From: Avi Kivity <avi@redhat.com>
To: Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>
Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org, aliguori@us.ibm.com,
mtosatti@redhat.com, ohmura.kei@lab.ntt.co.jp,
yoshikawa.takuya@oss.ntt.co.jp
Subject: Re: [RFC PATCH 04/20] Make QEMUFile buf expandable, and introduce qemu_realloc_buffer() and qemu_clear_buffer().
Date: Fri, 23 Apr 2010 16:14:42 +0300 [thread overview]
Message-ID: <4BD19D42.4060009@redhat.com> (raw)
In-Reply-To: <4BD16F8C.5010007@lab.ntt.co.jp>
On 04/23/2010 12:59 PM, Yoshiaki Tamura wrote:
> Avi Kivity wrote:
>> On 04/21/2010 08:57 AM, Yoshiaki Tamura wrote:
>>> Currently buf size is fixed at 32KB. It would be useful if it could
>>> be flexible.
>>>
>>
>> Why is this needed? The real buffering is in the kernel anyways; this is
>> only used to reduce the number of write() syscalls.
>
> This was introduced to buffer the transfered guests image transaction
> ally on the receiver side. The sender doesn't use it.
> In case of intermediate state, we just discard this buffer.
How large can it grow?
What's wrong with applying it (perhaps partially) to the guest state?
The next state transfer will overwrite it completely, no?
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com>
To: Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>
Cc: aliguori@us.ibm.com, kvm@vger.kernel.org,
ohmura.kei@lab.ntt.co.jp, mtosatti@redhat.com,
qemu-devel@nongnu.org, yoshikawa.takuya@oss.ntt.co.jp
Subject: [Qemu-devel] Re: [RFC PATCH 04/20] Make QEMUFile buf expandable, and introduce qemu_realloc_buffer() and qemu_clear_buffer().
Date: Fri, 23 Apr 2010 16:14:42 +0300 [thread overview]
Message-ID: <4BD19D42.4060009@redhat.com> (raw)
In-Reply-To: <4BD16F8C.5010007@lab.ntt.co.jp>
On 04/23/2010 12:59 PM, Yoshiaki Tamura wrote:
> Avi Kivity wrote:
>> On 04/21/2010 08:57 AM, Yoshiaki Tamura wrote:
>>> Currently buf size is fixed at 32KB. It would be useful if it could
>>> be flexible.
>>>
>>
>> Why is this needed? The real buffering is in the kernel anyways; this is
>> only used to reduce the number of write() syscalls.
>
> This was introduced to buffer the transfered guests image transaction
> ally on the receiver side. The sender doesn't use it.
> In case of intermediate state, we just discard this buffer.
How large can it grow?
What's wrong with applying it (perhaps partially) to the guest state?
The next state transfer will overwrite it completely, no?
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
next prev parent reply other threads:[~2010-04-23 13:14 UTC|newest]
Thread overview: 144+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-21 5:57 [RFC PATCH 00/20] Kemari for KVM v0.1 Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 01/20] Modify DIRTY_FLAG value and introduce DIRTY_IDX to use as indexes of bit-based phys_ram_dirty Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-22 19:26 ` Anthony Liguori
2010-04-22 19:26 ` [Qemu-devel] " Anthony Liguori
2010-04-23 2:09 ` Yoshiaki Tamura
2010-04-23 2:09 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 02/20] Introduce cpu_physical_memory_get_dirty_range() Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 03/20] Use cpu_physical_memory_set_dirty_range() to update phys_ram_dirty Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 04/20] Make QEMUFile buf expandable, and introduce qemu_realloc_buffer() and qemu_clear_buffer() Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 8:03 ` Stefan Hajnoczi
2010-04-21 8:03 ` [Qemu-devel] " Stefan Hajnoczi
2010-04-21 8:27 ` Yoshiaki Tamura
2010-04-21 8:27 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-23 9:53 ` Avi Kivity
2010-04-23 9:53 ` [Qemu-devel] " Avi Kivity
2010-04-23 9:59 ` Yoshiaki Tamura
2010-04-23 9:59 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-23 13:14 ` Avi Kivity [this message]
2010-04-23 13:14 ` Avi Kivity
2010-04-26 10:43 ` Yoshiaki Tamura
2010-04-26 10:43 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-23 13:26 ` Anthony Liguori
2010-04-23 13:26 ` [Qemu-devel] " Anthony Liguori
2010-04-21 5:57 ` [RFC PATCH 05/20] Introduce put_vector() and get_vector to QEMUFile and qemu_fopen_ops() Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-22 19:28 ` Anthony Liguori
2010-04-22 19:28 ` [Qemu-devel] " Anthony Liguori
2010-04-23 3:37 ` Yoshiaki Tamura
2010-04-23 3:37 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-23 13:22 ` Anthony Liguori
2010-04-23 13:22 ` [Qemu-devel] " Anthony Liguori
2010-04-23 13:48 ` Avi Kivity
2010-04-23 13:48 ` [Qemu-devel] " Avi Kivity
2010-05-03 9:32 ` Yoshiaki Tamura
2010-05-03 9:32 ` [Qemu-devel] " Yoshiaki Tamura
2010-05-03 12:05 ` Anthony Liguori
2010-05-03 12:05 ` [Qemu-devel] " Anthony Liguori
2010-05-03 15:36 ` Yoshiaki Tamura
2010-05-03 15:36 ` [Qemu-devel] " Yoshiaki Tamura
2010-05-03 16:07 ` Anthony Liguori
2010-05-03 16:07 ` [Qemu-devel] " Anthony Liguori
2010-04-26 10:43 ` Yoshiaki Tamura
