2013/10/18 Christoph Lameter <cl@xxxxxxxxx>: > n Thu, 17 Oct 2013, Joonsoo Kim wrote: > >> To prepare to implement byte sized index for managing the freelist >> of a slab, we should restrict the number of objects in a slab to be less >> or equal to 256, since byte only represent 256 different values. >> Setting the size of object to value equal or more than newly introduced >> SLAB_MIN_SIZE ensures that the number of objects in a slab is less or >> equal to 256 for a slab with 1 page. > > Ok so that results in a mininum size object size of 2^(12 - 8) = 2^4 == > 16 bytes on x86. This is not true for order 1 pages (which SLAB also > supports) where we need 32 bytes. According to current slab size calculating logic, slab whose object size is less or equal to 16 bytes use only order 0 page. So there is no problem. > Problems may arise on PPC or IA64 where the page size may be larger than > 64K. With 64K we have a mininum size of 2^(16 - 8) = 256 bytes. For those > arches we may need 16 bit sized indexes. Maybe make that compile time > determined base on page size? > 64KByte results in 16 bit sized indexes? Okay. I will try it. > Otherwise I like this approach. Simplifies a lot and its very cache > friendly. Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>