This is a really complicated question because it depends on when you're talking about, who you're talking about, and TOWARD whom you are talking about. Jeff Sahadeo has done some really great work on this topic (and he has a new book coming on this topic).

The short answer is that you certainly see this kind of thing before the fall of the Soviet Union, but I think you also see an intensification of it after the fall of the Soviet Union.

For further reading:

Jeff Sahadeo:

“Soviet Blacks and Place Making in Leningrad and Moscow” Slavic Review, 71, no. 2 (Summer 2012):331-358.

“The Accidental Traders: Marginalization and Opportunity from the Southern Republics to Late Soviet Moscow” Central Asian Survey 30, nos. 3-4 (2011): 521-540 (republished in Movement, Power and Place in Central Asia: Contested Trajectories (London: Routledge, 2012).

“Druzhba Narodov or Second-Class Citizenship? Soviet Asian Migrants in a Post-Colonial World” Central Asian Survey, 26, no. 4 (December 2007): 559-579 (revised and republished in Russia in Motion: Cultures of Mobility since 1850 ed. John Randolph and Eugene M. Avrutin (Urbana: University of Illinois Press, 2012), 150-171.

For a study that focuses on the earlier Soviet Union and that offers a very different perspective (because of that different time period)

Meredith Roman, Opposing Jim Crow: African Americans and the Soviet Indictment of U.S. Racism, 1928-1937 (Lincoln: University of Nebraska Press, 2012)