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 */
18 enum 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 */
38 struct 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
53 struct 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
86 extern spinlock_t pcpu_lock;
87
88 extern struct list_head *pcpu_chunk_lists;
89 extern int pcpu_nr_slots;
90 extern int pcpu_nr_empty_pop_pages;
91
92 extern struct pcpu_chunk *pcpu_first_chunk;
93 extern 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 */
pcpu_chunk_nr_blocks(struct pcpu_chunk * chunk)102 static 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 */
pcpu_nr_pages_to_map_bits(int pages)114 static 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 */
pcpu_chunk_map_bits(struct pcpu_chunk * chunk)126 static 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
pcpu_chunk_type(struct pcpu_chunk * chunk)132 static 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
pcpu_is_memcg_chunk(enum pcpu_chunk_type chunk_type)139 static inline bool pcpu_is_memcg_chunk(enum pcpu_chunk_type chunk_type)
140 {
141 return chunk_type == PCPU_CHUNK_MEMCG;
142 }
143
144 #else
pcpu_chunk_type(struct pcpu_chunk * chunk)145 static inline enum pcpu_chunk_type pcpu_chunk_type(struct pcpu_chunk *chunk)
146 {
147 return PCPU_CHUNK_ROOT;
148 }
149
pcpu_is_memcg_chunk(enum pcpu_chunk_type chunk_type)150 static inline bool pcpu_is_memcg_chunk(enum pcpu_chunk_type chunk_type)
151 {
152 return false;
153 }
154 #endif
155
pcpu_chunk_list(enum pcpu_chunk_type chunk_type)156 static 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
166 struct 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
177 extern struct percpu_stats pcpu_stats;
178 extern struct pcpu_alloc_info pcpu_stats_ai;
179
180 /*
181 * For debug purposes. We don't care about the flexible array.
182 */
pcpu_stats_save_ai(const struct pcpu_alloc_info * ai)183 static 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 */
pcpu_stats_area_alloc(struct pcpu_chunk * chunk,size_t size)199 static 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 */
pcpu_stats_area_dealloc(struct pcpu_chunk * chunk)223 static 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 */
pcpu_stats_chunk_alloc(void)236 static 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 */
pcpu_stats_chunk_dealloc(void)251 static 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
pcpu_stats_save_ai(const struct pcpu_alloc_info * ai)263 static inline void pcpu_stats_save_ai(const struct pcpu_alloc_info *ai)
264 {
265 }
266
pcpu_stats_area_alloc(struct pcpu_chunk * chunk,size_t size)267 static inline void pcpu_stats_area_alloc(struct pcpu_chunk *chunk, size_t size)
268 {
269 }
270
pcpu_stats_area_dealloc(struct pcpu_chunk * chunk)271 static inline void pcpu_stats_area_dealloc(struct pcpu_chunk *chunk)
272 {
273 }
274
pcpu_stats_chunk_alloc(void)275 static inline void pcpu_stats_chunk_alloc(void)
276 {
277 }
278
pcpu_stats_chunk_dealloc(void)279 static inline void pcpu_stats_chunk_dealloc(void)
280 {
281 }
282
283 #endif /* !CONFIG_PERCPU_STATS */
284
285 #endif
286
