{"thread":{"id":"40691","subject":"[PATCH v4 1/9] trace.c: add GIT_TRACE_PACK_STATS for pack usage statistics","startedAt":"2015-11-01T13:42:40Z","lastAt":"2015-11-16T21:51:07Z","messageCount":12,"participants":["Nguyễn Thái Ngọc Duy","David Turner","Johannes Schindelin"],"isPatch":true,"patchVersion":4,"patchTotal":9},"messages":[{"id":"272664","messageId":"1446385369-8669-1-git-send-email-pclouds@gmail.com","threadId":"40691","inReplyTo":null,"subject":"[PATCH v4 0/9] Reduce index load time","fromName":"Nguyễn Thái Ngọc Duy","fromEmail":"pclouds@gmail.com","sentAt":"2015-11-01T13:42:40Z","receivedAt":"2015-11-01T13:42:40Z","isPatch":true,"sender":{"key":"pclouds@gmail.com","avatar":"https://avatars.githubusercontent.com/u/720?v=4"},"body":"This is the rebased version since last time [1] with\ns/free_index_shm/release_index_shm/ as suggested by David Turner. It\nintroduces a daemon that can cache index data in memory so that\nsubsequent git processes can avoid reading (and more importantly,\nverifying) the index from disk. Together with split-index it should\nkeep index I/O cost down to minimum. The series can also be found at\n[2].\n\nOne of the factors that affected my design was Windows support. We\nnow have Dscho back, he can evaluate my approach for Windows.\n\nThis daemon is the foundation for watchman support later to reduce\nrefresh time. To be posted shortly after this.\n\n[0] http://mid.gmane.org/1406548995-28549-1-git-send-email-pclouds@gmail.com\n[2] http://github.com/pclouds/git/commits/index-helper\n\nNguyễn Thái Ngọc Duy (9):\n  trace.c: add GIT_TRACE_PACK_STATS for pack usage statistics\n  read-cache.c: fix constness of verify_hdr()\n  read-cache: allow to keep mmap'd memory after reading\n  index-helper: new daemon for caching index and related stuff\n  trace.c: add GIT_TRACE_INDEX_STATS for index  statistics\n  index-helper: add --strict\n  daemonize(): set a flag before exiting the main process\n  index-helper: add --detach\n  index-helper: add Windows support\n\n .gitignore                               |   1 +\n Documentation/git-index-helper.txt (new) |  56 +++++++\n Documentation/git.txt                    |   4 +\n Makefile                                 |   9 ++\n builtin/gc.c                             |   2 +-\n cache.h                                  |  12 +-\n config.mak.uname                         |   3 +\n daemon.c                                 |   2 +-\n git-compat-util.h                        |   1 +\n git.c                                    |   1 +\n index-helper.c (new)                     | 264 +++++++++++++++++++++++++++++++\n read-cache.c                             | 147 ++++++++++++++++-\n setup.c                                  |   4 +-\n sha1_file.c                              |  24 +++\n shm.c (new)                              | 163 +++++++++++++++++++\n shm.h (new)                              |  23 +++\n trace.c                                  |  16 ++\n trace.h                                  |   1 +\n 18 files changed, 721 insertions(+), 12 deletions(-)\n create mode 100644 Documentation/git-index-helper.txt\n create mode 100644 index-helper.c\n create mode 100644 shm.c\n create mode 100644 shm.h\n\n-- \n2.2.0.513.g477eb31\n"},{"id":"272656","messageId":"1446385369-8669-2-git-send-email-pclouds@gmail.com","threadId":"40691","inReplyTo":"1446385369-8669-1-git-send-email-pclouds@gmail.com","subject":"[PATCH v4 1/9] trace.c: add GIT_TRACE_PACK_STATS for pack usage statistics","fromName":"Nguyễn Thái Ngọc Duy","fromEmail":"pclouds@gmail.com","sentAt":"2015-11-01T13:42:41Z","receivedAt":"2015-11-01T13:42:41Z","isPatch":true,"sender":{"key":"pclouds@gmail.com","avatar":"https://avatars.githubusercontent.com/u/720?v=4"},"body":"trace_stats() is intended for GIT_TRACE_*_STATS variable group and\nGIT_TRACE_PACK_STATS is more like an example how new vars can be added.\n\nSigned-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>\n---\n Documentation/git.txt |  3 +++\n cache.h               |  2 ++\n git.c                 |  1 +\n sha1_file.c           | 24 ++++++++++++++++++++++++\n trace.c               | 13 +++++++++++++\n trace.h               |  1 +\n 6 files changed, 44 insertions(+)\n\ndiff --git a/Documentation/git.txt b/Documentation/git.txt\nindex 4585103..1086ced 100644\n--- a/Documentation/git.txt\n+++ b/Documentation/git.txt\n@@ -1045,6 +1045,9 @@ of clones and fetches.\n \ttime of each Git command.\n \tSee 'GIT_TRACE' for available trace output options.\n \n+'GIT_TRACE_PACK_STATS'::\n+\tPrint various statistics.\n+\n 'GIT_TRACE_SETUP'::\n \tEnables trace messages printing the .git, working tree and current\n \tworking directory after Git has completed its setup phase.\ndiff --git a/cache.h b/cache.h\nindex 3ba0b8f..8791dbc 100644\n--- a/cache.h\n+++ b/cache.h\n@@ -1747,4 +1747,6 @@ void stat_validity_update(struct stat_validity *sv, int fd);\n int versioncmp(const char *s1, const char *s2);\n void sleep_millisec(int millisec);\n \n+void report_pack_stats(struct trace_key *key);\n+\n #endif /* CACHE_H */\ndiff --git a/git.c b/git.c\nindex 6ed824c..f4018c5 100644\n--- a/git.c\n+++ b/git.c\n@@ -644,6 +644,7 @@ int main(int argc, char **av)\n \tgit_setup_gettext();\n \n \ttrace_command_performance(argv);\n+\ttrace_stats();\n \n \t/*\n \t * \"git-xxxx\" is the same as \"git xxxx\", but we obviously:\ndiff --git a/sha1_file.c b/sha1_file.c\nindex c5b31de..1d3508d 100644\n--- a/sha1_file.c\n+++ b/sha1_file.c\n@@ -517,6 +517,7 @@ static unsigned int peak_pack_open_windows;\n static unsigned int pack_open_windows;\n static unsigned int pack_open_fds;\n static unsigned int pack_max_fds;\n+static unsigned int pack_access_nr;\n static size_t peak_pack_mapped;\n static size_t pack_mapped;\n struct packed_git *packed_git;\n@@ -542,6 +543,28 @@ void pack_report(void)\n \t\tsz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));\n }\n \n+void report_pack_stats(struct trace_key *key)\n+{\n+\ttrace_printf_key(key, \"\\n\"\n+\t\t\t \"pack_report: getpagesize()            = %10\" SZ_FMT \"\\n\"\n+\t\t\t \"pack_report: core.packedGitWindowSize = %10\" SZ_FMT \"\\n\"\n+\t\t\t \"pack_report: core.packedGitLimit      = %10\" SZ_FMT \"\\n\"\n+\t\t\t \"pack_report: pack_used_ctr            = %10u\\n\"\n+\t\t\t \"pack_report: pack_mmap_calls          = %10u\\n\"\n+\t\t\t \"pack_report: pack_open_windows        = %10u / %10u\\n\"\n+\t\t\t \"pack_report: pack_mapped              = \"\n+\t\t\t \"%10\" SZ_FMT \" / %10\" SZ_FMT \"\\n\"\n+\t\t\t \"pack_report: pack accesss             = %10u\\n\",\n+\t\t\t sz_fmt(getpagesize()),\n+\t\t\t sz_fmt(packed_git_window_size),\n+\t\t\t sz_fmt(packed_git_limit),\n+\t\t\t pack_used_ctr,\n+\t\t\t pack_mmap_calls,\n+\t\t\t pack_open_windows, peak_pack_open_windows,\n+\t\t\t sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped),\n+\t\t\t pack_access_nr);\n+}\n+\n /*\n  * Open and mmap the index file at path, perform a couple of\n  * consistency checks, then record its information to p.  