Skip to content

Commit

Permalink
Merge branch 'nk/diff-index-fsmonitor'
Browse files Browse the repository at this point in the history
"git diff-index" codepath has been taught to trust fsmonitor status
to reduce number of lstat() calls.

* nk/diff-index-fsmonitor:
  fsmonitor: add perf test for git diff HEAD
  fsmonitor: add assertion that fsmonitor is valid to check_removed
  fsmonitor: skip lstat deletion check during git diff-index
  • Loading branch information
gitster committed Mar 24, 2021
2 parents e537784 + 7e5aa13 commit 858119f
Show file tree
Hide file tree
Showing 4 changed files with 32 additions and 10 deletions.
23 changes: 15 additions & 8 deletions diff-lib.c
Original file line number Diff line number Diff line change
Expand Up @@ -28,9 +28,10 @@
* exists for ce that is a submodule -- it is a submodule that is not
* checked out). Return negative for an error.
*/
static int check_removed(const struct cache_entry *ce, struct stat *st)
static int check_removed(const struct index_state *istate, const struct cache_entry *ce, struct stat *st)
{
if (lstat(ce->name, st) < 0) {
assert(is_fsmonitor_refreshed(istate));
if (!(ce->ce_flags & CE_FSMONITOR_VALID) && lstat(ce->name, st) < 0) {
if (!is_missing_file_error(errno))
return -1;
return 1;
Expand Down Expand Up @@ -136,7 +137,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
memset(&(dpath->parent[0]), 0,
sizeof(struct combine_diff_parent)*5);

changed = check_removed(ce, &st);
changed = check_removed(istate, ce, &st);
if (!changed)
wt_mode = ce_mode_from_stat(ce, st.st_mode);
else {
Expand Down Expand Up @@ -216,7 +217,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
} else {
struct stat st;

changed = check_removed(ce, &st);
changed = check_removed(istate, ce, &st);
if (changed) {
if (changed < 0) {
perror(ce->name);
Expand Down Expand Up @@ -278,7 +279,8 @@ static void diff_index_show_file(struct rev_info *revs,
oid, oid_valid, ce->name, dirty_submodule);
}

static int get_stat_data(const struct cache_entry *ce,
static int get_stat_data(const struct index_state *istate,
const struct cache_entry *ce,
const struct object_id **oidp,
unsigned int *modep,
int cached, int match_missing,
Expand All @@ -290,7 +292,7 @@ static int get_stat_data(const struct cache_entry *ce,
if (!cached && !ce_uptodate(ce)) {
int changed;
struct stat st;
changed = check_removed(ce, &st);
changed = check_removed(istate, ce, &st);
if (changed < 0)
return -1;
else if (changed) {
Expand Down Expand Up @@ -321,12 +323,13 @@ static void show_new_file(struct rev_info *revs,
const struct object_id *oid;
unsigned int mode;
unsigned dirty_submodule = 0;
struct index_state *istate = revs->diffopt.repo->index;

/*
* New file in the index: it might actually be different in
* the working tree.
*/
if (get_stat_data(new_file, &oid, &mode, cached, match_missing,
if (get_stat_data(istate, new_file, &oid, &mode, cached, match_missing,
&dirty_submodule, &revs->diffopt) < 0)
return;

Expand All @@ -342,8 +345,9 @@ static int show_modified(struct rev_info *revs,
unsigned int mode, oldmode;
const struct object_id *oid;
unsigned dirty_submodule = 0;
struct index_state *istate = revs->diffopt.repo->index;

if (get_stat_data(new_entry, &oid, &mode, cached, match_missing,
if (get_stat_data(istate, new_entry, &oid, &mode, cached, match_missing,
&dirty_submodule, &revs->diffopt) < 0) {
if (report_missing)
diff_index_show_file(revs, "-", old_entry,
Expand Down Expand Up @@ -574,13 +578,16 @@ int run_diff_index(struct rev_info *revs, unsigned int option)
struct object_id oid;
const char *name;
char merge_base_hex[GIT_MAX_HEXSZ + 1];
struct index_state *istate = revs->diffopt.repo->index;

if (revs->pending.nr != 1)
BUG("run_diff_index must be passed exactly one tree");

trace_performance_enter();
ent = revs->pending.objects;

refresh_fsmonitor(istate);

if (merge_base) {
diff_get_merge_base(revs, &oid);
name = oid_to_hex_r(merge_base_hex, &oid);
Expand Down
11 changes: 11 additions & 0 deletions fsmonitor.h
Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,17 @@ void refresh_fsmonitor(struct index_state *istate);
*/
int fsmonitor_is_trivial_response(const struct strbuf *query_result);

/*
* Check if refresh_fsmonitor has been called at least once.
* refresh_fsmonitor is idempotent. Returns true if fsmonitor is
* not enabled (since the state will be "fresh" w/ CE_FSMONITOR_VALID unset)
* This version is useful for assertions
*/
static inline int is_fsmonitor_refreshed(const struct index_state *istate)
{
return !core_fsmonitor || istate->fsmonitor_has_run_once;
}

/*
* Set the given cache entries CE_FSMONITOR_VALID bit. This should be
* called any time the cache entry has been updated to reflect the
Expand Down
4 changes: 2 additions & 2 deletions t/helper/test-chmtime.c
Original file line number Diff line number Diff line change
Expand Up @@ -109,9 +109,9 @@ int cmd__chmtime(int argc, const char **argv)
uintmax_t mtime;

if (stat(argv[i], &sb) < 0) {
fprintf(stderr, "Failed to stat %s: %s\n",
fprintf(stderr, "Failed to stat %s: %s. Skipping\n",
argv[i], strerror(errno));
return 1;
continue;
}

#ifdef GIT_WINDOWS_NATIVE
Expand Down
4 changes: 4 additions & 0 deletions t/perf/p7519-fsmonitor.sh
Original file line number Diff line number Diff line change
Expand Up @@ -216,6 +216,10 @@ test_fsmonitor_suite() {
git diff
'

test_perf_w_drop_caches "diff HEAD ($DESC)" '
git diff HEAD
'

test_perf_w_drop_caches "diff -- 0_files ($DESC)" '
git diff -- 1_file
'
Expand Down

0 comments on commit 858119f

Please sign in to comment.