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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2021-01-23 23:10:27 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-02-12 18:28:02 +0300 |
| commit | f9ab49184af093f0bf6c0e6583f5b25da2c09ff5 (patch) | |
| tree | bdbbb203e2420e9203768702df4d68e7f0ca894b /include/linux/blkdev.h | |
| parent | 0a2efafbb1c752a7041652445bc1232114409633 (diff) | |
| download | linux-f9ab49184af093f0bf6c0e6583f5b25da2c09ff5.tar.xz | |
blk-mq: Use llist_head for blk_cpu_done
With llist_head it is possible to avoid the locking (the irq-off region)
when items are added. This makes it possible to add items on a remote
CPU without additional locking.
llist_add() returns true if the list was previously empty. This can be
used to invoke the SMP function call / raise sofirq only if the first
item was added (otherwise it is already pending).
This simplifies the code a little and reduces the IRQ-off regions.
blk_mq_raise_softirq() needs a preempt-disable section to ensure the
request is enqueued on the same CPU as the softirq is raised.
Some callers (USB-storage) invoke this path in preemptible context.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/blkdev.h')
| -rw-r--r-- | include/linux/blkdev.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index f94ee3089e01..89a444c5a583 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -153,7 +153,7 @@ struct request { */ union { struct hlist_node hash; /* merge hash */ - struct list_head ipi_list; + struct llist_node ipi_list; }; /* |