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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - mm/page_ext.c
2 #include <linux/mmzone.h>
3 #include <linux/bootmem.h>
4 #include <linux/page_ext.h>
5 #include <linux/memory.h>
6 #include <linux/vmalloc.h>
7 #include <linux/kmemleak.h>
8 #include <linux/page_owner.h>
11 * struct page extension
13 * This is the feature to manage memory for extended data per page.
15 * Until now, we must modify struct page itself to store extra data per page.
16 * This requires rebuilding the kernel and it is really time consuming process.
17 * And, sometimes, rebuild is impossible due to third party module dependency.
18 * At last, enlarging struct page could cause un-wanted system behaviour change.
20 * This feature is intended to overcome above mentioned problems. This feature
21 * allocates memory for extended data per page in certain place rather than
22 * the struct page itself. This memory can be accessed by the accessor
23 * functions provided by this code. During the boot process, it checks whether
24 * allocation of huge chunk of memory is needed or not. If not, it avoids
25 * allocating memory at all. With this advantage, we can include this feature
26 * into the kernel in default and can avoid rebuild and solve related problems.
28 * To help these things to work well, there are two callbacks for clients. One
29 * is the need callback which is mandatory if user wants to avoid useless
30 * memory allocation at boot-time. The other is optional, init callback, which
31 * is used to do proper initialization after memory is allocated.
33 * The need callback is used to decide whether extended memory allocation is
34 * needed or not. Sometimes users want to deactivate some features in this
35 * boot and extra memory would be unneccessary. In this case, to avoid
36 * allocating huge chunk of memory, each clients represent their need of
37 * extra memory through the need callback. If one of the need callbacks
38 * returns true, it means that someone needs extra memory so that
39 * page extension core should allocates memory for page extension. If
40 * none of need callbacks return true, memory isn't needed at all in this boot
41 * and page extension core can skip to allocate memory. As result,
42 * none of memory is wasted.
44 * The init callback is used to do proper initialization after page extension
45 * is completely initialized. In sparse memory system, extra memory is
46 * allocated some time later than memmap is allocated. In other words, lifetime
47 * of memory for page extension isn't same with memmap for struct page.
48 * Therefore, clients can't store extra data until page extension is
49 * initialized, even if pages are allocated and used freely. This could
50 * cause inadequate state of extra data per page, so, to prevent it, client
51 * can utilize this callback to initialize the state of it correctly.
54 static struct page_ext_operations
*page_ext_ops
[] = {
56 #ifdef CONFIG_PAGE_POISONING
59 #ifdef CONFIG_PAGE_OWNER
64 static unsigned long total_usage
;
66 static bool __init
invoke_need_callbacks(void)
69 int entries
= ARRAY_SIZE(page_ext_ops
);
71 for (i
= 0; i
< entries
; i
++) {
72 if (page_ext_ops
[i
]->need
&& page_ext_ops
[i
]->need())
79 static void __init
invoke_init_callbacks(void)
82 int entries
= ARRAY_SIZE(page_ext_ops
);
84 for (i
= 0; i
< entries
; i
++) {
85 if (page_ext_ops
[i
]->init
)
86 page_ext_ops
[i
]->init();
90 #if !defined(CONFIG_SPARSEMEM)
93 void __meminit
pgdat_page_ext_init(struct pglist_data
*pgdat
)
95 pgdat
->node_page_ext
= NULL
;
98 struct page_ext
*lookup_page_ext(struct page
*page
)
100 unsigned long pfn
= page_to_pfn(page
);
101 unsigned long offset
;
102 struct page_ext
*base
;
104 base
= NODE_DATA(page_to_nid(page
))->node_page_ext
;
105 #ifdef CONFIG_DEBUG_VM
107 * The sanity checks the page allocator does upon freeing a
108 * page can reach here before the page_ext arrays are
109 * allocated when feeding a range of pages to the allocator
110 * for the first time during bootup or memory hotplug.
