summaryrefslogtreecommitdiff
path: root/mm/cma.c
blob: a75b17b03b66add6cf98b4ee4041c9434477f380 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Contiguous Memory Allocator
 *
 * Copyright (c) 2010-2011 by Samsung Electronics.
 * Copyright IBM Corporation, 2013
 * Copyright LG Electronics Inc., 2014
 * Written by:
 *	Marek Szyprowski <m.szyprowski@samsung.com>
 *	Michal Nazarewicz <mina86@mina86.com>
 *	Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
 *	Joonsoo Kim <iamjoonsoo.kim@lge.com>
 */

#define pr_fmt(fmt) "cma: " fmt

#ifdef CONFIG_CMA_DEBUG
#ifndef DEBUG
#  define DEBUG
#endif
#endif
#define CREATE_TRACE_POINTS

#include <linux/memblock.h>
#include <linux/err.h>
#include <linux/mm.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/log2.h>
#include <linux/cma.h>
#include <linux/highmem.h>
#include <linux/io.h>
#include <linux/kmemleak.h>
#include <trace/events/cma.h>

#include "cma.h"

struct cma cma_areas[MAX_CMA_AREAS];
unsigned cma_area_count;
static DEFINE_MUTEX(cma_mutex);

phys_addr_t cma_get_base(const struct cma *cma)
{
	return PFN_PHYS(cma->base_pfn);
}

unsigned long cma_get_size(const struct cma *cma)
{
	return cma->count << PAGE_SHIFT;
}

const char *cma_get_name(const struct cma *cma)
{
	return cma->name;
}

static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
					     unsigned int align_order)
{
	if (align_order <= cma->order_per_bit)
		return 0;
	return (1UL << (align_order - cma->order_per_bit)) - 1;
}

/*
 * Find the offset of the base PFN from the specified align_order.
 * The value returned is represented in order_per_bits.
 */
static unsigned long cma_bitmap_aligned_offset(const struct cma *cma,
					       unsigned int align_order)
{
	return (cma->base_pfn & ((1UL << align_order) - 1))
		>> cma->order_per_bit;
}

static unsigned long cma_bitmap_pages_to_bits(const struct cma *cma,
					      unsigned long pages)
{
	return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
}

static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,
			     unsigned long count)
{
	unsigned long bitmap_no, bitmap_count;
	unsigned long flags;

	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
	bitmap_count = cma_bitmap_pages_to_bits(cma, count);

	spin_lock_irqsave(&cma->lock, flags);
	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
	spin_unlock_irqrestore(&cma->lock, flags);
}

static void __init cma_activate_area(struct cma *cma)
{
	unsigned long base_pfn = cma->base_pfn, pfn;
	struct zone *zone;

	cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL);
	if (!cma->bitmap)
		goto out_error;

	/*
	 * alloc_contig_range() requires the pfn range specified to be in the
	 * same zone. Simplify by forcing the entire CMA resv range to be in the
	 * same zone.
	 */
	WARN_ON_ONCE(!pfn_valid(base_pfn));
	zone = page_zone(pfn_to_page(base_pfn));
	for (pfn = base_pfn + 1; pfn < base_pfn + cma->count; pfn++) {
		WARN_ON_ONCE(!pfn_valid(pfn));
		if (page_zone(pfn_to_page(pfn)) != zone)
			goto not_in_zone;
	}

	for (pfn = base_pfn; pfn < base_pfn + cma->count;
	     pfn += pageblock_nr_pages)
		init_cma_reserved_pageblock(pfn_to_page(pfn));

	spin_lock_init(&cma->lock);

#ifdef CONFIG_CMA_DEBUGFS
	INIT_HLIST_HEAD(&cma->mem_head);
	spin_lock_init(&cma->mem_head_lock);
#endif

	return;

not_in_zone:
	bitmap_free(cma->bitmap);
out_error:
	/* Expose all pages to the buddy, they are useless for CMA. */
	if (!cma->reserve_pages_on_error) {
		for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn++)
			free_reserved_page(pfn_to_page(pfn));
	}
	totalcma_pages -= cma->count;
	cma->count = 0;
	pr_err("CMA area %s could not be activated\n", cma->name);
	return;
}

static int __init cma_init_reserved_areas(void)
{
	int i;

	for (i = 0; i < cma_area_count; i++)
		cma_activate_area(&cma_areas[i]);

	return 0;
}
core_initcall(cma_init_reserved_areas);

void __init cma_reserve_pages_on_error(struct cma *cma)
{
	cma->reserve_pages_on_error = true;
}

