pack: move release_pack_memory()
[git/git.git] / packfile.c
CommitLineData
4f39cd82 1#include "cache.h"
6d6a80e0 2#include "mru.h"
0317f455 3#include "pack.h"
4f39cd82
JT
4
5char *odb_pack_name(struct strbuf *buf,
6 const unsigned char *sha1,
7 const char *ext)
8{
9 strbuf_reset(buf);
10 strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
11 sha1_to_hex(sha1), ext);
12 return buf->buf;
13}
14
15char *sha1_pack_name(const unsigned char *sha1)
16{
17 static struct strbuf buf = STRBUF_INIT;
18 return odb_pack_name(&buf, sha1, "pack");
19}
20
21char *sha1_pack_index_name(const unsigned char *sha1)
22{
23 static struct strbuf buf = STRBUF_INIT;
24 return odb_pack_name(&buf, sha1, "idx");
25}
6d6a80e0
JT
26
27unsigned int pack_used_ctr;
28unsigned int pack_mmap_calls;
29unsigned int peak_pack_open_windows;
30unsigned int pack_open_windows;
31unsigned int pack_open_fds;
32unsigned int pack_max_fds;
33size_t peak_pack_mapped;
34size_t pack_mapped;
35struct packed_git *packed_git;
36
37static struct mru packed_git_mru_storage;
38struct mru *packed_git_mru = &packed_git_mru_storage;
8e21176c
JT
39
40#define SZ_FMT PRIuMAX
41static inline uintmax_t sz_fmt(size_t s) { return s; }
42
43void pack_report(void)
44{
45 fprintf(stderr,
46 "pack_report: getpagesize() = %10" SZ_FMT "\n"
47 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
48 "pack_report: core.packedGitLimit = %10" SZ_FMT "\n",
49 sz_fmt(getpagesize()),
50 sz_fmt(packed_git_window_size),
51 sz_fmt(packed_git_limit));
52 fprintf(stderr,
53 "pack_report: pack_used_ctr = %10u\n"
54 "pack_report: pack_mmap_calls = %10u\n"
55 "pack_report: pack_open_windows = %10u / %10u\n"
56 "pack_report: pack_mapped = "
57 "%10" SZ_FMT " / %10" SZ_FMT "\n",
58 pack_used_ctr,
59 pack_mmap_calls,
60 pack_open_windows, peak_pack_open_windows,
61 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
62}
0317f455
JT
63
64/*
65 * Open and mmap the index file at path, perform a couple of
66 * consistency checks, then record its information to p. Return 0 on
67 * success.
68 */
69static int check_packed_git_idx(const char *path, struct packed_git *p)
70{
71 void *idx_map;
72 struct pack_idx_header *hdr;
73 size_t idx_size;
74 uint32_t version, nr, i, *index;
75 int fd = git_open(path);
76 struct stat st;
77
78 if (fd < 0)
79 return -1;
80 if (fstat(fd, &st)) {
81 close(fd);
82 return -1;
83 }
84 idx_size = xsize_t(st.st_size);
85 if (idx_size < 4 * 256 + 20 + 20) {
86 close(fd);
87 return error("index file %s is too small", path);
88 }
89 idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
90 close(fd);
91
92 hdr = idx_map;
93 if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
94 version = ntohl(hdr->idx_version);
95 if (version < 2 || version > 2) {
96 munmap(idx_map, idx_size);
97 return error("index file %s is version %"PRIu32
98 " and is not supported by this binary"
99 " (try upgrading GIT to a newer version)",
100 path, version);
101 }
102 } else
103 version = 1;
104
105 nr = 0;
106 index = idx_map;
107 if (version > 1)
108 index += 2; /* skip index header */
109 for (i = 0; i < 256; i++) {
110 uint32_t n = ntohl(index[i]);
111 if (n < nr) {
112 munmap(idx_map, idx_size);
113 return error("non-monotonic index %s", path);
114 }
115 nr = n;
116 }
117
118 if (version == 1) {
119 /*
120 * Total size:
121 * - 256 index entries 4 bytes each
122 * - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
123 * - 20-byte SHA1 of the packfile
124 * - 20-byte SHA1 file checksum
125 */
126 if (idx_size != 4*256 + nr * 24 + 20 + 20) {
127 munmap(idx_map, idx_size);
128 return error("wrong index v1 file size in %s", path);
129 }
130 } else if (version == 2) {
131 /*
132 * Minimum size:
133 * - 8 bytes of header
134 * - 256 index entries 4 bytes each
135 * - 20-byte sha1 entry * nr
136 * - 4-byte crc entry * nr
137 * - 4-byte offset entry * nr
138 * - 20-byte SHA1 of the packfile
139 * - 20-byte SHA1 file checksum
140 * And after the 4-byte offset table might be a
141 * variable sized table containing 8-byte entries
142 * for offsets larger than 2^31.
