[PATCH v2 0/2] arm64: fix the bugs found in the hugetlb test

Huang Shijie shijie.huang at arm.com
Mon Nov 7 21:44:37 PST 2016

(1) Backgroud
   For the arm64, the hugetlb page size can be 32M (PMD + Contiguous bit).
   In the 4K page environment, the max page order is 10 (max_order - 1),
   so 32M page is the gigantic page.    

   The arm64 MMU supports a Contiguous bit which is a hint that the PTE
   is one of a set of contiguous entries which can be cached in a single
   TLB entry.  Please refer to the arm64v8 mannul :
       DDI0487A_f_armv8_arm.pdf (in page D4-1811)

(2) The bugs   
   After I tested the libhugetlbfs, I found several bugs in arm64 code.
   This patch set has all the bug fixes for the arm64.
(3) The test result in the Softiron and Juno-r1 boards:

   This detail test result shows below (both the "make func" & "make stress"):

    4KB granule:

        1.1) PTE + Contiguous bit : 4K x 16 = 64K (per huge page size)
             Test result          : PASS

        1.2) PMD                  : 2M x  1 = 2M  (per huge page size)
             Test result          : PASS

        1.3) PMD + Contiguous bit : 2M x 16 = 32M (per huge page size)
             Test result          : PASS

    64KB granule:

        3.1) PTE + Contiguous bit : 64K x 32 = 2M (per huge page size)
             Test result          : PASS

        3.2) PMD + Contiguous bit : 512M x 32 = 16G (per huge page size)
             Test result          : no hardware to support this test

v1 -- > v2:
    1.) remove the redundant checks for PGD/PUD

Huang Shijie (2):
  arm64: hugetlb: remove the wrong pmd check in find_num_contig()
  arm64: hugetlb: fix the wrong address for several functions

 arch/arm64/mm/hugetlbpage.c | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)


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