On Thu, Mar 14, 2024 at 11:20 AM junxiao.bi@oracle.com wrote:
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This patch eliminated the benefit of blk_plug, i think it will not be good for IO performance perspective?
There is only one daemon thread, so IO should not be handled here as much as possible. The IO should be handled by the thread that is submitting the IO, and let daemon to hanldle the case that IO failed or can't be submitted at that time.
raid5 can have multiple threads calling handle_stripe(). See raid5_do_work(). Only chunk_aligned_read() can be handled in raid5_make_request.
I am not sure how much it will impact regarding drop the blk_plug.
Song, what's your take on this?
I think we need to evaluate the impact of (removing) blk_plug. We had some performance regressions related to blk_plug a couple years ago.
Thanks, Song