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->count);
  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
  56         mutex_lock(&cma->lock);
  57         for (;;) {
  58                 start = find_next_zero_bit(cma->bitmap, cma->count, end);
  59                 if (start >= cma->count)
  60                         break;
  61                 end = find_next_bit(cma->bitmap, cma->count, start);
  62                 maxchunk = max(end - start, maxchunk);
  63         }
  64         mutex_unlock(&cma->lock);
  65         *val = (u64)maxchunk << cma->order_per_bit;
  66
  67         return 0;
  68 }
  69 DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
  70
  71 static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
  72 {
  73         spin_lock(&cma->mem_head_lock);
  74         hlist_add_head(&mem->node, &cma->mem_head);
  75         spin_unlock(&cma->mem_head_lock);
  76 }
  77
  78 static struct cma_mem *cma_get_entry_from_list(struct cma *cma)
  79 {
  80         struct cma_mem *mem = NULL;
  81
  82         spin_lock(&cma->mem_head_lock);
  83         if (!hlist_empty(&cma->mem_head)) {
  84                 mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
  85                 hlist_del_init(&mem->node);
  86         }
  87         spin_unlock(&cma->mem_head_lock);
  88
  89         return mem;
  90 }
  91
  92 static int cma_free_mem(struct cma *cma, int count)
  93 {
  94         struct cma_mem *mem = NULL;
  95
  96         while (count) {
  97                 mem = cma_get_entry_from_list(cma);
  98                 if (mem == NULL)
  99                         return 0;
 100
 101                 if (mem->n <= count) {
 102                         cma_release(cma, mem->p, mem->n);
 103                         count -= mem->n;
 104                         kfree(mem);
 105                 } else if (cma->order_per_bit == 0) {
 106                         cma_release(cma, mem->p, count);
 107                         mem->p += count;
 108                         mem->n -= count;
 109                         count = 0;
 110                         cma_add_to_cma_mem_list(cma, mem);
 111                 } else {
 112                         pr_debug("cma: cannot release partial block when order_per_bit != 0\n");
 113                         cma_add_to_cma_mem_list(cma, mem);
 114                         break;
 115                 }
 116         }
 117
 118         return 0;
 119
 120 }
 121
 122 static int cma_free_write(void *data, u64 val)
 123 {
 124         int pages = val;
 125         struct cma *cma = data;
 126
 127         return cma_free_mem(cma, pages);
 128 }
 129 DEFINE_SIMPLE_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n");
 130
 131 static int cma_alloc_mem(struct cma *cma, int count)
 132 {
 133         struct cma_mem *mem;
 134         struct page *p;
 135
 136         mem = kzalloc(sizeof(*mem), GFP_KERNEL);
 137         if (!mem)
 138                 return -ENOMEM;
 139
 140         p = cma_alloc(cma, count, 0);
 141         if (!p) {
 142                 kfree(mem);
 143                 return -ENOMEM;
 144         }
 145
 146         mem->p = p;
 147         mem->n = count;
 148
 149         cma_add_to_cma_mem_list(cma, mem);
 150
 151         return 0;
 152 }
 153
 154 static int cma_alloc_write(void *data, u64 val)
 155 {
 156         int pages = val;
 157         struct cma *cma = data;
 158
 159         return cma_alloc_mem(cma, pages);
 160 }
 161 DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
 162
 163 static void cma_debugfs_add_one(struct cma *cma, int idx)
 164 {
 165         struct dentry *tmp;
 166         char name[16];
 167         int u32s;
 168
 169         sprintf(name, "cma-%d", idx);
 170
 171         tmp = debugfs_create_dir(name, cma_debugfs_root);
 172
 173         debugfs_create_file("alloc", S_IWUSR, cma_debugfs_root, cma,
 174                                 &cma_alloc_fops);
 175
 176         debugfs_create_file("free", S_IWUSR, cma_debugfs_root, cma,
 177                                 &cma_free_fops);
 178
 179         debugfs_create_file("base_pfn", S_IRUGO, tmp,
 180                                 &cma->base_pfn, &cma_debugfs_fops);
 181         debugfs_create_file("count", S_IRUGO, tmp,
 182                                 &cma->count, &cma_debugfs_fops);
 183         debugfs_create_file("order_per_bit", S_IRUGO, tmp,
 184                                 &cma->order_per_bit, &cma_debugfs_fops);
 185         debugfs_create_file("used", S_IRUGO, tmp, cma, &cma_used_fops);
 186         debugfs_create_file("maxchunk", S_IRUGO, tmp, cma, &cma_maxchunk_fops);
 187
 188         u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
 189         debugfs_create_u32_array("bitmap", S_IRUGO, tmp, (u32*)cma->bitmap, u32s);
 190 }
 191
 192 static int __init cma_debugfs_init(void)
 193 {
 194         int i;
 195
 196         cma_debugfs_root = debugfs_create_dir("cma", NULL);
 197         if (!cma_debugfs_root)
 198                 return -ENOMEM;
 199
 200         for (i = 0; i < cma_area_count; i++)
 201                 cma_debugfs_add_one(&cma_areas[i], i);
 202
 203         return 0;
 204 }
 205 late_initcall(cma_debugfs_init);