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[Qemu-devel] [PULL 5/8] migration/xbzrle: update cache and current_data
From: |
Juan Quintela |
Subject: |
[Qemu-devel] [PULL 5/8] migration/xbzrle: update cache and current_data in one place |
Date: |
Wed, 12 Jun 2019 12:48:05 +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 0/8] Migration patches, Juan Quintela, 2019/06/12
- [Qemu-devel] [PULL 4/8] migration/multifd: call multifd_send_sync_main when sending RAM_SAVE_FLAG_EOS, Juan Quintela, 2019/06/12
- [Qemu-devel] [PULL 3/8] migration-test: Add migration multifd test, Juan Quintela, 2019/06/12
- [Qemu-devel] [PULL 2/8] migration-test: rename parameter to parameter_int, Juan Quintela, 2019/06/12
- [Qemu-devel] [PULL 1/8] migration: fix multifd_recv event typo, Juan Quintela, 2019/06/12
- [Qemu-devel] [PULL 5/8] migration/xbzrle: update cache and current_data in one place,
Juan Quintela <=
- [Qemu-devel] [PULL 6/8] cutils: remove one unnecessary pointer operation, Juan Quintela, 2019/06/12
- [Qemu-devel] [PULL 7/8] migration/multifd: sync packet_num after all thread are done, Juan Quintela, 2019/06/12
- [Qemu-devel] [PULL 8/8] migratioin/ram.c: reset complete_round when we gets a queued page, Juan Quintela, 2019/06/12
- Re: [Qemu-devel] [PULL 0/8] Migration patches, Peter Maydell, 2019/06/13