Method and device for processing cache data and storage controller

The invention discloses a data processing method, a corresponding device and a corresponding storage controller. The data processing method comprises the following steps: obtaining the compression ratio D and deduplication ratio C of data, average sectional filling rate I, target sectional size C in cache and effective data size W in a target section; according to the obtained parameters, using a formula as shown in the specification, obtaining an eliminated data size N, and executing one of the following operations according to the value of N: under the condition that N is greater than or equal to Tmin and smaller than or equal to Tmax, writing the data with the size of N into the target section, eliminating the data of the target section to a storage medium, wherein when Tmin is a preset first threshold value, Tmax is a preset second threshold value; under the condition that N is greater than Tmax, writing the data with the size of N into the target section; and under the condition that N is smaller than Tm