mm/cma_debug.c

   1 /*
   2  * CMA DebugFS Interface
   3  *
   4  * Copyright (c) 2015 Sasha Levin <sasha.levin@oracle.com>
   5  */
   6
   7
   8 #include <linux/debugfs.h>
   9 #include <linux/cma.h>
  10 #include <linux/list.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/mm_types.h>
  14
  15 #include "cma.h"
  16
  17 struct cma_mem {
  18         struct hlist_node node;
  19         struct page *p;
  20         unsigned long n;
  21 };
  22
  23 static struct dentry *cma_debugfs_root;
  24
  25 static int cma_debugfs_get(void *data, u64 *val)
  26 {
  27         unsigned long *p = data;
  28
  29         *val = *p;
  30
  31         return 0;
  32 }
  33 DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
  34
  35 static int cma_used_get(void *data, u64 *val)
  36 {
  37         struct cma *cma = data;
  38         unsigned long used;
  39
  40         mutex_lock(&cma->lock);
  41         /* pages counter is smaller than sizeof(int) */
  42         used = bitmap_weight(cma->bitmap, (int)cma_bitmap_maxno(cma));
  43         mutex_unlock(&cma->lock);
  44         *val = (u64)used << cma->order_per_bit;
  45
  46         return 0;
  47 }
  48 DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
  49
  50 static int cma_maxchunk_get(void *data, u64 *val)
  51 {
  52         struct cma *cma = data;
  53         unsigned long maxchunk = 0;
  54         unsigned long start, end = 0;
  55         unsigned long bitmap_maxno = cma_bitmap_maxno(cma);
  56
  57         mutex_lock(&cma->lock);
  58         for (;;) {
  59                 start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end);
  60                 if (start >= cma->count)
  61                         break;
  62                 end = find_next_bit(cma->bitmap, bitmap_maxno, start);
  63                 maxchunk = max(end - start, maxchunk);
  64         }
  65         mutex_unlock(&cma->lock);
  66         *val = (u64)maxchunk << cma->order_per_bit;
  67
  68         return 0;
  69 }
  70 DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
  71
  72 static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
  73 {
  74         spin_lock(&cma->mem_head_lock);
  75         hlist_add_head(&mem->node, &cma->mem_head);
  76         spin_unlock(&cma->mem_head_lock);
  77 }
  78
  79 static struct cma_mem *cma_get_entry_from_list(struct cma *cma)
  80 {
  81         struct cma_mem *mem = NULL;
  82
  83         spin_lock(&cma->mem_head_lock);
  84         if (!hlist_empty(&cma->mem_head)) {
  85                 mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
  86                 hlist_del_init(&mem->node);
  87         }
  88         spin_unlock(&cma->mem_head_lock);
  89
  90         return mem;
  91 }
  92
  93 static int cma_free_mem(struct cma *cma, int count)
  94 {
  95         struct cma_mem *mem = NULL;
  96
  97         while (count) {
  98                 mem = cma_get_entry_from_list(cma);
  99                 if (mem == NULL)
 100                         return 0;
 101
 102                 if (mem->n <= count) {
 103                         cma_release(cma, mem->p, mem->n);
 104                         count -= mem->n;
 105                         kfree(mem);
 106                 } else if (cma->order_per_bit == 0) {
 107                         cma_release(cma, mem->p, count);
 108                         mem->p += count;
 109                         mem->n -= count;
 110                         count = 0;
 111                         cma_add_to_cma_mem_list(cma, mem);
 112                 } else {
 113                         pr_debug("cma: cannot release partial block when order_per_bit != 0\n");
 114                         cma_add_to_cma_mem_list(cma, mem);
 115                         break;
 116                 }
 117         }
 118
 119         return 0;
 120
 121 }
 122
 123 static int cma_free_write(void *data, u64 val)
 124 {
 125         int pages = val;
 126         struct cma *cma = data;
 127
 128         return cma_free_mem(cma, pages);
 129 }
 130 DEFINE_SIMPLE_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n");
 131
 132 static int cma_alloc_mem(struct cma *cma, int count)
 133 {
 134         struct cma_mem *mem;
 135         struct page *p;
 136
 137         mem = kzalloc(sizeof(*mem), GFP_KERNEL);
 138         if (!mem)
 139                 return -ENOMEM;
 140
 141         p = cma_alloc(cma, count, 0, GFP_KERNEL);
 142         if (!p) {
 143                 kfree(mem);
 144                 return -ENOMEM;
 145         }
 146
 147         mem->p = p;
 148         mem->n = count;
 149
 150         cma_add_to_cma_mem_list(cma, mem);
 151
 152         return 0;
 153 }
 154
 155 static int cma_alloc_write(void *data, u64 val)
 156 {
 157         int pages = val;
 158         struct cma *cma = data;
 159
 160         return cma_alloc_mem(cma, pages);
 161 }
 162 DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
 163
 164 static void cma_debugfs_add_one(struct cma *cma, int idx)
 165 {
 166         struct dentry *tmp;
 167         char name[16];
 168         int u32s;
 169
 170         scnprintf(name, sizeof(name), "cma-%s", cma->name);
 171
 172         tmp = debugfs_create_dir(name, cma_debugfs_root);
 173
 174         debugfs_create_file("alloc", S_IWUSR, tmp, cma,
 175                                 &cma_alloc_fops);
 176
 177         debugfs_create_file("free", S_IWUSR, tmp, cma,
 178                                 &cma_free_fops);
 179
 180         debugfs_create_file("base_pfn", S_IRUGO, tmp,
 181                                 &cma->base_pfn, &cma_debugfs_fops);
 182         debugfs_create_file("count", S_IRUGO, tmp,
 183                                 &cma->count, &cma_debugfs_fops);
 184         debugfs_create_file("order_per_bit", S_IRUGO, tmp,
 185                                 &cma->order_per_bit, &cma_debugfs_fops);
 186         debugfs_create_file("used", S_IRUGO, tmp, cma, &cma_used_fops);
 187         debugfs_create_file("maxchunk", S_IRUGO, tmp, cma, &cma_maxchunk_fops);
 188
 189         u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
 190         debugfs_create_u32_array("bitmap", S_IRUGO, tmp, (u32*)cma->bitmap, u32s);
 191 }
 192
 193 static int __init cma_debugfs_init(void)
 194 {
 195         int i;
 196
 197         cma_debugfs_root = debugfs_create_dir("cma", NULL);
 198         if (!cma_debugfs_root)
 199                 return -ENOMEM;
 200
 201         for (i = 0; i < cma_area_count; i++)
 202                 cma_debugfs_add_one(&cma_areas[i], i);
 203
 204         return 0;
 205 }
 206 late_initcall(cma_debugfs_init);