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[PATCH v7 3/3] multifd: Only flush once each full round of memory
From: |
Juan Quintela |
Subject: |
[PATCH v7 3/3] multifd: Only flush once each full round of memory |
Date: |
Tue, 11 Apr 2023 12:26:19 +0200 |
We need to add a new flag to mean to flush at that point.
Notice that we still flush at the end of setup and at the end of
complete stages.
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
Add missing qemu_fflush(), now it passes all tests always.
---
migration/migration.h | 3 +--
migration/migration.c | 6 +-----
migration/ram.c | 28 +++++++++++++++++++++++++++-
3 files changed, 29 insertions(+), 8 deletions(-)
diff --git a/migration/migration.h b/migration/migration.h
index d0d89411e2..816814a24e 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -373,8 +373,7 @@ struct MigrationState {
* only need to do this flush after we have go through all the
* dirty pages. For historical reasons, we do that after each
* section. This is suboptimal (we flush too many times).
- * Default value is false. Setting this property has no effect
- * until the patch that removes this comment. (since 8.1)
+ * Default value is false. (since 8.1)
*/
bool multifd_flush_after_each_section;
/*
diff --git a/migration/migration.c b/migration/migration.c
index ca773d00fc..353359b0d2 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2705,11 +2705,7 @@ bool migrate_multifd_flush_after_each_section(void)
{
MigrationState *s = migrate_get_current();
- /*
- * Until the patch that remove this comment, we always return that
- * the property is enabled.
- */
- return true || s->multifd_flush_after_each_section;
+ return s->multifd_flush_after_each_section;
}
bool migrate_pause_before_switchover(void)
diff --git a/migration/ram.c b/migration/ram.c
index f019b77808..977ab25351 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -85,6 +85,7 @@
#define RAM_SAVE_FLAG_XBZRLE 0x40
/* 0x80 is reserved in qemu-file.h for RAM_SAVE_FLAG_HOOK */
#define RAM_SAVE_FLAG_COMPRESS_PAGE 0x100
+#define RAM_SAVE_FLAG_MULTIFD_FLUSH 0x200
/* We can't use any flag that is bigger than 0x200 */
int (*xbzrle_encode_buffer_func)(uint8_t *, uint8_t *, int,
@@ -1595,6 +1596,7 @@ retry:
* associated with the search process.
*
* Returns:
+ * <0: An error happened
* PAGE_ALL_CLEAN: no dirty page found, give up
* PAGE_TRY_AGAIN: no dirty page found, retry for next block
* PAGE_DIRTY_FOUND: dirty page found
@@ -1622,6 +1624,15 @@ static int find_dirty_block(RAMState *rs,
PageSearchStatus *pss)
pss->page = 0;
pss->block = QLIST_NEXT_RCU(pss->block, next);
if (!pss->block) {
+ if (!migrate_multifd_flush_after_each_section()) {
+ QEMUFile *f = rs->pss[RAM_CHANNEL_PRECOPY].pss_channel;
+ int ret = multifd_send_sync_main(f);
+ if (ret < 0) {
+ return ret;
+ }
+ qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH);
+ qemu_fflush(f);
+ }
/*
* If memory migration starts over, we will meet a dirtied page
* which may still exists in compression threads's ring, so we
@@ -2614,6 +2625,9 @@ static int ram_find_and_save_block(RAMState *rs)
break;
} else if (res == PAGE_TRY_AGAIN) {
continue;
+ } else if (res < 0) {
+ pages = res;
+ break;
}
}
}
@@ -3300,6 +3314,10 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
return ret;
}
+ if (!migrate_multifd_flush_after_each_section()) {
+ qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH);
+ }
+
qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
qemu_fflush(f);
@@ -3485,6 +3503,9 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
return ret;
}
+ if (!migrate_multifd_flush_after_each_section()) {
+ qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH);
+ }
qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
qemu_fflush(f);
@@ -4165,7 +4186,9 @@ int ram_load_postcopy(QEMUFile *f, int channel)
}
decompress_data_with_multi_threads(f, page_buffer, len);
break;
-
+ case RAM_SAVE_FLAG_MULTIFD_FLUSH:
+ multifd_recv_sync_main();
+ break;
case RAM_SAVE_FLAG_EOS:
/* normal exit */
if (migrate_multifd_flush_after_each_section()) {
@@ -4439,6 +4462,9 @@ static int ram_load_precopy(QEMUFile *f)
break;
}
break;
+ case RAM_SAVE_FLAG_MULTIFD_FLUSH:
+ multifd_recv_sync_main();
+ break;
case RAM_SAVE_FLAG_EOS:
/* normal exit */
if (migrate_multifd_flush_after_each_section()) {
--
2.39.2