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190 lines
5.0 KiB
190 lines
5.0 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/slab.h> |
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#include <linux/kernel.h> |
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#include <linux/bitops.h> |
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#include <linux/cpumask.h> |
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#include <linux/export.h> |
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#include <linux/memblock.h> |
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#include <linux/numa.h> |
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/** |
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* cpumask_next_wrap - helper to implement for_each_cpu_wrap |
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* @n: the cpu prior to the place to search |
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* @mask: the cpumask pointer |
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* @start: the start point of the iteration |
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* @wrap: assume @n crossing @start terminates the iteration |
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* |
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* Returns >= nr_cpu_ids on completion |
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* |
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* Note: the @wrap argument is required for the start condition when |
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* we cannot assume @start is set in @mask. |
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*/ |
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unsigned int cpumask_next_wrap(int n, const struct cpumask *mask, int start, bool wrap) |
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{ |
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unsigned int next; |
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again: |
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next = cpumask_next(n, mask); |
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if (wrap && n < start && next >= start) { |
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return nr_cpumask_bits; |
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} else if (next >= nr_cpumask_bits) { |
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wrap = true; |
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n = -1; |
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goto again; |
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} |
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return next; |
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} |
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EXPORT_SYMBOL(cpumask_next_wrap); |
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/* These are not inline because of header tangles. */ |
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#ifdef CONFIG_CPUMASK_OFFSTACK |
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/** |
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* alloc_cpumask_var_node - allocate a struct cpumask on a given node |
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* @mask: pointer to cpumask_var_t where the cpumask is returned |
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* @flags: GFP_ flags |
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* |
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* Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is |
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* a nop returning a constant 1 (in <linux/cpumask.h>) |
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* Returns TRUE if memory allocation succeeded, FALSE otherwise. |
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* |
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* In addition, mask will be NULL if this fails. Note that gcc is |
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* usually smart enough to know that mask can never be NULL if |
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* CONFIG_CPUMASK_OFFSTACK=n, so does code elimination in that case |
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* too. |
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*/ |
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bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node) |
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{ |
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*mask = kmalloc_node(cpumask_size(), flags, node); |
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#ifdef CONFIG_DEBUG_PER_CPU_MAPS |
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if (!*mask) { |
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printk(KERN_ERR "=> alloc_cpumask_var: failed!\n"); |
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dump_stack(); |
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} |
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#endif |
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return *mask != NULL; |
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} |
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EXPORT_SYMBOL(alloc_cpumask_var_node); |
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/** |
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* alloc_bootmem_cpumask_var - allocate a struct cpumask from the bootmem arena. |
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* @mask: pointer to cpumask_var_t where the cpumask is returned |
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* |
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* Only defined when CONFIG_CPUMASK_OFFSTACK=y, otherwise is |
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* a nop (in <linux/cpumask.h>). |
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* Either returns an allocated (zero-filled) cpumask, or causes the |
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* system to panic. |
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*/ |
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void __init alloc_bootmem_cpumask_var(cpumask_var_t *mask) |
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{ |
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*mask = memblock_alloc(cpumask_size(), SMP_CACHE_BYTES); |
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if (!*mask) |
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panic("%s: Failed to allocate %u bytes\n", __func__, |
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cpumask_size()); |
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} |
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/** |
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* free_cpumask_var - frees memory allocated for a struct cpumask. |
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* @mask: cpumask to free |
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* |
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* This is safe on a NULL mask. |
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*/ |
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void free_cpumask_var(cpumask_var_t mask) |
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{ |
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kfree(mask); |
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} |
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EXPORT_SYMBOL(free_cpumask_var); |
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/** |
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* free_bootmem_cpumask_var - frees result of alloc_bootmem_cpumask_var |
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* @mask: cpumask to free |
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*/ |
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void __init free_bootmem_cpumask_var(cpumask_var_t mask) |
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{ |
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memblock_free(mask, cpumask_size()); |
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} |
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#endif |
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/** |
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* cpumask_local_spread - select the i'th cpu with local numa cpu's first |
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* @i: index number |
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* @node: local numa_node |
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* |
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* This function selects an online CPU according to a numa aware policy; |
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* local cpus are returned first, followed by non-local ones, then it |
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* wraps around. |
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* |
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* It's not very efficient, but useful for setup. |
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*/ |
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unsigned int cpumask_local_spread(unsigned int i, int node) |
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{ |
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unsigned int cpu; |
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/* Wrap: we always want a cpu. */ |
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i %= num_online_cpus(); |
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if (node == NUMA_NO_NODE) { |
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cpu = cpumask_nth(i, cpu_online_mask); |
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if (cpu < nr_cpu_ids) |
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return cpu; |
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} else { |
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/* NUMA first. */ |
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cpu = cpumask_nth_and(i, cpu_online_mask, cpumask_of_node(node)); |
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if (cpu < nr_cpu_ids) |
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return cpu; |
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i -= cpumask_weight_and(cpu_online_mask, cpumask_of_node(node)); |
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/* Skip NUMA nodes, done above. */ |
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cpu = cpumask_nth_andnot(i, cpu_online_mask, cpumask_of_node(node)); |
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if (cpu < nr_cpu_ids) |
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return cpu; |
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} |
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BUG(); |
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} |
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EXPORT_SYMBOL(cpumask_local_spread); |
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static DEFINE_PER_CPU(int, distribute_cpu_mask_prev); |
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/** |
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* Returns an arbitrary cpu within srcp1 & srcp2. |
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* |
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* Iterated calls using the same srcp1 and srcp2 will be distributed within |
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* their intersection. |
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* |
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* Returns >= nr_cpu_ids if the intersection is empty. |
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*/ |
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unsigned int cpumask_any_and_distribute(const struct cpumask *src1p, |
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const struct cpumask *src2p) |
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{ |
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unsigned int next, prev; |
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/* NOTE: our first selection will skip 0. */ |
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prev = __this_cpu_read(distribute_cpu_mask_prev); |
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next = find_next_and_bit_wrap(cpumask_bits(src1p), cpumask_bits(src2p), |
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nr_cpumask_bits, prev + 1); |
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if (next < nr_cpu_ids) |
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__this_cpu_write(distribute_cpu_mask_prev, next); |
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return next; |
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} |
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EXPORT_SYMBOL(cpumask_any_and_distribute); |
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unsigned int cpumask_any_distribute(const struct cpumask *srcp) |
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{ |
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unsigned int next, prev; |
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/* NOTE: our first selection will skip 0. */ |
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prev = __this_cpu_read(distribute_cpu_mask_prev); |
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next = find_next_bit_wrap(cpumask_bits(srcp), nr_cpumask_bits, prev + 1); |
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if (next < nr_cpu_ids) |
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__this_cpu_write(distribute_cpu_mask_prev, next); |
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return next; |
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} |
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EXPORT_SYMBOL(cpumask_any_distribute);
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