  Cyber-epidemics, the widespread of fake news or propaganda through social
media, can cause devastating economic and political consequences. A common
countermeasure against cyber-epidemics is to disable a small subset of
suspected social connections or accounts to effectively contain the epidemics.
An example is the recent shutdown of 125,000 ISIS-related Twitter accounts.
Despite many proposed methods to identify such subset, none are scalable enough
to provide high-quality solutions in nowadays billion-size networks.
  To this end, we investigate the Spread Interdiction problems that seek most
effective links (or nodes) for removal under the well-known Linear Threshold
model. We propose novel CPU-GPU methods that scale to networks with billions of
edges, yet, possess rigorous theoretical guarantee on the solution quality. At
the core of our methods is an $O(1)$-space out-of-core algorithm to generate a
new type of random walks, called Hitting Self-avoiding Walks (HSAWs). Such a
low memory requirement enables handling of big networks and, more importantly,
hiding latency via scheduling of millions of threads on GPUs. Comprehensive
experiments on real-world networks show that our algorithms provides much
higher quality solutions and are several order of magnitude faster than the
state-of-the art. Comparing to the (single-core) CPU counterpart, our GPU
implementations achieve significant speedup factors up to 177x on a single GPU
and 338x on a GPU pair.