Return 0 on\n@@ -2244,6 +2267,7 @@ static void write_pack_access_log(struct packed_git *p, off_t obj_offset)\n \tstatic struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);\n \ttrace_printf_key(&pack_access, \"%s %\"PRIuMAX\"\\n\",\n \t\t\t p->pack_name, (uintmax_t)obj_offset);\n+\tpack_access_nr++;\n }\n \n int do_check_packed_object_crc;\ndiff --git a/trace.c b/trace.c\nindex 4aeea60..b1d0885 100644\n--- a/trace.c\n+++ b/trace.c\n@@ -432,3 +432,16 @@ void trace_command_performance(const char **argv)\n \tsq_quote_argv(&command_line, argv, 0);\n \tcommand_start_time = getnanotime();\n }\n+\n+static struct trace_key trace_pack_stats = TRACE_KEY_INIT(PACK_STATS);\n+\n+static void print_stats_atexit(void)\n+{\n+\treport_pack_stats(&trace_pack_stats);\n+}\n+\n+void trace_stats(void)\n+{\n+\tif (trace_want(&trace_pack_stats))\n+\t\tatexit(print_stats_atexit);\n+}\ndiff --git a/trace.h b/trace.h\nindex 179b249..52bda4e 100644\n--- a/trace.h\n+++ b/trace.h\n@@ -19,6 +19,7 @@ extern void trace_disable(struct trace_key *key);\n extern uint64_t getnanotime(void);\n extern void trace_command_performance(const char **argv);\n extern void trace_verbatim(struct trace_key *key, const void *buf, unsigned len);\n+extern void trace_stats(void);\n \n #ifndef HAVE_VARIADIC_MACROS\n \n-- \n2.2.0.513.g477eb31\n"},{"id":"272657","messageId":"1446385369-8669-3-git-send-email-pclouds@gmail.com","threadId":"40691","inReplyTo":"1446385369-8669-1-git-send-email-pclouds@gmail.com","subject":"[PATCH v4 2/9] read-cache.c: fix constness of verify_hdr()","fromName":"Nguyễn Thái Ngọc Duy","fromEmail":"pclouds@gmail.com","sentAt":"2015-11-01T13:42:42Z","receivedAt":"2015-11-01T13:42:42Z","isPatch":true,"sender":{"key":"pclouds@gmail.com","avatar":"https://avatars.githubusercontent.com/u/720?v=4"},"body":"Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>\n---\n read-cache.c | 2 +-\n 1 file changed, 1 insertion(+), 1 deletion(-)\n\ndiff --git a/read-cache.c b/read-cache.c\nindex 84616c8..a76c789 100644\n--- a/read-cache.c\n+++ b/read-cache.c\n@@ -1345,7 +1345,7 @@ struct ondisk_cache_entry_extended {\n \t\t\t    ondisk_cache_entry_extended_size(ce_namelen(ce)) : \\\n \t\t\t    ondisk_cache_entry_size(ce_namelen(ce)))\n \n-static int verify_hdr(struct cache_header *hdr, unsigned long size)\n+static int verify_hdr(const struct cache_header *hdr, unsigned long size)\n {\n \tgit_SHA_CTX c;\n \tunsigned char sha1[20];\n-- \n2.2.0.513.g477eb31\n"},{"id":"272659","messageId":"1446385369-8669-4-git-send-email-pclouds@gmail.com","threadId":"40691","inReplyTo":"1446385369-8669-1-git-send-email-pclouds@gmail.com","subject":"[PATCH v4 3/9] read-cache: allow to keep mmap'd memory after reading","fromName":"Nguyễn Thái Ngọc Duy","fromEmail":"pclouds@gmail.com","sentAt":"2015-11-01T13:42:43Z","receivedAt":"2015-11-01T13:42:43Z","isPatch":true,"sender":{"key":"pclouds@gmail.com","avatar":"https://avatars.githubusercontent.com/u/720?v=4"},"body":"Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>\n---\n cache.h      |  3 +++\n read-cache.c | 13 ++++++++++++-\n 2 files changed, 15 insertions(+), 1 deletion(-)\n\ndiff --git a/cache.h b/cache.h\nindex 8791dbc..89e9aaf 100644\n--- a/cache.h\n+++ b/cache.h\n@@ -311,11 +311,14 @@ struct index_state {\n \tstruct split_index *split_index;\n \tstruct cache_time timestamp;\n \tunsigned name_hash_initialized : 1,\n+\t\t keep_mmap : 1,\n \t\t initialized : 1;\n \tstruct hashmap name_hash;\n \tstruct hashmap dir_hash;\n \tunsigned char sha1[20];\n \tstruct untracked_cache *untracked;\n+\tvoid *mmap;\n+\tsize_t mmap_size;\n };\n \n extern struct index_state the_index;\ndiff --git a/read-cache.c b/read-cache.c\nindex a76c789..7d04108 100644\n--- a/read-cache.c\n+++ b/read-cache.c\n@@ -1552,6 +1552,10 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)\n \tmmap = xmmap(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0);\n \tif (mmap == MAP_FAILED)\n \t\tdie_errno(\"unable to map index file\");\n+\tif (istate->keep_mmap) {\n+\t\tistate->mmap = mmap;\n+\t\tistate->mmap_size = mmap_size;\n+\t}\n \tclose(fd);\n \n \thdr = mmap;\n@@ -1604,10 +1608,12 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)\n \t\tsrc_offset += 8;\n \t\tsrc_offset += extsize;\n \t}\n-\tmunmap(mmap, mmap_size);\n+\tif (!istate->keep_mmap)\n+\t\tmunmap(mmap, mmap_size);\n \treturn istate->cache_nr;\n \n unmap:\n+\tistate->mmap = NULL;\n \tmunmap(mmap, mmap_size);\n \tdie(\"index file corrupt\");\n }\n@@ -1632,6 +1638,7 @@ int read_index_from(struct index_state *istate, const char *path)\n \t\tdiscard_index(split_index->base);\n \telse\n \t\tsplit_index->base = xcalloc(1, sizeof(*split_index->base));\n+\tsplit_index->base->keep_mmap = istate->keep_mmap;\n \tret = do_read_index(split_index->base,\n \t\t\t    git_path(\"sharedindex.%s\",\n \t\t\t\t     sha1_to_hex(split_index->base_sha1)), 1);\n@@ -1675,6 +1682,10 @@ int discard_index(struct index_state *istate)\n \tfree(istate->cache);\n \tistate->cache = NULL;\n \tistate->cache_alloc = 0;\n+\tif (istate->keep_mmap && istate->mmap) {\n+\t\tmunmap(istate->mmap, istate->mmap_size);\n+\t\tistate->mmap = NULL;\n+\t}\n \tdiscard_split_index(istate);\n \tfree_untracked_cache(istate->untracked);\n \tistate->untracked = NULL;\n-- \n2.2.0.513.g477eb31\n"},{"id":"272665","messageId":"1446385369-8669-5-git-send-email-pclouds@gmail.com","threadId":"40691","inReplyTo":"1446385369-8669-1-git-send-email-pclouds@gmail.com","subject":"[PATCH v4 4/9] index-helper: new daemon for caching index and related stuff","fromName":"Nguyễn Thái Ngọc Duy","fromEmail":"pclouds@gmail.com","sentAt":"2015-11-01T13:42:44Z","receivedAt":"2015-11-01T13:42:44Z","isPatch":true,"sender":{"key":"pclouds@gmail.com","avatar":"https://avatars.githubusercontent.com/u/720?v=4"},"body":"Instead of reading the index from disk and worrying about disk\ncorruption, the index is cached in memory (memory bit-flips happen\ntoo, but hopefully less often). The result is faster read. Read time\nis reduced by 70%.\n\nThe biggest gain is not having to verify the trailing SHA-1, which\ntakes lots of time especially on large index files. But this also\nopens doors for further optimiztions:\n\n - we could create an in-memory format that's essentially the memory\n   dump of the index to eliminate most of parsing/allocation\n   overhead. The mmap'd memory can be used straight away. Experiment\n   [1] shows we could reduce read time by 88%.\n\n - we could cache non-index info such as name hash\n\nThe shared memory's name folows the template \"git-<object>-<SHA1>\"\nwhere <SHA1> is the trailing SHA-1 of the index file. <object> is\n\"index\" for cached index files (and may be \"name-hash\" for name-hash\ncache). If such shared memory exists, it contains the same index\ncontent as on disk. The content is already validated by the daemon and\ngit won't validate it again (except comparing the trailing SHA-1s).\n\nGit can poke the daemon to tell it to refresh the index cache, or to\nkeep it alive some more minutes via UNIX signals. It can't give any\nreal index data directly to the daemon. Real data goes to disk first,\nthen the daemon reads and verifies it from there. Poking only happens\nfor $GIT_DIR/index, not temporary index files.