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Linux/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);
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         sprintf(name, "cma-%d", idx);
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);
207 

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