/**
 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
 * @base: Base address of the reserved area
 * @size: Size of the reserved area (in bytes),
 * @order_per_bit: Order of pages represented by one bit on bitmap.
 * @name: The name of the area. If this parameter is NULL, the name of
 *        the area will be set to "cmaN", where N is a running counter of
 *        used areas.
 * @res_cma: Pointer to store the created cma region.
 *
 * This function creates custom contiguous area from already reserved memory.
 */
int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
				 unsigned int order_per_bit,
				 const char *name,
				 struct cma **res_cma)
{
	struct cma *cma;

	/* Sanity checks */
	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
		pr_err("Not enough slots for CMA reserved regions!\n");
		return -ENOSPC;
	}

	if (!size || !memblock_is_region_reserved(base, size))
		return -EINVAL;

	/* alignment should be aligned with order_per_bit */
	if (!IS_ALIGNED(CMA_MIN_ALIGNMENT_PAGES, 1 << order_per_bit))
		return -EINVAL;

	/* ensure minimal alignment required by mm core */
	if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES))
		return -EINVAL;

	/*
	 * Each reserved area must be initialised later, when more kernel
	 * subsystems (like slab allocator) are available.
	 */
	cma = &cma_areas[cma_area_count];

	if (name)
		snprintf(cma->name, CMA_MAX_NAME, name);
	else
		snprintf(cma->name, CMA_MAX_NAME,  "cma%d\n", cma_area_count);

	cma->base_pfn = PFN_DOWN(base);
	cma->count = size >> PAGE_SHIFT;
	cma->order_per_bit = order_per_bit;
	*res_cma = cma;
	cma_area_count++;
	totalcma_pages += (size / PAGE_SIZE);

	return 0;
}

/**
 * cma_declare_contiguous_nid() - reserve custom contiguous area
 * @base: Base address of the reserved area optional, use 0 for any
 * @size: Size of the reserved area (in bytes),
 * @limit: End address of the reserved memory (optional, 0 for any).
 * @alignment: Alignment for the CMA area, should be power of 2 or zero
 * @order_per_bit: Order of pages represented by one bit on bitmap.
 * @fixed: hint about where to place the reserved area
 * @name: The name of the area. See function cma_init_reserved_mem()
 * @res_cma: Pointer to store the created cma region.
 * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
 *
 * This function reserves memory from early allocator. It should be
 * called by arch specific code once the early allocator (memblock or bootmem)
 * has been activated and all other subsystems have already allocated/reserved
 * memory. This function allows to create custom reserved areas.
 *
 * If @fixed is true, reserve contiguous area at exactly @base.  If false,
 * reserve in range from @base to @limit.
 */
int __init cma_declare_contiguous_nid(phys_addr_t base,
			phys_addr_t size, phys_addr_t limit,
			phys_addr_t alignment, unsigned int order_per_bit,
			bool fixed, const char *name, struct cma **res_cma,
			int nid)
{
	phys_addr_t memblock_end = memblock_end_of_DRAM();
	phys_addr_t highmem_start;
	int ret = 0;

	/*
	 * We can't use __pa(high_memory) directly, since high_memory
	 * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)
	 * complain. Find the boundary by adding one to the last valid
	 * address.
	 */
	highmem_start = __pa(high_memory - 1) + 1;
	pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
		__func__, &size, &base, &limit, &alignment);

	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
		pr_err("Not enough slots for CMA reserved regions!\n");
		return -ENOSPC;
	}

	if (!size)
		return -EINVAL;

	if (alignment && !is_power_of_2(alignment))
		return -EINVAL;

	/* Sanitise input arguments. */
	alignment = max_t(phys_addr_t, alignment, CMA_MIN_ALIGNMENT_BYTES);
	if (fixed && base & (alignment - 1)) {
		ret = -EINVAL;
		pr_err("Region at %pa must be aligned to %pa bytes\n",
			&base, &alignment);
		goto err;
	}
	base = ALIGN(base, alignment);
	size = ALIGN(size, alignment);
	limit &= ~(alignment - 1);

	if (!base)
		fixed = false;