\n\n$GIT_DIR/index-helper.pid contains a reference to daemon process (and\nit's pid on *nix). The file's mtime is updated every time it's accessed\n(or should be updated often enough). Old index-helper.pid is considered\nstale and ignored.\n\nindex-helper requires POSIX realtime extension. POSIX shm interface\nhowever is abstracted away so that Windows support can be added later.\n\nOn webkit.git with index format v2, duplicating 8 times to 1.4m\nentries and 200MB in size:\n\n(vanilla)      0.986986364 s: read_index_from .git/index\n(index-helper) 0.267850279 s: read_index_from .git/index\n\nInterestingly with index v4, we get less out of index-helper. It makes\nsense as v4 requires more processing after loading the index:\n\n(vanilla)      0.722496666 s: read_index_from .git/index\n(index-helper) 0.302741500 s: read_index_from .git/index\n\nSigned-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>\n---\n .gitignore                               |   1 +\n Documentation/git-index-helper.txt (new) |  44 +++++++++\n Makefile                                 |   9 ++\n cache.h                                  |   3 +\n config.mak.uname                         |   1 +\n git-compat-util.h                        |   1 +\n index-helper.c (new)                     | 162 +++++++++++++++++++++++++++++++\n read-cache.c                             | 106 ++++++++++++++++++--\n shm.c (new)                              |  67 +++++++++++++\n shm.h (new)                              |  23 +++++\n 10 files changed, 408 insertions(+), 9 deletions(-)\n create mode 100644 Documentation/git-index-helper.txt\n create mode 100644 index-helper.c\n create mode 100644 shm.c\n create mode 100644 shm.h\n\ndiff --git a/.gitignore b/.gitignore\nindex 1c2f832..f36f1d3 100644\n--- a/.gitignore\n+++ b/.gitignore\n@@ -71,6 +71,7 @@\n /git-http-fetch\n /git-http-push\n /git-imap-send\n+/git-index-helper\n /git-index-pack\n /git-init\n /git-init-db\ndiff --git a/Documentation/git-index-helper.txt b/Documentation/git-index-helper.txt\nnew file mode 100644\nindex 0000000..9db28cf\n--- /dev/null\n+++ b/Documentation/git-index-helper.txt\n@@ -0,0 +1,44 @@\n+git-index-helper(1)\n+===================\n+\n+NAME\n+----\n+git-index-helper - A simple cache daemon for speeding up index file access\n+\n+SYNOPSIS\n+--------\n+[verse]\n+'git index-helper' [options]\n+\n+DESCRIPTION\n+-----------\n+Keep the index file in memory for faster access. This daemon is per\n+repository.\n+\n+OPTIONS\n+-------\n+\n+--exit-after=<n>::\n+\tExit if the cached index is not accessed for `<n>`\n+\tminutes. Specify 0 to wait forever. Default is 10.\n+\n+NOTES\n+-----\n+On UNIX-like systems, $GIT_DIR/index-helper.pid contains the process\n+id of the daemon. At least on Linux, shared memory objects are\n+availble via /dev/shm with the name pattern \"git-<something>-<SHA1>\".\n+Normally the daemon will clean up shared memory objects when it exits.\n+But if it crashes, some objects could remain there and they can be\n+safely deleted with \"rm\" command. The following signals are used to\n+control the daemon:\n+\n+SIGHUP::\n+\tReread the index.\n+\n+SIGUSR1::\n+\tLet the daemon know the index is to be read. It keeps the\n+\tdaemon alive longer, unless `--exit-after=0` is used.\n+\n+GIT\n+---\n+Part of the linkgit:git[1] suite\ndiff --git a/Makefile b/Makefile\nindex 43ceeb9..c01cd2e 100644\n--- a/Makefile\n+++ b/Makefile\n@@ -363,6 +363,8 @@ all::\n # Define HAVE_BSD_SYSCTL if your platform has a BSD-compatible sysctl function.\n #\n # Define HAVE_GETDELIM if your system has the getdelim() function.\n+#\n+# Define HAVE_SHM if you platform support shm_* functions in librt.\n \n GIT-VERSION-FILE: FORCE\n \t@$(SHELL_PATH) ./GIT-VERSION-GEN\n@@ -784,6 +786,7 @@ LIB_OBJS += sha1-lookup.o\n LIB_OBJS += sha1_file.o\n LIB_OBJS += sha1_name.o\n LIB_OBJS += shallow.o\n+LIB_OBJS += shm.o\n LIB_OBJS += sideband.o\n LIB_OBJS += sigchain.o\n LIB_OBJS += split-index.o\n@@ -1403,6 +1406,12 @@ ifdef HAVE_DEV_TTY\n \tBASIC_CFLAGS += -DHAVE_DEV_TTY\n endif\n \n+ifdef HAVE_SHM\n+\tBASIC_CFLAGS\t+= -DHAVE_SHM\n+\tEXTLIBS\t        += -lrt\n+\tPROGRAM_OBJS\t+= index-helper.o\n+endif\n+\n ifdef DIR_HAS_BSD_GROUP_SEMANTICS\n \tCOMPAT_CFLAGS += -DDIR_HAS_BSD_GROUP_SEMANTICS\n endif\ndiff --git a/cache.h b/cache.h\nindex 89e9aaf..30a3a77 100644\n--- a/cache.h\n+++ b/cache.h\n@@ -312,6 +312,8 @@ struct index_state {\n \tstruct cache_time timestamp;\n \tunsigned name_hash_initialized : 1,\n \t\t keep_mmap : 1,\n+\t\t from_shm : 1,\n+\t\t to_shm : 1,\n \t\t initialized : 1;\n \tstruct hashmap name_hash;\n \tstruct hashmap dir_hash;\n@@ -520,6 +522,7 @@ extern int is_index_unborn(struct index_state *);\n extern int read_index_unmerged(struct index_state *);\n #define COMMIT_LOCK\t\t(1 << 0)\n #define CLOSE_LOCK\t\t(1 << 1)\n+#define REFRESH_DAEMON\t\t(1 << 2)\n extern int write_locked_index(struct index_state *, struct lock_file *lock, unsigned flags);\n extern int discard_index(struct index_state *);\n extern int unmerged_index(const struct index_state *);\ndiff --git a/config.mak.uname b/config.mak.uname\nindex f34dcaa..3167e36 100644\n--- a/config.mak.uname\n+++ b/config.mak.uname\n@@ -37,6 +37,7 @@ ifeq ($(uname_S),Linux)\n \tHAVE_CLOCK_GETTIME = YesPlease\n \tHAVE_CLOCK_MONOTONIC = YesPlease\n \tHAVE_GETDELIM = YesPlease\n+\tHAVE_SHM = YesPlease\n endif\n ifeq ($(uname_S),GNU/kFreeBSD)\n \tHAVE_ALLOCA_H = YesPlease\ndiff --git a/git-compat-util.h b/git-compat-util.h\nindex 8e39867..d8f6c3a 100644\n--- a/git-compat-util.h\n+++ b/git-compat-util.h\n@@ -499,6 +499,7 @@ static inline int ends_with(const char *str, const char *suffix)\n #define PROT_READ 1\n #define PROT_WRITE 2\n #define MAP_PRIVATE 1\n+#define MAP_SHARED 2\n #endif\n \n #define mmap git_mmap\ndiff --git a/index-helper.c b/index-helper.c\nnew file mode 100644\nindex 0000000..cf2971d\n--- /dev/null\n+++ b/index-helper.c\n@@ -0,0 +1,162 @@\n+#include \"cache.h\"\n+#include \"parse-options.h\"\n+#include \"sigchain.h\"\n+#include \"exec_cmd.h\"\n+#include \"split-index.h\"\n+#include \"shm.h\"\n+#include \"lockfile.h\"\n+\n+struct shm {\n+\tunsigned char sha1[20];\n+\tvoid *shm;\n+\tsize_t size;\n+};\n+\n+static struct shm shm_index;\n+static struct shm shm_base_index;\n+\n+static void release_index_shm(struct shm *is)\n+{\n+\tif (!is->shm)\n+\t\treturn;\n+\tmunmap(is->shm, is->size);\n+\tgit_shm_unlink(\"git-index-%s\", sha1_to_hex(is->sha1));\n+\tis->shm = NULL;\n+}\n+\n+static void cleanup_shm(void)\n+{\n+\trelease_index_shm(&shm_index);\n+\trelease_index_shm(&shm_base_index);\n+}\n+\n+static void cleanup(void)\n+{\n+\tunlink(git_path(\"index-helper.pid\"));\n+\tcleanup_shm();\n+}\n+\n+static void cleanup_on_signal(int sig)\n+{\n+\tcleanup();\n+\tsigchain_pop(sig);\n+\traise(sig);\n+}\n+\n+static void share_index(struct index_state *istate, struct shm *is)\n+{\n+\tvoid *new_mmap;\n+\tif (istate->mmap_size <= 20 ||\n+\t    hashcmp(istate->sha1,\n+\t\t    (unsigned char *)istate->mmap + istate->mmap_size - 20) ||\n+\t    !hashcmp(istate->sha1, is->sha1) ||\n+\t    git_shm_map(O_CREAT | O_EXCL | O_RDWR, 0700, istate->mmap_size,\n+\t\t\t&new_mmap, PROT_READ | PROT_WRITE, MAP_SHARED,\n+\t\t\t\"git-index-%s\", sha1_to_hex(istate->sha1)) < 0)\n+\t\treturn;\n+\n+\trelease_index_shm(is);\n+\tis->size = istate->mmap_size;\n+\tis->shm = new_mmap;\n+\thashcpy(is->sha1, istate->sha1);\n+\tmemcpy(new_mmap, istate->mmap, istate->mmap_size - 20);\n+\n+\t/*\n+\t * The trailing hash must be written last after everything is\n+\t * written. It's the indication that the shared memory is now\n+\t * ready.