mirrors/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

migration: extend migration_bitmap

Browse Source 
Prevously, if we hotplug a device(e.g. device_add e1000) during
migration is processing in source side, qemu will add a new ram
block but migration_bitmap is not extended.
In this case, migration_bitmap will overflow and lead qemu abort
unexpectedly.

Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Li Zhijian 2015-07-02 20:18:06 +08:00 committed by Juan Quintela
parent 2ff64038a5
commit dd63169766
3 changed files with 36 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
exec.c
View File

@ -1414,6 +1414,11 @@ static ram_addr_t ram_block_add(RAMBlock *new_block, Error **errp)
}
}
new_ram_size = MAX(old_ram_size,
(new_block->offset + new_block->max_length) >> TARGET_PAGE_BITS);
if (new_ram_size > old_ram_size) {
migration_bitmap_extend(old_ram_size, new_ram_size);
}
/* Keep the list sorted from biggest to smallest block. Unlike QTAILQ,
* QLIST (which has an RCU-friendly variant) does not have insertion at
* tail, so save the last element in last_block.

3
include/exec/exec-all.h
View File

@ -365,4 +365,7 @@ static inline bool cpu_can_do_io(CPUState *cpu)
return cpu->can_do_io != 0;
}
#if !defined(CONFIG_USER_ONLY)
void migration_bitmap_extend(ram_addr_t old, ram_addr_t new);
#endif
#endif

28
migration/ram.c
View File

@ -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;
@ -569,11 +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);
@ -1062,6 +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
@ -1078,6 +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();