From: Juan Quintela <quintela@redhat.com>
To: "Leonardo Brás" <leobras@redhat.com>
Cc: qemu-devel@nongnu.org,
"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
"Peter Xu" <peterx@redhat.com>, "Eric Blake" <eblake@redhat.com>,
"Philippe Mathieu-Daudé" <f4bug@amsat.org>,
"Yanan Wang" <wangyanan55@huawei.com>,
"Markus Armbruster" <armbru@redhat.com>,
"Eduardo Habkost" <eduardo@habkost.net>
Subject: Re: [PATCH v7 08/12] multifd: Add capability to enable/disable zero_page
Date: Fri, 19 Aug 2022 13:36:05 +0200 [thread overview]
Message-ID: <874jy81n4q.fsf@secure.mitica> (raw)
In-Reply-To: <cdf15834492aa55215ef75b6a963e1c7b3ff49a9.camel@redhat.com> ("Leonardo Brás"'s message of "Thu, 11 Aug 2022 06:29:44 -0300")
Leonardo Brás <leobras@redhat.com> wrote:
> On Tue, 2022-08-02 at 08:39 +0200, Juan Quintela wrote:
>> We have to enable it by default until we introduce the new code.
>>
>> Signed-off-by: Juan Quintela <quintela@redhat.com>
>>
>> ---
>>
>> Change it to a capability. As capabilities are off by default, have
>> to change MULTIFD_ZERO_PAGE to MAIN_ZERO_PAGE, so it is false for
>> default, and true for older versions.
>
> IIUC, the idea of a capability is to introduce some new features to the code,
> and let users enable or disable it.
All capabilities are false by default.
If we change the capability to be true by default, we need to teach
libvirt new tricks.
> If it introduce a new capability, is not very intuitive to think that it will be
> always true for older versions, and false for new ones.
It don't need to be intuitive, it just need to be documented correctly.
I think that is done, no?
> I would suggest adding it as MULTIFD_ZERO_PAGE, and let it disabled for now.
> When the full feature gets introduced, the capability could be enabled by
> default, if desired.
I have it that way before it was a capability.
but the info migrate_capabilities
showed everything false and this one true, wondering _why_ this one is
true.
So I decided to rename it, and make it true by default.
> What do you think?
I preffer it this way, why?
Because at some point in the future, we will remove the code that
implements the capability and the capability. So the idea is that we
don't want to use it for old code.
Later, Juan.
next prev parent reply other threads:[~2022-08-19 11:40 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-02 6:38 [PATCH v7 00/12] Migration: Transmit and detect zero pages in the multifd threads Juan Quintela
2022-08-02 6:38 ` [PATCH v7 01/12] multifd: Create page_size fields into both MultiFD{Recv, Send}Params Juan Quintela
2022-08-11 8:10 ` [PATCH v7 01/12] multifd: Create page_size fields into both MultiFD{Recv,Send}Params Leonardo Brás
2022-08-13 15:41 ` Juan Quintela
2022-08-02 6:38 ` [PATCH v7 02/12] multifd: Create page_count fields into both MultiFD{Recv, Send}Params Juan Quintela
2022-08-11 8:10 ` [PATCH v7 02/12] multifd: Create page_count fields into both MultiFD{Recv,Send}Params Leonardo Brás
2022-08-02 6:38 ` [PATCH v7 03/12] migration: Export ram_transferred_ram() Juan Quintela
2022-08-11 8:11 ` Leonardo Brás
2022-08-13 15:36 ` Juan Quintela
2022-08-02 6:38 ` [PATCH v7 04/12] multifd: Count the number of bytes sent correctly Juan Quintela
2022-08-11 8:11 ` Leonardo Brás
2022-08-19 9:35 ` Juan Quintela
2022-08-02 6:39 ` [PATCH v7 05/12] migration: Make ram_save_target_page() a pointer Juan Quintela
2022-08-11 8:11 ` Leonardo Brás
2022-08-19 9:51 ` Juan Quintela
2022-08-20 7:14 ` Leonardo Bras Soares Passos
2022-08-22 21:35 ` Juan Quintela
2022-08-02 6:39 ` [PATCH v7 06/12] multifd: Make flags field thread local Juan Quintela
2022-08-11 9:04 ` Leonardo Brás
2022-08-19 10:03 ` Juan Quintela
2022-08-20 7:24 ` Leonardo Bras Soares Passos
2022-08-23 13:00 ` Juan Quintela
2022-08-02 6:39 ` [PATCH v7 07/12] multifd: Prepare to send a packet without the mutex held Juan Quintela
2022-08-11 9:16 ` Leonardo Brás
2022-08-19 11:32 ` Juan Quintela
2022-08-20 7:27 ` Leonardo Bras Soares Passos
2022-08-02 6:39 ` [PATCH v7 08/12] multifd: Add capability to enable/disable zero_page Juan Quintela
2022-08-11 9:29 ` Leonardo Brás
2022-08-19 11:36 ` Juan Quintela [this message]
2022-08-02 6:39 ` [PATCH v7 09/12] migration: Export ram_release_page() Juan Quintela
2022-08-11 9:31 ` Leonardo Brás
2022-08-02 6:39 ` [PATCH v7 10/12] multifd: Support for zero pages transmission Juan Quintela
2022-09-02 13:27 ` Leonardo Brás
2022-11-14 12:09 ` Juan Quintela
2022-10-25 9:10 ` chuang xu
2022-11-14 12:10 ` Juan Quintela
2022-08-02 6:39 ` [PATCH v7 11/12] multifd: Zero " Juan Quintela
2022-09-02 13:27 ` Leonardo Brás
2022-11-14 12:20 ` Juan Quintela
2022-11-14 12:27 ` Juan Quintela
2022-08-02 6:39 ` [PATCH v7 12/12] So we use multifd to transmit zero pages Juan Quintela
2022-09-02 13:27 ` Leonardo Brás
2022-11-14 12:30 ` Juan Quintela
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