pack-objects: move read mutex to packing_data struct
[git/git.git] / pack-objects.h
CommitLineData
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1#ifndef PACK_OBJECTS_H
2#define PACK_OBJECTS_H
3
43fa44fa 4#include "object-store.h"
9ac3f0e5 5#include "thread-utils.h"
ef3ca954 6#include "pack.h"
43fa44fa 7
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8#define DEFAULT_DELTA_CACHE_SIZE (256 * 1024 * 1024)
9
0c6804ab 10#define OE_DFS_STATE_BITS 2
b5c0cbd8 11#define OE_DEPTH_BITS 12
43fa44fa 12#define OE_IN_PACK_BITS 10
0cb3c142 13#define OE_Z_DELTA_BITS 20
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14/*
15 * Note that oe_set_size() becomes expensive when the given size is
16 * above this limit. Don't lower it too much.
17 */
18#define OE_SIZE_BITS 31
9ac3f0e5 19#define OE_DELTA_SIZE_BITS 23
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20
21/*
22 * State flags for depth-first search used for analyzing delta cycles.
23 *
24 * The depth is measured in delta-links to the base (so if A is a delta
25 * against B, then A has a depth of 1, and B a depth of 0).
26 */
27enum dfs_state {
28 DFS_NONE = 0,
29 DFS_ACTIVE,
30 DFS_DONE,
31 DFS_NUM_STATES
32};
33
8d6ccce1 34/*
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35 * The size of struct nearly determines pack-objects's memory
36 * consumption. This struct is packed tight for that reason. When you
37 * add or reorder something in this struct, think a bit about this.
38 *
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39 * basic object info
40 * -----------------
41 * idx.oid is filled up before delta searching starts. idx.crc32 is
42 * only valid after the object is written out and will be used for
43 * generating the index. idx.offset will be both gradually set and
44 * used in writing phase (base objects get offset first, then deltas
45 * refer to them)
46 *
47 * "size" is the uncompressed object size. Compressed size of the raw
48 * data for an object in a pack is not stored anywhere but is computed
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49 * and made available when reverse .idx is made. Note that when a
50 * delta is reused, "size" is the uncompressed _delta_ size, not the
51 * canonical one after the delta has been applied.
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52 *
53 * "hash" contains a path name hash which is used for sorting the
54 * delta list and also during delta searching. Once prepare_pack()
55 * returns it's no longer needed.
56 *
57 * source pack info
58 * ----------------
59 * The (in_pack, in_pack_offset) tuple contains the location of the
60 * object in the source pack. in_pack_header_size allows quickly
61 * skipping the header and going straight to the zlib stream.
62 *
63 * "type" and "in_pack_type" both describe object type. in_pack_type
64 * may contain a delta type, while type is always the canonical type.
65 *
66 * deltas
67 * ------
68 * Delta links (delta, delta_child and delta_sibling) are created to
69 * reflect that delta graph from the source pack then updated or added
70 * during delta searching phase when we find better deltas.
71 *
72 * delta_child and delta_sibling are last needed in
73 * compute_write_order(). "delta" and "delta_size" must remain valid
74 * at object writing phase in case the delta is not cached.
75 *
76 * If a delta is cached in memory and is compressed, delta_data points
77 * to the data and z_delta_size contains the compressed size. If it's
78 * uncompressed [1], z_delta_size must be zero. delta_size is always
79 * the uncompressed size and must be valid even if the delta is not
80 * cached.
81 *
82 * [1] during try_delta phase we don't bother with compressing because
83 * the delta could be quickly replaced with a better one.
