1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _MM_PERCPU_INTERNAL_H
3#define _MM_PERCPU_INTERNAL_H
4
5#include <linux/types.h>
6#include <linux/percpu.h>
7
8/*
9 * There are two chunk types: root and memcg-aware.
10 * Chunks of each type have separate slots list.
11 *
12 * Memcg-aware chunks have an attached vector of obj_cgroup pointers, which is
13 * used to store memcg membership data of a percpu object.  Obj_cgroups are
14 * ref-counted pointers to a memory cgroup with an ability to switch dynamically
15 * to the parent memory cgroup.  This allows to reclaim a deleted memory cgroup
16 * without reclaiming of all outstanding objects, which hold a reference at it.
17 */
18enum pcpu_chunk_type {
19	PCPU_CHUNK_ROOT,
20#ifdef CONFIG_MEMCG_KMEM
21	PCPU_CHUNK_MEMCG,
22#endif
23	PCPU_NR_CHUNK_TYPES,
24	PCPU_FAIL_ALLOC = PCPU_NR_CHUNK_TYPES
25};
26
27/*
28 * pcpu_block_md is the metadata block struct.
29 * Each chunk's bitmap is split into a number of full blocks.
30 * All units are in terms of bits.
31 *
32 * The scan hint is the largest known contiguous area before the contig hint.
33 * It is not necessarily the actual largest contig hint though.  There is an
34 * invariant that the scan_hint_start > contig_hint_start iff
35 * scan_hint == contig_hint.  This is necessary because when scanning forward,
36 * we don't know if a new contig hint would be better than the current one.
37 */
38struct pcpu_block_md {
39	int			scan_hint;	/* scan hint for block */
40	int			scan_hint_start; /* block relative starting
41						    position of the scan hint */
42	int                     contig_hint;    /* contig hint for block */
43	int                     contig_hint_start; /* block relative starting
44						      position of the contig hint */
45	int                     left_free;      /* size of free space along
46						   the left side of the block */
47	int                     right_free;     /* size of free space along
48						   the right side of the block */
49	int                     first_free;     /* block position of first free */
50	int			nr_bits;	/* total bits responsible for */
51};
52
53struct pcpu_chunk {
54#ifdef CONFIG_PERCPU_STATS
55	int			nr_alloc;	/* # of allocations */
56	size_t			max_alloc_size; /* largest allocation size */
57#endif
58
59	struct list_head	list;		/* linked to pcpu_slot lists */
60	int			free_bytes;	/* free bytes in the chunk */
61	struct pcpu_block_md	chunk_md;
62	void			*base_addr;	/* base address of this chunk */
63
64	unsigned long		*alloc_map;	/* allocation map */
65	unsigned long		*bound_map;	/* boundary map */
66	struct pcpu_block_md	*md_blocks;	/* metadata blocks */
67
68	void			*data;		/* chunk data */
69	bool			immutable;	/* no [de]population allowed */
70	int			start_offset;	/* the overlap with the previous
71						   region to have a page aligned
72						   base_addr */
73	int			end_offset;	/* additional area required to
74						   have the region end page
75						   aligned */
76#ifdef CONFIG_MEMCG_KMEM
77	struct obj_cgroup	**obj_cgroups;	/* vector of object cgroups */
78#endif
79
80	int			nr_pages;	/* # of pages served by this chunk */
81	int			nr_populated;	/* # of populated pages */
82	int                     nr_empty_pop_pages; /* # of empty populated pages */
83	unsigned long		populated[];	/* populated bitmap */
84};
85
86extern spinlock_t pcpu_lock;
87
88extern struct list_head *pcpu_chunk_lists;
89extern int pcpu_nr_slots;
90extern int pcpu_nr_empty_pop_pages[];
91
92extern struct pcpu_chunk *pcpu_first_chunk;
93extern struct pcpu_chunk *pcpu_reserved_chunk;
94
95/**
96 * pcpu_chunk_nr_blocks - converts nr_pages to # of md_blocks
97 * @chunk: chunk of interest
98 *
99 * This conversion is from the number of physical pages that the chunk
100 * serves to the number of bitmap blocks used.
101 */
102static inline int pcpu_chunk_nr_blocks(struct pcpu_chunk *chunk)
103{
104	return chunk->nr_pages * PAGE_SIZE / PCPU_BITMAP_BLOCK_SIZE;
105}
106
107/**
108 * pcpu_nr_pages_to_map_bits - converts the pages to size of bitmap
109 * @pages: number of physical pages
110 *
111 * This conversion is from physical pages to the number of bits
112 * required in the bitmap.
113 */
114static inline int pcpu_nr_pages_to_map_bits(int pages)
115{
116	return pages * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE;
117}
118
119/**
120 * pcpu_chunk_map_bits - helper to convert nr_pages to size of bitmap
121 * @chunk: chunk of interest
122 *
123 * This conversion is from the number of physical pages that the chunk
124 * serves to the number of bits in the bitmap.
