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Re: [Qemu-devel] [PATCH v2 33/41] postcopy: introduce -postcopy and -pos
From: |
Isaku Yamahata |
Subject: |
Re: [Qemu-devel] [PATCH v2 33/41] postcopy: introduce -postcopy and -postcopy-flags option |
Date: |
Sat, 9 Jun 2012 01:07:24 +0900 |
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Fri, Jun 08, 2012 at 12:52:54PM +0200, Juan Quintela wrote:
> Isaku Yamahata <address@hidden> wrote:
> > This patch prepares for postcopy livemigration.
> > It introduces -postcopy option and its internal flag, migration_postcopy.
> > It introduces -postcopy-flags for chaging the behavior of incoming postcopy
> > mainly for benchmark/debug.
>
> Why do we need postcopy flag? -incoming should be enough to detect that
> we are doing postcopy.
>
> QLIST_HEAD(, LoadStateEntry) loadvm_handlers =
> QLIST_HEAD_INITIALIZER(loadvm_handlers);
> LoadStateEntry *le, *new_le;
> uint8_t section_type;
> unsigned int v;
> int ret;
>
> if (qemu_savevm_state_blocked(NULL)) {
> return -EINVAL;
> }
>
> v = qemu_get_be32(f);
> if (v != QEMU_VM_FILE_MAGIC)
> return -EINVAL;
>
> v = qemu_get_be32(f);
> if (v == QEMU_VM_FILE_VERSION_COMPAT) {
> fprintf(stderr, "SaveVM v2 format is obsolete and don't work
> anymore\n");
> return -ENOTSUP;
> }
> if (v != QEMU_VM_FILE_VERSION)
> return -ENOTSUP;
>
> Shouldn't we be able to change some version field here and make the
> "recognition of postcopy automatic"? Having to hack around a new
> command line option for each page is not going to be nice. And about
> postcopy flags, if they are for "incoming side", please consider just
> sent that flags on the stream as a first field?
Yes, you are right.
If bumping version is allowed, -postcopy can be dropped with auto detection.
-postcopy-flags can be dropped because it is used only for benchmark purpose
to change incoming side behavior independent of outgoing side.
--
yamahata
- [Qemu-devel] [PATCH v2 38/41] postcopy/outgoing: add forward, backward option to specify the size of prefault, (continued)
- [Qemu-devel] [PATCH v2 38/41] postcopy/outgoing: add forward, backward option to specify the size of prefault, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 10/41] arch_init: simplify a bit by ram_find_block(), Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 34/41] postcopy outgoing: add -p and -n option to migrate command, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 39/41] postcopy/outgoing: implement prefault, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 26/41] buffered_file: factor out buffer management logic, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 14/41] exec.c: export last_ram_offset(), Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 08/41] arch_init/ram_load: refactor ram_load, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 28/41] buffered_file: add qemu_file to read/write to buffer in memory, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 33/41] postcopy: introduce -postcopy and -postcopy-flags option, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 12/41] arch_init: factor out setting last_block, last_offset, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 36/41] postcopy: implement incoming part of postcopy live migration, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 41/41] migration/postcopy: add movebg mode, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 40/41] migrate: add -m (movebg) option to migrate command, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 37/41] postcopy: implement outgoing part of postcopy live migration, Isaku Yamahata, 2012/06/04
- [Qemu-devel] [PATCH v2 35/41] postcopy: introduce helper functions for postcopy, Isaku Yamahata, 2012/06/04