migration pull 2017-09-06

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Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20170906a' into staging

migration pull 2017-09-06

# gpg: Signature made Wed 06 Sep 2017 19:39:23 BST
# gpg:                using RSA key 0x0516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>"
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20170906a:
  migration: dump str in migrate_set_state trace
  snapshot/tests: Try loadvm twice
  migration: Reset rather than destroy main_thread_load_event
  runstate/migrate: Two more transitions
  host-utils: Simplify pow2ceil()
  host-utils: Proactively fix pow2floor(), switch to unsigned
  xbzrle: Drop unused cache_resize()
  migration: Report when bdrv_inactivate_all fails

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

include/qemu/host-utils.h

@@ -369,27 +369,35 @@ static inline bool is_power_of_2(uint64_t value)
     return !(value & (value - 1));
 }
 
-/* round down to the nearest power of 2*/
-static inline int64_t pow2floor(int64_t value)
+/**
+ * Return @value rounded down to the nearest power of two or zero.
+ */
+static inline uint64_t pow2floor(uint64_t value)
 {
-    if (!is_power_of_2(value)) {
-        value = 0x8000000000000000ULL >> clz64(value);
-    }
-    return value;
-}
-
-/* round up to the nearest power of 2 (0 if overflow) */
-static inline uint64_t pow2ceil(uint64_t value)
-{
-    uint8_t nlz = clz64(value);
-
-    if (is_power_of_2(value)) {
-        return value;
-    }
-    if (!nlz) {
+    if (!value) {
+        /* Avoid undefined shift by 64 */
         return 0;
     }
-    return 1ULL << (64 - nlz);
+    return 0x8000000000000000ull >> clz64(value);
+}
+
+/*
+ * Return @value rounded up to the nearest power of two modulo 2^64.
+ * This is *zero* for @value > 2^63, so be careful.
+ */
+static inline uint64_t pow2ceil(uint64_t value)
+{
+    int n = clz64(value - 1);
+
+    if (!n) {
+        /*
+         * @value - 1 has no leading zeroes, thus @value - 1 >= 2^63
+         * Therefore, either @value == 0 or @value > 2^63.
+         * If it's 0, return 1, else return 0.
+         */
+        return !value;
+    }
+    return 0x8000000000000000ull >> (n - 1);
 }
 
 /**

migration/migration.c

@@ -166,7 +166,7 @@ void migration_incoming_state_destroy(void)
         mis->from_src_file = NULL;
     }
 
-    qemu_event_destroy(&mis->main_thread_load_event);
+    qemu_event_reset(&mis->main_thread_load_event);
 }
 
 static void migrate_generate_event(int new_state)
@@ -913,8 +913,9 @@ void qmp_migrate_start_postcopy(Error **errp)
 
 void migrate_set_state(int *state, int old_state, int new_state)
 {
+    assert(new_state < MIGRATION_STATUS__MAX);
     if (atomic_cmpxchg(state, old_state, new_state) == old_state) {
-        trace_migrate_set_state(new_state);
+        trace_migrate_set_state(MigrationStatus_str(new_state));
         migrate_generate_event(new_state);
     }
 }

migration/page_cache.c

@@ -178,59 +178,3 @@ int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata,
 
     return 0;
 }
-
-int64_t cache_resize(PageCache *cache, int64_t new_num_pages)
-{
-    PageCache *new_cache;
-    int64_t i;
-
-    CacheItem *old_it, *new_it;
-
-    g_assert(cache);
-
-    /* cache was not inited */
-    if (cache->page_cache == NULL) {
-        return -1;
-    }
-
-    /* same size */
-    if (pow2floor(new_num_pages) == cache->max_num_items) {
-        return cache->max_num_items;
-    }
-
-    new_cache = cache_init(new_num_pages, cache->page_size);
-    if (!(new_cache)) {
-        DPRINTF("Error creating new cache\n");
-        return -1;
-    }
-
-    /* move all data from old cache */
-    for (i = 0; i < cache->max_num_items; i++) {
-        old_it = &cache->page_cache[i];
-        if (old_it->it_addr != -1) {
-            /* check for collision, if there is, keep MRU page */
-            new_it = cache_get_by_addr(new_cache, old_it->it_addr);
-            if (new_it->it_data && new_it->it_age >= old_it->it_age) {
-                /* keep the MRU page */
-                g_free(old_it->it_data);
-            } else {
-                if (!new_it->it_data) {
-                    new_cache->num_items++;
-                }
-                g_free(new_it->it_data);
-                new_it->it_data = old_it->it_data;
-                new_it->it_age = old_it->it_age;
-                new_it->it_addr = old_it->it_addr;
-            }
-        }
-    }
-
-    g_free(cache->page_cache);
-    cache->page_cache = new_cache->page_cache;
-    cache->max_num_items = new_cache->max_num_items;
-    cache->num_items = new_cache->num_items;
-
-    g_free(new_cache);
-
-    return cache->max_num_items;
-}

