A method and device for checking false sharing in deletion of a data block are disclosed. The method includes setting weight bits and a weight reset bit in a mapping pointer (MP) pointing to the data block, wherein the weight reset bit is configured to define whether a weight indicated by the weight bits has been increased; and determining, based on the weight bits and the weight reset bit, whether false sharing occurs. The method determines whether false sharing occurs accurately and with low cost by using a computable formula. All information for such computable formula comes from in-memory MP, with no need to load any extra metadata, for example, with no need to access Block Meta Data. The method also considers a scenario where a weight increase occurs during a weight split and merge with other pointers.