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qemu-kvm/SOURCES/kvm-migration-move-calling-save_zero_page-to-the-common-.patch

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From ea016aa3636ce101148bb6246d86474fc1cdcbf8 Mon Sep 17 00:00:00 2001
From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Date: Wed, 1 Aug 2018 13:55:12 +0100
Subject: [PATCH 08/21] migration: move calling save_zero_page to the common
place
RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-id: <20180801135522.11658-9-dgilbert@redhat.com>
Patchwork-id: 81582
O-Subject: [qemu-kvm RHEL8/virt212 PATCH 08/18] migration: move calling save_zero_page to the common place
Bugzilla: 1594384
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Juan Quintela <quintela@redhat.com>
From: Xiao Guangrong <xiaoguangrong@tencent.com>
save_zero_page() is always our first approach to try, move it to
the common place before calling ram_save_compressed_page
and ram_save_page
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@tencent.com>
Message-Id: <20180330075128.26919-9-xiaoguangrong@tencent.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
(cherry picked from commit d7400a3409982a52ac451cd3ca9caee9db670ca7)
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
migration/ram.c | 105 +++++++++++++++++++++++++++++++-------------------------
1 file changed, 59 insertions(+), 46 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index 9d6c41c..6e8a7e2 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1039,15 +1039,8 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)
trace_ram_save_page(block->idstr, (uint64_t)offset, p);
XBZRLE_cache_lock();
- pages = save_zero_page(rs, block, offset);
- if (pages > 0) {
- /* Must let xbzrle know, otherwise a previous (now 0'd) cached
- * page would be stale
- */
- xbzrle_cache_zero_page(rs, current_addr);
- ram_release_pages(block->idstr, offset, pages);
- } else if (!rs->ram_bulk_stage &&
- !migration_in_postcopy() && migrate_use_xbzrle()) {
+ if (!rs->ram_bulk_stage && !migration_in_postcopy() &&
+ migrate_use_xbzrle()) {
pages = save_xbzrle_page(rs, &p, current_addr, block,
offset, last_stage);
if (!last_stage) {
@@ -1195,40 +1188,23 @@ static int ram_save_compressed_page(RAMState *rs, PageSearchStatus *pss,
p = block->host + offset;
- /* When starting the process of a new block, the first page of
- * the block should be sent out before other pages in the same
- * block, and all the pages in last block should have been sent
- * out, keeping this order is important, because the 'cont' flag
- * is used to avoid resending the block name.
- */
if (block != rs->last_sent_block) {
- flush_compressed_data(rs);
- pages = save_zero_page(rs, block, offset);
- if (pages > 0) {
- ram_release_pages(block->idstr, offset, pages);
- } else {
- /*
- * Make sure the first page is sent out before other pages.
- *
- * we post it as normal page as compression will take much
- * CPU resource.
- */
- ram_counters.transferred += save_page_header(rs, rs->f, block,
- offset | RAM_SAVE_FLAG_PAGE);
- qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE,
- migrate_release_ram() &
- migration_in_postcopy());
- ram_counters.transferred += TARGET_PAGE_SIZE;
- ram_counters.normal++;
- pages = 1;
- }
+ /*
+ * Make sure the first page is sent out before other pages.
+ *
+ * we post it as normal page as compression will take much
+ * CPU resource.
+ */
+ ram_counters.transferred += save_page_header(rs, rs->f, block,
+ offset | RAM_SAVE_FLAG_PAGE);
+ qemu_put_buffer_async(rs->f, p, TARGET_PAGE_SIZE,
+ migrate_release_ram() &
+ migration_in_postcopy());
+ ram_counters.transferred += TARGET_PAGE_SIZE;
+ ram_counters.normal++;
+ pages = 1;
} else {
- pages = save_zero_page(rs, block, offset);
- if (pages == -1) {
- pages = compress_page_with_multi_thread(rs, block, offset);
- } else {
- ram_release_pages(block->idstr, offset, pages);
- }
+ pages = compress_page_with_multi_thread(rs, block, offset);
}
return pages;
@@ -1470,6 +1446,24 @@ err:
return -1;
}
+static bool save_page_use_compression(RAMState *rs)
+{
+ if (!migrate_use_compression()) {
+ return false;
+ }
+
+ /*
+ * If xbzrle is on, stop using the data compression after first
+ * round of migration even if compression is enabled. In theory,
+ * xbzrle can do better than compression.
+ */
+ if (rs->ram_bulk_stage || !migrate_use_xbzrle()) {
+ return true;
+ }
+
+ return false;
+}
+
/**
* ram_save_target_page: save one target page
*
@@ -1491,12 +1485,31 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss,
}
/*
- * If xbzrle is on, stop using the data compression after first
- * round of migration even if compression is enabled. In theory,
- * xbzrle can do better than compression.
+ * When starting the process of a new block, the first page of
+ * the block should be sent out before other pages in the same
+ * block, and all the pages in last block should have been sent
+ * out, keeping this order is important, because the 'cont' flag
+ * is used to avoid resending the block name.
*/
- if (migrate_use_compression() &&
- (rs->ram_bulk_stage || !migrate_use_xbzrle())) {
+ if (block != rs->last_sent_block && save_page_use_compression(rs)) {
+ flush_compressed_data(rs);
+ }
+
+ res = save_zero_page(rs, block, offset);
+ if (res > 0) {
+ /* Must let xbzrle know, otherwise a previous (now 0'd) cached
+ * page would be stale
+ */
+ if (!save_page_use_compression(rs)) {
+ XBZRLE_cache_lock();
+ xbzrle_cache_zero_page(rs, block->offset + offset);
+ XBZRLE_cache_unlock();
+ }
+ ram_release_pages(block->idstr, offset, res);
+ return res;
+ }
+
+ if (save_page_use_compression(rs)) {
return ram_save_compressed_page(rs, pss, last_stage);
}
--
1.8.3.1
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