[PATCH v11 13/13] block: apply COR-filter to block-stream jobs
vsementsov at virtuozzo.com
Fri Oct 16 15:45:22 UTC 2020
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.
So, I think, it's better to keep is_allocated() logic as is for now.
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