[PATCH v11 13/13] block: apply COR-filter to block-stream jobs
andrey.shinkevich at virtuozzo.com
Tue Oct 20 19:43:07 UTC 2020
On 16.10.2020 18:45, Vladimir Sementsov-Ogievskiy wrote:
> 15.10.2020 20:16, Andrey Shinkevich wrote:
>> On 14.10.2020 19:24, Max Reitz wrote:
>>> On 12.10.20 19:43, Andrey Shinkevich wrote:
>>>> block/stream.c | 93
>>>> tests/qemu-iotests/030 | 51 +++----------------------
>>>> tests/qemu-iotests/030.out | 4 +-
>>>> tests/qemu-iotests/141.out | 2 +-
>>>> tests/qemu-iotests/245 | 19 +++++++---
>>>> 5 files changed, 81 insertions(+), 88 deletions(-)
>>> Looks like stream_run() could be a bit streamlined now (the allocation
>>> checking should be unnecessary, unconditionally calling
>>> stream_populate() should be sufficient), but not necessary now.
>> That is what I had kept in my mind when I tackled this patch. But
>> there is an underwater reef to streamline. Namely, how the
>> block-stream job gets known about a long unallocated tail to exit the
>> loop earlier in the stream_run(). Shall we return the '-EOF' or
>> another error code from the cor_co_preadv_part() to be handled by the
>> stream_run()? Any other suggestions, if any, will be appreciated.
> Just calling read CHUNK by CHUNK may be less efficient than
> is_allocated()-driven loop: you may end up with splitting regions
> unaligned to CHUNK-granularity, which would not be splitted with
> is_allocated()-driven loop. Current loop allows chunks unaligned to CHUNK.
The cor_co_preadv_part() will check for the end of a file in the next
version. So, the unalignment is not going to be the issue.
> So, I think, it's better to keep is_allocated() logic as is for now.
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