[Qemu-devel] [PATCH v2 23/27] migration: don't use an array for storing migrate parameters

From: "Daniel P. Berrange" <berrange@redhat.com>
To: qemu-devel@nongnu.org
Cc: Amit Shah <amit.shah@redhat.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
	Juan Quintela <quintela@redhat.com>
Subject: [Qemu-devel] [PATCH v2 23/27] migration: don't use an array for storing migrate parameters
Date: Tue, 16 Feb 2016 16:15:14 +0000	[thread overview]
Message-ID: <1455639318-26578-24-git-send-email-berrange@redhat.com> (raw)
In-Reply-To: <1455639318-26578-1-git-send-email-berrange@redhat.com>

The MigrateState struct uses an array for storing migration
parameters. This presumes that all future parameters will
be integers too, which is not going to be the case. There
is no functional reason why an array is used, if anything
it makes the code less clear. The QAPI schema already
defines a struct - MigrationParameters - capable of storing
all the individual parameters, so just use that instead of
an array.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 include/migration/migration.h |  5 +++-
 migration/migration.c         | 56 +++++++++++++++++++------------------------
 migration/ram.c               |  6 ++---
 3 files changed, 30 insertions(+), 37 deletions(-)

diff --git a/include/migration/migration.h b/include/migration/migration.h
index 5d476e6..37f5ec8 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -134,9 +134,12 @@ struct MigrationState
     QemuThread thread;
     QEMUBH *cleanup_bh;
     QEMUFile *to_dst_file;
-    int parameters[MIGRATION_PARAMETER__MAX];
+
+    /* New style params from 'migrate-set-parameters' */
+    MigrationParameters parameters;
 
     int state;
+    /* Old style params from 'migrate' command */
     MigrationParams params;
 
     /* State related to return path */
diff --git a/migration/migration.c b/migration/migration.c
index 19ef9be..e35981f 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -82,16 +82,14 @@ MigrationState *migrate_get_current(void)
         .bandwidth_limit = MAX_THROTTLE,
         .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
         .mbps = -1,
-        .parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] =
-                DEFAULT_MIGRATE_COMPRESS_LEVEL,
-        .parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] =
-                DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT,
-        .parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
-                DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
-        .parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL] =
-                DEFAULT_MIGRATE_X_CPU_THROTTLE_INITIAL,
-        .parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] =
-                DEFAULT_MIGRATE_X_CPU_THROTTLE_INCREMENT,
+        .parameters = {
+            .compress_level = DEFAULT_MIGRATE_COMPRESS_LEVEL,
+            .compress_threads = DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT,
+            .decompress_threads = DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
+            .x_cpu_throttle_initial = DEFAULT_MIGRATE_X_CPU_THROTTLE_INITIAL,
+            .x_cpu_throttle_increment =
+              DEFAULT_MIGRATE_X_CPU_THROTTLE_INCREMENT,
+        },
     };
 
     if (!once) {
@@ -525,15 +523,11 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
     MigrationState *s = migrate_get_current();
 
     params = g_malloc0(sizeof(*params));
-    params->compress_level = s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL];
-    params->compress_threads =
-            s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
-    params->decompress_threads =
-            s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];
-    params->x_cpu_throttle_initial =
-            s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL];
-    params->x_cpu_throttle_increment =
-            s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT];
+    params->compress_level = s->parameters.compress_level;
+    params->compress_threads = s->parameters.compress_threads;
+    params->decompress_threads = s->parameters.decompress_threads;
+    params->x_cpu_throttle_initial = s->parameters.x_cpu_throttle_initial;
+    params->x_cpu_throttle_increment = s->parameters.x_cpu_throttle_increment;
 
     return params;
 }
@@ -733,7 +727,8 @@ void qmp_migrate_set_parameters(bool has_compress_level,
                                 bool has_x_cpu_throttle_initial,
                                 int64_t x_cpu_throttle_initial,
                                 bool has_x_cpu_throttle_increment,
-                                int64_t x_cpu_throttle_increment, Error **errp)
+                                int64_t x_cpu_throttle_increment,
+                                Error **errp)
 {
     MigrationState *s = migrate_get_current();
 
@@ -770,26 +765,23 @@ void qmp_migrate_set_parameters(bool has_compress_level,
     }
 
     if (has_compress_level) {
-        s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL] = compress_level;
+        s->parameters.compress_level = compress_level;
     }
     if (has_compress_threads) {
-        s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS] = compress_threads;
+        s->parameters.compress_threads = compress_threads;
     }
     if (has_decompress_threads) {
-        s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS] =
-                                                    decompress_threads;
+        s->parameters.decompress_threads = decompress_threads;
     }
     if (has_x_cpu_throttle_initial) {
-        s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL] =
-                                                    x_cpu_throttle_initial;
+        s->parameters.x_cpu_throttle_initial = x_cpu_throttle_initial;
     }
-
     if (has_x_cpu_throttle_increment) {
-        s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT] =
-                                                    x_cpu_throttle_increment;
+        s->parameters.x_cpu_throttle_increment = x_cpu_throttle_increment;
     }
 }
 
+
 void qmp_migrate_start_postcopy(Error **errp)
 {
     MigrationState *s = migrate_get_current();
@@ -1167,7 +1159,7 @@ int migrate_compress_level(void)
 
     s = migrate_get_current();
 
-    return s->parameters[MIGRATION_PARAMETER_COMPRESS_LEVEL];
+    return s->parameters.compress_level;
 }
 
 int migrate_compress_threads(void)
@@ -1176,7 +1168,7 @@ int migrate_compress_threads(void)
 
     s = migrate_get_current();
 
-    return s->parameters[MIGRATION_PARAMETER_COMPRESS_THREADS];
+    return s->parameters.compress_threads;
 }
 
 int migrate_decompress_threads(void)
@@ -1185,7 +1177,7 @@ int migrate_decompress_threads(void)
 
     s = migrate_get_current();
 
-    return s->parameters[MIGRATION_PARAMETER_DECOMPRESS_THREADS];
+    return s->parameters.decompress_threads;
 }
 
 bool migrate_use_events(void)
diff --git a/migration/ram.c b/migration/ram.c
index 96c749f..eead0f7 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -426,10 +426,8 @@ static size_t save_page_header(QEMUFile *f, RAMBlock *block, ram_addr_t offset)
 static void mig_throttle_guest_down(void)
 {
     MigrationState *s = migrate_get_current();
-    uint64_t pct_initial =
-            s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL];
-    uint64_t pct_icrement =
-            s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT];
+    uint64_t pct_initial = s->parameters.x_cpu_throttle_initial;
+    uint64_t pct_icrement = s->parameters.x_cpu_throttle_increment;
 
     /* We have not started throttling yet. Let's start it. */
     if (!cpu_throttle_active()) {
-- 
2.5.0
