Messages in this thread | | | Date | Wed, 21 Mar 2012 19:04:08 +0900 | From | "Jun'ichi Nomura" <> | Subject | Re: [dm-devel] [PATCH] Fix I/O counts in vmstat |
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Hi Mikulas,
> The decision whether bio is counted or not is made by the code that > submits the bio. This leads to some problems:
How about convering dm targets to use generic_make_request?
Since submit_bio counts vm events, it seems natural for caller to decide which function to use. Device driver does not know whether the requested I/O is for vm-to-device or device-to-device. We could still use iostat to measure throughput of individual block devices.
Thanks, -- Jun'ichi Nomura, NEC Corporation
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