84 */
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85struct object_entry {
86 struct pack_idx_entry idx;
2834bc27 87 void *delta_data; /* cached delta (uncompressed) */
3b13a5f2 88 off_t in_pack_offset;
2834bc27 89 uint32_t hash; /* name hint hash */
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90 unsigned size_:OE_SIZE_BITS;
91 unsigned size_valid:1;
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92 uint32_t delta_idx; /* delta base object */
93 uint32_t delta_child_idx; /* deltified objects who bases me */
94 uint32_t delta_sibling_idx; /* other deltified objects who
95 * uses the same base as me
96 */
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97 unsigned delta_size_:OE_DELTA_SIZE_BITS; /* delta data size (uncompressed) */
98 unsigned delta_size_valid:1;
9ac3f0e5 99 unsigned char in_pack_header_size;
3b13a5f2 100 unsigned in_pack_idx:OE_IN_PACK_BITS; /* already in pack */
0cb3c142 101 unsigned z_delta_size:OE_Z_DELTA_BITS;
3b13a5f2 102 unsigned type_valid:1;
3b13a5f2 103 unsigned no_try_delta:1;
9ac3f0e5 104 unsigned type_:TYPE_BITS;
fd9b1bae 105 unsigned in_pack_type:TYPE_BITS; /* could be delta */
c8d521fa 106
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107 unsigned preferred_base:1; /*
108 * we do not pack this, but is available
109 * to be used as the base object to delta
110 * objects against.
111 */
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112 unsigned tagged:1; /* near the very tip of refs */
113 unsigned filled:1; /* assigned write-order */
0c6804ab 114 unsigned dfs_state:OE_DFS_STATE_BITS;
b5c0cbd8 115 unsigned depth:OE_DEPTH_BITS;
6a1e32d5 116 unsigned ext_base:1; /* delta_idx points outside packlist */
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117
118 /*
3b13a5f2 119 * pahole results on 64-bit linux (gcc and clang)
7dbabbbe 120 *
9ac3f0e5 121 * size: 80, bit_padding: 9 bits
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122 *
123 * and on 32-bit (gcc)
124 *
9ac3f0e5 125 * size: 76, bit_padding: 9 bits
4cf2143e 126 */
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127};
128
129struct packing_data {
130 struct object_entry *objects;
131 uint32_t nr_objects, nr_alloc;
132
133 int32_t *index;
134 uint32_t index_size;
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135
136 unsigned int *in_pack_pos;
9ac3f0e5 137 unsigned long *delta_size;
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138
139 /*
140 * Only one of these can be non-NULL and they have different
141 * sizes. if in_pack_by_idx is allocated, oe_in_pack() returns
142 * the pack of an object using in_pack_idx field. If not,
143 * in_pack[] array is used the same way as in_pack_pos[]
144 */
145 struct packed_git **in_pack_by_idx;
146 struct packed_git **in_pack;
ac77d0c3 147
9ac3f0e5 148 pthread_mutex_t lock;
459307b1 149 pthread_mutex_t read_lock;
9ac3f0e5 150
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151 /*
152 * This list contains entries for bases which we know the other side
153 * has (e.g., via reachability bitmaps), but which aren't in our
154 * "objects" list.
155 */
156 struct object_entry *ext_bases;
157 uint32_t nr_ext, alloc_ext;
158
ac77d0c3 159 uintmax_t oe_size_limit;
9ac3f0e5 160 uintmax_t oe_delta_size_limit;
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161
162 /* delta islands */
163 unsigned int *tree_depth;
fe0ac2fb 164 unsigned char *layer;
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165};
166
43fa44fa 167void prepare_packing_data(struct packing_data *pdata);
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168
169static inline void packing_data_lock(struct packing_data *pdata)
170{
9ac3f0e5 171 pthread_mutex_lock(&pdata->lock);
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172}
173static inline void packing_data_unlock(struct packing_data *pdata)
174{
9ac3f0e5 175 pthread_mutex_unlock(&pdata->lock);
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176}
177
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178static inline void packing_data_read_lock(struct packing_data *pdata)
179{
180 pthread_mutex_lock(&pdata->read_lock);
181}
182static inline void packing_data_read_unlock(struct packing_data *pdata)
183{
184 pthread_mutex_unlock(&pdata->read_lock);
185}
186
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187struct object_entry *packlist_alloc(struct packing_data *pdata,
188 const unsigned char *sha1,
189 uint32_t index_pos);
190
191struct object_entry *packlist_find(struct packing_data *pdata,
192 const unsigned char *sha1,
193 uint32_t *index_pos);
194
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195static inline uint32_t pack_name_hash(const char *name)
196{
197 uint32_t c, hash = 0;
198
199 if (!name)
200 return 0;
201
202 /*
203 * This effectively just creates a sortable number from the
204 * last sixteen non-whitespace characters. Last characters
205 * count "most", so things that end in ".c" sort together.
