update $GIT_INDEX_FILE when there are racily clean entries

Traditional "opportunistic index update" done by read-only "diff" and
"status" was about updating cached lstat(2) information in the index for
the next round.  We missed another obvious optimization opportunity: when
there are racily clean entries that will cease to be racily clean by
updating $GIT_INDEX_FILE.  Detect that case and write $GIT_INDEX_FILE out
to give it a newer timestamp.

Noticed by Lasse Makholm by stracing "git status" in a fresh checkout and
counting the number of open(2) calls.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Junio C Hamano 2011-03-21 10:18:19 -07:00
parent ccdc4ec304
commit 483fbe2b7c

View File

@ -1545,12 +1545,25 @@ static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce)
return result;
}
static int has_racy_timestamp(struct index_state *istate)
{
int entries = istate->cache_nr;
int i;
for (i = 0; i < entries; i++) {
struct cache_entry *ce = istate->cache[i];
if (is_racy_timestamp(istate, ce))
return 1;
}
return 0;
}
/*
* Opportunisticly update the index but do not complain if we can't
*/
void update_index_if_able(struct index_state *istate, struct lock_file *lockfile)
{
if (istate->cache_changed &&
if ((istate->cache_changed || has_racy_timestamp(istate)) &&
!write_index(istate, lockfile->fd))
commit_locked_index(lockfile);
else