1. A system, comprising: a processor; and a memory containing a program which, when executed on the processor, performs an operation for zeroing pages of memory in a computing system where access to memory is non-uniform, the operation comprising: receiving, via a system call, a request to delete a memory region; sorting, after receiving the request, one or more pages of the memory region according to each associated affinity domain of each page, wherein each affinity domain comprises a cluster of processors and memory local to the cluster of processors; sending requests to zero the sorted one or more pages to one or more software threads that are attached to the respective affinity domain; and waiting, after sending the requests, to return to a system caller until a message is received, from the software threads in each affinity domain, indicating that all requests to zero have been processed.