xref: /openbmc/linux/mm/percpu-internal.h (revision e9b7b8b3)
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 #include <linux/memcontrol.h>
8 
9 /*
10  * pcpu_block_md is the metadata block struct.
11  * Each chunk's bitmap is split into a number of full blocks.
12  * All units are in terms of bits.
13  *
14  * The scan hint is the largest known contiguous area before the contig hint.
15  * It is not necessarily the actual largest contig hint though.  There is an
16  * invariant that the scan_hint_start > contig_hint_start iff
17  * scan_hint == contig_hint.  This is necessary because when scanning forward,
18  * we don't know if a new contig hint would be better than the current one.
19  */
20 struct pcpu_block_md {
21 	int			scan_hint;	/* scan hint for block */
22 	int			scan_hint_start; /* block relative starting
23 						    position of the scan hint */
24 	int                     contig_hint;    /* contig hint for block */
25 	int                     contig_hint_start; /* block relative starting
26 						      position of the contig hint */
27 	int                     left_free;      /* size of free space along
28 						   the left side of the block */
29 	int                     right_free;     /* size of free space along
30 						   the right side of the block */
31 	int                     first_free;     /* block position of first free */
32 	int			nr_bits;	/* total bits responsible for */
33 };
34 
35 struct pcpu_chunk {
36 #ifdef CONFIG_PERCPU_STATS
37 	int			nr_alloc;	/* # of allocations */
38 	size_t			max_alloc_size; /* largest allocation size */
39 #endif
40 
41 	struct list_head	list;		/* linked to pcpu_slot lists */
42 	int			free_bytes;	/* free bytes in the chunk */
43 	struct pcpu_block_md	chunk_md;
44 	unsigned long		*bound_map;	/* boundary map */
45 
46 	/*
47 	 * base_addr is the base address of this chunk.
48 	 * To reduce false sharing, current layout is optimized to make sure
49 	 * base_addr locate in the different cacheline with free_bytes and
50 	 * chunk_md.
51 	 */
52 	void			*base_addr ____cacheline_aligned_in_smp;
53 
54 	unsigned long		*alloc_map;	/* allocation map */
55 	struct pcpu_block_md	*md_blocks;	/* metadata blocks */
56 
57 	void			*data;		/* chunk data */
58 	bool			immutable;	/* no [de]population allowed */
59 	bool			isolated;	/* isolated from active chunk
60 						   slots */
61 	int			start_offset;	/* the overlap with the previous
62 						   region to have a page aligned
63 						   base_addr */
64 	int			end_offset;	/* additional area required to
65 						   have the region end page
66 						   aligned */
67 #ifdef CONFIG_MEMCG_KMEM
68 	struct obj_cgroup	**obj_cgroups;	/* vector of object cgroups */
69 #endif
70 
71 	int			nr_pages;	/* # of pages served by this chunk */
72 	int			nr_populated;	/* # of populated pages */
73 	int                     nr_empty_pop_pages; /* # of empty populated pages */
74 	unsigned long		populated[];	/* populated bitmap */
75 };
76 
77 extern spinlock_t pcpu_lock;
78 
79 extern struct list_head *pcpu_chunk_lists;
80 extern int pcpu_nr_slots;
81 extern int pcpu_sidelined_slot;
82 extern int pcpu_to_depopulate_slot;
83 extern int pcpu_nr_empty_pop_pages;
84 
85 extern struct pcpu_chunk *pcpu_first_chunk;
86 extern struct pcpu_chunk *pcpu_reserved_chunk;
87 
88 /**
89  * pcpu_chunk_nr_blocks - converts nr_pages to # of md_blocks
90  * @chunk: chunk of interest
91  *
92  * This conversion is from the number of physical pages that the chunk
93  * serves to the number of bitmap blocks used.
94  */
95 static inline int pcpu_chunk_nr_blocks(struct pcpu_chunk *chunk)
96 {
97 	return chunk->nr_pages * PAGE_SIZE / PCPU_BITMAP_BLOCK_SIZE;
98 }
99 
100 /**
101  * pcpu_nr_pages_to_map_bits - converts the pages to size of bitmap
102  * @pages: number of physical pages
103  *
104  * This conversion is from physical pages to the number of bits
105  * required in the bitmap.
106  */
107 static inline int pcpu_nr_pages_to_map_bits(int pages)
108 {
109 	return pages * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE;
110 }
111 
112 /**
113  * pcpu_chunk_map_bits - helper to convert nr_pages to size of bitmap
114  * @chunk: chunk of interest
115  *
116  * This conversion is from the number of physical pages that the chunk
117  * serves to the number of bits in the bitmap.
118  */
119 static inline int pcpu_chunk_map_bits(struct pcpu_chunk *chunk)
120 {
121 	return pcpu_nr_pages_to_map_bits(chunk->nr_pages);
122 }
123 
124 /**
125  * pcpu_obj_full_size - helper to calculate size of each accounted object
126  * @size: size of area to allocate in bytes
127  *
128  * For each accounted object there is an extra space which is used to store
129  * obj_cgroup membership if kmemcg is not disabled. Charge it too.
