On Fri, Aug 21, 2015 at 1:27 PM, Luck, Tony <tony.luck@xxxxxxxxx> wrote: > On Fri, Aug 21, 2015 at 11:38:13AM -0700, Yinghai Lu wrote: >> That commit could be reverted. >> According to >> https://lkml.org/lkml/2014/11/10/123 > > Do we really need to force the MIN_MEMORY_BLOCK_SIZE on small > systems? That is introduced in commit 982792c7 ("x86, mm: probe memory block size for generic x86 64bit "). that patch is used to make boot faster why create less entries in /sys/device/system/memory/. On system with less 64G ram, that will not have too many entries even with MIN_MEMORY_BLOCK_SIZE. > > What about this patch - which just uses max_pfn to choose > the block size. > > It seems that many systems with large amounts of memory > will have a nicely aligned max_pfn ... so they will get > the 2GB block size. If they don't have a well aligned > max_pfn, then they need to use a smaller size to avoid > the crash I saw. Good to me. > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > index 3fba623e3ba5..e14e90fd1cf8 100644 > --- a/arch/x86/mm/init_64.c > +++ b/arch/x86/mm/init_64.c > @@ -1195,15 +1195,6 @@ static unsigned long probe_memory_block_size(void) > /* start from 2g */ > unsigned long bz = 1UL<<31; > > - if (totalram_pages >= (64ULL << (30 - PAGE_SHIFT))) { > - pr_info("Using 2GB memory block size for large-memory system\n"); > - return 2UL * 1024 * 1024 * 1024; > - } > - > - /* less than 64g installed */ > - if ((max_pfn << PAGE_SHIFT) < (16UL << 32)) > - return MIN_MEMORY_BLOCK_SIZE; > - > /* get the tail size */ > while (bz > MIN_MEMORY_BLOCK_SIZE) { > if (!((max_pfn << PAGE_SHIFT) & (bz - 1))) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
