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[PULL 04/15] migration: Drop unnecessary check in ram's pending_exact()
From: |
peterx |
Subject: |
[PULL 04/15] migration: Drop unnecessary check in ram's pending_exact() |
Date: |
Fri, 26 Jan 2024 12:17:14 +0800 |
From: Peter Xu <peterx@redhat.com>
When the migration frameworks fetches the exact pending sizes, it means
this check:
remaining_size < s->threshold_size
Must have been done already, actually at migration_iteration_run():
if (must_precopy <= s->threshold_size) {
qemu_savevm_state_pending_exact(&must_precopy, &can_postcopy);
That should be after one round of ram_state_pending_estimate(). It makes
the 2nd check meaningless and can be dropped.
To say it in another way, when reaching ->state_pending_exact(), we
unconditionally sync dirty bits for precopy.
Then we can drop migrate_get_current() there too.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: 20240117075848.139045-3-peterx@redhat.com">https://lore.kernel.org/r/20240117075848.139045-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
---
migration/ram.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index c0cdcccb75..d5b7cd5ac2 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3213,21 +3213,20 @@ static void ram_state_pending_estimate(void *opaque,
uint64_t *must_precopy,
static void ram_state_pending_exact(void *opaque, uint64_t *must_precopy,
uint64_t *can_postcopy)
{
- MigrationState *s = migrate_get_current();
RAMState **temp = opaque;
RAMState *rs = *temp;
+ uint64_t remaining_size;
- uint64_t remaining_size = rs->migration_dirty_pages * TARGET_PAGE_SIZE;
-
- if (!migration_in_postcopy() && remaining_size < s->threshold_size) {
+ if (!migration_in_postcopy()) {
bql_lock();
WITH_RCU_READ_LOCK_GUARD() {
migration_bitmap_sync_precopy(rs, false);
}
bql_unlock();
- remaining_size = rs->migration_dirty_pages * TARGET_PAGE_SIZE;
}
+ remaining_size = rs->migration_dirty_pages * TARGET_PAGE_SIZE;
+
if (migrate_postcopy_ram()) {
/* We can do postcopy, and all the data is postcopiable */
*can_postcopy += remaining_size;
--
2.43.0
- [PULL 00/15] Migration 20240126 patches, peterx, 2024/01/25
- [PULL 01/15] userfaultfd: use 1ULL to build ioctl masks, peterx, 2024/01/25
- [PULL 02/15] migration: Plug memory leak on HMP migrate error path, peterx, 2024/01/25
- [PULL 03/15] migration: Make threshold_size an uint64_t, peterx, 2024/01/25
- [PULL 04/15] migration: Drop unnecessary check in ram's pending_exact(),
peterx <=
- [PULL 05/15] analyze-migration.py: Remove trick on parsing ramblocks, peterx, 2024/01/25
- [PULL 06/15] tests/qtest/migration: Don't use -cpu max for aarch64, peterx, 2024/01/25
- Re: [PULL 06/15] tests/qtest/migration: Don't use -cpu max for aarch64, Fabiano Rosas, 2024/01/26
- Re: [PULL 06/15] tests/qtest/migration: Don't use -cpu max for aarch64, Peter Maydell, 2024/01/26
- Re: [PULL 06/15] tests/qtest/migration: Don't use -cpu max for aarch64, Fabiano Rosas, 2024/01/26
- Re: [PULL 06/15] tests/qtest/migration: Don't use -cpu max for aarch64, Peter Xu, 2024/01/28
- Re: [PULL 06/15] tests/qtest/migration: Don't use -cpu max for aarch64, Fabiano Rosas, 2024/01/29
- Re: [PULL 06/15] tests/qtest/migration: Don't use -cpu max for aarch64, Fabiano Rosas, 2024/01/29
- Re: [PULL 06/15] tests/qtest/migration: Don't use -cpu max for aarch64, Peter Maydell, 2024/01/30
- Re: [PULL 06/15] tests/qtest/migration: Don't use -cpu max for aarch64, Peter Xu, 2024/01/30