#include "exec/ram_addr.h"
#include "hw/acpi/acpi.h"
#include "qemu/host-utils.h"
+#include "qemu/rcu_queue.h"
#ifdef DEBUG_ARCH_INIT
#define DPRINTF(fmt, ...) \
/* We don't care if this fails to allocate a new cache page
* as long as it updated an old one */
- cache_insert(XBZRLE.cache, current_addr, ZERO_TARGET_PAGE);
+ cache_insert(XBZRLE.cache, current_addr, ZERO_TARGET_PAGE,
+ bitmap_sync_count);
}
#define ENCODING_FLAG_XBZRLE 0x1
int encoded_len = 0, bytes_sent = -1;
uint8_t *prev_cached_page;
- if (!cache_is_cached(XBZRLE.cache, current_addr)) {
+ if (!cache_is_cached(XBZRLE.cache, current_addr, bitmap_sync_count)) {
acct_info.xbzrle_cache_miss++;
if (!last_stage) {
- if (cache_insert(XBZRLE.cache, current_addr, *current_data) == -1) {
+ if (cache_insert(XBZRLE.cache, current_addr, *current_data,
+ bitmap_sync_count) == -1) {
return -1;
} else {
/* update *current_data when the page has been
}
-/* Needs iothread lock! */
/* Fix me: there are too many global variables used in migration process. */
static int64_t start_time;
static int64_t bytes_xfer_prev;
num_dirty_pages_period = 0;
}
+/* Called with iothread lock held, to protect ram_list.dirty_memory[] */
static void migration_bitmap_sync(void)
{
RAMBlock *block;
trace_migration_bitmap_sync_start();
address_space_sync_dirty_bitmap(&address_space_memory);
- QTAILQ_FOREACH(block, &ram_list.blocks, next) {
+ rcu_read_lock();
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
migration_bitmap_sync_range(block->mr->ram_addr, block->used_length);
}
+ rcu_read_unlock();
+
trace_migration_bitmap_sync_end(migration_dirty_pages
- num_dirty_pages_init);
num_dirty_pages_period += migration_dirty_pages - num_dirty_pages_init;
/*
* ram_find_and_save_block: Finds a page to send and sends it to f
*
+ * Called within an RCU critical section.
+ *
* Returns: The number of bytes written.
* 0 means no dirty pages
*/
MemoryRegion *mr;
if (!block)
- block = QTAILQ_FIRST(&ram_list.blocks);
+ block = QLIST_FIRST_RCU(&ram_list.blocks);
while (true) {
mr = block->mr;
}
if (offset >= block->used_length) {
offset = 0;
- block = QTAILQ_NEXT(block, next);
+ block = QLIST_NEXT_RCU(block, next);
if (!block) {
- block = QTAILQ_FIRST(&ram_list.blocks);
+ block = QLIST_FIRST_RCU(&ram_list.blocks);
complete_round = true;
ram_bulk_stage = false;
}
}
}
}
+
last_seen_block = block;
last_offset = offset;
-
return bytes_sent;
}
RAMBlock *block;
uint64_t total = 0;
- QTAILQ_FOREACH(block, &ram_list.blocks, next)
+ rcu_read_lock();
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next)
total += block->used_length;
-
+ rcu_read_unlock();
return total;
}
#define MAX_WAIT 50 /* ms, half buffered_file limit */
+
+/* Each of ram_save_setup, ram_save_iterate and ram_save_complete has
+ * long-running RCU critical section. When rcu-reclaims in the code
+ * start to become numerous it will be necessary to reduce the
+ * granularity of these critical sections.
+ */
+
static int ram_save_setup(QEMUFile *f, void *opaque)
{
RAMBlock *block;
acct_clear();
}
+ /* iothread lock needed for ram_list.dirty_memory[] */
qemu_mutex_lock_iothread();
qemu_mutex_lock_ramlist();
+ rcu_read_lock();
bytes_transferred = 0;
reset_ram_globals();
* gaps due to alignment or unplugs.
