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| author | Stefan Hajnoczi <stefanha@redhat.com> | 2014-12-02 11:23:19 +0000 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-06-05 17:10:00 +0200 |
| commit | 5f2cb94688bd0b2c88e0fc1ac3c4582965b7b106 (patch) | |
| tree | 79b6b87ed4f58533b40c67a72ff66f16a73c5f24 /include/exec/ram_addr.h | |
| parent | 03eebc9e3246b9b3f5925aa41f7dfd7c1e467875 (diff) | |
| download | qemu-5f2cb94688bd0b2c88e0fc1ac3c4582965b7b106.zip | |
memory: make cpu_physical_memory_sync_dirty_bitmap() fully atomic
The fast path of cpu_physical_memory_sync_dirty_bitmap() directly
manipulates the dirty bitmap. Use atomic_xchg() to make the
test-and-clear atomic.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <1417519399-3166-7-git-send-email-stefanha@redhat.com>
[Only do xchg on nonzero words. - Paolo]
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/exec/ram_addr.h')
| -rw-r--r-- | include/exec/ram_addr.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index a2beea7925..c113f21140 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -224,12 +224,12 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(unsigned long *dest, for (k = page; k < page + nr; k++) { if (src[k]) { + unsigned long bits = atomic_xchg(&src[k], 0); unsigned long new_dirty; new_dirty = ~dest[k]; - dest[k] |= src[k]; - new_dirty &= src[k]; + dest[k] |= bits; + new_dirty &= bits; num_dirty += ctpopl(new_dirty); - src[k] = 0; } } } else { |