Merge branch 'jt/t5500-unflake'

[thirdparty/git.git] / grep.c

diff --git a/grep.c b/grep.c
index 0552b127c1ac11f06852be42d60b992aa2891fcf..13232a904aca4906f28aae2e04165d1fda47b922 100644 (file)
--- a/grep.c
+++ b/grep.c
@@ -1540,11 +1540,6 @@ static inline void grep_attr_unlock(void)
                pthread_mutex_unlock(&grep_attr_mutex);
 }
 
-/*
- * Same as git_attr_mutex, but protecting the thread-unsafe object db access.
- */
-pthread_mutex_t grep_read_mutex;
-
 static int match_funcname(struct grep_opt *opt, struct grep_source *gs, char *bol, char *eol)
 {
        xdemitconf_t *xecfg = opt->priv;
@@ -1741,13 +1736,20 @@ static int fill_textconv_grep(struct repository *r,
        }
 
        /*
-        * fill_textconv is not remotely thread-safe; it may load objects
-        * behind the scenes, and it modifies the global diff tempfile
-        * structure.
+        * fill_textconv is not remotely thread-safe; it modifies the global
+        * diff tempfile structure, writes to the_repo's odb and might
+        * internally call thread-unsafe functions such as the
+        * prepare_packed_git() lazy-initializator. Because of the last two, we
+        * must ensure mutual exclusion between this call and the object reading
+        * API, thus we use obj_read_lock() here.
+        *
+        * TODO: allowing text conversion to run in parallel with object
+        * reading operations might increase performance in the multithreaded
+        * non-worktreee git-grep with --textconv.
         */
-       grep_read_lock();
+       obj_read_lock();
        size = fill_textconv(r, driver, df, &buf);
-       grep_read_unlock();
+       obj_read_unlock();
        free_filespec(df);
 
        /*
@@ -1813,10 +1815,15 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
                grep_source_load_driver(gs, opt->repo->index);
                /*
                 * We might set up the shared textconv cache data here, which
-                * is not thread-safe.
+                * is not thread-safe. Also, get_oid_with_context() and
+                * parse_object() might be internally called. As they are not
+                * currenty thread-safe and might be racy with object reading,
+                * obj_read_lock() must be called.
                 */
                grep_attr_lock();
+               obj_read_lock();
                textconv = userdiff_get_textconv(opt->repo, gs->driver);
+               obj_read_unlock();
                grep_attr_unlock();
        }
 
@@ -2116,10 +2123,7 @@ static int grep_source_load_oid(struct grep_source *gs)
 {
        enum object_type type;
 
-       grep_read_lock();
        gs->buf = read_object_file(gs->identifier, &type, &gs->size);
-       grep_read_unlock();
-
        if (!gs->buf)
                return error(_("'%s': unable to read %s"),
                             gs->name,