On 10/5/21 1:54 PM, Andrew Morton wrote:
On Tue, 5 Oct 2021 13:25:29 -0700 Mike Kravetz mike.kravetz@oracle.com wrote:
For non-4K PAGE_SIZE configs, the largest gigantic huge page size is CONT_PMD_SHIFT order.
What are the user visible effects of this bug?
Sorry, I only recently got easy access to arm64 platforms. This is what I saw as a user:
The largest gigantic huge page size on arm64 with 64K PAGE_SIZE 64K is 16G. Therefore, one should be able to specify 'hugetlb_cma=16G' on the kernel command line so that 1 gigantic page can be allocated from CMA. However, when adding such an option the following message is produced:
hugetlb_cma: cma area should be at least 8796093022208 MiB
This is because the calculation for non-4K gigantic page order is incorrect in the arm64 specific routine arm64_hugetlb_cma_reserve().
Would you like me to send a new version with this in the commit message? Or, is it easier for you to just add it?