[Qemu-devel] [RFC PATCH 00/11] Block layer thread-safety, part 2

Paolo Bonzini posted 11 patches 6 years, 10 months ago
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block/io.c                 |  42 +++++++---
block/nbd-client.c         |  30 +++----
block/qcow2.c              |   4 +-
block/qed-cluster.c        |   4 +-
block/qed-l2-cache.c       |   6 ++
block/qed-table.c          |  24 ++++--
block/qed.c                | 195 +++++++++++++++++++++++++++------------------
block/qed.h                |  11 ++-
block/sheepdog.c           |  21 ++++-
block/ssh.c                |  24 ++++--
block/vdi.c                |  48 +++++------
block/vpc.c                |  20 ++---
block/vvfat.c              |   8 +-
include/block/block_int.h  |   2 +-
include/qemu/coroutine.h   |  19 +++++
util/qemu-coroutine-lock.c |  35 ++++++++
16 files changed, 326 insertions(+), 167 deletions(-)
[Qemu-devel] [RFC PATCH 00/11] Block layer thread-safety, part 2
Posted by Paolo Bonzini 6 years, 10 months ago
This part takes care of drivers and devices, making sure that they can
accept concurrent I/O from multiple AioContext.  Only RFC for now because it
depends on Kevin's QED conversion to coroutines, which is still in flux.

The following drivers are thread-safe without using any QemuMutex/CoMutex:
crypto, gluster, null, rbd, win32-aio.

The following drivers already use mutexes for everything except possibly
snapshots, which do not (yet?) need protection: bochs, cloop, dmg, qcow,
parallels, vhdx, vmdk, curl, iscsi, nfs.

The following drivers already use mutexes for _almost_ everything: vpc
(missing get_block_status), vdi (missing bitmap access), vvfat (missing
commit), nbd (s->in_flight not protected), qcow2 (must call CoQueue APIs
under CoMutex).  They are fixed by patches 1-6.

The following drivers must be changed to use CoMutex to protect internal
data: qed (patches 7-9), sheepdog (patch 10).

The following driver must be changed to support I/O from any AioContext:
ssh.  It is fixed by patch 11.

Paolo

Paolo Bonzini (11):
  qcow2: call CoQueue APIs under CoMutex
  coroutine-lock: add qemu_co_rwlock_downgrade and qemu_co_rwlock_upgrade
  vdi: make it thread-safe
  vpc: make it thread-safe
  vvfat: make it thread-safe
  nbd: make it thread-safe
  qed: move tail of qed_aio_write_main to qed_aio_write_{cow,alloc}
  block: invoke .bdrv_drain callback in coroutine context and from AioContext
  qed: protect table cache with CoMutex
  sheepdog: add queue_lock
  ssh: support I/O from any AioContext

 block/io.c                 |  42 +++++++---
 block/nbd-client.c         |  30 +++----
 block/qcow2.c              |   4 +-
 block/qed-cluster.c        |   4 +-
 block/qed-l2-cache.c       |   6 ++
 block/qed-table.c          |  24 ++++--
 block/qed.c                | 195 +++++++++++++++++++++++++++------------------
 block/qed.h                |  11 ++-
 block/sheepdog.c           |  21 ++++-
 block/ssh.c                |  24 ++++--
 block/vdi.c                |  48 +++++------
 block/vpc.c                |  20 ++---
 block/vvfat.c              |   8 +-
 include/block/block_int.h  |   2 +-
 include/qemu/coroutine.h   |  19 +++++
 util/qemu-coroutine-lock.c |  35 ++++++++
 16 files changed, 326 insertions(+), 167 deletions(-)