125 */
126static inline int pcpu_chunk_map_bits(struct pcpu_chunk *chunk)
127{
128	return pcpu_nr_pages_to_map_bits(chunk->nr_pages);
129}
130
131#ifdef CONFIG_MEMCG_KMEM
132static inline enum pcpu_chunk_type pcpu_chunk_type(struct pcpu_chunk *chunk)
133{
134	if (chunk->obj_cgroups)
135		return PCPU_CHUNK_MEMCG;
136	return PCPU_CHUNK_ROOT;
137}
138
139static inline bool pcpu_is_memcg_chunk(enum pcpu_chunk_type chunk_type)
140{
141	return chunk_type == PCPU_CHUNK_MEMCG;
142}
143
144#else
145static inline enum pcpu_chunk_type pcpu_chunk_type(struct pcpu_chunk *chunk)
146{
147	return PCPU_CHUNK_ROOT;
148}
149
150static inline bool pcpu_is_memcg_chunk(enum pcpu_chunk_type chunk_type)
151{
152	return false;
153}
154#endif
155
156static inline struct list_head *pcpu_chunk_list(enum pcpu_chunk_type chunk_type)
157{
158	return &pcpu_chunk_lists[pcpu_nr_slots *
159				 pcpu_is_memcg_chunk(chunk_type)];
160}
161
162#ifdef CONFIG_PERCPU_STATS
163
164#include <linux/spinlock.h>
165
166struct percpu_stats {
167	u64 nr_alloc;		/* lifetime # of allocations */
168	u64 nr_dealloc;		/* lifetime # of deallocations */
169	u64 nr_cur_alloc;	/* current # of allocations */
170	u64 nr_max_alloc;	/* max # of live allocations */
171	u32 nr_chunks;		/* current # of live chunks */
172	u32 nr_max_chunks;	/* max # of live chunks */
173	size_t min_alloc_size;	/* min allocaiton size */
174	size_t max_alloc_size;	/* max allocation size */
175};
176
177extern struct percpu_stats pcpu_stats;
178extern struct pcpu_alloc_info pcpu_stats_ai;
179
180/*
181 * For debug purposes. We don't care about the flexible array.
182 */
183static inline void pcpu_stats_save_ai(const struct pcpu_alloc_info *ai)
184{
185	memcpy(&pcpu_stats_ai, ai, sizeof(struct pcpu_alloc_info));
186
187	/* initialize min_alloc_size to unit_size */
188	pcpu_stats.min_alloc_size = pcpu_stats_ai.unit_size;
189}
190
191/*
192 * pcpu_stats_area_alloc - increment area allocation stats
193 * @chunk: the location of the area being allocated
194 * @size: size of area to allocate in bytes
195 *
196 * CONTEXT:
197 * pcpu_lock.
198 */
199static inline void pcpu_stats_area_alloc(struct pcpu_chunk *chunk, size_t size)
200{
201	lockdep_assert_held(&pcpu_lock);
202
203	pcpu_stats.nr_alloc++;
204	pcpu_stats.nr_cur_alloc++;
205	pcpu_stats.nr_max_alloc =
206		max(pcpu_stats.nr_max_alloc, pcpu_stats.nr_cur_alloc);
207	pcpu_stats.min_alloc_size =
208		min(pcpu_stats.min_alloc_size, size);
209	pcpu_stats.max_alloc_size =
210		max(pcpu_stats.max_alloc_size, size);
211
212	chunk->nr_alloc++;
213	chunk->max_alloc_size = max(chunk->max_alloc_size, size);
214}
215
216/*
217 * pcpu_stats_area_dealloc - decrement allocation stats
218 * @chunk: the location of the area being deallocated
219 *
220 * CONTEXT:
221 * pcpu_lock.
222 */
223static inline void pcpu_stats_area_dealloc(struct pcpu_chunk *chunk)
224{
225	lockdep_assert_held(&pcpu_lock);
226
227	pcpu_stats.nr_dealloc++;
228	pcpu_stats.nr_cur_alloc--;
229
230	chunk->nr_alloc--;
231}
232
233/*
234 * pcpu_stats_chunk_alloc - increment chunk stats
235 */
236static inline void pcpu_stats_chunk_alloc(void)
237{
238	unsigned long flags;
239	spin_lock_irqsave(&pcpu_lock, flags);
240
241	pcpu_stats.nr_chunks++;
242	pcpu_stats.nr_max_chunks =
243		max(pcpu_stats.nr_max_chunks, pcpu_stats.nr_chunks);
244
245	spin_unlock_irqrestore(&pcpu_lock, flags);
246}
247
248/*
249 * pcpu_stats_chunk_dealloc - decrement chunk stats
250 */
251static inline void pcpu_stats_chunk_dealloc(void)
252{
253	unsigned long flags;
254	spin_lock_irqsave(&pcpu_lock, flags);
255
256	pcpu_stats.nr_chunks--;
257
258	spin_unlock_irqrestore(&pcpu_lock, flags);
259}
260
261#else
262
263static inline void pcpu_stats_save_ai(const struct pcpu_alloc_info *ai)
264{
265}
266
267static inline void pcpu_stats_area_alloc(struct pcpu_chunk *chunk, size_t size)
268{
269}
270
271static inline void pcpu_stats_area_dealloc(struct pcpu_chunk *chunk)
272{
273}
274
275static inline void pcpu_stats_chunk_alloc(void)
276{
277}
278
279static inline void pcpu_stats_chunk_dealloc(void)
280{
281}
282
283#endif /* !CONFIG_PERCPU_STATS */
284
285#endif
286