2010-04-26 10:43 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 06/20] Introduce iovec util functions, qemu_iovec_to_vector() and qemu_iovec_to_size() Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 07/20] Introduce qemu_put_vector() and qemu_put_vector_prepare() to use put_vector() in QEMUFile Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-22 19:29 ` Anthony Liguori
2010-04-22 19:29 ` [Qemu-devel] " Anthony Liguori
2010-04-23 4:02 ` Yoshiaki Tamura
2010-04-23 4:02 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-23 13:23 ` Anthony Liguori
2010-04-23 13:23 ` [Qemu-devel] " Anthony Liguori
2010-04-26 10:43 ` Yoshiaki Tamura
2010-04-26 10:43 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 08/20] Introduce RAMSaveIO and use cpu_physical_memory_get_dirty_range() to check multiple dirty pages Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-22 19:31 ` Anthony Liguori
2010-04-22 19:31 ` [Qemu-devel] " Anthony Liguori
2010-04-21 5:57 ` [RFC PATCH 09/20] Introduce writev and read to FdMigrationState Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 10/20] Introduce skip_header parameter to qemu_loadvm_state() so that it can be called iteratively without reading the header Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-22 19:34 ` Anthony Liguori
2010-04-22 19:34 ` [Qemu-devel] " Anthony Liguori
2010-04-23 4:25 ` Yoshiaki Tamura
2010-04-23 4:25 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 11/20] Introduce some socket util functions Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 12/20] Introduce fault tolerant VM transaction QEMUFile and ft_mode Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 13/20] Introduce util functions to control ft_transaction from savevm layer Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 14/20] Upgrade QEMU_FILE_VERSION from 3 to 4, and introduce qemu_savevm_state_all() Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-22 19:37 ` Anthony Liguori
2010-04-22 19:37 ` [Qemu-devel] " Anthony Liguori
2010-04-23 3:29 ` Yoshiaki Tamura
2010-04-23 3:29 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 15/20] Introduce FT mode support to configure Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-22 19:38 ` Anthony Liguori
2010-04-22 19:38 ` [Qemu-devel] " Anthony Liguori
2010-04-23 3:09 ` Yoshiaki Tamura
2010-04-23 3:09 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 16/20] Introduce event_tap fucntions and ft_tranx_ready() Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 17/20] Modify migrate_fd_put_ready() when ft_mode is on Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 18/20] Modify tcp_accept_incoming_migration() to handle ft_mode, and add a hack not to close fd when ft_mode is enabled Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 19/20] Insert do_event_tap() to virtio-{blk,net}, comment out assert() on cpu_single_env temporally Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] [RFC PATCH 19/20] Insert do_event_tap() to virtio-{blk, net}, " Yoshiaki Tamura
2010-04-22 19:39 ` Anthony Liguori
2010-04-22 19:39 ` [Qemu-devel] " Anthony Liguori
2010-04-23 4:51 ` Yoshiaki Tamura
2010-04-23 4:51 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-21 5:57 ` [RFC PATCH 20/20] Introduce -k option to enable FT migration mode (Kemari) Yoshiaki Tamura
2010-04-21 5:57 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-22 8:58 ` [Qemu-devel] [RFC PATCH 00/20] Kemari for KVM v0.1 Dor Laor
2010-04-22 8:58 ` Dor Laor
2010-04-22 10:35 ` Yoshiaki Tamura
2010-04-22 10:35 ` Yoshiaki Tamura
2010-04-22 11:36 ` Takuya Yoshikawa
2010-04-22 11:36 ` Takuya Yoshikawa
2010-04-22 12:35 ` Yoshiaki Tamura
2010-04-22 12:35 ` Yoshiaki Tamura
2010-04-22 12:19 ` Dor Laor
2010-04-22 13:16 ` Yoshiaki Tamura
2010-04-22 20:33 ` Anthony Liguori
2010-04-22 20:33 ` Anthony Liguori
2010-04-23 1:53 ` Yoshiaki Tamura
2010-04-23 1:53 ` Yoshiaki Tamura
2010-04-23 13:20 ` Anthony Liguori
2010-04-23 13:20 ` Anthony Liguori
2010-04-26 10:44 ` Yoshiaki Tamura
2010-04-26 10:44 ` Yoshiaki Tamura
2010-04-22 20:38 ` Dor Laor
2010-04-23 5:17 ` Yoshiaki Tamura
2010-04-23 7:36 ` Fernando Luis Vázquez Cao
2010-04-23 7:36 ` Fernando Luis Vázquez Cao
2010-04-25 21:52 ` Dor Laor
2010-04-25 21:52 ` Dor Laor
2010-04-22 16:15 ` Jamie Lokier
2010-04-22 16:15 ` Jamie Lokier
2010-04-23 0:20 ` Yoshiaki Tamura
2010-04-23 0:20 ` Yoshiaki Tamura
2010-04-23 15:07 ` Jamie Lokier
2010-04-23 15:07 ` Jamie Lokier
2010-04-22 19:42 ` Anthony Liguori
2010-04-22 19:42 ` [Qemu-devel] " Anthony Liguori
2010-04-23 0:45 ` Yoshiaki Tamura
2010-04-23 0:45 ` [Qemu-devel] " Yoshiaki Tamura
2010-04-23 13:10 ` Anthony Liguori
2010-04-23 13:10 ` [Qemu-devel] " Anthony Liguori
2010-04-23 13:24 ` Avi Kivity
2010-04-23 13:24 ` [Qemu-devel] " Avi Kivity
2010-04-26 10:44 ` Yoshiaki Tamura
2010-04-26 10:44 ` [Qemu-devel] " Yoshiaki Tamura
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