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authorDr. David Alan Gilbert <dgilbert@redhat.com>2014-03-19 18:32:31 +0000
committerJuan Quintela <quintela@redhat.com>2014-05-05 22:15:03 +0200
commitd97326eec2ca1313eaf0b5cffd69af5663b5af5d (patch)
tree9329c32143b42fa2c79a13e166a3e7439c4343d0 /arch_init.c
parent0d6ab3ab9149767eba192ec5ad659fd34e55a291 (diff)
Init the XBZRLE.lock in ram_mig_init
Initialising the XBZRLE.lock earlier simplifies the lock use. Based on Markus's patch in: http://lists.gnu.org/archive/html/qemu-devel/2014-03/msg03879.html Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Gonglei <arei.gonglei@huawei.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
Diffstat (limited to 'arch_init.c')
-rw-r--r--arch_init.c61
1 files changed, 31 insertions, 30 deletions
diff --git a/arch_init.c b/arch_init.c
index aeebb8ecb2..5e2022857a 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -45,6 +45,7 @@
#include "hw/audio/pcspk.h"
#include "migration/page_cache.h"
#include "qemu/config-file.h"
+#include "qemu/error-report.h"
#include "qmp-commands.h"
#include "trace.h"
#include "exec/cpu-all.h"
@@ -167,11 +168,8 @@ static struct {
/* Cache for XBZRLE, Protected by lock. */
PageCache *cache;
QemuMutex lock;
-} XBZRLE = {
- .encoded_buf = NULL,
- .current_buf = NULL,
- .cache = NULL,
-};
+} XBZRLE;
+
/* buffer used for XBZRLE decoding */
static uint8_t *xbzrle_decoded_buf;
@@ -187,41 +185,44 @@ static void XBZRLE_cache_unlock(void)
qemu_mutex_unlock(&XBZRLE.lock);
}
+/*
+ * called from qmp_migrate_set_cache_size in main thread, possibly while
+ * a migration is in progress.
+ * A running migration maybe using the cache and might finish during this
+ * call, hence changes to the cache are protected by XBZRLE.lock().
+ */
int64_t xbzrle_cache_resize(int64_t new_size)
{
- PageCache *new_cache, *cache_to_free;
+ PageCache *new_cache;
+ int64_t ret;
if (new_size < TARGET_PAGE_SIZE) {
return -1;
}
- /* no need to lock, the current thread holds qemu big lock */
+ XBZRLE_cache_lock();
+
if (XBZRLE.cache != NULL) {
- /* check XBZRLE.cache again later */
if (pow2floor(new_size) == migrate_xbzrle_cache_size()) {
- return pow2floor(new_size);
+ goto out_new_size;
}
new_cache = cache_init(new_size / TARGET_PAGE_SIZE,
TARGET_PAGE_SIZE);
if (!new_cache) {
- DPRINTF("Error creating cache\n");
- return -1;
- }
-
- XBZRLE_cache_lock();
- /* the XBZRLE.cache may have be destroyed, check it again */
- if (XBZRLE.cache != NULL) {
- cache_to_free = XBZRLE.cache;
- XBZRLE.cache = new_cache;
- } else {
- cache_to_free = new_cache;
+ error_report("Error creating cache");
+ ret = -1;
+ goto out;
}
- XBZRLE_cache_unlock();
- cache_fini(cache_to_free);
+ cache_fini(XBZRLE.cache);
+ XBZRLE.cache = new_cache;
}
- return pow2floor(new_size);
+out_new_size:
+ ret = pow2floor(new_size);
+out:
+ XBZRLE_cache_unlock();
+ return ret;
}
/* accounting for migration statistics */
@@ -732,28 +733,27 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
dirty_rate_high_cnt = 0;
if (migrate_use_xbzrle()) {
- qemu_mutex_lock_iothread();
+ XBZRLE_cache_lock();
XBZRLE.cache = cache_init(migrate_xbzrle_cache_size() /
TARGET_PAGE_SIZE,
TARGET_PAGE_SIZE);
if (!XBZRLE.cache) {
- qemu_mutex_unlock_iothread();
- DPRINTF("Error creating cache\n");
+ XBZRLE_cache_unlock();
+ error_report("Error creating cache");
return -1;
}
- qemu_mutex_init(&XBZRLE.lock);
- qemu_mutex_unlock_iothread();
+ XBZRLE_cache_unlock();
/* We prefer not to abort if there is no memory */
XBZRLE.encoded_buf = g_try_malloc0(TARGET_PAGE_SIZE);
if (!XBZRLE.encoded_buf) {
- DPRINTF("Error allocating encoded_buf\n");
+ error_report("Error allocating encoded_buf");
return -1;
}
XBZRLE.current_buf = g_try_malloc(TARGET_PAGE_SIZE);
if (!XBZRLE.current_buf) {
- DPRINTF("Error allocating current_buf\n");
+ error_report("Error allocating current_buf");
g_free(XBZRLE.encoded_buf);
XBZRLE.encoded_buf = NULL;
return -1;
@@ -1119,6 +1119,7 @@ static SaveVMHandlers savevm_ram_handlers = {
void ram_mig_init(void)
{
+ qemu_mutex_init(&XBZRLE.lock);
register_savevm_live(NULL, "ram", 0, 4, &savevm_ram_handlers, NULL);
}