From: Peter Xu <peterx@redhat.com>
To: Leonardo Bras Soares Passos <leobras@redhat.com>
Cc: "Elena Ufimtseva" <elena.ufimtseva@oracle.com>,
"John G Johnson" <john.g.johnson@oracle.com>,
"Jagannathan Raman" <jag.raman@oracle.com>,
qemu-block@nongnu.org, "Juan Quintela" <quintela@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>,
"Daniel P. Berrangé" <berrange@redhat.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>,
"Fam Zheng" <fam@euphon.net>
Subject: Re: [PATCH v1 2/3] io: Add zerocopy and errqueue
Date: Thu, 9 Sep 2021 12:40:37 -0400 [thread overview]
Message-ID: <YTo5BRw/M2Cdrpvw@t490s> (raw)
In-Reply-To: <CAJ6HWG4GTiqvXjyLnBTEaP6fBCt76cR=imLRfM1eYi3qp9QiPg@mail.gmail.com>
On Thu, Sep 09, 2021 at 01:58:39AM -0300, Leonardo Bras Soares Passos wrote:
> FWIW, what I had in mind for a (theoretical) migration setup with
> io_async_writev() + io_async_flush():
One trivial concern is it's not strictly just "async" because "async" can
happen on any nonblocking fd; here it's more "zerocopy" specific. But as long
as Dan is okay with it I'm fine too to start with "async", as long as we do
proper documentation on the requirement of lifecycle of the buffers.
> - For guest RAM we can decide not to rw_lock memory on zerocopy,
> because there is no need,
> - For headers, we can decide to not use async (use io_writev() instead),
> - flush() can happen each iteration of migration, or at each N
> seconds, or at the end.
I think we should only need the flush at the end of precopy, and that should
also cover when switching to postcopy. We could merge this flush() into the
existing per-iteration sync of multi-fd, but it's not strictly necessary, imho.
We can see which is easier. The rest looks good to me. Thanks,
--
Peter Xu
next prev parent reply other threads:[~2021-09-09 16:41 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-31 11:02 [PATCH v1 0/3] QIOChannel flags + multifd zerocopy Leonardo Bras
2021-08-31 11:02 ` [PATCH v1 1/3] io: Enable write flags for QIOChannel Leonardo Bras
2021-09-01 20:54 ` Eric Blake
2021-09-02 8:26 ` Leonardo Bras Soares Passos
2021-08-31 11:02 ` [PATCH v1 2/3] io: Add zerocopy and errqueue Leonardo Bras
2021-08-31 12:57 ` Daniel P. Berrangé
2021-08-31 20:27 ` Peter Xu
2021-09-01 8:50 ` Daniel P. Berrangé
2021-09-01 15:52 ` Peter Xu
2021-09-01 15:59 ` Daniel P. Berrangé
2021-09-02 7:07 ` Leonardo Bras Soares Passos
2021-09-02 6:59 ` Leonardo Bras Soares Passos
2021-09-07 16:44 ` Peter Xu
2021-09-08 20:13 ` Leonardo Bras Soares Passos
2021-09-08 21:04 ` Peter Xu
2021-09-02 6:38 ` Leonardo Bras Soares Passos
2021-09-02 8:47 ` Daniel P. Berrangé
2021-09-02 9:34 ` Leonardo Bras Soares Passos
2021-09-02 9:49 ` Daniel P. Berrangé
2021-09-02 10:19 ` Leonardo Bras Soares Passos
2021-09-02 10:28 ` Daniel P. Berrangé
2021-09-07 11:06 ` Dr. David Alan Gilbert
2021-09-07 18:09 ` Peter Xu
2021-09-08 8:30 ` Dr. David Alan Gilbert
2021-09-08 15:24 ` Peter Xu
2021-09-09 8:49 ` Dr. David Alan Gilbert
2021-09-08 20:25 ` Leonardo Bras Soares Passos
2021-09-08 21:09 ` Peter Xu
2021-09-08 21:57 ` Daniel P. Berrangé
2021-09-09 2:05 ` Peter Xu
2021-09-09 4:58 ` Leonardo Bras Soares Passos
2021-09-09 16:40 ` Peter Xu [this message]
2021-08-31 11:02 ` [PATCH v1 3/3] migration: multifd: Enable zerocopy Leonardo Bras
2021-08-31 13:16 ` Daniel P. Berrangé
2021-08-31 20:29 ` Peter Xu
2021-09-01 8:53 ` Daniel P. Berrangé
2021-09-01 15:35 ` Peter Xu
2021-09-01 15:44 ` Daniel P. Berrangé
2021-09-01 16:01 ` Peter Xu
2021-09-02 7:57 ` Leonardo Bras Soares Passos
2021-09-07 11:13 ` Dr. David Alan Gilbert
2021-09-08 15:26 ` Daniel P. Berrangé
2021-09-02 7:23 ` Jason Wang
2021-09-02 8:08 ` Leonardo Bras Soares Passos
2021-09-02 7:27 ` Leonardo Bras Soares Passos
2021-09-02 7:22 ` Leonardo Bras Soares Passos
2021-09-02 8:20 ` Daniel P. Berrangé
2021-09-02 8:52 ` Leonardo Bras Soares Passos
2021-09-02 9:20 ` Daniel P. Berrangé
2021-09-02 9:49 ` Leonardo Bras Soares Passos
2021-09-02 9:59 ` Daniel P. Berrangé
2021-09-02 10:25 ` Leonardo Bras Soares Passos
2021-09-07 11:17 ` Dr. David Alan Gilbert
2021-09-07 18:32 ` Peter Xu
2021-09-08 2:59 ` Jason Wang
2021-09-08 3:24 ` Peter Xu
2021-09-08 3:26 ` Jason Wang
2021-09-08 8:19 ` Dr. David Alan Gilbert
2021-09-08 15:19 ` Peter Xu
2021-09-09 1:10 ` Jason Wang
2021-08-31 21:24 ` [PATCH v1 0/3] QIOChannel flags + multifd zerocopy Peter Xu
2021-09-01 19:21 ` Leonardo Bras Soares Passos
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