Re: [PATCH v7 09/10] blk-mq: prevent offlining hk CPUs with associated online isolated CPUs

From: Hannes Reinecke
Date: Thu Jul 03 2025 - 02:59:09 EST


On 7/2/25 18:33, Daniel Wagner wrote:
When isolcpus=io_queue is enabled, and the last housekeeping CPU for a
given hctx goes offline, there would be no CPU left to handle I/O. To
prevent I/O stalls, prevent offlining housekeeping CPUs that are still
serving isolated CPUs.

When isolcpus=io_queue is enabled and the last housekeeping CPU
for a given hctx goes offline, no CPU would be left to handle I/O.
To prevent I/O stalls, disallow offlining housekeeping CPUs that are
still serving isolated CPUs.

Signed-off-by: Daniel Wagner <wagi@xxxxxxxxxx>
---
block/blk-mq.c | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
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