206 */
207 while ((c = *name++) != 0) {
208 if (isspace(c))
209 continue;
210 hash = (hash >> 2) + (c << 24);
211 }
212 return hash;
213}
214
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215static inline enum object_type oe_type(const struct object_entry *e)
216{
217 return e->type_valid ? e->type_ : OBJ_BAD;
218}
219
220static inline void oe_set_type(struct object_entry *e,
221 enum object_type type)
222{
223 if (type >= OBJ_ANY)
224 BUG("OBJ_ANY cannot be set in pack-objects code");
225
226 e->type_valid = type >= OBJ_NONE;
227 e->type_ = (unsigned)type;
228}
229
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230static inline unsigned int oe_in_pack_pos(const struct packing_data *pack,
231 const struct object_entry *e)
232{
233 return pack->in_pack_pos[e - pack->objects];
234}
235
236static inline void oe_set_in_pack_pos(const struct packing_data *pack,
237 const struct object_entry *e,
238 unsigned int pos)
239{
240 pack->in_pack_pos[e - pack->objects] = pos;
241}
242
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243static inline struct packed_git *oe_in_pack(const struct packing_data *pack,
244 const struct object_entry *e)
245{
246 if (pack->in_pack_by_idx)
247 return pack->in_pack_by_idx[e->in_pack_idx];
248 else
249 return pack->in_pack[e - pack->objects];
250}
251
252void oe_map_new_pack(struct packing_data *pack,
253 struct packed_git *p);
254static inline void oe_set_in_pack(struct packing_data *pack,
255 struct object_entry *e,
256 struct packed_git *p)
257{
258 if (!p->index)
259 oe_map_new_pack(pack, p);
260 if (pack->in_pack_by_idx)
261 e->in_pack_idx = p->index;
262 else
263 pack->in_pack[e - pack->objects] = p;
264}
265
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266static inline struct object_entry *oe_delta(
267 const struct packing_data *pack,
268 const struct object_entry *e)
269{
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270 if (!e->delta_idx)
271 return NULL;
272 if (e->ext_base)
273 return &pack->ext_bases[e->delta_idx - 1];
274 else
898eba5e 275 return &pack->objects[e->delta_idx - 1];
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276}
277
278static inline void oe_set_delta(struct packing_data *pack,
279 struct object_entry *e,
280 struct object_entry *delta)
281{
282 if (delta)
283 e->delta_idx = (delta - pack->objects) + 1;
284 else
285 e->delta_idx = 0;
286}
287
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288void oe_set_delta_ext(struct packing_data *pack,
289 struct object_entry *e,
290 const unsigned char *sha1);
291
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292static inline struct object_entry *oe_delta_child(
293 const struct packing_data *pack,
294 const struct object_entry *e)
295{
296 if (e->delta_child_idx)
297 return &pack->objects[e->delta_child_idx - 1];
298 return NULL;
299}
300
301static inline void oe_set_delta_child(struct packing_data *pack,
302 struct object_entry *e,
303 struct object_entry *delta)
304{
305 if (delta)
306 e->delta_child_idx = (delta - pack->objects) + 1;
307 else
308 e->delta_child_idx = 0;
309}
310
311static inline struct object_entry *oe_delta_sibling(
312 const struct packing_data *pack,
313 const struct object_entry *e)
314{
315 if (e->delta_sibling_idx)
316 return &pack->objects[e->delta_sibling_idx - 1];
317 return NULL;
318}
319
320static inline void oe_set_delta_sibling(struct packing_data *pack,
321 struct object_entry *e,
322 struct object_entry *delta)
323{
324 if (delta)
325 e->delta_sibling_idx = (delta - pack->objects) + 1;
326 else
327 e->delta_sibling_idx = 0;
328}
329
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330unsigned long oe_get_size_slow(struct packing_data *pack,
