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[Qemu-devel] [PATCH v10 3/7] migration: use bitmap_mutex in migration_bi
From: |
Wei Wang |
Subject: |
[Qemu-devel] [PATCH v10 3/7] migration: use bitmap_mutex in migration_bitmap_clear_dirty |
Date: |
Mon, 3 Dec 2018 10:18:27 +0800 |
The bitmap mutex is used to synchronize threads to update the dirty
bitmap and the migration_dirty_pages counter. For example, the free
page optimization clears bits of free pages from the bitmap in an
iothread context. This patch makes migration_bitmap_clear_dirty update
the bitmap and counter under the mutex.
Signed-off-by: Wei Wang <address@hidden>
CC: Dr. David Alan Gilbert <address@hidden>
CC: Juan Quintela <address@hidden>
CC: Michael S. Tsirkin <address@hidden>
CC: Peter Xu <address@hidden>
---
migration/ram.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/migration/ram.c b/migration/ram.c
index 7e7deec..01d267f 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -316,7 +316,7 @@ struct RAMState {
uint64_t target_page_count;
/* number of dirty bits in the bitmap */
uint64_t migration_dirty_pages;
- /* protects modification of the bitmap */
+ /* Protects modification of the bitmap and migration dirty pages */
QemuMutex bitmap_mutex;
/* The RAMBlock used in the last src_page_requests */
RAMBlock *last_req_rb;
@@ -1556,11 +1556,14 @@ static inline bool
migration_bitmap_clear_dirty(RAMState *rs,
{
bool ret;
+ qemu_mutex_lock(&rs->bitmap_mutex);
ret = test_and_clear_bit(page, rb->bmap);
if (ret) {
rs->migration_dirty_pages--;
}
+ qemu_mutex_unlock(&rs->bitmap_mutex);
+
return ret;
}
--
1.8.3.1