diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index a9eb38775c42ac..c890b7298d7610 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -2168,13 +2168,15 @@ is_valid_fd(int fd)
    some platforms.
 
    fcntl(fd, F_GETFD) is even faster, because it only checks the process table.
+   It is preferred over dup() when available, since it cannot fail with the
+   "too many open files" error (EMFILE).
 
    bpo-30225: On macOS Tiger, when stdout is redirected to a pipe and the other
    side of the pipe is closed, dup(1) succeed, whereas fstat(1, &st) fails with
    EBADF. FreeBSD has similar issue (bpo-32849).
 
-   Only use dup() on platforms where dup() is enough to detect invalid FD in
-   corner cases: on Linux and Windows (bpo-32849).
+   Only use dup() on Linux where dup() is enough to detect invalid FD
+   (bpo-32849).
 */
     if (fd < 0) {
         return 0;