On Mon, Oct 17, 2011 at 11:54 PM, Stefan Hajnoczi <stefa...@gmail.com> wrote: > On Mon, Oct 17, 2011 at 11:26 AM, Kevin Wolf <kw...@redhat.com> wrote: >> Am 26.09.2011 09:24, schrieb Zhi Yong Wu: >>> On Sat, Sep 24, 2011 at 12:19 AM, Kevin Wolf <kw...@redhat.com> wrote: >>>> Am 08.09.2011 12:11, schrieb Zhi Yong Wu: >>>>> Note: >>>>> 1.) When bps/iops limits are specified to a small value such as 511 >>>>> bytes/s, this VM will hang up. We are considering how to handle this >>>>> senario. >>>>> 2.) When "dd" command is issued in guest, if its option bs is set to >>>>> a large value such as "bs=1024K", the result speed will slightly bigger >>>>> than the limits. >>>>> >>>>> For these problems, if you have nice thought, pls let us know.:) >>>>> >>>>> Signed-off-by: Zhi Yong Wu <wu...@linux.vnet.ibm.com> >>>>> --- >>>>> block.c | 259 >>>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--- >>>>> block.h | 1 - >>>>> 2 files changed, 248 insertions(+), 12 deletions(-) >>>> >>>> One general comment: What about synchronous and/or coroutine I/O >>>> operations? Do you think they are just not important enough to consider >>>> here or were they forgotten? >>> For sync ops, we assume that it will be converse into async mode at >>> some point of future, right? >>> For coroutine I/O, it is introduced in image driver layer, and behind >>> bdrv_aio_readv/writev. I think that we need not consider them, right? >> >> Meanwhile the block layer has been changed to handle all requests in >> terms of coroutines. So you would best move your intercepting code into >> the coroutine functions. > > Some additional info: the advantage of handling all requests in > coroutines is that there is now a single place where you can put I/O > throttling. It will work for bdrv_read(), bdrv_co_readv(), and > bdrv_aio_readv(). There is no code duplication, just put the I/O > throttling logic in bdrv_co_do_readv(). got it. thanks. > > Stefan >
-- Regards, Zhi Yong Wu
