diff options
author | Jeff King <peff@peff.net> | 2014-09-10 14:03:52 +0400 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2014-09-10 21:58:32 +0400 |
commit | 9540ce5030853ffbb7e11c30aa59a5e45095d32c (patch) | |
tree | daaa9507ddd96312a5c41708d3554ccf5cf0169b /refs.c | |
parent | 0c72b98f31bf6eabd75be565a08ffcf0d8e74b1f (diff) |
refs: write packed_refs file using stdio
We write each line of a new packed-refs file individually
using a write() syscall (and sometimes 2, if the ref is
peeled). Since each line is only about 50-100 bytes long,
this creates a lot of system call overhead.
We can instead open a stdio handle around our descriptor and
use fprintf to write to it. The extra buffering is not a
problem for us, because nobody will read our new packed-refs
file until we call commit_lock_file (by which point we have
flushed everything).
On a pathological repository with 8.5 million refs, this
dropped the time to run `git pack-refs` from 20s to 6s.
Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'refs.c')
-rw-r--r-- | refs.c | 39 |
1 files changed, 16 insertions, 23 deletions
@@ -2191,25 +2191,12 @@ struct ref_lock *lock_any_ref_for_update(const char *refname, * Write an entry to the packed-refs file for the specified refname. * If peeled is non-NULL, write it as the entry's peeled value. */ -static void write_packed_entry(int fd, char *refname, unsigned char *sha1, +static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1, unsigned char *peeled) { - char line[PATH_MAX + 100]; - int len; - - len = snprintf(line, sizeof(line), "%s %s\n", - sha1_to_hex(sha1), refname); - /* this should not happen but just being defensive */ - if (len > sizeof(line)) - die("too long a refname '%s'", refname); - write_or_die(fd, line, len); - - if (peeled) { - if (snprintf(line, sizeof(line), "^%s\n", - sha1_to_hex(peeled)) != PEELED_LINE_LENGTH) - die("internal error"); - write_or_die(fd, line, PEELED_LINE_LENGTH); - } + fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname); + if (peeled) + fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled)); } /* @@ -2217,13 +2204,12 @@ static void write_packed_entry(int fd, char *refname, unsigned char *sha1, */ static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data) { - int *fd = cb_data; enum peel_status peel_status = peel_entry(entry, 0); if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG) error("internal error: %s is not a valid packed reference!", entry->name); - write_packed_entry(*fd, entry->name, entry->u.value.sha1, + write_packed_entry(cb_data, entry->name, entry->u.value.sha1, peel_status == PEEL_PEELED ? entry->u.value.peeled : NULL); return 0; @@ -2259,15 +2245,22 @@ int commit_packed_refs(void) get_packed_ref_cache(&ref_cache); int error = 0; int save_errno = 0; + FILE *out; if (!packed_ref_cache->lock) die("internal error: packed-refs not locked"); - write_or_die(packed_ref_cache->lock->fd, - PACKED_REFS_HEADER, strlen(PACKED_REFS_HEADER)); + out = fdopen(packed_ref_cache->lock->fd, "w"); + if (!out) + die_errno("unable to fdopen packed-refs descriptor"); + + fprintf_or_die(out, "%s", PACKED_REFS_HEADER); do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache), - 0, write_packed_entry_fn, - &packed_ref_cache->lock->fd); + 0, write_packed_entry_fn, out); + if (fclose(out)) + die_errno("write error"); + packed_ref_cache->lock->fd = -1; + if (commit_lock_file(packed_ref_cache->lock)) { save_errno = errno; error = -1; |