4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Ming Lei <[email protected]> commit bffa9909a6b48d8ca3398dec601bc9162a4020c4 upstream. >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()). Cc: Stefan Haberland <[email protected]> Cc: Keith Busch <[email protected]> Cc: [email protected] Fixes: 4b855ad37194 ("blk-mq: Create hctx for each present CPU) Tested-by: Christian Borntraeger <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Reviewed-by: Sagi Grimberg <[email protected]> Signed-off-by: Ming Lei <[email protected]> Signed-off-by: Jens Axboe <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- block/blk-mq-cpumap.c | 5 ----- 1 file changed, 5 deletions(-) --- a/block/blk-mq-cpumap.c +++ b/block/blk-mq-cpumap.c @@ -16,11 +16,6 @@ static int cpu_to_queue_index(unsigned int nr_queues, const int cpu) { - /* - * Non present CPU will be mapped to queue index 0. - */ - if (!cpu_present(cpu)) - return 0; return cpu % nr_queues; }
