1 #include <linux/debugfs.h> 2 #include <linux/mm.h> 3 #include <linux/slab.h> 4 #include <linux/uaccess.h> 5 #include <linux/bootmem.h> 6 #include <linux/stacktrace.h> 7 #include <linux/page_owner.h> 8 #include "internal.h" 9 10 static bool page_owner_disabled = true; 11 bool page_owner_inited __read_mostly; 12 13 static void init_early_allocated_pages(void); 14 15 static int early_page_owner_param(char *buf) 16 { 17 if (!buf) 18 return -EINVAL; 19 20 if (strcmp(buf, "on") == 0) 21 page_owner_disabled = false; 22 23 return 0; 24 } 25 early_param("page_owner", early_page_owner_param); 26 27 static bool need_page_owner(void) 28 { 29 if (page_owner_disabled) 30 return false; 31 32 return true; 33 } 34 35 static void init_page_owner(void) 36 { 37 if (page_owner_disabled) 38 return; 39 40 page_owner_inited = true; 41 init_early_allocated_pages(); 42 } 43 44 struct page_ext_operations page_owner_ops = { 45 .need = need_page_owner, 46 .init = init_page_owner, 47 }; 48 49 void __reset_page_owner(struct page *page, unsigned int order) 50 { 51 int i; 52 struct page_ext *page_ext; 53 54 for (i = 0; i < (1 << order); i++) { 55 page_ext = lookup_page_ext(page + i); 56 __clear_bit(PAGE_EXT_OWNER, &page_ext->flags); 57 } 58 } 59 60 void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask) 61 { 62 struct page_ext *page_ext; 63 struct stack_trace *trace; 64 65 page_ext = lookup_page_ext(page); 66 67 trace = &page_ext->trace; 68 trace->nr_entries = 0; 69 trace->max_entries = ARRAY_SIZE(page_ext->trace_entries); 70 trace->entries = &page_ext->trace_entries[0]; 71 trace->skip = 3; 72 save_stack_trace(&page_ext->trace); 73 74 page_ext->order = order; 75 page_ext->gfp_mask = gfp_mask; 76 77 __set_bit(PAGE_EXT_OWNER, &page_ext->flags); 78 } 79 80 static ssize_t 81 print_page_owner(char __user *buf, size_t count, unsigned long pfn, 82 struct page *page, struct page_ext *page_ext) 83 { 84 int ret; 85 int pageblock_mt, page_mt; 86 char *kbuf; 87 88 kbuf = kmalloc(count, GFP_KERNEL); 89 if (!kbuf) 90 return -ENOMEM; 91 92 ret = snprintf(kbuf, count, 93 "Page allocated via order %u, mask 0x%x\n", 94 page_ext->order, page_ext->gfp_mask); 95 96 if (ret >= count) 97 goto err; 98 99 /* Print information relevant to grouping pages by mobility */ 100 pageblock_mt = get_pfnblock_migratetype(page, pfn); 101 page_mt = gfpflags_to_migratetype(page_ext->gfp_mask); 102 ret += snprintf(kbuf + ret, count - ret, 103 "PFN %lu Block %lu type %d %s Flags %s%s%s%s%s%s%s%s%s%s%s%s\n", 104 pfn, 105 pfn >> pageblock_order, 106 pageblock_mt, 107 pageblock_mt != page_mt ? "Fallback" : " ", 108 PageLocked(page) ? "K" : " ", 109 PageError(page) ? "E" : " ", 110 PageReferenced(page) ? "R" : " ", 111 PageUptodate(page) ? "U" : " ", 112 PageDirty(page) ? "D" : " ", 113 PageLRU(page) ? "L" : " ", 114 PageActive(page) ? "A" : " ", 115 PageSlab(page) ? "S" : " ", 116 PageWriteback(page) ? "W" : " ", 117 PageCompound(page) ? "C" : " ", 118 PageSwapCache(page) ? "B" : " ", 119 PageMappedToDisk(page) ? "M" : " "); 120 121 if (ret >= count) 122 goto err; 123 124 ret += snprint_stack_trace(kbuf + ret, count - ret, 125 &page_ext->trace, 0); 126 if (ret >= count) 127 goto err; 128 129 ret += snprintf(kbuf + ret, count - ret, "\n"); 130 if (ret >= count) 131 goto err; 132 133 if (copy_to_user(buf, kbuf, ret)) 134 ret = -EFAULT; 135 136 kfree(kbuf); 137 return ret; 138 139 err: 140 kfree(kbuf); 141 return -ENOMEM; 142 } 143 144 static ssize_t 145 read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) 146 { 147 unsigned long pfn; 148 struct page *page; 149 struct page_ext *page_ext; 150 151 if (!page_owner_inited) 152 return -EINVAL; 153 154 page = NULL; 155 pfn = min_low_pfn + *ppos; 156 157 /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ 158 while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) 159 pfn++; 