\n+\t */\n+\thashcpy((unsigned char *)new_mmap + istate->mmap_size - 20, is->sha1);\n+}\n+\n+static void share_the_index(void)\n+{\n+\tif (the_index.split_index && the_index.split_index->base)\n+\t\tshare_index(the_index.split_index->base, &shm_base_index);\n+\tshare_index(&the_index, &shm_index);\n+\tdiscard_index(&the_index);\n+}\n+\n+static void refresh(int sig)\n+{\n+\tthe_index.keep_mmap = 1;\n+\tthe_index.to_shm    = 1;\n+\tif (read_cache() < 0)\n+\t\tdie(_(\"could not read index\"));\n+\tshare_the_index();\n+}\n+\n+#ifdef HAVE_SHM\n+\n+static void do_nothing(int sig)\n+{\n+\t/*\n+\t * what we need is the signal received and interrupts\n+\t * sleep(). We don't need to do anything else when receving\n+\t * the signal\n+\t */\n+}\n+\n+static void loop(const char *pid_file, int idle_in_seconds)\n+{\n+\tsigchain_pop(SIGHUP);\t/* pushed by sigchain_push_common */\n+\tsigchain_push(SIGHUP, refresh);\n+\tsigchain_push(SIGUSR1, do_nothing);\n+\trefresh(0);\n+\twhile (sleep(idle_in_seconds))\n+\t\t; /* do nothing, all is handled by signal handlers already */\n+}\n+\n+#else\n+\n+static void loop(const char *pid_file, int idle_in_seconds)\n+{\n+\tdie(_(\"index-helper is not supported on this platform\"));\n+}\n+\n+#endif\n+\n+static const char * const usage_text[] = {\n+\tN_(\"git index-helper [options]\"),\n+\tNULL\n+};\n+\n+int main(int argc, char **argv)\n+{\n+\tstatic struct lock_file lock;\n+\tstruct strbuf sb = STRBUF_INIT;\n+\tconst char *prefix;\n+\tint fd, idle_in_minutes = 10;\n+\tstruct option options[] = {\n+\t\tOPT_INTEGER(0, \"exit-after\", &idle_in_minutes,\n+\t\t\t    N_(\"exit if not used after some minutes\")),\n+\t\tOPT_END()\n+\t};\n+\n+\tgit_extract_argv0_path(argv[0]);\n+\tgit_setup_gettext();\n+\n+\tif (argc == 2 && !strcmp(argv[1], \"-h\"))\n+\t\tusage_with_options(usage_text, options);\n+\n+\tprefix = setup_git_directory();\n+\tif (parse_options(argc, (const char **)argv, prefix,\n+\t\t\t  options, usage_text, 0))\n+\t\tdie(_(\"too many arguments\"));\n+\n+\tfd = hold_lock_file_for_update(&lock,\n+\t\t\t\t       git_path(\"index-helper.pid\"),\n+\t\t\t\t       LOCK_DIE_ON_ERROR);\n+\tstrbuf_addf(&sb, \"%\" PRIuMAX, (uintmax_t) getpid());\n+\twrite_in_full(fd, sb.buf, sb.len);\n+\tcommit_lock_file(&lock);\n+\n+\tatexit(cleanup);\n+\tsigchain_push_common(cleanup_on_signal);\n+\n+\tif (!idle_in_minutes)\n+\t\tidle_in_minutes = 0xffffffff / 60;\n+\tloop(sb.buf, idle_in_minutes * 60);\n+\tstrbuf_release(&sb);\n+\treturn 0;\n+}\ndiff --git a/read-cache.c b/read-cache.c\nindex 7d04108..6c98e98 100644\n--- a/read-cache.c\n+++ b/read-cache.c\n@@ -18,6 +18,7 @@\n #include \"varint.h\"\n #include \"split-index.h\"\n #include \"utf8.h\"\n+#include \"shm.h\"\n \n static struct cache_entry *refresh_cache_entry(struct cache_entry *ce,\n \t\t\t\t\t       unsigned int options);\n@@ -1519,6 +1520,81 @@ static void check_ce_order(struct index_state *istate)\n \t}\n }\n \n+static void do_poke(struct strbuf *sb, int refresh_cache)\n+{\n+\tchar\t*start = sb->buf;\n+\tchar\t*end   = NULL;\n+\tpid_t\t pid   = strtoul(start, &end, 10);\n+\tif (!end || end != sb->buf + sb->len)\n+\t\treturn;\n+\tkill(pid, refresh_cache ? SIGHUP : SIGUSR1);\n+}\n+\n+static void poke_daemon(struct index_state *istate,\n+\t\t\tconst struct stat *st, int refresh_cache)\n+{\n+\tint fd;\n+\tstruct strbuf sb;\n+\n+\t/* if this is from index-helper, do not poke itself (recursively) */\n+\tif (istate->to_shm)\n+\t\treturn;\n+\n+\tfd = open(git_path(\"index-helper.pid\"), O_RDONLY);\n+\tif (fd < 0)\n+\t\treturn;\n+\tstrbuf_init(&sb, st->st_size + 1);\n+\tstrbuf_setlen(&sb, st->st_size);\n+\tif (read_in_full(fd, sb.buf, st->st_size) == st->st_size)\n+\t\tdo_poke(&sb, refresh_cache);\n+\tclose(fd);\n+\tstrbuf_release(&sb);\n+}\n+\n+static int is_main_index(struct index_state *istate)\n+{\n+\treturn istate == &the_index ||\n+\t\t(the_index.split_index &&\n+\t\t istate == the_index.split_index->base);\n+}\n+\n+/*\n+ * Try to open and verify a cached shm index if available. Return 0 if\n+ * succeeds (istate->mmap and istate->mmap_size are updated). Return\n+ * negative otherwise.\n+ */\n+static int try_shm(struct index_state *istate)\n+{\n+\tvoid *new_mmap = NULL;\n+\tsize_t old_size = istate->mmap_size;\n+\tssize_t new_length;\n+\tconst unsigned char *sha1;\n+\tstruct stat st;\n+\n+\tif (!is_main_index(istate) ||\n+\t    old_size <= 20 ||\n+\t    stat(git_path(\"index-helper.pid\"), &st))\n+\t\treturn -1;\n+\tpoke_daemon(istate, &st, 0);\n+\tsha1 = (unsigned char *)istate->mmap + old_size - 20;\n+\tnew_length = git_shm_map(O_RDONLY, 0700, -1, &new_mmap,\n+\t\t\t\t PROT_READ, MAP_SHARED,\n+\t\t\t\t \"git-index-%s\", sha1_to_hex(sha1));\n+\tif (new_length <= 20 ||\n+\t    hashcmp((unsigned char *)istate->mmap + old_size - 20,\n+\t\t    (unsigned char *)new_mmap + new_length - 20)) {\n+\t\tif (new_mmap)\n+\t\t\tmunmap(new_mmap, new_length);\n+\t\tpoke_daemon(istate, &st, 1);\n+\t\treturn -1;\n+\t}\n+\tmunmap(istate->mmap, istate->mmap_size);\n+\tistate->mmap = new_mmap;\n+\tistate->mmap_size = new_length;\n+\tistate->from_shm = 1;\n+\treturn 0;\n+}\n+\n /* remember to discard_cache() before reading a different cache! */\n int do_read_index(struct index_state *istate, const char *path, int must_exist)\n {\n@@ -1533,6 +1609,7 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)\n \tif (istate->initialized)\n \t\treturn istate->cache_nr;\n \n+\tistate->from_shm = 0;\n \tistate->timestamp.sec = 0;\n \tistate->timestamp.nsec = 0;\n \tfd = open(path, O_RDONLY);\n@@ -1552,15 +1629,17 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)\n \tmmap = xmmap(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0);\n \tif (mmap == MAP_FAILED)\n \t\tdie_errno(\"unable to map index file\");\n-\tif (istate->keep_mmap) {\n-\t\tistate->mmap = mmap;\n-\t\tistate->mmap_size = mmap_size;\n-\t}\n \tclose(fd);\n \n-\thdr = mmap;\n-\tif (verify_hdr(hdr, mmap_size) < 0)\n+\tistate->mmap = mmap;\n+\tistate->mmap_size = mmap_size;\n+\tif (try_shm(istate) &&\n+\t    verify_hdr(istate->mmap, istate->mmap_size) < 0)\n \t\tgoto unmap;\n+\thdr = mmap = istate->mmap;\n+\tmmap_size = istate->mmap_size;\n+\tif (!istate->keep_mmap)\n+\t\tistate->mmap = NULL;\n \n \thashcpy(istate->sha1, (const unsigned char *)hdr + mmap_size - 20);\n \tistate->version = ntohl(hdr->hdr_version);\n@@ -1639,6 +1718,8 @@ int read_index_from(struct index_state *istate, const char *path)\n \telse\n \t\tsplit_index->base = xcalloc(1, sizeof(*split_index->base));\n \tsplit_index->base->keep_mmap = istate->keep_mmap;\n+\tsplit_index->base->to_shm    = istate->to_shm;\n+\tsplit_index->base->from_shm  = istate->from_shm;\n \tret = do_read_index(split_index->base,\n \t\t\t    git_path(\"sharedindex.