When we remove a ramblock, we should decrease the dirty bitmap blocks of ramlist to avoid memory leakage. This patch rebuilds dirty_memory_ extend to support both "extend" and "decrease".
Reported-by: Euler Robot <euler.ro...@huawei.com> Signed-off-by: Keqian Zhu <zhukeqi...@huawei.com> --- softmmu/physmem.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-) diff --git a/softmmu/physmem.c b/softmmu/physmem.c index 3027747c03..3e4f29f126 100644 --- a/softmmu/physmem.c +++ b/softmmu/physmem.c @@ -1816,17 +1816,19 @@ void qemu_ram_msync(RAMBlock *block, ram_addr_t start, ram_addr_t length) } /* Called with ram_list.mutex held */ -static void dirty_memory_extend(ram_addr_t old_ram_size, +static void dirty_memory_resize(ram_addr_t old_ram_size, ram_addr_t new_ram_size) { ram_addr_t old_num_blocks = DIV_ROUND_UP(old_ram_size, DIRTY_MEMORY_BLOCK_SIZE); ram_addr_t new_num_blocks = DIV_ROUND_UP(new_ram_size, DIRTY_MEMORY_BLOCK_SIZE); + ram_addr_t cpy_num_blocks = MIN(old_num_blocks, new_num_blocks); + bool extend = new_num_blocks > old_num_blocks; int i; - /* Only need to extend if block count increased */ - if (new_num_blocks <= old_num_blocks) { + /* Only need to resize if block count changed */ + if (new_num_blocks == old_num_blocks) { return; } @@ -1839,15 +1841,26 @@ static void dirty_memory_extend(ram_addr_t old_ram_size, new_blocks = g_malloc(sizeof(*new_blocks) + sizeof(new_blocks->blocks[0]) * new_num_blocks); - if (old_num_blocks) { + if (cpy_num_blocks) { memcpy(new_blocks->blocks, old_blocks->blocks, - old_num_blocks * sizeof(old_blocks->blocks[0])); + cpy_num_blocks * sizeof(old_blocks->blocks[0])); } - for (j = old_num_blocks; j < new_num_blocks; j++) { - new_blocks->blocks[j] = bitmap_new(DIRTY_MEMORY_BLOCK_SIZE); + if (extend) { + for (j = cpy_num_blocks; j < new_num_blocks; j++) { + new_blocks->blocks[j] = bitmap_new(DIRTY_MEMORY_BLOCK_SIZE); + } + } else { + for (j = cpy_num_blocks; j < old_num_blocks; j++) { + /* We are safe to free it, for that it is out-of-use */ + g_free(old_blocks->blocks[j]); + } } + if (!new_num_blocks) { + g_free(new_blocks); + new_blocks = NULL; + } qatomic_rcu_set(&ram_list.dirty_memory[i], new_blocks); if (old_blocks) { @@ -1894,7 +1907,7 @@ static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared) new_ram_size = MAX(old_ram_size, (new_block->offset + new_block->max_length) >> TARGET_PAGE_BITS); if (new_ram_size > old_ram_size) { - dirty_memory_extend(old_ram_size, new_ram_size); + dirty_memory_resize(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 -- 2.23.0