160 161 drain_all_pages(NULL); 162 163 /* Find an allocated page */ 164 for (; pfn < max_pfn; pfn++) { 165 /* 166 * If the new page is in a new MAX_ORDER_NR_PAGES area, 167 * validate the area as existing, skip it if not 168 */ 169 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) { 170 pfn += MAX_ORDER_NR_PAGES - 1; 171 continue; 172 } 173 174 /* Check for holes within a MAX_ORDER area */ 175 if (!pfn_valid_within(pfn)) 176 continue; 177 178 page = pfn_to_page(pfn); 179 if (PageBuddy(page)) { 180 unsigned long freepage_order = page_order_unsafe(page); 181 182 if (freepage_order < MAX_ORDER) 183 pfn += (1UL << freepage_order) - 1; 184 continue; 185 } 186 187 page_ext = lookup_page_ext(page); 188 189 /* 190 * Some pages could be missed by concurrent allocation or free, 191 * because we don't hold the zone lock. 192 */ 193 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) 194 continue; 195 196 /* Record the next PFN to read in the file offset */ 197 *ppos = (pfn - min_low_pfn) + 1; 198 199 return print_page_owner(buf, count, pfn, page, page_ext); 200 } 201 202 return 0; 203 } 204 205 static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) 206 { 207 struct page *page; 208 struct page_ext *page_ext; 209 unsigned long pfn = zone->zone_start_pfn, block_end_pfn; 210 unsigned long end_pfn = pfn + zone->spanned_pages; 211 unsigned long count = 0; 212 213 /* Scan block by block. First and last block may be incomplete */ 214 pfn = zone->zone_start_pfn; 215 216 /* 217 * Walk the zone in pageblock_nr_pages steps. If a page block spans 218 * a zone boundary, it will be double counted between zones. This does 219 * not matter as the mixed block count will still be correct 220 */ 221 for (; pfn < end_pfn; ) { 222 if (!pfn_valid(pfn)) { 223 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); 224 continue; 225 } 226 227 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages); 228 block_end_pfn = min(block_end_pfn, end_pfn); 229 230 page = pfn_to_page(pfn); 231 232 for (; pfn < block_end_pfn; pfn++) { 233 if (!pfn_valid_within(pfn)) 234 continue; 235 236 page = pfn_to_page(pfn); 237 238 /* 239 * We are safe to check buddy flag and order, because 240 * this is init stage and only single thread runs. 241 */ 242 if (PageBuddy(page)) { 243 pfn += (1UL << page_order(page)) - 1; 244 continue; 245 } 246 247 if (PageReserved(page)) 248 continue; 249 250 page_ext = lookup_page_ext(page); 251 252 /* Maybe overraping zone */ 253 if (test_bit(PAGE_EXT_OWNER, &page_ext->flags)) 254 continue; 255 256 /* Found early allocated page */ 257 set_page_owner(page, 0, 0); 258 count++; 259 } 260 } 261 262 pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n", 263 pgdat->node_id, zone->name, count); 264 } 265 266 static void init_zones_in_node(pg_data_t *pgdat) 267 { 268 struct zone *zone; 269 struct zone *node_zones = pgdat->node_zones; 270 unsigned long flags; 271 272 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { 273 if (!populated_zone(zone)) 274 continue; 275 276 spin_lock_irqsave(&zone->lock, flags); 277 init_pages_in_zone(pgdat, zone); 278 spin_unlock_irqrestore(&zone->lock, flags); 279 } 280 } 281 282 static void init_early_allocated_pages(void) 283 { 284 pg_data_t *pgdat; 285 286 drain_all_pages(NULL); 287 for_each_online_pgdat(pgdat) 288 init_zones_in_node(pgdat); 289 } 290 291 static const struct file_operations proc_page_owner_operations = { 292 .read = read_page_owner, 293 }; 294 295 static int __init pageowner_init(void) 296 { 297 struct dentry *dentry; 298 299 if (!page_owner_inited) { 300 pr_info("page_owner is disabled\n"); 301 return 0; 302 } 303 304 dentry = debugfs_create_file("page_owner", S_IRUSR, NULL, 305 NULL, &proc_page_owner_operations); 306 if (IS_ERR(dentry)) 307 return PTR_ERR(dentry); 308 309 return 0; 310 } 311 module_init(pageowner_init) 312