*/
migration_dirty_pages = 0;
- QTAILQ_FOREACH(block, &ram_list.blocks, next) {
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
uint64_t block_pages;
block_pages = block->used_length >> TARGET_PAGE_BITS;
memory_global_dirty_log_start();
migration_bitmap_sync();
+ qemu_mutex_unlock_ramlist();
qemu_mutex_unlock_iothread();
qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
- QTAILQ_FOREACH(block, &ram_list.blocks, next) {
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
qemu_put_byte(f, strlen(block->idstr));
qemu_put_buffer(f, (uint8_t *)block->idstr, strlen(block->idstr));
qemu_put_be64(f, block->used_length);
}
- qemu_mutex_unlock_ramlist();
+ rcu_read_unlock();
ram_control_before_iterate(f, RAM_CONTROL_SETUP);
ram_control_after_iterate(f, RAM_CONTROL_SETUP);
int64_t t0;
int total_sent = 0;
- qemu_mutex_lock_ramlist();
-
+ rcu_read_lock();
if (ram_list.version != last_version) {
reset_ram_globals();
}
+ /* Read version before ram_list.blocks */
+ smp_rmb();
+
ram_control_before_iterate(f, RAM_CONTROL_ROUND);
t0 = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
}
i++;
}
-
- qemu_mutex_unlock_ramlist();
+ rcu_read_unlock();
/*
* Must occur before EOS (or any QEMUFile operation)
return total_sent;
}
+/* Called with iothread lock */
static int ram_save_complete(QEMUFile *f, void *opaque)
{
- qemu_mutex_lock_ramlist();
+ rcu_read_lock();
+
migration_bitmap_sync();
ram_control_before_iterate(f, RAM_CONTROL_FINISH);
ram_control_after_iterate(f, RAM_CONTROL_FINISH);
migration_end();
- qemu_mutex_unlock_ramlist();
+ rcu_read_unlock();
qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
return 0;
if (remaining_size < max_size) {
qemu_mutex_lock_iothread();
+ rcu_read_lock();
migration_bitmap_sync();
+ rcu_read_unlock();
qemu_mutex_unlock_iothread();
remaining_size = ram_save_remaining() * TARGET_PAGE_SIZE;
}
return 0;
}
+/* Must be called from within a rcu critical section.
+ * Returns a pointer from within the RCU-protected ram_list.
+ */
static inline void *host_from_stream_offset(QEMUFile *f,
ram_addr_t offset,
int flags)
qemu_get_buffer(f, (uint8_t *)id, len);
id[len] = 0;
- QTAILQ_FOREACH(block, &ram_list.blocks, next) {
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
if (!strncmp(id, block->idstr, sizeof(id)) &&
block->max_length > offset) {
return memory_region_get_ram_ptr(block->mr) + offset;
ret = -EINVAL;
}
+ /* This RCU critical section can be very long running.
+ * When RCU reclaims in the code start to become numerous,
+ * it will be necessary to reduce the granularity of this
+ * critical section.
+ */
+ rcu_read_lock();
while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) {
ram_addr_t addr, total_ram_bytes;
void *host;
id[len] = 0;
length = qemu_get_be64(f);
- QTAILQ_FOREACH(block, &ram_list.blocks, next) {
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
if (!strncmp(id, block->idstr, sizeof(id))) {
if (length != block->used_length) {
Error *local_err = NULL;
ret = qemu_ram_resize(block->offset, length, &local_err);
if (local_err) {
- error_report("%s", error_get_pretty(local_err));
- error_free(local_err);
+ error_report_err(local_err);
}
}
break;
ret = -EINVAL;
break;
}
-
ch = qemu_get_byte(f);
ram_handle_compressed(host, ch, TARGET_PAGE_SIZE);
break;
ret = -EINVAL;
break;
}
-
qemu_get_buffer(f, host, TARGET_PAGE_SIZE);
break;
case RAM_SAVE_FLAG_XBZRLE:
ret = -EINVAL;
break;
}
-
if (load_xbzrle(f, addr, host) < 0) {
error_report("Failed to decompress XBZRLE page at "
RAM_ADDR_FMT, addr);
}
}
+ rcu_read_unlock();
DPRINTF("Completed load of VM with exit code %d seq iteration "
"%" PRIu64 "\n", ret, seq_iter);
return ret;
projects / qemu.git / blobdiff