On 5/13/21 8:20 PM, Ming Lei wrote:
> In case of shared sbitmap, request won't be held in plug list any more
> sine commit 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per
> tagset"), this way makes request merge from flush plug list & batching
> submission not possible, so cause performance regression.
>
> Yanhui reports performance regression when running sequential IO
> test(libaio, 16 jobs, 8 depth for each job) in VM, and the VM disk
> is emulated with image stored on xfs/megaraid_sas.
>
> Fix the issue by recovering original behavior to allow to hold request
> in plug list.
Applied, thanks.
--
Jens Axboe
