diff options
Diffstat (limited to 'migration/ram.c')
| -rw-r--r-- | migration/ram.c | 55 |
1 files changed, 48 insertions, 7 deletions
diff --git a/migration/ram.c b/migration/ram.c index 57368e1..c696814 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -222,6 +222,7 @@ static RAMBlock *last_seen_block; static RAMBlock *last_sent_block; static ram_addr_t last_offset; static unsigned long *migration_bitmap; +static QemuMutex migration_bitmap_mutex; static uint64_t migration_dirty_pages; static uint32_t last_version; static bool ram_bulk_stage; @@ -494,6 +495,7 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t **current_data, return 1; } +/* Called with rcu_read_lock() to protect migration_bitmap */ static inline ram_addr_t migration_bitmap_find_and_reset_dirty(MemoryRegion *mr, ram_addr_t start) @@ -502,26 +504,31 @@ ram_addr_t migration_bitmap_find_and_reset_dirty(MemoryRegion *mr, unsigned long nr = base + (start >> TARGET_PAGE_BITS); uint64_t mr_size = TARGET_PAGE_ALIGN(memory_region_size(mr)); unsigned long size = base + (mr_size >> TARGET_PAGE_BITS); + unsigned long *bitmap; unsigned long next; + bitmap = atomic_rcu_read(&migration_bitmap); if (ram_bulk_stage && nr > base) { next = nr + 1; } else { - next = find_next_bit(migration_bitmap, size, nr); + next = find_next_bit(bitmap, size, nr); } if (next < size) { - clear_bit(next, migration_bitmap); + clear_bit(next, bitmap); migration_dirty_pages--; } return (next - base) << TARGET_PAGE_BITS; } +/* Called with rcu_read_lock() to protect migration_bitmap */ static void migration_bitmap_sync_range(ram_addr_t start, ram_addr_t length) { + unsigned long *bitmap; + bitmap = atomic_rcu_read(&migration_bitmap); migration_dirty_pages += - cpu_physical_memory_sync_dirty_bitmap(migration_bitmap, start, length); + cpu_physical_memory_sync_dirty_bitmap(bitmap, start, length); } @@ -563,11 +570,13 @@ static void migration_bitmap_sync(void) trace_migration_bitmap_sync_start(); address_space_sync_dirty_bitmap(&address_space_memory); + qemu_mutex_lock(&migration_bitmap_mutex); 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(); + qemu_mutex_unlock(&migration_bitmap_mutex); trace_migration_bitmap_sync_end(migration_dirty_pages - num_dirty_pages_init); @@ -1017,10 +1026,15 @@ void free_xbzrle_decoded_buf(void) static void migration_end(void) { - if (migration_bitmap) { + /* caller have hold iothread lock or is in a bh, so there is + * no writing race against this migration_bitmap + */ + unsigned long *bitmap = migration_bitmap; + atomic_rcu_set(&migration_bitmap, NULL); + if (bitmap) { memory_global_dirty_log_stop(); - g_free(migration_bitmap); - migration_bitmap = NULL; + synchronize_rcu(); + g_free(bitmap); } XBZRLE_cache_lock(); @@ -1051,6 +1065,30 @@ static void reset_ram_globals(void) #define MAX_WAIT 50 /* ms, half buffered_file limit */ +void migration_bitmap_extend(ram_addr_t old, ram_addr_t new) +{ + /* called in qemu main thread, so there is + * no writing race against this migration_bitmap + */ + if (migration_bitmap) { + unsigned long *old_bitmap = migration_bitmap, *bitmap; + bitmap = bitmap_new(new); + + /* prevent migration_bitmap content from being set bit + * by migration_bitmap_sync_range() at the same time. + * it is safe to migration if migration_bitmap is cleared bit + * at the same time. + */ + qemu_mutex_lock(&migration_bitmap_mutex); + bitmap_copy(bitmap, old_bitmap, old); + bitmap_set(bitmap, old, new - old); + atomic_rcu_set(&migration_bitmap, bitmap); + qemu_mutex_unlock(&migration_bitmap_mutex); + migration_dirty_pages += new - old; + synchronize_rcu(); + g_free(old_bitmap); + } +} /* Each of ram_save_setup, ram_save_iterate and ram_save_complete has * long-running RCU critical section. When rcu-reclaims in the code @@ -1067,6 +1105,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque) dirty_rate_high_cnt = 0; bitmap_sync_count = 0; migration_bitmap_sync_init(); + qemu_mutex_init(&migration_bitmap_mutex); if (migrate_use_xbzrle()) { XBZRLE_cache_lock(); @@ -1477,6 +1516,8 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) error_report_err(local_err); } } + ram_control_load_hook(f, RAM_CONTROL_BLOCK_REG, + block->idstr); break; } } @@ -1545,7 +1586,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) break; default: if (flags & RAM_SAVE_FLAG_HOOK) { - ram_control_load_hook(f, flags); + ram_control_load_hook(f, RAM_CONTROL_HOOK, NULL); } else { error_report("Unknown combination of migration flags: %#x", flags); |