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[Qemu-devel] [PULL 04/21] migration/xbzrle: update cache and current_dat
From: |
Juan Quintela |
Subject: |
[Qemu-devel] [PULL 04/21] migration/xbzrle: update cache and current_data in one place |
Date: |
Mon, 15 Jul 2019 15:51:08 +0200 |
From: Wei Yang <address@hidden>
When we are not in the last_stage, we need to update the cache if page
is not the same.
Currently this procedure is scattered in two places and mixed with
encoding status check.
This patch extract this general step out to make the code a little bit
easy to read.
Signed-off-by: Wei Yang <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Juan Quintela <address@hidden>
---
migration/ram.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index 74c9306c78..d3d72b6f4f 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1585,25 +1585,30 @@ static int save_xbzrle_page(RAMState *rs, uint8_t
**current_data,
encoded_len = xbzrle_encode_buffer(prev_cached_page, XBZRLE.current_buf,
TARGET_PAGE_SIZE, XBZRLE.encoded_buf,
TARGET_PAGE_SIZE);
+
+ /*
+ * Update the cache contents, so that it corresponds to the data
+ * sent, in all cases except where we skip the page.
+ */
+ if (!last_stage && encoded_len != 0) {
+ memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
+ /*
+ * In the case where we couldn't compress, ensure that the caller
+ * sends the data from the cache, since the guest might have
+ * changed the RAM since we copied it.
+ */
+ *current_data = prev_cached_page;
+ }
+
if (encoded_len == 0) {
trace_save_xbzrle_page_skipping();
return 0;
} else if (encoded_len == -1) {
trace_save_xbzrle_page_overflow();
xbzrle_counters.overflow++;
- /* update data in the cache */
- if (!last_stage) {
- memcpy(prev_cached_page, *current_data, TARGET_PAGE_SIZE);
- *current_data = prev_cached_page;
- }
return -1;
}
- /* we need to update the data in the cache, in order to get the same data
*/
- if (!last_stage) {
- memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
- }
-
/* Send XBZRLE based compressed page */
bytes_xbzrle = save_page_header(rs, rs->f, block,
offset | RAM_SAVE_FLAG_XBZRLE);
--
2.21.0
- [Qemu-devel] [PULL 00/21] Migration pull request, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 01/21] migration: fix multifd_recv event typo, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 02/21] migration-test: rename parameter to parameter_int, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 03/21] migration/multifd: call multifd_send_sync_main when sending RAM_SAVE_FLAG_EOS, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 04/21] migration/xbzrle: update cache and current_data in one place,
Juan Quintela <=
- [Qemu-devel] [PULL 05/21] cutils: remove one unnecessary pointer operation, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 06/21] migration/multifd: sync packet_num after all thread are done, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 07/21] migration/ram.c: reset complete_round when we gets a queued page, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 08/21] migration: No need to take rcu during sync_dirty_bitmap, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 09/21] memory: Don't set migration bitmap when without migration, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 10/21] bitmap: Add bitmap_copy_with_{src|dst}_offset(), Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 11/21] memory: Pass mr into snapshot_and_clear_dirty, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 12/21] memory: Introduce memory listener hook log_clear(), Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 13/21] kvm: Update comments for sync_dirty_bitmap, Juan Quintela, 2019/07/15
- [Qemu-devel] [PULL 14/21] kvm: Persistent per kvmslot dirty bitmap, Juan Quintela, 2019/07/15