Re: [PATCH 2/8] blk-mq: don't keep offline CPUs mapped to hctx 0

On Sun, Apr 08, 2018 at 05:48:08PM +0800, Ming Lei wrote:

...

From commit 4b855ad37194 ("blk-mq: Create hctx for each present CPU),

blk-mq doesn't remap queue after CPU topo is changed, that said when some of these offline CPUs become online, they are still mapped to hctx 0, then hctx 0 may become the bottleneck of IO dispatch and completion.

This patch sets up the mapping from the beginning, and aligns to queue mapping for PCI device (blk_mq_pci_map_queues()).

Please kill the now pointless cpu_to_queue_index function.

Otherwise looks good:

Reviewed-by: Christoph Hellwig hch@lst.de