130  */
131 static inline size_t pcpu_obj_full_size(size_t size)
132 {
133 	size_t extra_size = 0;
134 
135 #ifdef CONFIG_MEMCG_KMEM
136 	if (!mem_cgroup_kmem_disabled())
137 		extra_size += size / PCPU_MIN_ALLOC_SIZE * sizeof(struct obj_cgroup *);
138 #endif
139 
140 	return size * num_possible_cpus() + extra_size;
141 }
142 
143 #ifdef CONFIG_PERCPU_STATS
144 
145 #include <linux/spinlock.h>
146 
147 struct percpu_stats {
148 	u64 nr_alloc;		/* lifetime # of allocations */
149 	u64 nr_dealloc;		/* lifetime # of deallocations */
150 	u64 nr_cur_alloc;	/* current # of allocations */
151 	u64 nr_max_alloc;	/* max # of live allocations */
152 	u32 nr_chunks;		/* current # of live chunks */
153 	u32 nr_max_chunks;	/* max # of live chunks */
154 	size_t min_alloc_size;	/* min allocation size */
155 	size_t max_alloc_size;	/* max allocation size */
156 };
157 
158 extern struct percpu_stats pcpu_stats;
159 extern struct pcpu_alloc_info pcpu_stats_ai;
160 
161 /*
162  * For debug purposes. We don't care about the flexible array.
163  */
164 static inline void pcpu_stats_save_ai(const struct pcpu_alloc_info *ai)
165 {
166 	memcpy(&pcpu_stats_ai, ai, sizeof(struct pcpu_alloc_info));
167 
168 	/* initialize min_alloc_size to unit_size */
169 	pcpu_stats.min_alloc_size = pcpu_stats_ai.unit_size;
170 }
171 
172 /*
173  * pcpu_stats_area_alloc - increment area allocation stats
174  * @chunk: the location of the area being allocated
175  * @size: size of area to allocate in bytes
176  *
177  * CONTEXT:
178  * pcpu_lock.
179  */
180 static inline void pcpu_stats_area_alloc(struct pcpu_chunk *chunk, size_t size)
181 {
182 	lockdep_assert_held(&pcpu_lock);
183 
184 	pcpu_stats.nr_alloc++;
185 	pcpu_stats.nr_cur_alloc++;
186 	pcpu_stats.nr_max_alloc =
187 		max(pcpu_stats.nr_max_alloc, pcpu_stats.nr_cur_alloc);
188 	pcpu_stats.min_alloc_size =
189 		min(pcpu_stats.min_alloc_size, size);
190 	pcpu_stats.max_alloc_size =
191 		max(pcpu_stats.max_alloc_size, size);
192 
193 	chunk->nr_alloc++;
194 	chunk->max_alloc_size = max(chunk->max_alloc_size, size);
195 }
196 
197 /*
198  * pcpu_stats_area_dealloc - decrement allocation stats
199  * @chunk: the location of the area being deallocated
200  *
201  * CONTEXT:
202  * pcpu_lock.
203  */
204 static inline void pcpu_stats_area_dealloc(struct pcpu_chunk *chunk)
205 {
206 	lockdep_assert_held(&pcpu_lock);
207 
208 	pcpu_stats.nr_dealloc++;
209 	pcpu_stats.nr_cur_alloc--;
210 
211 	chunk->nr_alloc--;
212 }
213 
214 /*
215  * pcpu_stats_chunk_alloc - increment chunk stats
216  */
217 static inline void pcpu_stats_chunk_alloc(void)
218 {
219 	unsigned long flags;
220 	spin_lock_irqsave(&pcpu_lock, flags);
221 
222 	pcpu_stats.nr_chunks++;
223 	pcpu_stats.nr_max_chunks =
224 		max(pcpu_stats.nr_max_chunks, pcpu_stats.nr_chunks);
225 
226 	spin_unlock_irqrestore(&pcpu_lock, flags);
227 }
228 
229 /*
230  * pcpu_stats_chunk_dealloc - decrement chunk stats
231  */
232 static inline void pcpu_stats_chunk_dealloc(void)
233 {
234 	unsigned long flags;
235 	spin_lock_irqsave(&pcpu_lock, flags);
236 
237 	pcpu_stats.nr_chunks--;
238 
239 	spin_unlock_irqrestore(&pcpu_lock, flags);
240 }
241 
242 #else
243 
244 static inline void pcpu_stats_save_ai(const struct pcpu_alloc_info *ai)
245 {
246 }
247 
248 static inline void pcpu_stats_area_alloc(struct pcpu_chunk *chunk, size_t size)
249 {
250 }
251 
252 static inline void pcpu_stats_area_dealloc(struct pcpu_chunk *chunk)
253 {
254 }
255 
256 static inline void pcpu_stats_chunk_alloc(void)
257 {
258 }
259 
260 static inline void pcpu_stats_chunk_dealloc(void)
261 {
262 }
263 
264 #endif /* !CONFIG_PERCPU_STATS */
265 
266 #endif
267