%s\",\n \t\t\t\t     sha1_to_hex(split_index->base_sha1)), 1);\n@@ -1689,6 +1770,8 @@ int discard_index(struct index_state *istate)\n \tdiscard_split_index(istate);\n \tfree_untracked_cache(istate->untracked);\n \tistate->untracked = NULL;\n+\tistate->from_shm = 0;\n+\tistate->to_shm   = 0;\n \treturn 0;\n }\n \n@@ -2115,9 +2198,14 @@ static int do_write_locked_index(struct index_state *istate, struct lock_file *l\n \t\treturn ret;\n \tassert((flags & (COMMIT_LOCK | CLOSE_LOCK)) !=\n \t       (COMMIT_LOCK | CLOSE_LOCK));\n-\tif (flags & COMMIT_LOCK)\n-\t\treturn commit_locked_index(lock);\n-\telse if (flags & CLOSE_LOCK)\n+\tif (flags & COMMIT_LOCK) {\n+\t\tstruct stat st;\n+\t\tret = commit_locked_index(lock);\n+\t\tif (!ret && is_main_index(istate) &&\n+\t\t    !stat(git_path(\"index-helper.pid\"), &st))\n+\t\t\tpoke_daemon(istate, &st, 1);\n+\t\treturn ret;\n+\t} else if (flags & CLOSE_LOCK)\n \t\treturn close_lock_file(lock);\n \telse\n \t\treturn ret;\ndiff --git a/shm.c b/shm.c\nnew file mode 100644\nindex 0000000..4ec1a00\n--- /dev/null\n+++ b/shm.c\n@@ -0,0 +1,67 @@\n+#include \"git-compat-util.h\"\n+#include \"shm.h\"\n+\n+#ifdef HAVE_SHM\n+\n+#define SHM_PATH_LEN 72\t\t/* we don't create very long paths.. */\n+\n+ssize_t git_shm_map(int oflag, int perm, ssize_t length, void **mmap,\n+\t\t    int prot, int flags, const char *fmt, ...)\n+{\n+\tva_list ap;\n+\tchar path[SHM_PATH_LEN];\n+\tint fd;\n+\n+\tpath[0] = '/';\n+\tva_start(ap, fmt);\n+\tvsprintf(path + 1, fmt, ap);\n+\tva_end(ap);\n+\tfd = shm_open(path, oflag, perm);\n+\tif (fd < 0)\n+\t\treturn -1;\n+\tif (length > 0 && ftruncate(fd, length)) {\n+\t\tshm_unlink(path);\n+\t\tclose(fd);\n+\t\treturn -1;\n+\t}\n+\tif (length < 0 && !(oflag & O_CREAT)) {\n+\t\tstruct stat st;\n+\t\tif (fstat(fd, &st))\n+\t\t\tdie_errno(\"unable to stat %s\", path);\n+\t\tlength = st.st_size;\n+\t}\n+\t*mmap = xmmap(NULL, length, prot, flags, fd, 0);\n+\tclose(fd);\n+\tif (*mmap == MAP_FAILED) {\n+\t\t*mmap = NULL;\n+\t\tshm_unlink(path);\n+\t\treturn -1;\n+\t}\n+\treturn length;\n+}\n+\n+void git_shm_unlink(const char *fmt, ...)\n+{\n+\tva_list ap;\n+\tchar path[SHM_PATH_LEN];\n+\n+\tpath[0] = '/';\n+\tva_start(ap, fmt);\n+\tvsprintf(path + 1, fmt, ap);\n+\tva_end(ap);\n+\tshm_unlink(path);\n+}\n+\n+#else\n+\n+ssize_t git_shm_map(int oflag, int perm, ssize_t length, void **mmap,\n+\t\t    int prot, int flags, const char *fmt, ...)\n+{\n+\treturn -1;\n+}\n+\n+void git_shm_unlink(const char *fmt, ...)\n+{\n+}\n+\n+#endif\ndiff --git a/shm.h b/shm.h\nnew file mode 100644\nindex 0000000..798d3fd\n--- /dev/null\n+++ b/shm.h\n@@ -0,0 +1,23 @@\n+#ifndef SHM_H\n+#define SHM_H\n+\n+/*\n+ * Create or open a shared memory and mmap it. Return mmap size if\n+ * successful, -1 otherwise. If successful mmap contains the mmap'd\n+ * pointer. If oflag does not contain O_CREAT and length is negative,\n+ * the mmap size is retrieved from existing shared memory object.\n+ *\n+ * The mmap could be freed by munmap, even on Windows. Note that on\n+ * Windows, git_shm_unlink() is no-op, so the last unmap will destroy\n+ * the shared memory.\n+ */\n+ssize_t git_shm_map(int oflag, int perm, ssize_t length, void **mmap,\n+\t\t    int prot, int flags, const char *fmt, ...);\n+\n+/*\n+ * Unlink a shared memory object. Only needed on POSIX platforms. On\n+ * Windows this is no-op.\n+ */\n+void git_shm_unlink(const char *fmt, ...);\n+\n+#endif\n-- \n2.2.0.513.g477eb31\n"},{"id":"272658","messageId":"1446385369-8669-6-git-send-email-pclouds@gmail.com","threadId":"40691","inReplyTo":"1446385369-8669-1-git-send-email-pclouds@gmail.com","subject":"[PATCH v4 5/9] trace.c: add GIT_TRACE_INDEX_STATS for index statistics","fromName":"Nguyễn Thái Ngọc Duy","fromEmail":"pclouds@gmail.com","sentAt":"2015-11-01T13:42:45Z","receivedAt":"2015-11-01T13:42:45Z","isPatch":true,"sender":{"key":"pclouds@gmail.com","avatar":"https://avatars.githubusercontent.com/u/720?v=4"},"body":"Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>\n---\n Documentation/git.txt |  1 +\n cache.h               |  1 +\n read-cache.c          | 16 ++++++++++++++++\n trace.c               |  5 ++++-\n 4 files changed, 22 insertions(+), 1 deletion(-)\n\ndiff --git a/Documentation/git.txt b/Documentation/git.txt\nindex 1086ced..f2078aa 100644\n--- a/Documentation/git.txt\n+++ b/Documentation/git.txt\n@@ -1046,6 +1046,7 @@ of clones and fetches.\n \tSee 'GIT_TRACE' for available trace output options.\n \n 'GIT_TRACE_PACK_STATS'::\n+'GIT_TRACE_INDEX_STATS'::\n \tPrint various statistics.\n \n 'GIT_TRACE_SETUP'::\ndiff --git a/cache.h b/cache.h\nindex 30a3a77..69c2365 100644\n--- a/cache.h\n+++ b/cache.h\n@@ -1754,5 +1754,6 @@ int versioncmp(const char *s1, const char *s2);\n void sleep_millisec(int millisec);\n \n void report_pack_stats(struct trace_key *key);\n+void report_index_stats(struct trace_key *key);\n \n #endif /* CACHE_H */\ndiff --git a/read-cache.c b/read-cache.c\nindex 6c98e98..6ae50c7 100644\n--- a/read-cache.c\n+++ b/read-cache.c\n@@ -50,6 +50,10 @@ static struct cache_entry *refresh_cache_entry(struct cache_entry *ce,\n struct index_state the_index;\n static const char *alternate_index_output;\n \n+static unsigned int nr_read_index;\n+static unsigned int nr_read_shm_index;\n+static unsigned int nr_write_index;\n+\n static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)\n {\n \tistate->cache[nr] = ce;\n@@ -1592,6 +1596,7 @@ static int try_shm(struct index_state *istate)\n \tistate->mmap = new_mmap;\n \tistate->mmap_size = new_length;\n \tistate->from_shm = 1;\n+\tnr_read_shm_index++;\n \treturn 0;\n }\n \n@@ -1689,6 +1694,7 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)\n \t}\n \tif (!istate->keep_mmap)\n \t\tmunmap(mmap, mmap_size);\n+\tnr_read_index++;\n \treturn istate->cache_nr;\n \n unmap:\n@@ -2174,6 +2180,7 @@ static int do_write_index(struct index_state *istate, int newfd,\n \t\treturn -1;\n \tistate->timestamp.sec = (unsigned int)st.st_mtime;\n \tistate->timestamp.nsec = ST_MTIME_NSEC(st);\n+\tnr_write_index++;\n \treturn 0;\n }\n \n@@ -2400,3 +2407,12 @@ void stat_validity_update(struct stat_validity *sv, int fd)\n \t\tfill_stat_data(sv->sd, &st);\n \t}\n }\n+\n+void report_index_stats(struct trace_key *key)\n+{\n+\ttrace_printf_key(key, \"\\n\"\n+\t\t\t \"index stats: file reads        = %10u\\n\"\n+\t\t\t \"index stats: cache reads       = %10u\\n\"\n+\t\t\t \"index stats: file writes       = %10u\\n\",\n+\t\t\t nr_read_index, nr_read_shm_index, nr_write_index);\n+}\ndiff --git a/trace.c b/trace.c\nindex b1d0885..eea1fa8 100644\n--- a/trace.c\n+++ b/trace.c\n@@ -434,14 +434,17 @@ void trace_command_performance(const char **argv)\n }\n \n static struct trace_key trace_pack_stats = TRACE_KEY_INIT(PACK_STATS);\n+static struct trace_key trace_index_stats = TRACE_KEY_INIT(INDEX_STATS);\n \n static void print_stats_atexit(void)\n {\n \treport_pack_stats(&trace_pack_stats);\n+\treport_index_stats(&trace_index_stats);\n }\n \n void trace_stats(void)\n {\n-\tif (trace_want(&trace_pack_stats))\n+\tif (trace_want(&trace_pack_stats) ||\n+\t    trace_want(&trace_index_stats))\n \t\tatexit(print_stats_atexit);\n }\n-- \n2.2.0.513.g477eb31\n"},{"id":"272661","messageId":"1446385369-8669-7-git-send-email-pclouds@gmail.com","threadId":"40691","inReplyTo":"1446385369-8669-1-git-send-email-pclouds@gmail.com","subject":"[PATCH v4 6/9] index-helper: add --strict","fromName":"Nguyễn Thái Ngọc Duy","fromEmail":"pclouds@gmail.com","sentAt":"2015-11-01T13:42:46Z","receivedAt":"2015-11-01T13:42:46Z","isPatch":true,"sender":{"key":"pclouds@gmail.com","avatar":"https://avatars.githubusercontent.com/u/720?v=4"},"body":"There's are \"holes\" in the index-helper approach because the shared\nmemory is not verified again by git. If $USER is compromised, shared\nmemory could be modified. But then they can already modify\n$GIT_DIR/index. A more realistic risk is some bugs in index-helper\nproduce corrupt shared memory. --strict is added to avoid that\n\nStrictly speaking there's still a very small gap where corrupt shared\nmemory could still be read by git: after we write the trailing SHA-1 in\nthe shared memory (thus signaling \"this shm is ready\") and before\nverify_shm() detects an error.\n\nSigned-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>\n---\n Documentation/git-index-helper.txt |  9 +++++++\n cache.h                            |  1 +\n index-helper.c                     | 48 ++++++++++++++++++++++++++++++++++++++\n read-cache.c                       |  9 ++++---\n 4 files changed, 64 insertions(+), 3 deletions(-)\n\ndiff --git a/Documentation/git-index-helper.txt b/Documentation/git-index-helper.txt\nindex 9db28cf..ad40366 100644\n--- a/Documentation/git-index-helper.txt\n+++ b/Documentation/git-index-helper.txt\n@@ -22,6 +22,15 @@ OPTIONS\n \tExit if the cached index is not accessed for `<n>`\n \tminutes. Specify 0 to wait forever. Default is 10.\n \n+--strict::\n+--no-strict::\n+\tStrict mode makes index-helper verify the shared memory after\n+\tit's created. If the result does not match what's read from\n+\t$GIT_DIR/index, the shared memory is destroyed. This makes\n+\tindex-helper take more than double the amount of time required\n+\tfor reading an index, but because it will happen in the\n+\tbackground, it's not noticable. `--strict` is enabled by default.\n+\n NOTES\n -----\n On UNIX-like systems, $GIT_DIR/index-helper.pid contains the process\ndiff --git a/cache.h b/cache.h\nindex 69c2365..dd3df26 100644\n--- a/cache.h\n+++ b/cache.h\n@@ -314,6 +314,7 @@ struct index_state {\n \t\t keep_mmap : 1,\n \t\t from_shm : 1,\n \t\t to_shm : 1,\n+\t\t always_verify_trailing_sha1 : 1,\n \t\t initialized : 1;\n \tstruct hashmap name_hash;\n \tstruct hashmap dir_hash;\ndiff --git a/index-helper.c b/index-helper.c\nindex cf2971d..1140bc0 100644\n--- a/index-helper.c\n+++ b/index-helper.c\n@@ -14,6 +14,7 @@ struct shm {\n \n static struct shm shm_index;\n static struct shm shm_base_index;\n+static int to_verify = 1;\n \n static void release_index_shm(struct shm *is)\n {\n@@ -69,11 +70,56 @@ static void share_index(struct index_state *istate, struct shm *is)\n \thashcpy((unsigned char *)new_mmap + istate->mmap_size - 20, is->sha1);\n }\n \n+static int verify_shm(void)\n+{\n+\tint i;\n+\tstruct index_state istate;\n+\tmemset(&istate, 0, sizeof(istate));\n+\tistate.always_verify_trailing_sha1 = 1;\n+\tistate.to_shm = 1;\n+\ti = read_index(&istate);\n+\tif (i != the_index.cache_nr)\n+\t\tgoto done;\n+\tfor (; i < the_index.cache_nr; i++) {\n+\t\tstruct cache_entry *base, *ce;\n+\t\t/* namelen is checked separately */\n+\t\tconst unsigned int ondisk_flags =\n+\t\t\tCE_STAGEMASK | CE_VALID | CE_EXTENDED_FLAGS;\n+\t\tunsigned int ce_flags, base_flags, ret;\n+\t\tbase = the_index.cache[i];\n+\t\tce = istate.cache[i];\n+\t\tif (ce->ce_namelen != base->ce_namelen ||\n+\t\t    strcmp(ce->name, base->name)) {\n+\t\t\twarning(\"mismatch at entry %d\", i);\n+\t\t\tbreak;\n+\t\t}\n+\t\tce_flags = ce->ce_flags;\n+\t\tbase_flags = base->ce_flags;\n+\t\t/* only on-disk flags matter */\n+\t\tce->ce_flags   &= ondisk_flags;\n+\t\tbase->ce_flags &= ondisk_flags;\n+\t\tret = memcmp(&ce->ce_stat_data, &base->ce_stat_data,\n+\t\t\t     offsetof(struct cache_entry, name) -\n+\t\t\t     offsetof(struct cache_entry, ce_stat_data));\n+\t\tce->ce_flags = ce_flags;\n+\t\tbase->ce_flags = base_flags;\n+\t\tif (ret) {\n+\t\t\twarning(\"mismatch at entry %d\", i);\n+\t\t\tbreak;\n+\t\t}\n+\t}\n+done:\n+\tdiscard_index(&istate);\n+\treturn i == the_index.cache_nr;\n+}\n+\n static void share_the_index(void)\n {\n \tif (the_index.split_index && the_index.split_index->base)\n \t\tshare_index(the_index.split_index->base, &shm_base_index);\n \tshare_index(&the_index, &shm_index);\n+\tif (to_verify && !verify_shm())\n+\t\tcleanup_shm();\n \tdiscard_index(&the_index);\n }\n \n@@ -130,6 +176,8 @@ int main(int argc, char **argv)\n \tstruct option options[] = {\n \t\tOPT_INTEGER(0, \"exit-after\", &idle_in_minutes,\n \t\t\t    N_(\"exit if not used after some minutes\")),\n+\t\tOPT_BOOL(0, \"strict\", &to_verify,\n+\t\t\t \"verify shared memory after creating\"),\n \t\tOPT_END()\n \t};\n \ndiff --git a/read-cache.c b/read-cache.c\nindex 6ae50c7..3ae2bc1 100644\n--- a/read-cache.c\n+++ b/read-cache.c\n@@ -1638,9 +1638,12 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)\n \n \tistate->mmap = mmap;\n \tistate->mmap_size = mmap_size;\n-\tif (try_shm(istate) &&\n-\t    verify_hdr(istate->mmap, istate->mmap_size) < 0)\n-\t\tgoto unmap;\n+\tif (try_shm(istate)) {\n+\t\tif (verify_hdr(istate->mmap, istate->mmap_size) < 0)\n+\t\t\tgoto unmap;\n+\t} else if (istate->always_verify_trailing_sha1 &&\n+\t\t   verify_hdr(istate->mmap, istate->mmap_size) < 0)\n+\t\t\tgoto unmap;\n \thdr = mmap = istate->mmap;\n \tmmap_size = istate->mmap_size;\n \tif (!istate->keep_mmap)\n-- \n2.2.0.513.g477eb31\n"},{"id":"272660","messageId":"1446385369-8669-8-git-send-email-pclouds@gmail.com","threadId":"40691","inReplyTo":"1446385369-8669-1-git-send-email-pclouds@gmail.com","subject":"[PATCH v4 7/9] daemonize(): set a flag before exiting the main process","fromName":"Nguyễn Thái Ngọc Duy","fromEmail":"pclouds@gmail.com","sentAt":"2015-11-01T13:42:47Z","receivedAt":"2015-11-01T13:42:47Z","isPatch":true,"sender":{"key":"pclouds@gmail.com","avatar":"https://avatars.githubusercontent.com/u/720?v=4"},"body":"This allows signal handlers and atexit functions to realize this\nsituation and not clean up.