Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> writes: > On Thu, 01 Sep 2016 16:04:57 -0700 "Huang\, Ying" <ying.huang@xxxxxxxxx> wrote: > >> >> } >> >> >> >> -#define SWAPFILE_CLUSTER 256 >> >> +#define SWAPFILE_CLUSTER 512 >> >> #define LATENCY_LIMIT 256 >> >> >> > >> > What happens to architectures which have different HPAGE_SIZE and/or >> > PAGE_SIZE? >> >> For the architecture with HPAGE_SIZE / PAGE_SIZE == 512 (for example >> x86_64), the huge page swap optimizing will be turned on. For other >> architectures, it will be turned off as before. >> >> This mostly because I don't know whether it is a good idea to turn on >> THP swap optimizing for the architectures other than x86_64. For >> example, it appears that the huge page size is 8M (1<<23) on SPARC. But >> I don't know whether 8M is too big for a swap cluster. And it appears >> that the huge page size could be as large as 512M on MIPS. > > This doesn't sounds very organized. If some architecture with some > config happens to have HPAGE_SIZE / PAGE_SIZE == 512 then the feature > will be turned on; otherwise it will be turned off. Nobody will even > notice that it happened. > > Would it not be better to do > > #ifdef CONFIG_SOMETHING > #define SWAPFILE_CLUSTER (HPAGE_SIZE / PAGE_SIZE) > #else > #define SWAPFILE_CLUSTER 256 > #endif > > and, by using CONFIG_SOMETHING in the other appropriate places, enable > the feature in the usual fashion? Yes. That is better. I will change it in the next version. Best Regards, Huang, Ying -- 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>