(6/19/12 7:21 PM), Nathan Zimmer wrote: > On Fri, Jun 01, 2012 at 01:22:15PM -0400, KOSAKI Motohiro wrote: >> (6/1/12 10:24 AM), Nathan Zimmer wrote: >>> On Thu, May 31, 2012 at 04:35:53PM -0400, KOSAKI Motohiro wrote: >>>> (5/31/12 4:25 PM), Andrew Morton wrote: >>>>> On Thu, 31 May 2012 16:09:15 -0400 >>>>> KOSAKI Motohiro<kosaki.motohiro@xxxxxxxxx> wrote: >>>>> >>>>>>> --- a/mm/shmem.c >>>>>>> +++ b/mm/shmem.c >>>>>>> @@ -929,7 +929,7 @@ static struct page *shmem_alloc_page(gfp_t gfp, >>>>>>> /* >>>>>>> * alloc_page_vma() will drop the shared policy reference >>>>>>> */ >>>>>>> - return alloc_page_vma(gfp,&pvma, 0); >>>>>>> + return alloc_page_vma(gfp,&pvma, info->node_offset<< PAGE_SHIFT ); >>>>>> >>>>>> 3rd argument of alloc_page_vma() is an address. This is type error. >>>>> >>>>> Well, it's an unsigned long... >>>>> >>>>> But yes, it is conceptually wrong and *looks* weird. I think we can >>>>> address that by overcoming our peculair aversion to documenting our >>>>> code, sigh. This? >>>> >>>> Sorry, no. >>>> >>>> addr agrument of alloc_pages_vma() have two meanings. >>>> >>>> 1) interleave node seed >>>> 2) look-up key of shmem policy >>>> >>>> I think this patch break (2). shmem_get_policy(pol, addr) assume caller honor to >>>> pass correct address. >>> >>> But the pseudo vma we generated in shmem_alloc_page the vm_ops are set to NULL. >>> So get_vma_policy will return the policy provided by the pseudo vma and not reach >>> the shmem_get_policy. >> >> yes, and it is bug source. we may need to change soon. I guess the right way is >> to make vm_ops->interleave and interleave_nid uses it if povided. > > If we provide vm_ops then won't shmem_get_policy get called? > That would be an issue since shmem_get_policy assumes vm_file is non NULL. > >> btw, I don't think node_random() is good idea. it is random(pid + jiffies + cycle). >> current->cpuset_mem_spread_rotor is per-thread value. but you now need per-inode >> interleave offset. maybe, just inode addition is enough. Why do you need randomness? > > I don't really need the randomness, the rotor should be good enough. > The correct way to get that is cpuset_mem_spread_node(), yes? I think that's good idea too. -- 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>