migration: stop compression to allocate and free memory frequently
Current code uses compress2() to compress memory which manages memory
internally, that causes huge memory is allocated and freed very
frequently
More worse, frequently returning memory to kernel will flush TLBs
and trigger invalidation callbacks on mmu-notification which
interacts with KVM MMU, that dramatically reduce the performance
of VM
So, we maintain the memory by ourselves and reuse it for each
compression
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>
Message-Id: <20180330075128.26919-3-xiaoguangrong@tencent.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
diff --git a/migration/qemu-file.h b/migration/qemu-file.h
index f4f356a..2ccfcfb 100644
--- a/migration/qemu-file.h
+++ b/migration/qemu-file.h
@@ -25,6 +25,8 @@
#ifndef MIGRATION_QEMU_FILE_H
#define MIGRATION_QEMU_FILE_H
+#include <zlib.h>
+
/* Read a chunk of data from a file at the given position. The pos argument
* can be ignored if the file is only be used for streaming. The number of
* bytes actually read should be returned.
@@ -132,8 +134,8 @@
size_t qemu_peek_buffer(QEMUFile *f, uint8_t **buf, size_t size, size_t offset);
size_t qemu_get_buffer_in_place(QEMUFile *f, uint8_t **buf, size_t size);
-ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size,
- int level);
+ssize_t qemu_put_compression_data(QEMUFile *f, z_stream *stream,
+ const uint8_t *p, size_t size);
int qemu_put_qemu_file(QEMUFile *f_des, QEMUFile *f_src);
/*
