(QEMUFile *f)
     multifd_send_state->pages = p->pages;
     p->pages = pages;
     transferred = ((uint64_t) pages->num) * p->page_size + p->packet_len;
-    qemu_file_acct_rate_limit(f, transferred);
+    migration_rate_account(transferred);
     qemu_mutex_unlock(&p->mutex);
     stat64_add(&mig_stats.transferred, transferred);
     stat64_add(&mig_stats.multifd_bytes, transferred);

migration/options.c

@@ -23,6 +23,7 @@
 #include "migration/colo.h"
 #include "migration/misc.h"
 #include "migration.h"
+#include "migration-stats.h"
 #include "qemu-file.h"
 #include "ram.h"
 #include "options.h"
@@ -1242,8 +1243,7 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
     if (params->has_max_bandwidth) {
         s->parameters.max_bandwidth = params->max_bandwidth;
         if (s->to_dst_file && !migration_in_postcopy()) {
-            qemu_file_set_rate_limit(s->to_dst_file,
-                                s->parameters.max_bandwidth);
+            migration_rate_set(s->parameters.max_bandwidth);
         }
     }
 
@@ -1272,8 +1272,7 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
     if (params->has_max_postcopy_bandwidth) {
         s->parameters.max_postcopy_bandwidth = params->max_postcopy_bandwidth;
         if (s->to_dst_file && migration_in_postcopy()) {
-            qemu_file_set_rate_limit(s->to_dst_file,
-                    s->parameters.max_postcopy_bandwidth);
+            migration_rate_set(s->parameters.max_postcopy_bandwidth);
         }
     }
     if (params->has_max_cpu_throttle) {

migration/options.h

@@ -17,13 +17,6 @@
 #include "hw/qdev-properties.h"
 #include "hw/qdev-properties-system.h"
 
-/* constants */
-
-/* Amount of time to allocate to each "chunk" of bandwidth-throttled
- * data. */
-#define BUFFER_DELAY     100
-#define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
-
 /* migration properties */
 
 extern Property migration_properties[];