1 #include <linux/debugfs.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>
10 static bool page_owner_disabled
= true;
11 bool page_owner_inited __read_mostly
;
13 static void init_early_allocated_pages(void);
15 static int early_page_owner_param(char *buf
)
20 if (strcmp(buf
, "on") == 0)
21 page_owner_disabled
= false;
25 early_param("page_owner", early_page_owner_param
);
27 static bool need_page_owner(void)
29 if (page_owner_disabled
)
35 static void init_page_owner(void)
37 if (page_owner_disabled
)
40 page_owner_inited
= true;
41 init_early_allocated_pages();
44 struct page_ext_operations page_owner_ops
= {
45 .need
= need_page_owner
,
46 .init
= init_page_owner
,
49 void __reset_page_owner(struct page
*page
, unsigned int order
)
52 struct page_ext
*page_ext
;
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
);
60 void __set_page_owner(struct page
*page
, unsigned int order
, gfp_t gfp_mask
)
62 struct page_ext
*page_ext
= lookup_page_ext(page
);
63 struct stack_trace trace
= {
65 .max_entries
= ARRAY_SIZE(page_ext
->trace_entries
),
66 .entries
= &page_ext
->trace_entries
[0],
70 save_stack_trace(&trace
);
72 page_ext
->order
= order
;
73 page_ext
->gfp_mask
= gfp_mask
;
74 page_ext
->nr_entries
= trace
.nr_entries
;
76 __set_bit(PAGE_EXT_OWNER
, &page_ext
->flags
);
79 gfp_t
__get_page_owner_gfp(struct page
*page
)
81 struct page_ext
*page_ext
= lookup_page_ext(page
);
83 return page_ext
->gfp_mask
;
87 print_page_owner(char __user
*buf
, size_t count
, unsigned long pfn
,
88 struct page
*page
, struct page_ext
*page_ext
)
91 int pageblock_mt
, page_mt
;
93 struct stack_trace trace
= {
94 .nr_entries
= page_ext
->nr_entries
,
95 .entries
= &page_ext
->trace_entries
[0],
98 kbuf
= kmalloc(count
, GFP_KERNEL
);
102 ret
= snprintf(kbuf
, count
,
103 "Page allocated via order %u, mask %#x(%pGg)\n",
104 page_ext
->order
, page_ext
->gfp_mask
,
105 &page_ext
->gfp_mask
);
110 /* Print information relevant to grouping pages by mobility */
111 pageblock_mt
= get_pfnblock_migratetype(page
, pfn
);
112 page_mt
= gfpflags_to_migratetype(page_ext
->gfp_mask
);
113 ret
+= snprintf(kbuf
+ ret
, count
- ret
,
114 "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
116 migratetype_names
[page_mt
],
117 pfn
>> pageblock_order
,
118 migratetype_names
[pageblock_mt
],
119 page
->flags
, &page
->flags
);
124 ret
+= snprint_stack_trace(kbuf
+ ret
, count
- ret
, &trace
, 0);
128 ret
+= snprintf(kbuf
+ ret
, count
- ret
, "\n");
132 if (copy_to_user(buf
, kbuf
, ret
))
144 read_page_owner(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
148 struct page_ext
*page_ext
;
150 if (!page_owner_inited
)
154 pfn
= min_low_pfn
+ *ppos
;
156 /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
157 while (!pfn_valid(pfn
) && (pfn
& (MAX_ORDER_NR_PAGES
- 1)) != 0)
160 drain_all_pages(NULL
);
162 /* Find an allocated page */
163 for (; pfn
< max_pfn
; pfn
++) {
165 * If the new page is in a new MAX_ORDER_NR_PAGES area,
166 * validate the area as existing, skip it if not
168 if ((pfn
& (MAX_ORDER_NR_PAGES
- 1)) == 0 && !pfn_valid(pfn
)) {
169 pfn
+= MAX_ORDER_NR_PAGES
- 1;
173 /* Check for holes within a MAX_ORDER area */
174 if (!pfn_valid_within(pfn
))
177 page
= pfn_to_page(pfn
);
178 if (PageBuddy(page
)) {
179 unsigned long freepage_order
= page_order_unsafe(page
);
181 if (freepage_order
< MAX_ORDER
)
182 pfn
+= (1UL << freepage_order
) - 1;
186 page_ext
= lookup_page_ext(page
);
189 * Some pages could be missed by concurrent allocation or free,
190 * because we don't hold the zone lock.
192 if (!test_bit(PAGE_EXT_OWNER
, &page_ext
->flags
))
195 /* Record the next PFN to read in the file offset */
196 *ppos
= (pfn
- min_low_pfn
) + 1;
198 return print_page_owner(buf
, count
, pfn
, page
, page_ext
);
204 static void init_pages_in_zone(pg_data_t
*pgdat
, struct zone
*zone
)
207 struct page_ext
*page_ext
;
208 unsigned long pfn
= zone
->zone_start_pfn
, block_end_pfn
;
209 unsigned long end_pfn
= pfn
+ zone
->spanned_pages
;
210 unsigned long count
= 0;
212 /* Scan block by block. First and last block may be incomplete */
213 pfn
= zone
->zone_start_pfn
;
216 * Walk the zone in pageblock_nr_pages steps. If a page block spans
217 * a zone boundary, it will be double counted between zones. This does
218 * not matter as the mixed block count will still be correct
220 for (; pfn
< end_pfn
; ) {
221 if (!pfn_valid(pfn
)) {
222 pfn
= ALIGN(pfn
+ 1, MAX_ORDER_NR_PAGES
);
226 block_end_pfn
= ALIGN(pfn
+ 1, pageblock_nr_pages
);
227 block_end_pfn
= min(block_end_pfn
, end_pfn
);
229 page
= pfn_to_page(pfn
);
231 for (; pfn
< block_end_pfn
; pfn
++) {
232 if (!pfn_valid_within(pfn
))
235 page
= pfn_to_page(pfn
);
238 * We are safe to check buddy flag and order, because
239 * this is init stage and only single thread runs.
241 if (PageBuddy(page
)) {
242 pfn
+= (1UL << page_order(page
)) - 1;
246 if (PageReserved(page
))
249 page_ext
= lookup_page_ext(page
);
251 /* Maybe overraping zone */
252 if (test_bit(PAGE_EXT_OWNER
, &page_ext
->flags
))
255 /* Found early allocated page */
256 set_page_owner(page
, 0, 0);
261 pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
262 pgdat
->node_id
, zone
->name
, count
);
265 static void init_zones_in_node(pg_data_t
*pgdat
)
268 struct zone
*node_zones
= pgdat
->node_zones
;
271 for (zone
= node_zones
; zone
- node_zones
< MAX_NR_ZONES
; ++zone
) {
272 if (!populated_zone(zone
))
275 spin_lock_irqsave(&zone
->lock
, flags
);
276 init_pages_in_zone(pgdat
, zone
);
277 spin_unlock_irqrestore(&zone
->lock
, flags
);
281 static void init_early_allocated_pages(void)
285 drain_all_pages(NULL
);
286 for_each_online_pgdat(pgdat
)
287 init_zones_in_node(pgdat
);
290 static const struct file_operations proc_page_owner_operations
= {
291 .read
= read_page_owner
,
294 static int __init
pageowner_init(void)
296 struct dentry
*dentry
;
298 if (!page_owner_inited
) {
299 pr_info("page_owner is disabled\n");
303 dentry
= debugfs_create_file("page_owner", S_IRUSR
, NULL
,
304 NULL
, &proc_page_owner_operations
);
306 return PTR_ERR(dentry
);
310 late_initcall(pageowner_init
)