When it comes to making one of the world’s largest companies more committed to racial diversity, General Motors CEO Mary Barra knows there’s no easy or quick fix.

In June, after police officers killed George Floyd, Barra told her employees that she was “impatient and disgusted” with the country’s response to systemic racism and promised that “there is much we can do” at General Motors to make a difference. Since then, she has created an “inclusion advisory board” at the company and appointed a chief diversity, inclusion, and equity officer; formalized inclusive behavior as a category that GM considers core to its culture and by which it will eventually assess employees; and reviewed a wide array of GM practices, including hiring and internal development, as well as its relationships with suppliers and car dealers.

But these are just the early steps of what Barra says will be a very long and painstaking effort to make permanent change. And she’s encouraging both her employees and other companies’ executives to be similarly patient when it comes to improving corporate America’s often dismal track record on racial diversity.

“We’re trying to be very transparent with the workforce in that, yes, we’re going to continue to make progress. But this is a journey that we’re beginning,” Barra said on September 29 at Fortune’s virtual Most Powerful Women Summit. “We want to have realistic expectations. And we want to keep everyone engaged.

“Part of this is being vulnerable, and sharing that, you know, we don’t have all the answers. The other day, somebody said, ‘We’re all learning real-time.’ And I was so encouraged by it,” she added. “We have a long way to go. But I'm encouraged by the engagement.”

Barra also has taken some practical steps to make GM’s senior leadership team think more long-term about diversifying its talent pipeline. That’s often been a shortcoming across Fortune 500 companies, only four of which currently have a Black CEO, and few of which have traditionally done much to recruit, promote, or retain nonwhite candidates. At the late of September, Wells Fargo CEO Charlie Scharf drew criticism and later apologized for a June memo to employees claiming that “the unfortunate reality is that there is a very limited pool of Black talent to recruit from.”

At GM, Barra has asked her 230 senior leaders to consider diverse candidates any time an internal position opens up—but also to be proactive about developing employees of color for such future promotions.

“If you don’t have a diverse slate, then tell me what you’re going to do so that three years from now, the slate will be diverse,” she said. “And that’s causing a lot of discussion.”