From: Paolo Bonzini <pbonzini@redhat.com>
To: Alex Bligh <alex@alex.org.uk>
Cc: aarcange@redhat.com, Lei Li <lilei@linux.vnet.ibm.com>,
quintela@redhat.com, qemu-devel@nongnu.org,
mrhines@linux.vnet.ibm.com,
Anthony Liguori <anthony@codemonkey.ws>,
lagarcia@br.ibm.com, rcj@linux.vnet.ibm.com
Subject: Re: [Qemu-devel] [PATCH 13/18] arch_init: adjust ram_save_setup() for migrate_is_localhost
Date: Fri, 23 Aug 2013 10:06:03 +0200 [thread overview]
Message-ID: <521717EB.7020406@redhat.com> (raw)
In-Reply-To: <18FE72B095A0C28E7B5AD40D@nimrod.local>
Il 23/08/2013 09:57, Alex Bligh ha scritto:
>
>
> --On 23 August 2013 09:48:42 +0200 Paolo Bonzini <pbonzini@redhat.com>
> wrote:
>
>> As a matter of fact, 2^28 madvise system calls will take much, much
>> longer than 100ms.
>
> Probably a stupid question, but why would you need to do one call per
> page? It takes a 'size_t length' parameter.
Right now migration is done a page at a time, and so is madvise AFAIU.
However, even with a larger length parameter I suspect it would alone
take more than 2 cycles per page.
So one way to do this could be to add a flag to "migrate" that would
migrate devices only, and use shared memory in both the source and the
target.
There is still a problem, because we must make sure the destination
doesn't write to memory (e.g. read firmware) when initializing the
board, because that would overwrite the memory of the running instance.
But it looks more promising than page flipping.
Paolo
next prev parent reply other threads:[~2013-08-23 8:07 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-21 7:18 [Qemu-devel] [PATCH 0/18 RFC v3] Localhost migration Lei Li
2013-08-21 7:18 ` [Qemu-devel] [PATCH 01/18] migration: export MIG_STATE_xxx flags Lei Li
2013-08-21 7:18 ` [Qemu-devel] [PATCH 02/18] savevm: export qemu_save_device_state() Lei Li
2013-08-21 11:13 ` Paolo Bonzini
2013-08-21 7:18 ` [Qemu-devel] [PATCH 03/18] rename is_active to is_block_active Lei Li
2013-08-21 7:18 ` [Qemu-devel] [PATCH 04/18] savevm: set right return value for qemu_file_rate_limit Lei Li
2013-08-21 10:42 ` Paolo Bonzini
2013-08-23 3:18 ` Lei Li
2013-08-23 5:34 ` Paolo Bonzini
2013-08-23 9:11 ` Lei Li
2013-08-23 9:14 ` Paolo Bonzini
2013-08-23 9:18 ` Lei Li
2013-08-23 9:22 ` Paolo Bonzini
2013-08-23 9:25 ` Lei Li
2013-08-21 7:18 ` [Qemu-devel] [PATCH 05/18] savevm: add comments for qemu_file_get_error() Lei Li
2013-08-21 10:43 ` Paolo Bonzini
2013-08-21 7:18 ` [Qemu-devel] [PATCH 06/18] bugfix: wrong error set by ram_control_load_hook() Lei Li
2013-08-21 10:40 ` Paolo Bonzini
2013-08-23 3:22 ` Lei Li
2013-08-23 5:34 ` Paolo Bonzini
2013-08-23 6:31 ` Lei Li
2013-08-21 7:18 ` [Qemu-devel] [PATCH 07/18] arch_init: export RAM_SAVE_xxx flags Lei Li
2013-08-21 10:49 ` Paolo Bonzini
2013-08-22 20:14 ` Michael R. Hines
2013-08-23 7:36 ` Paolo Bonzini
2013-08-21 7:18 ` [Qemu-devel] [PATCH 08/18] migration-local: introduce qemu_fopen_local() Lei Li
2013-08-22 20:42 ` Michael R. Hines
2013-08-23 7:44 ` Lei Li
2013-08-28 3:26 ` Lei Li
2013-08-28 6:37 ` Paolo Bonzini
2013-08-29 8:28 ` Lei Li
2013-08-29 14:05 ` Michael R. Hines
2013-08-21 7:18 ` [Qemu-devel] [PATCH 09/18] exec: export qemu_get_ram_block() Lei Li
2013-08-21 7:18 ` [Qemu-devel] [PATCH 10/18] migration-local: implementation of outgoing part Lei Li
2013-08-21 10:44 ` Paolo Bonzini
2013-08-22 20:49 ` Michael R. Hines
2013-08-21 7:18 ` [Qemu-devel] [PATCH 11/18] migration: introduce capability localhost Lei Li
2013-08-21 15:08 ` Eric Blake
2013-08-28 4:22 ` Lei Li
2013-08-21 15:18 ` Paolo Bonzini
2013-08-22 20:50 ` Michael R. Hines
2013-08-23 7:40 ` Paolo Bonzini
2013-08-23 7:51 ` Lei Li
2013-08-23 8:01 ` Paolo Bonzini
2013-08-23 9:21 ` Lei Li
2013-08-21 7:18 ` [Qemu-devel] [PATCH 12/18] arch_init: factor out ram_save_blocks() Lei Li
2013-08-21 7:18 ` [Qemu-devel] [PATCH 13/18] arch_init: adjust ram_save_setup() for migrate_is_localhost Lei Li
2013-08-21 10:48 ` Paolo Bonzini
2013-08-23 6:25 ` Lei Li
2013-08-23 7:48 ` Paolo Bonzini
2013-08-23 7:57 ` Alex Bligh
2013-08-23 8:06 ` Paolo Bonzini [this message]
2013-08-23 9:00 ` Lei Li
2013-08-23 9:12 ` Paolo Bonzini
2013-08-21 7:18 ` [Qemu-devel] [PATCH 14/18] arch_init: skip migration_bitmap_sync for local migration Lei Li
2013-08-21 10:50 ` Paolo Bonzini
2013-08-21 7:18 ` [Qemu-devel] [PATCH 15/18] migration: adjust migration_thread " Lei Li
2013-08-21 10:47 ` Paolo Bonzini
2013-08-21 7:18 ` [Qemu-devel] [PATCH 16/18] migration-local: implementation of incoming part Lei Li
2013-08-21 7:18 ` Lei Li
2013-08-21 7:18 ` [Qemu-devel] [PATCH 17/18] migration: add prefix for local migration to incoming migration Lei Li
2013-08-21 10:52 ` Paolo Bonzini
2013-08-23 14:02 ` Lei Li
2013-08-21 7:18 ` [Qemu-devel] [PATCH 18/18] hmp: better fomat for info migrate_capabilities Lei Li
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