regionlist: For pre-allocation, do not wait for the buddy

src/fellow_log.c

@@ -6655,7 +6655,7 @@ fellow_log_dle_submit(struct fellow_fd *ffd,
 		if (prealloc == NULL &&
 		    ffd->logbuf->regions_to_free == NULL &&
 		    prep->tofree.n) {
-			prealloc = regionlist_alloc(ffd->membuddy);
+			prealloc = regionlist_alloc_nowait(ffd->membuddy);
 		}
 
 		AZ(pthread_mutex_lock(&ffd->logmtx));

src/fellow_regionlist.h

@@ -216,6 +216,18 @@ regionlist_alloc(buddy_t *membuddy)
 	return (regionlist_init(alloc, membuddy));
 }
 
+static struct regionlist *
+regionlist_alloc_nowait(buddy_t *membuddy)
+{
+	struct buddy_ptr_page alloc;
+
+	alloc = buddy_alloc1_ptr_page(membuddy, regl_bits, regl_bits_cram);
+	if (alloc.ptr == NULL)
+		return (NULL);
+
+	return (regionlist_init(alloc, membuddy));
+}
+
 static unsigned
 regionlist_used(const struct regionlist *rl)
 {