115 offset
= pfn
- round_down(node_start_pfn(page_to_nid(page
)),
117 return base
+ offset
;
120 static int __init
alloc_node_page_ext(int nid
)
122 struct page_ext
*base
;
123 unsigned long table_size
;
124 unsigned long nr_pages
;
126 nr_pages
= NODE_DATA(nid
)->node_spanned_pages
;
131 * Need extra space if node range is not aligned with
132 * MAX_ORDER_NR_PAGES. When page allocator's buddy algorithm
133 * checks buddy's status, range could be out of exact node range.
135 if (!IS_ALIGNED(node_start_pfn(nid
), MAX_ORDER_NR_PAGES
) ||
136 !IS_ALIGNED(node_end_pfn(nid
), MAX_ORDER_NR_PAGES
))
137 nr_pages
+= MAX_ORDER_NR_PAGES
;
139 table_size
= sizeof(struct page_ext
) * nr_pages
;
141 base
= memblock_virt_alloc_try_nid_nopanic(
142 table_size
, PAGE_SIZE
, __pa(MAX_DMA_ADDRESS
),
143 BOOTMEM_ALLOC_ACCESSIBLE
, nid
);
146 NODE_DATA(nid
)->node_page_ext
= base
;
147 total_usage
+= table_size
;
151 void __init
page_ext_init_flatmem(void)
156 if (!invoke_need_callbacks())
159 for_each_online_node(nid
) {
160 fail
= alloc_node_page_ext(nid
);
164 pr_info("allocated %ld bytes of page_ext\n", total_usage
);
165 invoke_init_callbacks();
169 pr_crit("allocation of page_ext failed.\n");
170 panic("Out of memory");
173 #else /* CONFIG_FLAT_NODE_MEM_MAP */
175 struct page_ext
*lookup_page_ext(struct page
*page
)
177 unsigned long pfn
= page_to_pfn(page
);
178 struct mem_section
*section
= __pfn_to_section(pfn
);
179 #ifdef CONFIG_DEBUG_VM
181 * The sanity checks the page allocator does upon freeing a
182 * page can reach here before the page_ext arrays are
183 * allocated when feeding a range of pages to the allocator
184 * for the first time during bootup or memory hotplug.
186 if (!section
->page_ext
)
189 return section
->page_ext
+ pfn
;
192 static void *__meminit
alloc_page_ext(size_t size
, int nid
)
194 gfp_t flags
= GFP_KERNEL
| __GFP_ZERO
| __GFP_NOWARN
;
197 addr
= alloc_pages_exact_nid(nid
, size
, flags
);
199 kmemleak_alloc(addr
, size
, 1, flags
);
203 if (node_state(nid
, N_HIGH_MEMORY
))
204 addr
= vzalloc_node(size
, nid
);
206 addr
= vzalloc(size
);
211 static int __meminit
init_section_page_ext(unsigned long pfn
, int nid
)
213 struct mem_section
*section
;
214 struct page_ext
*base
;
215 unsigned long table_size
;
217 section
= __pfn_to_section(pfn
);
219 if (section
->page_ext
)
222 table_size
= sizeof(struct page_ext
) * PAGES_PER_SECTION
;
223 base
= alloc_page_ext(table_size
, nid
);
226 * The value stored in section->page_ext is (base - pfn)
227 * and it does not point to the memory block allocated above,
228 * causing kmemleak false positives.
230 kmemleak_not_leak(base
);
233 pr_err("page ext allocation failure\n");
238 * The passed "pfn" may not be aligned to SECTION. For the calculation
239 * we need to apply a mask.
