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| author | Sebastian Andrzej Siewior <[email protected]> | 2021-01-23 20:10:27 +0000 |
|---|---|---|
| committer | Jens Axboe <[email protected]> | 2021-02-12 15:28:02 +0000 |
| commit | f9ab49184af093f0bf6c0e6583f5b25da2c09ff5 (patch) | |
| tree | bdbbb203e2420e9203768702df4d68e7f0ca894b /drivers/gpu/drm/lima/lima_devfreq.c | |
| parent | blk-mq: Always complete remote completions requests in softirq (diff) | |
| download | kernel-f9ab49184af093f0bf6c0e6583f5b25da2c09ff5.tar.gz kernel-f9ab49184af093f0bf6c0e6583f5b25da2c09ff5.zip | |
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 <[email protected]>
Reviewed-by: Daniel Wagner <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Diffstat (limited to 'drivers/gpu/drm/lima/lima_devfreq.c')
0 files changed, 0 insertions, 0 deletions