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[PATCH v2 1/2] ramlist: Make dirty bitmap blocks of ramlist resizable
From: |
Keqian Zhu |
Subject: |
[PATCH v2 1/2] ramlist: Make dirty bitmap blocks of ramlist resizable |
Date: |
Mon, 30 Nov 2020 21:11:03 +0800 |
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.robot@huawei.com>
Signed-off-by: Keqian Zhu <zhukeqian1@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