On Tue 26-06-12 00:35:22, Gavin Shan wrote: [...] > >> In order to fully utilize the memory chunk allocated from bootmem > >> allocator, it'd better to assure memory sector descriptor won't run > >> across the boundary (PAGE_SIZE). OK, I misread this part of the changelog changelog. > > > >Why? The memory is continuous, right? > > Yes, the memory is conginous and the capacity of specific entry > in mem_section[NR_SECTION_ROOTS] has been defined as follows: > > > #define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section)) > > Also, the memory is prone to be allocated from bootmem by function > alloc_bootmem_node(), which has PAGE_SIZE alignment. So I think it's > reasonable to introduce the extra check here from my personal view :-) No it is not necessary because we will never cross the page boundary because (SECTIONS_PER_ROOT uses an int division) -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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>