migration/page_cache.h

@@ -72,15 +72,4 @@ uint8_t *get_cached_data(const PageCache *cache, uint64_t addr);
 int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata,
                  uint64_t current_age);
 
-/**
- * cache_resize: resize the page cache. In case of size reduction the extra
- * pages will be freed
- *
- * Returns -1 on error new cache size on success
- *
- * @cache pointer to the PageCache struct
- * @num_pages: new page cache size (in pages)
- */
-int64_t cache_resize(PageCache *cache, int64_t num_pages);
-
 #endif

migration/savevm.c

@@ -1157,6 +1157,8 @@ int qemu_savevm_state_complete_precopy(QEMUFile *f, bool iterable_only,
          * bdrv_invalidate_cache_all() on the other end won't fail. */
         ret = bdrv_inactivate_all();
         if (ret) {
+            error_report("%s: bdrv_inactivate_all() failed (%d)",
+                         __func__, ret);
             qemu_file_set_error(f, ret);
             return ret;
         }

migration/trace-events

@@ -80,7 +80,7 @@ ram_save_queue_pages(const char *rbname, size_t start, size_t len) "%s: start: 0
 # migration/migration.c
 await_return_path_close_on_source_close(void) ""
 await_return_path_close_on_source_joining(void) ""
-migrate_set_state(int new_state) "new state %d"
+migrate_set_state(const char *new_state) "new state %s"
 migrate_fd_cleanup(void) ""
 migrate_fd_error(const char *error_desc) "error=%s"
 migrate_fd_cancel(void) ""

tests/qemu-iotests/068

@@ -78,7 +78,7 @@ for extra_args in \
     # Give qemu some time to boot before saving the VM state
     { sleep 1; printf "savevm 0\nquit\n"; } | _qemu $extra_args
     # Now try to continue from that VM state (this should just work)
-    echo quit | _qemu $extra_args -loadvm 0
+    { sleep 1; printf "loadvm 0\nloadvm 0\nquit\n"; } | _qemu $extra_args -S
 done
 
 # success, all done

tests/qemu-iotests/068.out

@@ -7,6 +7,8 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm 0
 (qemu) quit
 QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) loadvm 0
+(qemu) loadvm 0
 (qemu) quit
 
 === Saving and reloading a VM state to/from a qcow2 image (-object iothread,id=iothread0 -set device.hba0.iothread=iothread0) ===
@@ -16,5 +18,7 @@ QEMU X.Y.Z monitor - type 'help' for more information
 (qemu) savevm 0
 (qemu) quit
 QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) loadvm 0
+(qemu) loadvm 0
 (qemu) quit
 *** done

vl.c

@@ -621,6 +621,7 @@ static const RunStateTransition runstate_transitions_def[] = {
 
     { RUN_STATE_PAUSED, RUN_STATE_RUNNING },
     { RUN_STATE_PAUSED, RUN_STATE_FINISH_MIGRATE },
+    { RUN_STATE_PAUSED, RUN_STATE_POSTMIGRATE },
     { RUN_STATE_PAUSED, RUN_STATE_PRELAUNCH },
     { RUN_STATE_PAUSED, RUN_STATE_COLO},
 
@@ -633,6 +634,7 @@ static const RunStateTransition runstate_transitions_def[] = {
     { RUN_STATE_PRELAUNCH, RUN_STATE_INMIGRATE },
 
     { RUN_STATE_FINISH_MIGRATE, RUN_STATE_RUNNING },
+    { RUN_STATE_FINISH_MIGRATE, RUN_STATE_PAUSED },
     { RUN_STATE_FINISH_MIGRATE, RUN_STATE_POSTMIGRATE },
     { RUN_STATE_FINISH_MIGRATE, RUN_STATE_PRELAUNCH },
     { RUN_STATE_FINISH_MIGRATE, RUN_STATE_COLO},