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Re: [Qemu-devel] [PATCH v3 00/29] postcopy+vhost-user/shared ram
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v3 00/29] postcopy+vhost-user/shared ram |
Date: |
Tue, 27 Feb 2018 22:23:01 +0200 |
On Tue, Feb 27, 2018 at 08:05:25PM +0000, Dr. David Alan Gilbert wrote:
> * Michael S. Tsirkin (address@hidden) wrote:
> > On Fri, Feb 16, 2018 at 01:15:56PM +0000, Dr. David Alan Gilbert (git)
> > wrote:
> > > From: "Dr. David Alan Gilbert" <address@hidden>
> > >
> > > Hi,
> > > This is the first non-RFC version of this patch set that
> > > enables postcopy migration with shared memory to a vhost user process.
> > > It's based off current head.
> > >
> > > I've tested with vhost-user-bridge and a modified dpdk; both very
> > > lightly.
> > >
> > > Compared to v2 we're now using the just-merged reworks to the vhost
> > > code (suggested by Igor), so that the huge page region merging is now a
> > > lot simpler
> > > in this series. The handshake between the client and the qemu for the
> > > set-mem-table is now a bit more complex to resolve a previous race where
> > > the client would start sending requests to the qemu prior to the qemu
> > > being ready to accept them.
> > >
> > > Dave
> >
> > From vhost-user POV this seems mostly fine to me.
>
> OK, great - it would be nice to get this merged in the upcoming release
> (Hint: Anyone else please review!)
>
> > I would like to have dependency of specific messages on the
> > protocol features documented, and the order of messages
> > documented a bit more explicitly.
>
> Something like the following? (appropriately merged in with the
> individual commits):
>
> diff --git a/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt
> index 4bf7d8ef99..7841812766 100644
> --- a/docs/interop/vhost-user.txt
> +++ b/docs/interop/vhost-user.txt
> @@ -461,7 +461,7 @@ Master message types
> for each memory mapped region. The size and ordering of the fds matches
> the number and ordering of memory regions.
>
> - When postcopy-listening has been received, SET_MEM_TABLE replies with
> + When VHOST_USER_POSTCOPY_LISTEN has been received, SET_MEM_TABLE
> replies with
> the bases of the memory mapped regions to the master. It must have
> mmap'd
> the regions but not yet accessed them and should not yet generate a
> userfault
> event. Note NEED_REPLY_MASK is not set in this case.
> @@ -687,7 +687,8 @@ Master message types
> Master payload: N/A
> Slave payload: userfault fd + u64
>
> - Master advises slave that a migration with postcopy enabled is
> underway,
> + When VHOST_USER_PROTOCOL_F_PAGEFAULT is supported, the
> + master advises slave that a migration with postcopy enabled is
> underway,
> the slave must open a userfaultfd for later use.
> Note that at this stage the migration is still in precopy mode.
>
> @@ -696,6 +697,8 @@ Master message types
> Master payload: N/A
>
> Master advises slave that a transition to postcopy mode has happened.
> + This is always sent sometime after a VHOST_USER_POSTCOPY_ADVISE, and
> + thus only when VHOST_USER_PROTOCOL_F_PAGEFAULT is supported.
>
> * VHOST_USER_POSTCOPY_END
> Id: 28
> @@ -704,6 +707,8 @@ Master message types
> Master advises that postcopy migration has now completed. The
> slave must disable the userfaultfd. The response is an acknowledgement
> only.
> + This message is sent at the end of the migration, after
> + VHOST_USER_POSTCOPY_LISTEN was previously sent.
And maybe mention VHOST_USER_PROTOCOL_F_PAGEFAULT here too.
