Revision 73e08e711d9c1d79fae01daed4b0e1fee5f8a275 authored by Jens Axboe on 26 January 2020, 16:53:12 UTC, committed by Jens Axboe on 26 January 2020, 16:56:05 UTC
This ends up being too restrictive for tasks that willingly fork and share the ring between forks. Andres reports that this breaks his postgresql work. Since we're close to 5.5 release, revert this change for now. Cc: stable@vger.kernel.org Fixes: 44d282796f81 ("io_uring: only allow submit from owning task") Reported-by: Andres Freund <andres@anarazel.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 parent 1292e97
blk-mq-cpumap.c
// SPDX-License-Identifier: GPL-2.0
/*
* CPU <-> hardware queue mapping helpers
*
* Copyright (C) 2013-2014 Jens Axboe
*/
#include <linux/kernel.h>
#include <linux/threads.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/blk-mq.h>
#include "blk.h"
#include "blk-mq.h"
static int queue_index(struct blk_mq_queue_map *qmap,
unsigned int nr_queues, const int q)
{
return qmap->queue_offset + (q % nr_queues);
}
static int get_first_sibling(unsigned int cpu)
{
unsigned int ret;
ret = cpumask_first(topology_sibling_cpumask(cpu));
if (ret < nr_cpu_ids)
return ret;
return cpu;
}
int blk_mq_map_queues(struct blk_mq_queue_map *qmap)
{
unsigned int *map = qmap->mq_map;
unsigned int nr_queues = qmap->nr_queues;
unsigned int cpu, first_sibling, q = 0;
for_each_possible_cpu(cpu)
map[cpu] = -1;
/*
* Spread queues among present CPUs first for minimizing
* count of dead queues which are mapped by all un-present CPUs
*/
for_each_present_cpu(cpu) {
if (q >= nr_queues)
break;
map[cpu] = queue_index(qmap, nr_queues, q++);
}
for_each_possible_cpu(cpu) {
if (map[cpu] != -1)
continue;
/*
* First do sequential mapping between CPUs and queues.
* In case we still have CPUs to map, and we have some number of
* threads per cores then map sibling threads to the same queue
* for performance optimizations.
*/
if (q < nr_queues) {
map[cpu] = queue_index(qmap, nr_queues, q++);
} else {
first_sibling = get_first_sibling(cpu);
if (first_sibling == cpu)
map[cpu] = queue_index(qmap, nr_queues, q++);
else
map[cpu] = map[first_sibling];
}
}
return 0;
}
EXPORT_SYMBOL_GPL(blk_mq_map_queues);
/**
* blk_mq_hw_queue_to_node - Look up the memory node for a hardware queue index
* @qmap: CPU to hardware queue map.
* @index: hardware queue index.
*
* We have no quick way of doing reverse lookups. This is only used at
* queue init time, so runtime isn't important.
*/
int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index)
{
int i;
for_each_possible_cpu(i) {
if (index == qmap->mq_map[i])
return local_memory_node(cpu_to_node(i));
}
return NUMA_NO_NODE;
}
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