-- 
2.13.0


Re: [Qemu-devel] [RFC PATCH 00/11] Block layer thread-safety, part 2
Posted by Stefan Hajnoczi 6 years, 9 months ago
On Wed, May 31, 2017 at 11:43:19AM +0200, Paolo Bonzini wrote:
> This part takes care of drivers and devices, making sure that they can
> accept concurrent I/O from multiple AioContext.  Only RFC for now because it
> depends on Kevin's QED conversion to coroutines, which is still in flux.
> 
> The following drivers are thread-safe without using any QemuMutex/CoMutex:
> crypto, gluster, null, rbd, win32-aio.
> 
> The following drivers already use mutexes for everything except possibly
> snapshots, which do not (yet?) need protection: bochs, cloop, dmg, qcow,
> parallels, vhdx, vmdk, curl, iscsi, nfs.
> 
> The following drivers already use mutexes for _almost_ everything: vpc
> (missing get_block_status), vdi (missing bitmap access), vvfat (missing
> commit), nbd (s->in_flight not protected), qcow2 (must call CoQueue APIs
> under CoMutex).  They are fixed by patches 1-6.
> 
> The following drivers must be changed to use CoMutex to protect internal
> data: qed (patches 7-9), sheepdog (patch 10).
> 
> The following driver must be changed to support I/O from any AioContext:
> ssh.  It is fixed by patch 11.
> 
> Paolo
> 
> Paolo Bonzini (11):
>   qcow2: call CoQueue APIs under CoMutex
>   coroutine-lock: add qemu_co_rwlock_downgrade and qemu_co_rwlock_upgrade
>   vdi: make it thread-safe
>   vpc: make it thread-safe
>   vvfat: make it thread-safe
>   nbd: make it thread-safe
>   qed: move tail of qed_aio_write_main to qed_aio_write_{cow,alloc}
>   block: invoke .bdrv_drain callback in coroutine context and from AioContext
>   qed: protect table cache with CoMutex
>   sheepdog: add queue_lock
>   ssh: support I/O from any AioContext
> 
>  block/io.c                 |  42 +++++++---
>  block/nbd-client.c         |  30 +++----
>  block/qcow2.c              |   4 +-
>  block/qed-cluster.c        |   4 +-
>  block/qed-l2-cache.c       |   6 ++
>  block/qed-table.c          |  24 ++++--
>  block/qed.c                | 195 +++++++++++++++++++++++++++------------------
>  block/qed.h                |  11 ++-
>  block/sheepdog.c           |  21 ++++-
>  block/ssh.c                |  24 ++++--
>  block/vdi.c                |  48 +++++------
>  block/vpc.c                |  20 ++---
>  block/vvfat.c              |   8 +-
>  include/block/block_int.h  |   2 +-
>  include/qemu/coroutine.h   |  19 +++++
>  util/qemu-coroutine-lock.c |  35 ++++++++
>  16 files changed, 326 insertions(+), 167 deletions(-)
> 
> -- 
> 2.13.0
> 
> 

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Re: [Qemu-devel] [RFC PATCH 00/11] Block layer thread-safety, part 2
Posted by Paolo Bonzini 6 years, 9 months ago

On 08/06/2017 14:52, Stefan Hajnoczi wrote:
> On Wed, May 31, 2017 at 11:43:19AM +0200, Paolo Bonzini wrote:
>> This part takes care of drivers and devices, making sure that they can
>> accept concurrent I/O from multiple AioContext.  Only RFC for now because it
>> depends on Kevin's QED conversion to coroutines, which is still in flux.
>>
>> The following drivers are thread-safe without using any QemuMutex/CoMutex:
>> crypto, gluster, null, rbd, win32-aio.
>>
>> The following drivers already use mutexes for everything except possibly
>> snapshots, which do not (yet?) need protection: bochs, cloop, dmg, qcow,
>> parallels, vhdx, vmdk, curl, iscsi, nfs.
>>
>> The following drivers already use mutexes for _almost_ everything: vpc
>> (missing get_block_status), vdi (missing bitmap access), vvfat (missing
>> commit), nbd (s->in_flight not protected), qcow2 (must call CoQueue APIs
>> under CoMutex).  They are fixed by patches 1-6.
>>
>> The following drivers must be changed to use CoMutex to protect internal
>> data: qed (patches 7-9), sheepdog (patch 10).
>>
>> The following driver must be changed to support I/O from any AioContext:
>> ssh.  It is fixed by patch 11.
>>
>> Paolo
>>
>> Paolo Bonzini (11):
>>   qcow2: call CoQueue APIs under CoMutex
>>   coroutine-lock: add qemu_co_rwlock_downgrade and qemu_co_rwlock_upgrade
>>   vdi: make it thread-safe
>>   vpc: make it thread-safe
>>   vvfat: make it thread-safe
>>   nbd: make it thread-safe
>>   qed: move tail of qed_aio_write_main to qed_aio_write_{cow,alloc}
>>   block: invoke .bdrv_drain callback in coroutine context and from AioContext
>>   qed: protect table cache with CoMutex
>>   sheepdog: add queue_lock
>>   ssh: support I/O from any AioContext
>>
>>  block/io.c                 |  42 +++++++---
>>  block/nbd-client.c         |  30 +++----
>>  block/qcow2.c              |   4 +-
>>  block/qed-cluster.c        |   4 +-
>>  block/qed-l2-cache.c       |   6 ++
>>  block/qed-table.c          |  24 ++++--
>>  block/qed.c                | 195 +++++++++++++++++++++++++++------------------
>>  block/qed.h                |  11 ++-
>>  block/sheepdog.c           |  21 ++++-
>>  block/ssh.c                |  24 ++++--
>>  block/vdi.c                |  48 +++++------
>>  block/vpc.c                |  20 ++---
>>  block/vvfat.c              |   8 +-
>>  include/block/block_int.h  |   2 +-
>>  include/qemu/coroutine.h   |  19 +++++
>>  util/qemu-coroutine-lock.c |  35 ++++++++
>>  16 files changed, 326 insertions(+), 167 deletions(-)
>>
>> -- 
>> 2.13.0
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

Thanks, I'll repost once QED is converted to coroutines, and send part 3
when I have some time.

Paolo