6.6-stable review patch. If anyone has any objections, please let me know.
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From: Ming Lei ming.lei@redhat.com
commit 7b815817aa58d2e2101feb2fcf64c60cae0b2695 upstream.
Commit a46c27026da1 ("blk-mq: don't schedule block kworker on isolated CPUs") rules out isolated CPUs from hctx->cpumask, and hctx->cpumask should only be used for scheduling kworker.
Add helper blk_mq_cpu_mapped_to_hctx() and apply it into cpuhp handlers.
This patch avoids to forget clearing INACTIVE of hctx state in case that one isolated CPU becomes online, and fixes hang issue when allocating request from this hctx's tags.
Cc: Raju Cheerla rcheerla@redhat.com Fixes: a46c27026da1 ("blk-mq: don't schedule block kworker on isolated CPUs") Signed-off-by: Ming Lei ming.lei@redhat.com Link: https://lore.kernel.org/r/20240517020514.149771-1-ming.lei@redhat.com Tested-by: Raju Cheerla rcheerla@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- block/blk-mq.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)
--- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3617,12 +3617,28 @@ static int blk_mq_hctx_notify_offline(un return ret; }
+/* + * Check if one CPU is mapped to the specified hctx + * + * Isolated CPUs have been ruled out from hctx->cpumask, which is supposed + * to be used for scheduling kworker only. For other usage, please call this + * helper for checking if one CPU belongs to the specified hctx + */ +static bool blk_mq_cpu_mapped_to_hctx(unsigned int cpu, + const struct blk_mq_hw_ctx *hctx) +{ + struct blk_mq_hw_ctx *mapped_hctx = blk_mq_map_queue_type(hctx->queue, + hctx->type, cpu); + + return mapped_hctx == hctx; +} + static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node) { struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_online);
- if (cpumask_test_cpu(cpu, hctx->cpumask)) + if (blk_mq_cpu_mapped_to_hctx(cpu, hctx)) clear_bit(BLK_MQ_S_INACTIVE, &hctx->state); return 0; } @@ -3640,7 +3656,7 @@ static int blk_mq_hctx_notify_dead(unsig enum hctx_type type;
hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead); - if (!cpumask_test_cpu(cpu, hctx->cpumask)) + if (!blk_mq_cpu_mapped_to_hctx(cpu, hctx)) return 0;
ctx = __blk_mq_get_ctx(hctx->queue, cpu);