It is software mechnism that allow the kernel to keep in RAM some informatiom that is normally stored on a disk . so data on a disk can be quickly satisfied without a slow access to the disk itself.

It is a software mechanism introduced to bypass the kernel memory allocator => slab allocator. Slab allocator avoid buddy allocator when It allocate new memory.

Besides the dentry cache and the inode cache, Linux uses other disk caches. The most important one, called, the page cache,