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100 lines
2.2 KiB
100 lines
2.2 KiB
/* Copyright (c) 2016 Facebook |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of version 2 of the GNU General Public |
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* License as published by the Free Software Foundation. |
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*/ |
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#include "percpu_freelist.h" |
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int pcpu_freelist_init(struct pcpu_freelist *s) |
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{ |
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int cpu; |
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s->freelist = alloc_percpu(struct pcpu_freelist_head); |
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if (!s->freelist) |
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return -ENOMEM; |
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for_each_possible_cpu(cpu) { |
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struct pcpu_freelist_head *head = per_cpu_ptr(s->freelist, cpu); |
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raw_spin_lock_init(&head->lock); |
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head->first = NULL; |
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} |
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return 0; |
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} |
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void pcpu_freelist_destroy(struct pcpu_freelist *s) |
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{ |
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free_percpu(s->freelist); |
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} |
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static inline void __pcpu_freelist_push(struct pcpu_freelist_head *head, |
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struct pcpu_freelist_node *node) |
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{ |
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raw_spin_lock(&head->lock); |
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node->next = head->first; |
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head->first = node; |
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raw_spin_unlock(&head->lock); |
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} |
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void pcpu_freelist_push(struct pcpu_freelist *s, |
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struct pcpu_freelist_node *node) |
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{ |
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struct pcpu_freelist_head *head = this_cpu_ptr(s->freelist); |
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__pcpu_freelist_push(head, node); |
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} |
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void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size, |
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u32 nr_elems) |
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{ |
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struct pcpu_freelist_head *head; |
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unsigned long flags; |
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int i, cpu, pcpu_entries; |
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pcpu_entries = nr_elems / num_possible_cpus() + 1; |
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i = 0; |
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/* disable irq to workaround lockdep false positive |
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* in bpf usage pcpu_freelist_populate() will never race |
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* with pcpu_freelist_push() |
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*/ |
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local_irq_save(flags); |
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for_each_possible_cpu(cpu) { |
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again: |
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head = per_cpu_ptr(s->freelist, cpu); |
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__pcpu_freelist_push(head, buf); |
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i++; |
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buf += elem_size; |
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if (i == nr_elems) |
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break; |
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if (i % pcpu_entries) |
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goto again; |
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} |
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local_irq_restore(flags); |
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} |
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struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s) |
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{ |
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struct pcpu_freelist_head *head; |
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struct pcpu_freelist_node *node; |
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int orig_cpu, cpu; |
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orig_cpu = cpu = raw_smp_processor_id(); |
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while (1) { |
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head = per_cpu_ptr(s->freelist, cpu); |
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raw_spin_lock(&head->lock); |
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node = head->first; |
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if (node) { |
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head->first = node->next; |
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raw_spin_unlock(&head->lock); |
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return node; |
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} |
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raw_spin_unlock(&head->lock); |
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cpu = cpumask_next(cpu, cpu_possible_mask); |
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if (cpu >= nr_cpu_ids) |
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cpu = 0; |
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if (cpu == orig_cpu) |
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return NULL; |
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} |
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}
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