	/* size should be aligned with order_per_bit */
	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
		return -EINVAL;

	/*
	 * If allocating at a fixed base the request region must not cross the
	 * low/high memory boundary.
	 */
	if (fixed && base < highmem_start && base + size > highmem_start) {
		ret = -EINVAL;
		pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
			&base, &highmem_start);
		goto err;
	}

	/*
	 * If the limit is unspecified or above the memblock end, its effective
	 * value will be the memblock end. Set it explicitly to simplify further
	 * checks.
	 */
	if (limit == 0 || limit > memblock_end)
		limit = memblock_end;

	if (base + size > limit) {
		ret = -EINVAL;
		pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n",
			&size, &base, &limit);
		goto err;
	}

	/* Reserve memory */
	if (fixed) {
		if (memblock_is_region_reserved(base, size) ||
		    memblock_reserve(base, size) < 0) {
			ret = -EBUSY;
			goto err;
		}
	} else {
		phys_addr_t addr = 0;

		/*
		 * All pages in the reserved area must come from the same zone.
		 * If the requested region crosses the low/high memory boundary,
		 * try allocating from high memory first and fall back to low
		 * memory in case of failure.
		 */
		if (base < highmem_start && limit > highmem_start) {
			addr = memblock_alloc_range_nid(size, alignment,
					highmem_start, limit, nid, true);
			limit = highmem_start;
		}

		/*
		 * If there is enough memory, try a bottom-up allocation first.
		 * It will place the new cma area close to the start of the node
		 * and guarantee that the compaction is moving pages out of the
		 * cma area and not into it.
		 * Avoid using first 4GB to not interfere with constrained zones
		 * like DMA/DMA32.
		 */
#ifdef CONFIG_PHYS_ADDR_T_64BIT
		if (!memblock_bottom_up() && memblock_end >= SZ_4G + size) {
			memblock_set_bottom_up(true);
			addr = memblock_alloc_range_nid(size, alignment, SZ_4G,
							limit, nid, true);
			memblock_set_bottom_up(false);
		}
#endif

		if (!addr) {
			addr = memblock_alloc_range_nid(size, alignment, base,
					limit, nid, true);
			if (!addr) {
				ret = -ENOMEM;
				goto err;
			}
		}

		/*
		 * kmemleak scans/reads tracked objects for pointers to other
		 * objects but this address isn't mapped and accessible
		 */
		kmemleak_ignore_phys(addr);
		base = addr;
	}

	ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);
	if (ret)
		goto free_mem;

	pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
		&base);
	return 0;

free_mem:
	memblock_phys_free(base, size);
err:
	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
	return ret;
}

#ifdef CONFIG_CMA_DEBUG
static void cma_debug_show_areas(struct cma *cma)
{
	unsigned long next_zero_bit, next_set_bit, nr_zero;
	unsigned long start = 0;
	unsigned long nr_part, nr_total = 0;
	unsigned long nbits = cma_bitmap_maxno(cma);

	spin_lock_irq(&cma->lock);
	pr_info("number of available pages: ");
	for (;;) {
		next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start);
		if (next_zero_bit >= nbits)
			break;
		next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit);
		nr_zero = next_set_bit - next_zero_bit;
		nr_part = nr_zero << cma->order_per_bit;
		pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part,
			next_zero_bit);
		nr_total += nr_part;
		start = next_zero_bit + nr_zero;
	}
	pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count);
	spin_unlock_irq(&cma->lock);
}
#else
static inline void cma_debug_show_areas(struct cma *cma) { }
#endif

