Subversion Repositories HelenOS-doc

      allocator is that deployment of lists of preallocated, commonly used

      allocator is that commonly used objects are preallocated in continuous

      objects. Whenever an object is to be allocated, the slab allocator takes

      areas of physical memory called slabs<footnote>

      the first item from the list corresponding to the object type. This

          <para>Slabs are in fact blocks of physical memory frames allocated

      avoids the overhead of allocating and dellocating commonly used types of

          from the frame allocator.</para>

      sizes of the requested and allocated object match, the slab allocator

        </footnote>. Whenever an object is to be allocated, the slab allocator

      significantly eliminates internal fragmentation. Moreover, each list can

      returns the first available item from a suitable slab corresponding to

      have a constructor and a destructor, which leads to performance gains

      the object type<footnote>

      because constructed and then destroyed objects don't need to be

          <para>The mechanism is rather more complicated, see the next

      reinitialized<footnote>

          paragraph.</para>

          <para>Provided that the assumption that the destructor leaves the

        </footnote>. Due to the fact that the sizes of the requested and

          object in a consistent state holds.</para>

      allocated object match, the slab allocator significantly freduces

        </footnote>.</para>

      internal fragmentation.</para>

      <para>In the slab allocator, objects of one type are kept in continuous

      <para>Slabs of one object type are organized in a structure called slab

      areas of physical memory called slabs. Slabs can span from one to

      cache. There are ususally more slabs in the slab cache, depending on

      several physical memory frames. Slabs of objects of one type are stored

      previous allocations. If the the slab cache runs out of available slabs,

      in slab caches. When the allocator needs to allocate an object, it

      new slabs are allocated. In order to exploit parallelism and to avoid

      searches available slabs. When the slab does not contain any free

      locking of shared spinlocks, slab caches can have variants of

      obejct, a new slab is allocated and added to the cache. Contrary to

      slab. When it is allocated from there, the slab allocator calls a

      allocation, deallocated objects are returned to their respective slabs.

      constructor that is registered in the respective slab cache. The

      Empty slabs are deallocated immediately while empty slab caches are not

      can be precedently allocated again. Note that allocations satisfied from

      freed until HelenOS runs short of memory.</para>

      <para>Should HelenOS run short of memory, it would start deallocating

               empty magazines are deallocated when not needed

               empty magazines are deallocated when not needed