mirror of
https://github.com/torvalds/linux.git
synced 2024-12-05 10:32:35 +00:00
1abdfe706a
The current implementation of cpumask_local_spread() does not respect the isolated CPUs, i.e., even if a CPU has been isolated for Real-Time task, it will return it to the caller for pinning of its IRQ threads. Having these unwanted IRQ threads on an isolated CPU adds up to a latency overhead. Restrict the CPUs that are returned for spreading IRQs only to the available housekeeping CPUs. Signed-off-by: Alex Belits <abelits@marvell.com> Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200625223443.2684-2-nitesh@redhat.com
270 lines
6.8 KiB
C
270 lines
6.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/slab.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/bitops.h>
|
|
#include <linux/cpumask.h>
|
|
#include <linux/export.h>
|
|
#include <linux/memblock.h>
|
|
#include <linux/numa.h>
|
|
#include <linux/sched/isolation.h>
|
|
|
|
/**
|
|
* cpumask_next - get the next cpu in a cpumask
|
|
* @n: the cpu prior to the place to search (ie. return will be > @n)
|
|
* @srcp: the cpumask pointer
|
|
*
|
|
* Returns >= nr_cpu_ids if no further cpus set.
|
|
*/
|
|
unsigned int cpumask_next(int n, const struct cpumask *srcp)
|
|
{
|
|
/* -1 is a legal arg here. */
|
|
if (n != -1)
|
|
cpumask_check(n);
|
|
return find_next_bit(cpumask_bits(srcp), nr_cpumask_bits, n + 1);
|
|
}
|
|
EXPORT_SYMBOL(cpumask_next);
|
|
|
|
/**
|
|
* cpumask_next_and - get the next cpu in *src1p & *src2p
|
|
* @n: the cpu prior to the place to search (ie. return will be > @n)
|
|
* @src1p: the first cpumask pointer
|
|
* @src2p: the second cpumask pointer
|
|
*
|
|
* Returns >= nr_cpu_ids if no further cpus set in both.
|
|
*/
|
|
int cpumask_next_and(int n, const struct cpumask *src1p,
|
|
const struct cpumask *src2p)
|
|
{
|
|
/* -1 is a legal arg here. */
|
|
if (n != -1)
|
|
cpumask_check(n);
|
|
return find_next_and_bit(cpumask_bits(src1p), cpumask_bits(src2p),
|
|
nr_cpumask_bits, n + 1);
|
|
}
|
|
EXPORT_SYMBOL(cpumask_next_and);
|
|
|
|
/**
|
|
* cpumask_any_but - return a "random" in a cpumask, but not this one.
|
|
* @mask: the cpumask to search
|
|
* @cpu: the cpu to ignore.
|
|
*
|
|
* Often used to find any cpu but smp_processor_id() in a mask.
|
|
* Returns >= nr_cpu_ids if no cpus set.
|
|
*/
|
|
int cpumask_any_but(const struct cpumask *mask, unsigned int cpu)
|
|
{
|
|
unsigned int i;
|
|
|
|
cpumask_check(cpu);
|
|
for_each_cpu(i, mask)
|
|
if (i != cpu)
|
|
break;
|
|
return i;
|
|
}
|
|
EXPORT_SYMBOL(cpumask_any_but);
|
|
|
|
/**
|
|
* cpumask_next_wrap - helper to implement for_each_cpu_wrap
|
|
* @n: the cpu prior to the place to search
|
|
* @mask: the cpumask pointer
|
|
* @start: the start point of the iteration
|
|
* @wrap: assume @n crossing @start terminates the iteration
|
|
*
|
|
* Returns >= nr_cpu_ids on completion
|
|
*
|
|
* Note: the @wrap argument is required for the start condition when
|
|
* we cannot assume @start is set in @mask.
|
|
*/
|
|
int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap)
|
|
{
|
|
int next;
|
|
|
|
again:
|
|
next = cpumask_next(n, mask);
|
|
|
|
if (wrap && n < start && next >= start) {
|
|
return nr_cpumask_bits;
|
|
|
|
} else if (next >= nr_cpumask_bits) {
|
|
wrap = true;
|
|
n = -1;
|
|
goto again;
|
|
}
|
|
|
|
return next;
|
|
}
|
|
EXPORT_SYMBOL(cpumask_next_wrap);
|
|
|
|
/* These are not inline because of header tangles. */
|
|
#ifdef CONFIG_CPUMASK_OFFSTACK
|
|
/**
|
|
* alloc_cpumask_var_node - allocate a struct cpumask on a given node
|
|
* @mask: pointer to cpumask_var_t where the cpumask is returned
|
|
* @flags: GFP_ flags
|
|
*
|
|
* Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
|
|
* a nop returning a constant 1 (in <linux/cpumask.h>)
|
|
* Returns TRUE if memory allocation succeeded, FALSE otherwise.
|
|
*
|
|
* In addition, mask will be NULL if this fails. Note that gcc is
|
|
* usually smart enough to know that mask can never be NULL if
|
|
* CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case
|
|
* too.
