include/linux/cpu_rmap.h

   1 /*
   2  * cpu_rmap.c: CPU affinity reverse-map support
   3  * Copyright 2011 Solarflare Communications Inc.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published
   7  * by the Free Software Foundation, incorporated herein by reference.
   8  */
   9
  10 #include <linux/cpumask.h>
  11 #include <linux/gfp.h>
  12 #include <linux/slab.h>
  13
  14 /**
  15  * struct cpu_rmap - CPU affinity reverse-map
  16  * @size: Number of objects to be reverse-mapped
  17  * @used: Number of objects added
  18  * @obj: Pointer to array of object pointers
  19  * @near: For each CPU, the index and distance to the nearest object,
  20  *      based on affinity masks
  21  */
  22 struct cpu_rmap {
  23         u16             size, used;
  24         void            **obj;
  25         struct {
  26                 u16     index;
  27                 u16     dist;
  28         }               near[0];
  29 };
  30 #define CPU_RMAP_DIST_INF 0xffff
  31
  32 extern struct cpu_rmap *alloc_cpu_rmap(unsigned int size, gfp_t flags);
  33
  34 /**
  35  * free_cpu_rmap - free CPU affinity reverse-map
  36  * @rmap: Reverse-map allocated with alloc_cpu_rmap(), or %NULL
  37  */
  38 static inline void free_cpu_rmap(struct cpu_rmap *rmap)
  39 {
  40         kfree(rmap);
  41 }
  42
  43 extern int cpu_rmap_add(struct cpu_rmap *rmap, void *obj);
  44 extern int cpu_rmap_update(struct cpu_rmap *rmap, u16 index,
  45                            const struct cpumask *affinity);
  46
  47 static inline u16 cpu_rmap_lookup_index(struct cpu_rmap *rmap, unsigned int cpu)
  48 {
  49         return rmap->near[cpu].index;
  50 }
  51
  52 static inline void *cpu_rmap_lookup_obj(struct cpu_rmap *rmap, unsigned int cpu)
  53 {
  54         return rmap->obj[rmap->near[cpu].index];
  55 }
  56
  57 #ifdef CONFIG_GENERIC_HARDIRQS
  58
  59 /**
  60  * alloc_irq_cpu_rmap - allocate CPU affinity reverse-map for IRQs
  61  * @size: Number of objects to be mapped
  62  *
  63  * Must be called in process context.
  64  */
  65 static inline struct cpu_rmap *alloc_irq_cpu_rmap(unsigned int size)
  66 {
  67         return alloc_cpu_rmap(size, GFP_KERNEL);
  68 }
  69 extern void free_irq_cpu_rmap(struct cpu_rmap *rmap);
  70
  71 extern int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq);
  72
  73 #endif