> Slave message types
> -------------------
>
> Dave
>
> >
> >
> >
> > > Dr. David Alan Gilbert (29):
> > > migrate: Update ram_block_discard_range for shared
> > > qemu_ram_block_host_offset
> > > postcopy: use UFFDIO_ZEROPAGE only when available
> > > postcopy: Add notifier chain
> > > postcopy: Add vhost-user flag for postcopy and check it
> > > vhost-user: Add 'VHOST_USER_POSTCOPY_ADVISE' message
> > > libvhost-user: Support sending fds back to qemu
> > > libvhost-user: Open userfaultfd
> > > postcopy: Allow registering of fd handler
> > > vhost+postcopy: Register shared ufd with postcopy
> > > vhost+postcopy: Transmit 'listen' to client
> > > postcopy+vhost-user: Split set_mem_table for postcopy
> > > migration/ram: ramblock_recv_bitmap_test_byte_offset
> > > libvhost-user+postcopy: Register new regions with the ufd
> > > vhost+postcopy: Send address back to qemu
> > > vhost+postcopy: Stash RAMBlock and offset
> > > vhost+postcopy: Send requests to source for shared pages
> > > vhost+postcopy: Resolve client address
> > > postcopy: wake shared
> > > postcopy: postcopy_notify_shared_wake
> > > vhost+postcopy: Add vhost waker
> > > vhost+postcopy: Call wakeups
> > > libvhost-user: mprotect & madvises for postcopy
> > > vhost-user: Add VHOST_USER_POSTCOPY_END message
> > > vhost+postcopy: Wire up POSTCOPY_END notify
> > > vhost: Huge page align and merge
> > > postcopy: Allow shared memory
> > > libvhost-user: Claim support for postcopy
> > > postcopy shared docs
> > >
> > > contrib/libvhost-user/libvhost-user.c | 303 ++++++++++++++++++++++++-
> > > contrib/libvhost-user/libvhost-user.h | 8 +
> > > docs/devel/migration.rst | 41 ++++
> > > docs/interop/vhost-user.txt | 42 ++++
> > > exec.c | 85 +++++--
> > > hw/virtio/trace-events | 16 +-
> > > hw/virtio/vhost-user.c | 411
> > > +++++++++++++++++++++++++++++++++-
> > > hw/virtio/vhost.c | 66 +++++-
> > > include/exec/cpu-common.h | 4 +
> > > migration/migration.c | 6 +
> > > migration/migration.h | 4 +
> > > migration/postcopy-ram.c | 350 +++++++++++++++++++++++------
> > > migration/postcopy-ram.h | 69 ++++++
> > > migration/ram.c | 5 +
> > > migration/ram.h | 1 +
> > > migration/savevm.c | 13 ++
> > > migration/trace-events | 6 +
> > > trace-events | 3 +-
> > > vl.c | 2 +
> > > 19 files changed, 1337 insertions(+), 98 deletions(-)
> > >
> > > --
> > > 2.14.3
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PATCH v3 26/29] vhost: Huge page align and merge, (continued)
- [Qemu-devel] [PATCH v3 26/29] vhost: Huge page align and merge, Dr. David Alan Gilbert (git), 2018/02/16
- [Qemu-devel] [PATCH v3 27/29] postcopy: Allow shared memory, Dr. David Alan Gilbert (git), 2018/02/16
- [Qemu-devel] [PATCH v3 28/29] libvhost-user: Claim support for postcopy, Dr. David Alan Gilbert (git), 2018/02/16
- [Qemu-devel] [PATCH v3 23/29] libvhost-user: mprotect & madvises for postcopy, Dr. David Alan Gilbert (git), 2018/02/16
- [Qemu-devel] [PATCH v3 24/29] vhost-user: Add VHOST_USER_POSTCOPY_END message, Dr. David Alan Gilbert (git), 2018/02/16
- [Qemu-devel] [PATCH v3 29/29] postcopy shared docs, Dr. David Alan Gilbert (git), 2018/02/16
- Re: [Qemu-devel] [PATCH v3 00/29] postcopy+vhost-user/shared ram, Michael S. Tsirkin, 2018/02/27