Skip to content

Q
qemu

openeuler / qemu

通知 10
Star 0
Fork 0
Q
qemu

体验新版 GitCode，发现更多精彩内容 >>

切换分支/标签
  1. 07 11月, 2013 18 次提交
  3. 06 11月, 2013 1 次提交
  5. 31 10月, 2013 1 次提交
  7. 30 10月, 2013 7 次提交
  9. 29 10月, 2013 4 次提交
    • K
      block: Avoid unecessary drv->bdrv_getlength() calls · b94a2610
      由 Kevin Wolf 提交于 
      The block layer generally keeps the size of an image cached in
bs->total_sectors so that it doesn't have to perform expensive
operations to get the size whenever it needs it.

This doesn't work however when using a backend that can change its size
without qemu being aware of it, i.e. passthrough of removable media like
CD-ROMs or floppy disks. For this reason, the caching is disabled when a
removable device is used.

It is obvious that checking whether the _guest_ device has removable
media isn't the right thing to do when we want to know whether the size
of the host backend can change. To make things worse, non-top-level
BlockDriverStates never have any device attached, which makes qemu
assume they are removable, so drv->bdrv_getlength() is always called on
the protocol layer. In the case of raw-posix, this causes unnecessary
lseek() system calls, which turned out to be rather expensive.

This patch completely changes the logic and disables bs->total_sectors
caching only for certain block driver types, for which a size change is
expected: host_cdrom and host_floppy on POSIX, host_device on win32; also
the raw format in case it sits on top of one of these protocols, but in
the common case the nested bdrv_getlength() call on the protocol driver
will use the cache again and avoid an expensive drv->bdrv_getlength()
call.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
      b94a2610
    • L
      sheepdog: pass copy_policy in the request · 1841f880
      由 Liu Yuan 提交于 
      Currently copy_policy isn't used. Recent sheepdog supports erasure coding, which
make use of copy_policy internally, but require client explicitly passing
copy_policy from base inode to newly creately inode for snapshot related
operations.

If connected sheep daemon doesn't utilize copy_policy, passing it to sheep
daemon is just one extra null effect operation. So no compatibility problem.

With this patch, sheepdog can provide erasure coded volume for QEMU VM.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NLiu Yuan <namei.unix@gmail.com>
Acked-by: NMORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      1841f880
    • L
      sheepdog: explicitly set copies as type uint8_t · 29a67f7e
      由 Liu Yuan 提交于 
      'copies' is actually uint8_t since day one, but request headers and some helper
functions parameterize it as uint32_t for unknown reasons and effectively
reserve 24 bytes for possible future use. This patch explicitly set the correct
for copies and reserve the left bytes.

This is a preparation patch that allow passing copy_policy in request header.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NLiu Yuan <namei.unix@gmail.com>
Acked-by: NMORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      29a67f7e
    • M
      qcow2: Flush image after creation · ba2ab2f2
      由 Max Reitz 提交于 
      Opening the qcow2 image with BDRV_O_NO_FLUSH prevents any flushes during
the image creation. This means that the image has not yet been flushed
to disk when qemu-img create exits. This flush is delayed until the next
operation on the image involving opening it without BDRV_O_NO_FLUSH and
closing (or directly flushing) it. For large images and/or images with a
small cluster size and preallocated metadata, this flush may take a
significant amount of time and may occur unexpectedly.

Reopening the image without BDRV_O_NO_FLUSH right before the end of
qcow2_create2() results in hoisting the potentially costly flush into
the image creation, which is expected to take some time (whereas
successive image operations may be not).
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NBenoit Canet <benoit@irqsave.net>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      ba2ab2f2
  11. 26 10月, 2013 1 次提交
  13. 24 10月, 2013 3 次提交
  15. 18 10月, 2013 2 次提交
  17. 17 10月, 2013 1 次提交
  19. 11 10月, 2013 2 次提交