From 53c2f9d1b1151a853542b224d78169f68f919ef1 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 15 May 2025 16:50:04 +0200 Subject: block: Protect against concurrent isolated cpuset change The block subsystem prevents running the workqueue to isolated CPUs, including those defined by cpuset isolated partitions. Since HK_TYPE_DOMAIN will soon contain both and be subject to runtime modifications, synchronize against housekeeping using the relevant lock. For full support of cpuset changes, the block subsystem may need to propagate changes to isolated cpumask through the workqueue in the future. Signed-off-by: Frederic Weisbecker Acked-by: Jens Axboe Cc: Jens Axboe Cc: Marco Crivellari Cc: Michal Hocko Cc: Peter Zijlstra Cc: Tejun Heo Cc: Thomas Gleixner Cc: Vlastimil Babka Cc: Waiman Long Cc: linux-block@vger.kernel.org --- block/blk-mq.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'block') diff --git a/block/blk-mq.c b/block/blk-mq.c index 1978eef95dca..0037af1216f3 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -4257,12 +4257,16 @@ static void blk_mq_map_swqueue(struct request_queue *q) /* * Rule out isolated CPUs from hctx->cpumask to avoid - * running block kworker on isolated CPUs + * running block kworker on isolated CPUs. + * FIXME: cpuset should propagate further changes to isolated CPUs + * here. */ + rcu_read_lock(); for_each_cpu(cpu, hctx->cpumask) { if (cpu_is_isolated(cpu)) cpumask_clear_cpu(cpu, hctx->cpumask); } + rcu_read_unlock(); /* * Initialize batch roundrobin counts -- cgit v1.2.3