Re: [PATCH] index-pack: protect deepest_delta in multithread code

-- >8 --
Subject: [PATCH] index-pack: guard nr_resolved_deltas reads by lock

The threaded parts of index-pack increment the number of resolved
deltas in nr_resolved_deltas guarded by counter_mutex.  However, the
per-thread outer loop accessed nr_resolved_deltas without any locks.

This is not wrong as such, since it doesn't matter all that much
whether we get an outdated value.  However, unless someone proves that
this one lock makes all the performance difference, it would be much
cleaner to guard _all_ accesses to the variable with the lock.

Signed-off-by: Thomas Rast <redacted>
---
 builtin/index-pack.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index b3fee45..6be99e2 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c

@@ -968,7 +968,9 @@ static void *threaded_second_pass(void *data)
        for (;;) {
                int i;
                work_lock();
+               counter_lock();
                display_progress(progress, nr_resolved_deltas);
+               counter_unlock();
                while (nr_dispatched < nr_objects &&
                       is_delta_type(objects[nr_dispatched].type))
                        nr_dispatched++;