331 const struct object_entry *e);
332static inline unsigned long oe_size(struct packing_data *pack,
333 const struct object_entry *e)
334{
335 if (e->size_valid)
336 return e->size_;
337
338 return oe_get_size_slow(pack, e);
339}
340
341static inline int oe_size_less_than(struct packing_data *pack,
342 const struct object_entry *lhs,
343 unsigned long rhs)
344{
345 if (lhs->size_valid)
346 return lhs->size_ < rhs;
347 if (rhs < pack->oe_size_limit) /* rhs < 2^x <= lhs ? */
348 return 0;
349 return oe_get_size_slow(pack, lhs) < rhs;
350}
351
352static inline int oe_size_greater_than(struct packing_data *pack,
353 const struct object_entry *lhs,
354 unsigned long rhs)
355{
356 if (lhs->size_valid)
357 return lhs->size_ > rhs;
358 if (rhs < pack->oe_size_limit) /* rhs < 2^x <= lhs ? */
359 return 1;
360 return oe_get_size_slow(pack, lhs) > rhs;
361}
362
363static inline void oe_set_size(struct packing_data *pack,
364 struct object_entry *e,
365 unsigned long size)
366{
367 if (size < pack->oe_size_limit) {
368 e->size_ = size;
369 e->size_valid = 1;
370 } else {
371 e->size_valid = 0;
372 if (oe_get_size_slow(pack, e) != size)
373 BUG("'size' is supposed to be the object size!");
374 }
375}
376
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377static inline unsigned long oe_delta_size(struct packing_data *pack,
378 const struct object_entry *e)
379{
380 if (e->delta_size_valid)
381 return e->delta_size_;
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382
383 /*
ce498e09 384 * pack->delta_size[] can't be NULL because oe_set_delta_size()
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385 * must have been called when a new delta is saved with
386 * oe_set_delta().
387 * If oe_delta() returns NULL (i.e. default state, which means
388 * delta_size_valid is also false), then the caller must never
389 * call oe_delta_size().
390 */
391 return pack->delta_size[e - pack->objects];
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392}
393
394static inline void oe_set_delta_size(struct packing_data *pack,
395 struct object_entry *e,
396 unsigned long size)
397{
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398 if (size < pack->oe_delta_size_limit) {
399 e->delta_size_ = size;
400 e->delta_size_valid = 1;
401 } else {
402 packing_data_lock(pack);
403 if (!pack->delta_size)
404 ALLOC_ARRAY(pack->delta_size, pack->nr_alloc);
405 packing_data_unlock(pack);
406
407 pack->delta_size[e - pack->objects] = size;
408 e->delta_size_valid = 0;
409 }
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410}
411
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412static inline unsigned int oe_tree_depth(struct packing_data *pack,
413 struct object_entry *e)
414{
415 if (!pack->tree_depth)
416 return 0;
417 return pack->tree_depth[e - pack->objects];
418}
419
420static inline void oe_set_tree_depth(struct packing_data *pack,
421 struct object_entry *e,
422 unsigned int tree_depth)
423{
424 if (!pack->tree_depth)
e159b810 425 CALLOC_ARRAY(pack->tree_depth, pack->nr_alloc);
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426 pack->tree_depth[e - pack->objects] = tree_depth;
427}
428
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429static inline unsigned char oe_layer(struct packing_data *pack,
430 struct object_entry *e)
431{
432 if (!pack->layer)
433 return 0;
434 return pack->layer[e - pack->objects];
435}
436
437static inline void oe_set_layer(struct packing_data *pack,
438 struct object_entry *e,
439 unsigned char layer)
440{
441 if (!pack->layer)
e159b810 442 CALLOC_ARRAY(pack->layer, pack->nr_alloc);
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443 pack->layer[e - pack->objects] = layer;
444}
445
2834bc27 446#endif