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[PATCH v3 07/13] migration/ram: Discard RAM when growing RAM blocks afte
From: |
David Hildenbrand |
Subject: |
[PATCH v3 07/13] migration/ram: Discard RAM when growing RAM blocks after ram_postcopy_incoming_init() |
Date: |
Wed, 26 Feb 2020 16:52:58 +0100 |
In case we grow our RAM after ram_postcopy_incoming_init() (e.g., when
synchronizing the RAM block state with the migration source), the resized
part would not get discarded. Let's perform that when being notified
about a resize while postcopy has been advised, but is not listening
yet. With precopy, the process is as following:
1. VM created
- RAM blocks are created
2. Incomming migration started
- Postcopy is advised
- All pages in RAM blocks are discarded
3. Precopy starts
- RAM blocks are resized to match the size on the migration source.
- RAM pages from precopy stream are loaded
- Uffd handler is registered, postcopy starts listening
4. Guest started, postcopy running
- Pagefaults get resolved, pages get placed
Reviewed-by: Peter Xu <address@hidden>
Cc: "Dr. David Alan Gilbert" <address@hidden>
Cc: Juan Quintela <address@hidden>
Cc: Peter Xu <address@hidden>
Signed-off-by: David Hildenbrand <address@hidden>
---
migration/ram.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/migration/ram.c b/migration/ram.c
index 39c7d1c4a6..d5a4d69e1c 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3714,6 +3714,7 @@ static SaveVMHandlers savevm_ram_handlers = {
static void ram_mig_ram_block_resized(RAMBlockNotifier *n, void *host,
size_t old_size, size_t new_size)
{
+ PostcopyState ps = postcopy_state_get();
ram_addr_t offset;
Error *err = NULL;
RAMBlock *rb = qemu_ram_block_from_host(host, false, &offset);
@@ -3734,6 +3735,35 @@ static void ram_mig_ram_block_resized(RAMBlockNotifier
*n, void *host,
error_free(err);
migration_cancel();
}
+
+ switch (ps) {
+ case POSTCOPY_INCOMING_ADVISE:
+ /*
+ * Update what ram_postcopy_incoming_init()->init_range() does at the
+ * time postcopy was advised. Syncing RAM blocks with the source will
+ * result in RAM resizes.
+ */
+ if (old_size < new_size) {
+ if (ram_discard_range(rb->idstr, old_size, new_size - old_size)) {
+ error_report("RAM block '%s' discard of resized RAM failed",
+ rb->idstr);
+ }
+ }
+ break;
+ case POSTCOPY_INCOMING_NONE:
+ case POSTCOPY_INCOMING_RUNNING:
+ case POSTCOPY_INCOMING_END:
+ /*
+ * Once our guest is running, postcopy does no longer care about
+ * resizes. When growing, the new memory was not available on the
+ * source, no handler needed.
+ */
+ break;
+ default:
+ error_report("RAM block '%s' resized during postcopy state: %d",
+ rb->idstr, ps);
+ exit(-1);
+ }
}
static RAMBlockNotifier ram_mig_ram_notifier = {
--
2.24.1
- [PATCH v3 00/13] migrate/ram: Fix resizing RAM blocks while migrating, David Hildenbrand, 2020/02/26
- [PATCH v3 01/13] util: vfio-helpers: Factor out and fix processing of existing ram blocks, David Hildenbrand, 2020/02/26
- [PATCH v3 02/13] stubs/ram-block: Remove stubs that are no longer needed, David Hildenbrand, 2020/02/26
- [PATCH v3 03/13] numa: Teach ram block notifiers about resizeable ram blocks, David Hildenbrand, 2020/02/26
- [PATCH v3 04/13] numa: Make all callbacks of ram block notifiers optional, David Hildenbrand, 2020/02/26
- [PATCH v3 05/13] migration/ram: Handle RAM block resizes during precopy, David Hildenbrand, 2020/02/26
- [PATCH v3 06/13] exec: Relax range check in ram_block_discard_range(), David Hildenbrand, 2020/02/26
- [PATCH v3 07/13] migration/ram: Discard RAM when growing RAM blocks after ram_postcopy_incoming_init(),
David Hildenbrand <=
- [PATCH v3 08/13] migration/ram: Simplify host page handling in ram_load_postcopy(), David Hildenbrand, 2020/02/26
- [PATCH v3 09/13] migration/ram: Consolidate variable reset after placement in ram_load_postcopy(), David Hildenbrand, 2020/02/26
- [PATCH v3 10/13] migration/ram: Handle RAM block resizes during postcopy, David Hildenbrand, 2020/02/26
- [PATCH v3 11/13] migration/multifd: Print used_length of memory block, David Hildenbrand, 2020/02/26
- [PATCH v3 12/13] migration/ram: Use offset_in_ramblock() in range checks, David Hildenbrand, 2020/02/26
- [PATCH v3 13/13] migration/ram: Tolerate partially changed mappings in postcopy code, David Hildenbrand, 2020/02/26