|
|
*/
|
|
bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
|
|
{
|
|
*mask = kmalloc_node(cpumask_size(), flags, node);
|
|
|
|
#ifdef CONFIG_DEBUG_PER_CPU_MAPS
|
|
if (!*mask) {
|
|
printk(KERN_ERR "=> alloc_cpumask_var: failed!\n");
|
|
dump_stack();
|
|
}
|
|
#endif
|
|
|
|
return *mask != NULL;
|
|
}
|
|
EXPORT_SYMBOL(alloc_cpumask_var_node);
|
|
|
|
bool zalloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node)
|
|
{
|
|
return alloc_cpumask_var_node(mask, flags | __GFP_ZERO, node);
|
|
}
|
|
EXPORT_SYMBOL(zalloc_cpumask_var_node);
|
|
|
|
/**
|
|
* alloc_cpumask_var - allocate a struct cpumask
|
|
* @mask: pointer to cpumask_var_t where the cpumask is returned
|
|
* @flags: GFP_ flags
|
|
*
|
|
* Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
|
|
* a nop returning a constant 1 (in <linux/cpumask.h>).
|
|
*
|
|
* See alloc_cpumask_var_node.
|
|
*/
|
|
bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
|
|
{
|
|
return alloc_cpumask_var_node(mask, flags, NUMA_NO_NODE);
|
|
}
|
|
EXPORT_SYMBOL(alloc_cpumask_var);
|
|
|
|
bool zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
|
|
{
|
|
return alloc_cpumask_var(mask, flags | __GFP_ZERO);
|
|
}
|
|
EXPORT_SYMBOL(zalloc_cpumask_var);
|
|
|
|
/**
|
|
* alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena.
|
|
* @mask: pointer to cpumask_var_t where the cpumask is returned
|
|
*
|
|
* Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is
|
|
* a nop (in <linux/cpumask.h>).
|
|
* Either returns an allocated (zero-filled) cpumask, or causes the
|
|
* system to panic.
|
|
*/
|
|
void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask)
|
|
{
|
|
*mask = memblock_alloc(cpumask_size(), SMP_CACHE_BYTES);
|
|
if (!*mask)
|
|
panic("%s: Failed to allocate %u bytes\n", __func__,
|
|
cpumask_size());
|
|
}
|
|
|
|
/**
|
|
* free_cpumask_var - frees memory allocated for a struct cpumask.
|
|
* @mask: cpumask to free
|
|
*
|
|
* This is safe on a NULL mask.
|
|
*/
|
|
void free_cpumask_var(cpumask_var_t mask)
|
|
{
|
|
kfree(mask);
|
|
}
|
|
EXPORT_SYMBOL(free_cpumask_var);
|
|
|
|
/**
|
|
* free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var
|
|
* @mask: cpumask to free
|
|
*/
|
|
void __init free_bootmem_cpumask_var(cpumask_var_t mask)
|
|
{
|
|
memblock_free_early(__pa(mask), cpumask_size());
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* cpumask_local_spread - select the i'th cpu with local numa cpu's first
|
|
* @i: index number
|
|
* @node: local numa_node
|
|
*
|
|
* This function selects an online CPU according to a numa aware policy;
|
|
* local cpus are returned first, followed by non-local ones, then it
|
|
* wraps around.
|
|
*
|
|
* It's not very efficient, but useful for setup.
|
|
*/
|
|
unsigned int cpumask_local_spread(unsigned int i, int node)
|
|
{
|
|
int cpu, hk_flags;
|
|
const struct cpumask *mask;
|
|
|
|
hk_flags = HK_FLAG_DOMAIN | HK_FLAG_MANAGED_IRQ;
|
|
mask = housekeeping_cpumask(hk_flags);
|
|
/* Wrap: we always want a cpu. */
|
|
i %= cpumask_weight(mask);
|
|
|
|
if (node == NUMA_NO_NODE) {
|
|
for_each_cpu(cpu, mask) {
|
|
if (i-- == 0)
|
|
return cpu;
|
|
}
|
|
} else {
|
|
/* NUMA first. */
|
|
for_each_cpu_and(cpu, cpumask_of_node(node), mask) {
|
|
if (i-- == 0)
|
|
return cpu;
|
|
}
|
|
|
|
for_each_cpu(cpu, mask) {
|
|
/* Skip NUMA nodes, done above. */
|
|
if (cpumask_test_cpu(cpu, cpumask_of_node(node)))
|
|
continue;
|
|
|
|
if (i-- == 0)
|
|
return cpu;
|
|
}
|
|
}
|
|
BUG();
|
|
}
|
|
EXPORT_SYMBOL(cpumask_local_spread);
|
|
|
|
static DEFINE_PER_CPU(int, distribute_cpu_mask_prev);
|
|
|
|
/**
|
|
* Returns an arbitrary cpu within srcp1 & srcp2.
|
|
*
|
|
* Iterated calls using the same srcp1 and srcp2 will be distributed within
|
|
* their intersection.
|
|
*
|
|
* Returns >= nr_cpu_ids if the intersection is empty.
|
|
*/
|
|
int cpumask_any_and_distribute(const struct cpumask *src1p,
|
|
const struct cpumask *src2p)
|
|
{
|
|
int next, prev;
|
|
|
|
/* NOTE: our first selection will skip 0. */
|
|
prev = __this_cpu_read(distribute_cpu_mask_prev);
|
|
|
|
next = cpumask_next_and(prev, src1p, src2p);
|
|
if (next >= nr_cpu_ids)
|
|
next = cpumask_first_and(src1p, src2p);
|
|
|
|
if (next < nr_cpu_ids)
|
|
__this_cpu_write(distribute_cpu_mask_prev, next);
|
|
|
|
return next;
|
|
}
|
|
EXPORT_SYMBOL(cpumask_any_and_distribute);
|