rewriting. Consequently, this mechanism introduces additional read and write operations, the extent of which depends on
the specific policy deployed, as well as on the system parameters. These additional writes result in the multiplication of user
writes, a phenomenon referred to as ‘‘write amplification’’. As the number of erase/write operations that can be performed
before an SSD wears out is limited, the extent of the write amplification is critical because it negatively affects the lifetime
and endurance of SSDs. Therefore, a garbage-collection mechanism is efficient when it keeps the write amplification as low
as possible, and also achieves a good wear leveling in the sense of blocks being worn out as evenly as possible. To achieve
these goals, various garbage-collection policies have been proposed in the literature, such as the ‘‘greedy’’ and ‘‘cost-benefit’’
policies [3,4]. In this paper we consider the greedy policy, which selects blocks with the smallest number of valid pages, suc