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So we can make it more readable by >>> replace it with huge_page_size(h) / SZ_1K. >>> >>> Signed-off-by: Miaohe Lin >>> --- >>> fs/hugetlbfs/inode.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c >>> index 25c1857ff45d..f94b8f6553fa 100644 >>> --- a/fs/hugetlbfs/inode.c >>> +++ b/fs/hugetlbfs/inode.c >>> @@ -1519,8 +1519,8 @@ static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h) >>> put_fs_context(fc); >>> } >>> if (IS_ERR(mnt)) >>> - pr_err("Cannot mount internal hugetlbfs for page size %uK", >>> - 1U << (h->order + PAGE_SHIFT - 10)); >>> + pr_err("Cannot mount internal hugetlbfs for page size %luK", >>> + huge_page_size(h) / SZ_1K); >> >> I appreciate the effort to make the code more readable. The existing >> calculation does take a minute to understand. However, it is correct and >> anyone modifying the code should be able to understand. >> >> With my compiler, your proposed change adds an additional instruction to >> the routine mount_one_hugetlbfs. I know this is not significant, but still > > I thought compiler would generate the same code... > >> it does increase the kernel size for a change that is of questionable value. >> >> In the kernel, size in KB is often calculated as (size << (PAGE_SHIFT - 10)). >> If you change the calculation in the hugetlb code to be: >>> huge_page_size(h) << (PAGE_SHIFT - 10) > > I'am sorry but this looks not really correct. I think the calculation shoud be > huge_page_size(h) >> 10. What do you think? My bad! I was looking at code that converts page counts to KB. Sorry. Yes, huge_page_size(h) >> 10 is correct. -- Mike Kravetz