\n\nSigned-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>\n---\n builtin/gc.c | 2 +-\n cache.h      | 2 +-\n daemon.c     | 2 +-\n setup.c      | 4 +++-\n 4 files changed, 6 insertions(+), 4 deletions(-)\n\ndiff --git a/builtin/gc.c b/builtin/gc.c\nindex df3e454..e59c9d2 100644\n--- a/builtin/gc.c\n+++ b/builtin/gc.c\n@@ -369,7 +369,7 @@ int cmd_gc(int argc, const char **argv, const char *prefix)\n \t\t\t * failure to daemonize is ok, we'll continue\n \t\t\t * in foreground\n \t\t\t */\n-\t\t\tdaemonized = !daemonize();\n+\t\t\tdaemonized = !daemonize(NULL);\n \t\t}\n \t} else\n \t\tadd_repack_all_option();\ndiff --git a/cache.h b/cache.h\nindex dd3df26..9633acc 100644\n--- a/cache.h\n+++ b/cache.h\n@@ -490,7 +490,7 @@ extern int set_git_dir_init(const char *git_dir, const char *real_git_dir, int);\n extern int init_db(const char *template_dir, unsigned int flags);\n \n extern void sanitize_stdfds(void);\n-extern int daemonize(void);\n+extern int daemonize(int *);\n \n #define alloc_nr(x) (((x)+16)*3/2)\n \ndiff --git a/daemon.c b/daemon.c\nindex 56679a1..9f9f057 100644\n--- a/daemon.c\n+++ b/daemon.c\n@@ -1364,7 +1364,7 @@ int main(int argc, char **argv)\n \t\treturn execute();\n \n \tif (detach) {\n-\t\tif (daemonize())\n+\t\tif (daemonize(NULL))\n \t\t\tdie(\"--detach not supported on this platform\");\n \t} else\n \t\tsanitize_stdfds();\ndiff --git a/setup.c b/setup.c\nindex d343725..968af3d 100644\n--- a/setup.c\n+++ b/setup.c\n@@ -1015,7 +1015,7 @@ void sanitize_stdfds(void)\n \t\tclose(fd);\n }\n \n-int daemonize(void)\n+int daemonize(int *daemonized)\n {\n #ifdef NO_POSIX_GOODIES\n \terrno = ENOSYS;\n@@ -1027,6 +1027,8 @@ int daemonize(void)\n \t\tcase -1:\n \t\t\tdie_errno(\"fork failed\");\n \t\tdefault:\n+\t\t\tif (daemonized)\n+\t\t\t\t*daemonized = 1;\n \t\t\texit(0);\n \t}\n \tif (setsid() == -1)\n-- \n2.2.0.513.g477eb31\n"},{"id":"272662","messageId":"1446385369-8669-9-git-send-email-pclouds@gmail.com","threadId":"40691","inReplyTo":"1446385369-8669-1-git-send-email-pclouds@gmail.com","subject":"[PATCH v4 8/9] index-helper: add --detach","fromName":"Nguyễn Thái Ngọc Duy","fromEmail":"pclouds@gmail.com","sentAt":"2015-11-01T13:42:48Z","receivedAt":"2015-11-01T13:42:48Z","isPatch":true,"sender":{"key":"pclouds@gmail.com","avatar":"https://avatars.githubusercontent.com/u/720?v=4"},"body":"Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>\n---\n Documentation/git-index-helper.txt |  3 +++\n index-helper.c                     | 10 ++++++++--\n 2 files changed, 11 insertions(+), 2 deletions(-)\n\ndiff --git a/Documentation/git-index-helper.txt b/Documentation/git-index-helper.txt\nindex ad40366..9ced091 100644\n--- a/Documentation/git-index-helper.txt\n+++ b/Documentation/git-index-helper.txt\n@@ -31,6 +31,9 @@ OPTIONS\n \tfor reading an index, but because it will happen in the\n \tbackground, it's not noticable. `--strict` is enabled by default.\n \n+--detach::\n+\tDetach from the shell.\n+\n NOTES\n -----\n On UNIX-like systems, $GIT_DIR/index-helper.pid contains the process\ndiff --git a/index-helper.c b/index-helper.c\nindex 1140bc0..4dd9656 100644\n--- a/index-helper.c\n+++ b/index-helper.c\n@@ -14,7 +14,7 @@ struct shm {\n \n static struct shm shm_index;\n static struct shm shm_base_index;\n-static int to_verify = 1;\n+static int daemonized, to_verify = 1;\n \n static void release_index_shm(struct shm *is)\n {\n@@ -33,6 +33,8 @@ static void cleanup_shm(void)\n \n static void cleanup(void)\n {\n+\tif (daemonized)\n+\t\treturn;\n \tunlink(git_path(\"index-helper.pid\"));\n \tcleanup_shm();\n }\n@@ -172,12 +174,13 @@ int main(int argc, char **argv)\n \tstatic struct lock_file lock;\n \tstruct strbuf sb = STRBUF_INIT;\n \tconst char *prefix;\n-\tint fd, idle_in_minutes = 10;\n+\tint fd, idle_in_minutes = 10, detach = 0;\n \tstruct option options[] = {\n \t\tOPT_INTEGER(0, \"exit-after\", &idle_in_minutes,\n \t\t\t    N_(\"exit if not used after some minutes\")),\n \t\tOPT_BOOL(0, \"strict\", &to_verify,\n \t\t\t \"verify shared memory after creating\"),\n+\t\tOPT_BOOL(0, \"detach\", &detach, \"detach the process\"),\n \t\tOPT_END()\n \t};\n \n@@ -202,6 +205,9 @@ int main(int argc, char **argv)\n \tatexit(cleanup);\n \tsigchain_push_common(cleanup_on_signal);\n \n+\tif (detach && daemonize(&daemonized))\n+\t\tdie_errno(\"unable to detach\");\n+\n \tif (!idle_in_minutes)\n \t\tidle_in_minutes = 0xffffffff / 60;\n \tloop(sb.buf, idle_in_minutes * 60);\n-- \n2.2.0.513.g477eb31\n"},{"id":"272663","messageId":"1446385369-8669-10-git-send-email-pclouds@gmail.com","threadId":"40691","inReplyTo":"1446385369-8669-1-git-send-email-pclouds@gmail.com","subject":"[PATCH v4 9/9] index-helper: add Windows support","fromName":"Nguyễn Thái Ngọc Duy","fromEmail":"pclouds@gmail.com","sentAt":"2015-11-01T13:42:49Z","receivedAt":"2015-11-01T13:42:49Z","isPatch":true,"sender":{"key":"pclouds@gmail.com","avatar":"https://avatars.githubusercontent.com/u/720?v=4"},"body":"Windows supports shared memory, but the semantics is a bit different\nthan POSIX shm. The most noticeable thing is there's no way to get the\nshared memory's size by the reader, and wrapping fstat to do that\nwould be hell. So the shm size is added near the end, hidden away from\nshm users (storing it in headers would cause more problems with munmap,\nstoring it as a separate shm is even worse).\n\nPostMessage is used instead of UNIX signals for\nnotification. Lightweight (at least code-wise) on the client side.\n\nSigned-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>\n---\n config.mak.uname |  2 ++\n index-helper.c   | 48 ++++++++++++++++++++++++++++\n read-cache.c     | 13 ++++++++\n shm.c            | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++\n 4 files changed, 159 insertions(+)\n\ndiff --git a/config.mak.uname b/config.mak.uname\nindex 3167e36..260fa82 100644\n--- a/config.mak.uname\n+++ b/config.mak.uname\n@@ -391,6 +391,7 @@ ifndef DEBUG\n else\n \tBASIC_CFLAGS += -Zi -MDd\n endif\n+\tPROGRAM_OBJS += index-helper.o\n \tX = .exe\n endif\n ifeq ($(uname_S),Interix)\n@@ -545,6 +546,7 @@ ifneq (,$(wildcard ../THIS_IS_MSYSGIT))\n else\n \tNO_CURL = YesPlease\n endif\n+\tPROGRAM_OBJS += index-helper.o\n endif\n ifeq ($(uname_S),QNX)\n \tCOMPAT_CFLAGS += -DSA_RESTART=0\ndiff --git a/index-helper.c b/index-helper.c\nindex 4dd9656..cf26da7 100644\n--- a/index-helper.c\n+++ b/index-helper.c\n@@ -155,6 +155,51 @@ static void loop(const char *pid_file, int idle_in_seconds)\n \t\t; /* do nothing, all is handled by signal handlers already */\n }\n \n+#elif defined(GIT_WINDOWS_NATIVE)\n+\n+static void loop(const char *pid_file, int idle_in_seconds)\n+{\n+\tHWND hwnd;\n+\tUINT_PTR timer = 0;\n+\tMSG msg;\n+\tHINSTANCE hinst = GetModuleHandle(NULL);\n+\tWNDCLASS wc;\n+\n+\t/*\n+\t * Emulate UNIX signals by sending WM_USER+x to a\n+\t * window. Register window class and create a new window to\n+\t * catch these messages.\n+\t */\n+\tmemset(&wc, 0, sizeof(wc));\n+\twc.lpfnWndProc\t = DefWindowProc;\n+\twc.hInstance\t = hinst;\n+\twc.lpszClassName = \"git-index-helper\";\n+\tif (!RegisterClass(&wc))\n+\t\tdie_errno(_(\"could not register new window class\"));\n+\n+\thwnd = CreateWindow(\"git-index-helper\", pid_file,\n+\t\t\t    0, 0, 0, 1, 1, NULL, NULL, hinst, NULL);\n+\tif (!hwnd)\n+\t\tdie_errno(_(\"could not register new window\"));\n+\n+\trefresh(0);\n+\twhile (1) {\n+\t\ttimer = SetTimer(hwnd, timer, idle_in_seconds * 1000, NULL);\n+\t\tif (!timer)\n+\t\t\tdie(_(\"no timer!