Hello Joonsoo, On (02/18/16 17:28), Joonsoo Kim wrote: > 2016-02-18 12:02 GMT+09:00 Sergey Senozhatsky > <sergey.senozhatsky.work@xxxxxxxxx>: > > ZS_MAX_PAGES_PER_ZSPAGE does not have to be order or 2. The existing > > limit of 4 pages per zspage sets a tight limit on ->huge classes, which > > results in increased memory wastage and consumption. > > There is a reason that it is order of 2. Increasing ZS_MAX_PAGES_PER_ZSPAGE > is related to ZS_MIN_ALLOC_SIZE. If we don't have enough OBJ_INDEX_BITS, > ZS_MIN_ALLOC_SIZE would be increase and it causes regression on some > system. Thanks! do you mean PHYSMEM_BITS != BITS_PER_LONG systems? PAE/LPAE? isn't it the case that on those systems ZS_MIN_ALLOC_SIZE already bigger than 32? MAX_PHYSMEM_BITS 36 _PFN_BITS 36 - 12 OBJ_INDEX_BITS (32 - (36 - 12) - 1) ZS_MIN_ALLOC_SIZE MAX(32, 4 << 12 >> (32 - (36 - 12) - 1)) != 32 -ss -- 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>