From: David Hildenbrand <david@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Eduardo Habkost" <ehabkost@redhat.com>,
"Juan Quintela" <quintela@redhat.com>,
"Michael S . Tsirkin" <mst@redhat.com>,
"David Hildenbrand" <david@redhat.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
"Peter Xu" <peterx@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Richard Henderson" <rth@twiddle.net>
Subject: [PATCH v4 07/13] migration/ram: Discard RAM when growing RAM blocks after ram_postcopy_incoming_init()
Date: Tue, 21 Apr 2020 10:52:54 +0200 [thread overview]
Message-ID: <20200421085300.7734-8-david@redhat.com> (raw)
In-Reply-To: <20200421085300.7734-1-david@redhat.com>
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 <peterx@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Juan Quintela <quintela@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
migration/ram.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/migration/ram.c b/migration/ram.c
index d587ecbd92..2704d32def 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3756,6 +3756,7 @@ 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);
@@ -3776,6 +3777,35 @@ 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 = {
--
2.25.1
next prev parent reply other threads:[~2020-04-21 8:58 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 8:52 [PATCH v4 00/13] migrate/ram: Fix resizing RAM blocks while migrating David Hildenbrand
2020-04-21 8:52 ` [PATCH v4 01/13] util: vfio-helpers: Factor out and fix processing of existing ram blocks David Hildenbrand
2020-04-21 8:52 ` [PATCH v4 02/13] stubs/ram-block: Remove stubs that are no longer needed David Hildenbrand
2020-04-21 8:52 ` [PATCH v4 03/13] numa: Teach ram block notifiers about resizeable ram blocks David Hildenbrand
2020-04-21 8:52 ` [PATCH v4 04/13] numa: Make all callbacks of ram block notifiers optional David Hildenbrand
2020-04-21 8:52 ` [PATCH v4 05/13] migration/ram: Handle RAM block resizes during precopy David Hildenbrand
2020-04-21 8:52 ` [PATCH v4 06/13] exec: Relax range check in ram_block_discard_range() David Hildenbrand
2020-04-21 8:52 ` David Hildenbrand [this message]
2020-04-21 8:52 ` [PATCH v4 08/13] migration/ram: Simplify host page handling in ram_load_postcopy() David Hildenbrand
2020-04-21 8:52 ` [PATCH v4 09/13] migration/ram: Consolidate variable reset after placement " David Hildenbrand
2020-04-24 10:25 ` Dr. David Alan Gilbert
2020-05-07 15:42 ` Dr. David Alan Gilbert
2020-05-07 15:57 ` David Hildenbrand
2020-05-07 19:00 ` Dr. David Alan Gilbert
2020-05-08 7:17 ` David Hildenbrand
2020-04-21 8:52 ` [PATCH v4 10/13] migration/ram: Handle RAM block resizes during postcopy David Hildenbrand
2020-04-21 8:52 ` [PATCH v4 11/13] migration/multifd: Print used_length of memory block David Hildenbrand
2020-04-21 8:52 ` [PATCH v4 12/13] migration/ram: Use offset_in_ramblock() in range checks David Hildenbrand
2020-04-21 8:53 ` [PATCH v4 13/13] migration/ram: Tolerate partially changed mappings in postcopy code David Hildenbrand
2020-04-30 14:43 ` [PATCH v4 00/13] migrate/ram: Fix resizing RAM blocks while migrating David Hildenbrand
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