/**
 * cma_alloc() - allocate pages from contiguous area
 * @cma:   Contiguous memory region for which the allocation is performed.
 * @count: Requested number of pages.
 * @align: Requested alignment of pages (in PAGE_SIZE order).
 * @no_warn: Avoid printing message about failed allocation
 *
 * This function allocates part of contiguous memory on specific
 * contiguous memory area.
 */
struct page *cma_alloc(struct cma *cma, unsigned long count,
		       unsigned int align, bool no_warn)
{
	unsigned long mask, offset;
	unsigned long pfn = -1;
	unsigned long start = 0;
	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
	unsigned long i;
	struct page *page = NULL;
	int ret = -ENOMEM;

	if (!cma || !cma->count || !cma->bitmap)
		goto out;

	pr_debug("%s(cma %p, count %lu, align %d)\n", __func__, (void *)cma,
		 count, align);

	if (!count)
		goto out;

	trace_cma_alloc_start(cma->name, count, align);

	mask = cma_bitmap_aligned_mask(cma, align);
	offset = cma_bitmap_aligned_offset(cma, align);
	bitmap_maxno = cma_bitmap_maxno(cma);
	bitmap_count = cma_bitmap_pages_to_bits(cma, count);

	if (bitmap_count > bitmap_maxno)
		goto out;

	for (;;) {
		spin_lock_irq(&cma->lock);
		bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
				bitmap_maxno, start, bitmap_count, mask,
				offset);
		if (bitmap_no >= bitmap_maxno) {
			spin_unlock_irq(&cma->lock);
			break;
		}
		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
		/*
		 * It's safe to drop the lock here. We've marked this region for
		 * our exclusive use. If the migration fails we will take the
		 * lock again and unmark it.
		 */
		spin_unlock_irq(&cma->lock);

		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
		mutex_lock(&cma_mutex);
		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
				     GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
		mutex_unlock(&cma_mutex);
		if (ret == 0) {
			page = pfn_to_page(pfn);
			break;
		}

		cma_clear_bitmap(cma, pfn, count);
		if (ret != -EBUSY)
			break;

		pr_debug("%s(): memory range at %p is busy, retrying\n",
			 __func__, pfn_to_page(pfn));

		trace_cma_alloc_busy_retry(cma->name, pfn, pfn_to_page(pfn),
					   count, align);
		/* try again with a bit different memory target */
		start = bitmap_no + mask + 1;
	}

	trace_cma_alloc_finish(cma->name, pfn, page, count, align, ret);

	/*
	 * CMA can allocate multiple page blocks, which results in different
	 * blocks being marked with different tags. Reset the tags to ignore
	 * those page blocks.
	 */
	if (page) {
		for (i = 0; i < count; i++)
			page_kasan_tag_reset(page + i);
	}

	if (ret && !no_warn) {
		pr_err_ratelimited("%s: %s: alloc failed, req-size: %lu pages, ret: %d\n",
				   __func__, cma->name, count, ret);
		cma_debug_show_areas(cma);
	}

	pr_debug("%s(): returned %p\n", __func__, page);
out:
	if (page) {
		count_vm_event(CMA_ALLOC_SUCCESS);
		cma_sysfs_account_success_pages(cma, count);
	} else {
		count_vm_event(CMA_ALLOC_FAIL);
		if (cma)
			cma_sysfs_account_fail_pages(cma, count);
	}

	return page;
}

bool cma_pages_valid(struct cma *cma, const struct page *pages,
		     unsigned long count)
{
	unsigned long pfn;

	if (!cma || !pages)
		return false;

	pfn = page_to_pfn(pages);

	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) {
		pr_debug("%s(page %p, count %lu)\n", __func__,
						(void *)pages, count);
		return false;
	}

	return true;
}

/**
 * cma_release() - release allocated pages
 * @cma:   Contiguous memory region for which the allocation is performed.
 * @pages: Allocated pages.
 * @count: Number of allocated pages.
 *
 * This function releases memory allocated by cma_alloc().
 * It returns false when provided pages do not belong to contiguous area and
 * true otherwise.
 */
bool cma_release(struct cma *cma, const struct page *pages,
		 unsigned long count)
{
	unsigned long pfn;

	if (!cma_pages_valid(cma, pages, count))
		return false;

	pr_debug("%s(page %p, count %lu)\n", __func__, (void *)pages, count);

	pfn = page_to_pfn(pages);

	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);

	free_contig_range(pfn, count);
	cma_clear_bitmap(cma, pfn, count);
	trace_cma_release(cma->name, pfn, pages, count);

	return true;
}

int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data)
{
	int i;

	for (i = 0; i < cma_area_count; i++) {
		int ret = it(&cma_areas[i], data);

		if (ret)
			return ret;
	}

	return 0;
}