Slab Allocation - Basis

Basis

The primary motivation for slab allocation is that the initialization and destruction of kernel data objects can actually outweigh the cost of allocating memory for them. As object creation and deletion are widely employed by the kernel, mitigating overhead costs of initialization can result in significant performance gains. The notion of object caching was therefore introduced in order to avoid the invocation of functions used to initialize object state.

With slab allocation, memory chunks suitable to fit data objects of certain type or size are preallocated. The slab allocator keeps track of these chunks, known as caches, so that when a request to allocate memory for a data object of a certain type is received it can instantly satisfy the request with an already allocated slot. Destruction of the object, however, does not free up the memory, but only opens a slot which is put in the list of free slots by the slab allocator. The next call to allocate memory of the same size will return the now unused memory slot. This process eliminates the need to search for suitable memory space and greatly alleviates memory fragmentation. In this context a slab is one or more contiguous pages in the memory containing pre-allocated memory chunks.

Read more about this topic:  Slab Allocation

Famous quotes containing the word basis:

    Far from being the basis of the good society, the family, with its narrow privacy and tawdry secrets, is the source of all our discontents.
    Sir Edmund Leach (20th century)

    Association with women is the basis of good manners.
    Johann Wolfgang Von Goethe (1749–1832)

    Self-alienation is the source of all degradation as well as, on the contrary, the basis of all true elevation. The first step will be a look inward, an isolating contemplation of our self. Whoever remains standing here proceeds only halfway. The second step must be an active look outward, an autonomous, determined observation of the outer world.
    Novalis [Friedrich Von Hardenberg] (1772–1801)