Revision b22fa62a35d7f2029d757a518d78041822b7c7c1 authored by Pavel Begunkov on 21 October 2021, 12:20:29 UTC, committed by Jens Axboe on 21 October 2021, 17:19:38 UTC
Another change to the API io-wq worker limitation API added in 5.15, apply the limit to all prior users that already registered a tctx. It may be confusing as it's now, in particular the change covers the following 2 cases: TASK1 | TASK2 _________________________________________________ ring = create() | | limit_iowq_workers() *not limited* | TASK1 | TASK2 _________________________________________________ ring = create() | | issue_requests() limit_iowq_workers() | | *not limited* A note on locking, it's safe to traverse ->tctx_list as we hold ->uring_lock, but do that after dropping sqd->lock to avoid possible problems. It's also safe to access tctx->io_wq there because tasks kill it only after removing themselves from tctx_list, see io_uring_cancel_generic() -> io_uring_clean_tctx() Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d6e09ecc3545e4dc56e43c906ee3d71b7ae21bed.1634818641.git.asml.silence@gmail.com Reviewed-by: Hao Xu <haoxu@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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blk-mq-rdma.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2017 Sagi Grimberg.
*/
#include <linux/blk-mq.h>
#include <linux/blk-mq-rdma.h>
#include <rdma/ib_verbs.h>
/**
* blk_mq_rdma_map_queues - provide a default queue mapping for rdma device
* @map: CPU to hardware queue map.
* @dev: rdma device to provide a mapping for.
* @first_vec: first interrupt vectors to use for queues (usually 0)
*
* This function assumes the rdma device @dev has at least as many available
* interrupt vetors as @set has queues. It will then query it's affinity mask
* and built queue mapping that maps a queue to the CPUs that have irq affinity
* for the corresponding vector.
*
* In case either the driver passed a @dev with less vectors than
* @set->nr_hw_queues, or @dev does not provide an affinity mask for a
* vector, we fallback to the naive mapping.
*/
int blk_mq_rdma_map_queues(struct blk_mq_queue_map *map,
struct ib_device *dev, int first_vec)
{
const struct cpumask *mask;
unsigned int queue, cpu;
for (queue = 0; queue < map->nr_queues; queue++) {
mask = ib_get_vector_affinity(dev, first_vec + queue);
if (!mask)
goto fallback;
for_each_cpu(cpu, mask)
map->mq_map[cpu] = map->queue_offset + queue;
}
return 0;
fallback:
return blk_mq_map_queues(map);
}
EXPORT_SYMBOL_GPL(blk_mq_rdma_map_queues);
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