From: Juan Quintela <quintela@redhat.com>
To: qemu-devel@nongnu.org
Cc: Laurent Vivier <lvivier@redhat.com>,
Thomas Huth <thuth@redhat.com>,
zhanghailiang <zhang.zhanghailiang@huawei.com>,
Juan Quintela <quintela@redhat.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
Wei Yang <richardw.yang@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: [Qemu-devel] [PULL 5/5] migratioin/ram: leave RAMBlock->bmap blank on allocating
Date: Wed, 5 Jun 2019 13:53:18 +0200 [thread overview]
Message-ID: <20190605115318.9972-6-quintela@redhat.com> (raw)
In-Reply-To: <20190605115318.9972-1-quintela@redhat.com>
From: Wei Yang <richardw.yang@linux.intel.com>
During migration, we would sync bitmap from ram_list.dirty_memory to
RAMBlock.bmap in cpu_physical_memory_sync_dirty_bitmap().
Since we set RAMBlock.bmap and ram_list.dirty_memory both to all 1, this
means at the first round this sync is meaningless and is a duplicated
work.
Leaving RAMBlock->bmap blank on allocating would have a side effect on
migration_dirty_pages, since it is calculated from the result of
cpu_physical_memory_sync_dirty_bitmap(). To keep it right, we need to
set migration_dirty_pages to 0 in ram_state_init().
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
migration/ram.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index 03a9cce9f9..082aea9d23 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3173,11 +3173,11 @@ static int ram_state_init(RAMState **rsp)
QSIMPLEQ_INIT(&(*rsp)->src_page_requests);
/*
- * Count the total number of pages used by ram blocks not including any
- * gaps due to alignment or unplugs.
+ * This must match with the initial values of dirty bitmap.
+ * Currently we initialize the dirty bitmap to all zeros so
+ * here the total dirty page count is zero.
*/
- (*rsp)->migration_dirty_pages = ram_bytes_total() >> TARGET_PAGE_BITS;
-
+ (*rsp)->migration_dirty_pages = 0;
ram_state_reset(*rsp);
return 0;
@@ -3192,8 +3192,16 @@ static void ram_list_init_bitmaps(void)
if (ram_bytes_total()) {
RAMBLOCK_FOREACH_NOT_IGNORED(block) {
pages = block->max_length >> TARGET_PAGE_BITS;
+ /*
+ * The initial dirty bitmap for migration must be set with all
+ * ones to make sure we'll migrate every guest RAM page to
+ * destination.
+ * Here we didn't set RAMBlock.bmap simply because it is already
+ * set in ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION] in
+ * ram_block_add, and that's where we'll sync the dirty bitmaps.
+ * Here setting RAMBlock.bmap would be fine too but not necessary.
+ */
block->bmap = bitmap_new(pages);
- bitmap_set(block->bmap, 0, pages);
if (migrate_postcopy_ram()) {
block->unsentmap = bitmap_new(pages);
bitmap_set(block->unsentmap, 0, pages);
--
2.21.0
next prev parent reply other threads:[~2019-06-05 11:55 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-05 11:53 [Qemu-devel] [PULL 0/5] Migration patches Juan Quintela
2019-06-05 11:53 ` [Qemu-devel] [PULL 1/5] migration/ram.c: MultiFDSendParams.sem_sync is not really used Juan Quintela
2019-06-05 11:53 ` [Qemu-devel] [PULL 2/5] migration/ram.c: multifd_send_state->count " Juan Quintela
2019-06-05 11:53 ` [Qemu-devel] [PULL 3/5] migration: Fix fd protocol for incoming defer Juan Quintela
2019-06-05 11:53 ` [Qemu-devel] [PULL 4/5] migration-test: Add a test for fd protocol Juan Quintela
2019-06-05 11:53 ` Juan Quintela [this message]
2019-06-05 12:26 ` [Qemu-devel] [PULL 5/5] migratioin/ram: leave RAMBlock->bmap blank on allocating Philippe Mathieu-Daudé
2019-06-05 13:36 ` Wei Yang
2019-06-05 13:37 ` Wei Yang
2019-06-06 10:32 ` [Qemu-devel] [PULL 0/5] Migration patches Peter Maydell
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