| Message ID | 1543803511-34793-4-git-send-email-wei.w.wang@intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | virtio-balloon: free page hint support | expand |
On Mon, Dec 03, 2018 at 10:18:27AM +0800, Wei Wang wrote: > 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 <wei.w.wang@intel.com> > CC: Dr. David Alan Gilbert <dgilbert@redhat.com> > CC: Juan Quintela <quintela@redhat.com> > CC: Michael S. Tsirkin <mst@redhat.com> > CC: Peter Xu <peterx@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com>
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; }
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 <wei.w.wang@intel.com> CC: Dr. David Alan Gilbert <dgilbert@redhat.com> CC: Juan Quintela <quintela@redhat.com> CC: Michael S. Tsirkin <mst@redhat.com> CC: Peter Xu <peterx@redhat.com> --- migration/ram.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)