241 pfn
&= PAGE_SECTION_MASK
;
242 section
->page_ext
= base
- pfn
;
243 total_usage
+= table_size
;
246 #ifdef CONFIG_MEMORY_HOTPLUG
247 static void free_page_ext(void *addr
)
249 if (is_vmalloc_addr(addr
)) {
252 struct page
*page
= virt_to_page(addr
);
255 table_size
= sizeof(struct page_ext
) * PAGES_PER_SECTION
;
257 BUG_ON(PageReserved(page
));
258 free_pages_exact(addr
, table_size
);
262 static void __free_page_ext(unsigned long pfn
)
264 struct mem_section
*ms
;
265 struct page_ext
*base
;
267 ms
= __pfn_to_section(pfn
);
268 if (!ms
|| !ms
->page_ext
)
270 base
= ms
->page_ext
+ pfn
;
275 static int __meminit
online_page_ext(unsigned long start_pfn
,
276 unsigned long nr_pages
,
279 unsigned long start
, end
, pfn
;
282 start
= SECTION_ALIGN_DOWN(start_pfn
);
283 end
= SECTION_ALIGN_UP(start_pfn
+ nr_pages
);
287 * In this case, "nid" already exists and contains valid memory.
288 * "start_pfn" passed to us is a pfn which is an arg for
289 * online__pages(), and start_pfn should exist.
291 nid
= pfn_to_nid(start_pfn
);
292 VM_BUG_ON(!node_state(nid
, N_ONLINE
));
295 for (pfn
= start
; !fail
&& pfn
< end
; pfn
+= PAGES_PER_SECTION
) {
296 if (!pfn_present(pfn
))
298 fail
= init_section_page_ext(pfn
, nid
);
304 for (pfn
= start
; pfn
< end
; pfn
+= PAGES_PER_SECTION
)
305 __free_page_ext(pfn
);
310 static int __meminit
offline_page_ext(unsigned long start_pfn
,
311 unsigned long nr_pages
, int nid
)
313 unsigned long start
, end
, pfn
;
315 start
= SECTION_ALIGN_DOWN(start_pfn
);
316 end
= SECTION_ALIGN_UP(start_pfn
+ nr_pages
);
318 for (pfn
= start
; pfn
< end
; pfn
+= PAGES_PER_SECTION
)
319 __free_page_ext(pfn
);
324 static int __meminit
page_ext_callback(struct notifier_block
*self
,
325 unsigned long action
, void *arg
)
327 struct memory_notify
*mn
= arg
;
331 case MEM_GOING_ONLINE
:
332 ret
= online_page_ext(mn
->start_pfn
,
333 mn
->nr_pages
, mn
->status_change_nid
);
336 offline_page_ext(mn
->start_pfn
,
337 mn
->nr_pages
, mn
->status_change_nid
);
339 case MEM_CANCEL_ONLINE
:
340 offline_page_ext(mn
->start_pfn
,
341 mn
->nr_pages
, mn
->status_change_nid
);
343 case MEM_GOING_OFFLINE
:
346 case MEM_CANCEL_OFFLINE
:
350 return notifier_from_errno(ret
);
355 void __init
page_ext_init(void)
360 if (!invoke_need_callbacks())
363 for_each_node_state(nid
, N_MEMORY
) {
364 unsigned long start_pfn
, end_pfn
;
366 start_pfn
= node_start_pfn(nid
);
367 end_pfn
= node_end_pfn(nid
);
369 * start_pfn and end_pfn may not be aligned to SECTION and the
370 * page->flags of out of node pages are not initialized. So we
371 * scan [start_pfn, the biggest section's pfn < end_pfn) here.
373 for (pfn
= start_pfn
; pfn
< end_pfn
;
374 pfn
= ALIGN(pfn
+ 1, PAGES_PER_SECTION
)) {
379 * Nodes's pfns can be overlapping.
380 * We know some arch can have a nodes layout such as
381 * -------------pfn-------------->
382 * N0 | N1 | N2 | N0 | N1 | N2|....
384 if (pfn_to_nid(pfn
) != nid
)
386 if (init_section_page_ext(pfn
, nid
))
390 hotplug_memory_notifier(page_ext_callback
, 0);
391 pr_info("allocated %ld bytes of page_ext\n", total_usage
);
392 invoke_init_callbacks();
396 panic("Out of memory");
399 void __meminit
pgdat_page_ext_init(struct pglist_data
*pgdat
)