143 */
144 unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
145 unsigned long max_size = min_size;
146 if (nr)
147 max_size += (nr - 1)*8;
148 if (idx_size < min_size || idx_size > max_size) {
149 munmap(idx_map, idx_size);
150 return error("wrong index v2 file size in %s", path);
151 }
152 if (idx_size != min_size &&
153 /*
154 * make sure we can deal with large pack offsets.
155 * 31-bit signed offset won't be enough, neither
156 * 32-bit unsigned one will be.
157 */
158 (sizeof(off_t) <= 4)) {
159 munmap(idx_map, idx_size);
160 return error("pack too large for current definition of off_t in %s", path);
161 }
162 }
163
164 p->index_version = version;
165 p->index_data = idx_map;
166 p->index_size = idx_size;
167 p->num_objects = nr;
168 return 0;
169}
170
171int open_pack_index(struct packed_git *p)
172{
173 char *idx_name;
174 size_t len;
175 int ret;
176
177 if (p->index_data)
178 return 0;
179
180 if (!strip_suffix(p->pack_name, ".pack", &len))
181 die("BUG: pack_name does not end in .pack");
182 idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
183 ret = check_packed_git_idx(idx_name, p);
184 free(idx_name);
185 return ret;
186}
187
188static struct packed_git *alloc_packed_git(int extra)
189{
190 struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
191 memset(p, 0, sizeof(*p));
192 p->pack_fd = -1;
193 return p;
194}
195
196struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
197{
198 const char *path = sha1_pack_name(sha1);
199 size_t alloc = st_add(strlen(path), 1);
200 struct packed_git *p = alloc_packed_git(alloc);
201
202 memcpy(p->pack_name, path, alloc); /* includes NUL */
203 hashcpy(p->sha1, sha1);
204 if (check_packed_git_idx(idx_path, p)) {
205 free(p);
206 return NULL;
207 }
208
209 return p;
210}
f0e17e86
JT
211
212static void scan_windows(struct packed_git *p,
213 struct packed_git **lru_p,
214 struct pack_window **lru_w,
215 struct pack_window **lru_l)
216{
217 struct pack_window *w, *w_l;
218
219 for (w_l = NULL, w = p->windows; w; w = w->next) {
220 if (!w->inuse_cnt) {
221 if (!*lru_w || w->last_used < (*lru_w)->last_used) {
222 *lru_p = p;
223 *lru_w = w;
224 *lru_l = w_l;
225 }
226 }
227 w_l = w;
228 }
229}
230
231int unuse_one_window(struct packed_git *current)
232{
233 struct packed_git *p, *lru_p = NULL;
234 struct pack_window *lru_w = NULL, *lru_l = NULL;
235
236 if (current)
237 scan_windows(current, &lru_p, &lru_w, &lru_l);
238 for (p = packed_git; p; p = p->next)
239 scan_windows(p, &lru_p, &lru_w, &lru_l);
240 if (lru_p) {
241 munmap(lru_w->base, lru_w->len);
242 pack_mapped -= lru_w->len;
243 if (lru_l)
244 lru_l->next = lru_w->next;
245 else
246 lru_p->windows = lru_w->next;
247 free(lru_w);
248 pack_open_windows--;
249 return 1;
250 }
251 return 0;
252}
253
254void release_pack_memory(size_t need)
255{
256 size_t cur = pack_mapped;
257 while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
258 ; /* nothing */
259}