\"));\n+\t\tif (!GetMessage(&msg, hwnd, 0, 0) || msg.message == WM_TIMER)\n+\t\t\tbreak;\n+\t\tswitch (msg.message) {\n+\t\tcase WM_USER:\n+\t\t\trefresh(0);\n+\t\t\tbreak;\n+\t\tdefault:\n+\t\t\t/* just reset the timer */\n+\t\t\tbreak;\n+\t\t}\n+\t}\n+}\n+\n #else\n \n static void loop(const char *pid_file, int idle_in_seconds)\n@@ -198,6 +243,9 @@ int main(int argc, char **argv)\n \tfd = hold_lock_file_for_update(&lock,\n \t\t\t\t       git_path(\"index-helper.pid\"),\n \t\t\t\t       LOCK_DIE_ON_ERROR);\n+#ifdef GIT_WINDOWS_NATIVE\n+\tstrbuf_addstr(&sb, \"HWND\");\n+#endif\n \tstrbuf_addf(&sb, \"%\" PRIuMAX, (uintmax_t) getpid());\n \twrite_in_full(fd, sb.buf, sb.len);\n \tcommit_lock_file(&lock);\ndiff --git a/read-cache.c b/read-cache.c\nindex 3ae2bc1..f609776 100644\n--- a/read-cache.c\n+++ b/read-cache.c\n@@ -1524,6 +1524,18 @@ static void check_ce_order(struct index_state *istate)\n \t}\n }\n \n+#if defined(GIT_WINDOWS_NATIVE)\n+static void do_poke(struct strbuf *sb, int refresh_cache)\n+{\n+\tHWND hwnd;\n+\tif (!starts_with(sb->buf, \"HWND\"))\n+\t\treturn;\n+\thwnd = FindWindow(\"git-index-helper\", sb->buf);\n+\tif (!hwnd)\n+\t\treturn;\n+\tPostMessage(hwnd, refresh_cache ? WM_USER : WM_USER + 1, 0, 0);\n+}\n+#else\n static void do_poke(struct strbuf *sb, int refresh_cache)\n {\n \tchar\t*start = sb->buf;\n@@ -1533,6 +1545,7 @@ static void do_poke(struct strbuf *sb, int refresh_cache)\n \t\treturn;\n \tkill(pid, refresh_cache ? SIGHUP : SIGUSR1);\n }\n+#endif\n \n static void poke_daemon(struct index_state *istate,\n \t\t\tconst struct stat *st, int refresh_cache)\ndiff --git a/shm.c b/shm.c\nindex 4ec1a00..04d8a35 100644\n--- a/shm.c\n+++ b/shm.c\n@@ -52,6 +52,102 @@ void git_shm_unlink(const char *fmt, ...)\n \tshm_unlink(path);\n }\n \n+#elif defined(GIT_WINDOWS_NATIVE)\n+\n+#define SHM_PATH_LEN 82\t/* a little bit longer than POSIX because of \"Local\\\\\" */\n+\n+static ssize_t create_shm_map(int oflag, int perm, ssize_t length,\n+\t\t\t      void **mmap, int prot, int flags,\n+\t\t\t      const char *path, unsigned long page_size)\n+{\n+\tsize_t real_length;\n+\tvoid *last_page;\n+\tHANDLE h;\n+\n+\tassert(perm   == 0700);\n+\tassert(oflag  == (O_CREAT | O_EXCL | O_RDWR));\n+\tassert(prot   == (PROT_READ | PROT_WRITE));\n+\tassert(flags  == MAP_SHARED);\n+\tassert(length >= 0);\n+\n+\treal_length = length;\n+\tif (real_length % page_size)\n+\t\treal_length += page_size - (real_length % page_size);\n+\treal_length += page_size;\n+\th = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0,\n+\t\t\t      real_length, path);\n+\tif (!h)\n+\t\treturn -1;\n+\t*mmap = MapViewOfFile(h, FILE_MAP_ALL_ACCESS, 0, 0, real_length);\n+\tCloseHandle(h);\n+\tif (!*mmap)\n+\t\treturn -1;\n+\tlast_page = (unsigned char *)*mmap + real_length - page_size;\n+\t*(unsigned long *)last_page = length;\n+\treturn length;\n+}\n+\n+static ssize_t open_shm_map(int oflag, int perm, ssize_t length, void **mmap,\n+\t\t\t    int prot, int flags, const char *path,\n+\t\t\t    unsigned long page_size)\n+{\n+\tvoid *last_page;\n+\tHANDLE h;\n+\n+\tassert(perm   == 0700);\n+\tassert(oflag  == O_RDONLY);\n+\tassert(prot   == PROT_READ);\n+\tassert(flags  == MAP_SHARED);\n+\tassert(length <= 0);\n+\n+\th = OpenFileMapping(FILE_MAP_READ, FALSE, path);\n+\tif (!h)\n+\t\treturn -1;\n+\t*mmap = MapViewOfFile(h, FILE_MAP_READ, 0, 0, 0);\n+\tCloseHandle(h);\n+\tif (!*mmap)\n+\t\treturn -1;\n+\tif (length < 0) {\n+\t\tMEMORY_BASIC_INFORMATION mbi;\n+\t\tif (!VirtualQuery(*mmap, &mbi, sizeof(mbi))) {\n+\t\t\tUnmapViewOfFile(*mmap);\n+\t\t\treturn -1;\n+\t\t}\n+\t\tif (mbi.RegionSize % page_size)\n+\t\t\tdie(\"expected size %lu to be %lu aligned\",\n+\t\t\t\t    mbi.RegionSize, page_size);\n+\t\tlast_page = (unsigned char *)*mmap + mbi.RegionSize - page_size;\n+\t\tlength = *(unsigned long *)last_page;\n+\t}\n+\treturn length;\n+}\n+\n+ssize_t git_shm_map(int oflag, int perm, ssize_t length, void **mmap,\n+\t\t    int prot, int flags, const char *fmt, ...)\n+{\n+\tSYSTEM_INFO si;\n+\tva_list ap;\n+\tchar path[SHM_PATH_LEN];\n+\n+\tGetSystemInfo(&si);\n+\n+\tstrcpy(path, \"Local\\\\\");\n+\tva_start(ap, fmt);\n+\tvsprintf(path + strlen(path), fmt, ap);\n+\tva_end(ap);\n+\n+\tif (oflag & O_CREAT)\n+\t\treturn create_shm_map(oflag, perm, length, mmap, prot,\n+\t\t\t\t      flags, path, si.dwPageSize);\n+\telse\n+\t\treturn open_shm_map(oflag, perm, length, mmap, prot,\n+\t\t\t\t    flags, path, si.dwPageSize);\n+}\n+\n+void git_shm_unlink(const char *fmt, ...)\n+{\n+}\n+\n #else\n \n ssize_t git_shm_map(int oflag, int perm, ssize_t length, void **mmap,\n-- \n2.2.0.513.g477eb31\n"},{"id":"272765","messageId":"1446502451.4131.26.camel@twopensource.com","threadId":"40691","inReplyTo":"1446385369-8669-5-git-send-email-pclouds@gmail.com","subject":"Re: [PATCH v4 4/9] index-helper: new daemon for caching index and related stuff","fromName":"David Turner","fromEmail":"dturner@twopensource.com","sentAt":"2015-11-02T22:14:11Z","receivedAt":"2015-11-02T22:14:11Z","isPatch":true,"sender":{"key":"novalis@novalis.org","avatar":"https://avatars.githubusercontent.com/u/77003?v=4"},"body":"On Sun, 2015-11-01 at 14:42 +0100, Nguyễn Thái Ngọc Duy wrote:\n> +\tmemcpy(new_mmap, istate->mmap, istate->mmap_size - 20);\n> +\n> +\t/*\n> +\t * The trailing hash must be written last after everything is\n> +\t * written. It's the indication that the shared memory is now\n> +\t * ready.\n> +\t */\n> +\thashcpy((unsigned char *)new_mmap + istate->mmap_size - 20, is->sha1);\n> +}\n\nYou need a memory barrier here.  Otherwise, compilers may reorder these\nstatements.\n\n> +#define SHM_PATH_LEN 72\t\t/* we don't create very long paths.. */\n> +\n> +ssize_t git_shm_map(int oflag, int perm, ssize_t length, void **mmap,\n> +\t\t    int prot, int flags, const char *fmt, ...)\n> +{\n> +\tva_list ap;\n> +\tchar path[SHM_PATH_LEN];\n> +\tint fd;\n> +\n> +\tpath[0] = '/';\n> +\tva_start(ap, fmt);\n> +\tvsprintf(path + 1, fmt, ap);\n> +\tva_end(ap);\n\nThis would be safer with vsnprintf.\n"},{"id":"273386","messageId":"alpine.DEB.1.00.1511162249480.1686@s15462909.onlinehome-server.info","threadId":"40691","inReplyTo":"1446385369-8669-1-git-send-email-pclouds@gmail.com","subject":"Re: [PATCH v4 0/9] Reduce index load time","fromName":"Johannes Schindelin","fromEmail":"johannes.schindelin@gmx.de","sentAt":"2015-11-16T21:51:07Z","receivedAt":"2015-11-16T21:51:07Z","isPatch":true,"sender":{"key":"johannes.schindelin@gmx.de","avatar":"https://avatars.githubusercontent.com/u/127790?v=4"},"body":"Hi Duy,\n\nOn Sun, 1 Nov 2015, Nguyễn Thái Ngọc Duy wrote:\n\n> This is the rebased version since last time [1] with\n> s/free_index_shm/release_index_shm/ as suggested by David Turner. It\n> introduces a daemon that can cache index data in memory so that\n> subsequent git processes can avoid reading (and more importantly,\n> verifying) the index from disk. Together with split-index it should\n> keep index I/O cost down to minimum. The series can also be found at\n> [2].\n> \n> One of the factors that affected my design was Windows support. We\n> now have Dscho back, he can evaluate my approach for Windows.\n\nYou flatter me! ;-)\n\nSeriously again, this patch series comes at a very good time: I will have\na closer look soon (sorry about being so vague, but I am once again a\nlittle bit short on time/brain cycles).\n\nThanks!\nDscho"}]}