This is the follow up of "[PATCH RFC] memory: Don't allow to resize RAM while migrating" [1]
This series contains some (slightly modified) patches also contained in: "[PATCH v2 fixed 00/16] Ram blocks with resizable anonymous allocations under POSIX" [2] That series will be based on this series. The last patch (#13) in this series could be moved to the other series, but I decided to include it in here for now (similar context). I realized that resizing RAM blocks while the guest is being migrated (precopy: resize while still running on the source, postcopy: resize while already running on the target) is buggy. In case of precopy, we can simply cancel migration. Postcopy handling is more involved. Resizing can currently happen during a guest reboot, triggered by ACPI rebuilds. Along with the fixes, some cleanups. [1] https://lkml.kernel.org/r/20200213172016.196609-1-da...@redhat.com [2] https://lkml.kernel.org/r/20200212134254.11073-1-da...@redhat.com I was now able to actually test resizing while migrating. I am using the prototype of virtio-mem to test (which also makes use of resizable allocations). Things I was able to reproduce: - Resize while still running on the migration source. Migration is canceled -- Test case for "migraton/ram: Handle RAM block resizes during precopy" - Resize (grow+shrink) on the migration target during postcopy migration (when syncing RAM blocks), while not yet running on the target -- Test case for "migration/ram: Discard new RAM when growing RAM blocks and the VM is stopped", and overall RAM size synchronization. Seems to work just fine. - Resize (grow+shrink) on the migration tagret during postcopy migration while already running on the target. -- Test case for "migration/ram: Handle RAM block resizes during postcopy" -- Test case for "migration/ram: Tolerate partially changed mappings in postcopy code" - I can see that -ENOENT is actually triggered and that migration succeeds. Migration seems to work just fine. In addition I run avocado-vt migration tests + usual QEMU checks. v1 -> v2: - "util: vfio-helpers: Factor out and fix processing of existing ram blocks" -- Stringify error - "migraton/ram: Handle RAM block resizes during precopy" -- Simplified check if we're migrating on the source - "exec: Relax range check in ram_block_discard_range()" -- Added to make discard during resizes actually work - "migration/ram: Discard new RAM when growing RAM blocks after ram_postcopy_incoming_init()" -- Better checks if in the right postcopy mode. -- Better patch subject/description/comments - "migration/ram: Handle RAM block resizes during postcopy" -- Better comments -- Adapt to changed postcopy checks - "migrate/ram: Get rid of "place_source" in ram_load_postcopy()" -- Dropped, as broken - "migration/ram: Tolerate partially changed mappings in postcopy code" -- Better comment / description. Clarify that no implicit wakeup will happen -- Warn on EINVAL (older kernels) -- Wake up any waiter explicitly David Hildenbrand (13): util: vfio-helpers: Factor out and fix processing of existing ram blocks stubs/ram-block: Remove stubs that are no longer needed numa: Teach ram block notifiers about resizeable ram blocks numa: Make all callbacks of ram block notifiers optional migration/ram: Handle RAM block resizes during precopy exec: Relax range check in ram_block_discard_range() migration/ram: Discard RAM when growing RAM blocks after ram_postcopy_incoming_init() migration/ram: Simplify host page handling in ram_load_postcopy() migration/ram: Consolidate variable reset after placement in ram_load_postcopy() migration/ram: Handle RAM block resizes during postcopy migration/multifd: Print used_length of memory block migration/ram: Use offset_in_ramblock() in range checks migration/ram: Tolerate partially changed mappings in postcopy code exec.c | 27 +++++-- hw/core/numa.c | 41 +++++++++-- hw/i386/xen/xen-mapcache.c | 7 +- include/exec/cpu-common.h | 1 + include/exec/memory.h | 10 +-- include/exec/ramblock.h | 10 +++ include/exec/ramlist.h | 13 ++-- migration/migration.c | 9 ++- migration/migration.h | 1 + migration/multifd.c | 2 +- migration/postcopy-ram.c | 52 +++++++++++++- migration/ram.c | 144 ++++++++++++++++++++++++++++--------- stubs/ram-block.c | 20 ------ target/i386/hax-mem.c | 5 +- target/i386/sev.c | 18 ++--- util/vfio-helpers.c | 41 ++++------- 16 files changed, 283 insertions(+), 118 deletions(-) -- 2.24.1