On Tue, Jan 8, 2013 at 12:59 PM, Steve Capper [off-list ref] wrote:

On Fri, Jan 04, 2013 at 05:04:57AM +0000, Christoffer Dall wrote:

quoted

On Thu, Oct 18, 2012 at 12:15 PM, Steve Capper [off-list ref] wrote:

quoted

Much of the required code for THP has been implemented in the earlier non-LPAE
HugeTLB patch.

One more domain bits is used (to store whether or not the THP is splitting).

s/bits/bit/

Thanks.

quoted

quoted

Some THP helper functions are defined; and we have to re-define pmd_page such
that it distinguishes between page tables and sections.

super nit: not sure the semi-colon is warranted here.

Cheers, it is a superfluous semicolon.

quoted

quoted

Signed-off-by: Will Deacon <redacted>
Signed-off-by: Steve Capper <redacted>
---
 arch/arm/Kconfig                      |    2 +-
 arch/arm/include/asm/pgtable-2level.h |   68 ++++++++++++++++++++++++++++++++-
 arch/arm/include/asm/pgtable-3level.h |    2 +
 arch/arm/include/asm/pgtable.h        |    7 +++-
 4 files changed, 75 insertions(+), 4 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 9621d5f..d459673 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig

@@ -1773,7 +1773,7 @@ config SYS_SUPPORTS_HUGETLBFS

 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
        def_bool y
-       depends on ARM_LPAE
+       depends on SYS_SUPPORTS_HUGETLBFS

 source "mm/Kconfig"

diff --git a/arch/arm/include/asm/pgtable-2level.h b/arch/arm/include/asm/pgtable-2level.h
index 34f4775..67eabb4 100644
--- a/arch/arm/include/asm/pgtable-2level.h
+++ b/arch/arm/include/asm/pgtable-2level.h

@@ -179,6 +179,13 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
                clean_pmd_entry(pmdp);  \
        } while (0)

+

stray whitespace?

Thanks.

quoted

quoted

+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#define _PMD_HUGE(pmd) ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_SECT)
+#else
+#define _PMD_HUGE(pmd) (0)
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
 /* we don't need complex calculations here as the pmd is folded into the pgd */
 #define pmd_addr_end(addr,end) (end)

@@ -197,7 +204,6 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)

 #define HPAGE_SHIFT             PMD_SHIFT
 #define HPAGE_SIZE              (_AC(1, UL) << HPAGE_SHIFT)
-#define HPAGE_MASK              (~(HPAGE_SIZE - 1))
 #define HUGETLB_PAGE_ORDER      (HPAGE_SHIFT - PAGE_SHIFT)

 #define HUGE_LINUX_PTE_COUNT       (PAGE_OFFSET >> HPAGE_SHIFT)

@@ -209,6 +215,7 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
  */
 #define PMD_DSECT_DIRTY                (_AT(pmdval_t, 1) << 5)
 #define PMD_DSECT_AF           (_AT(pmdval_t, 1) << 6)
+#define PMD_DSECT_SPLITTING    (_AT(pmdval_t, 1) << 7)

 #define PMD_BIT_FUNC(fn,op) \
 static inline pmd_t pmd_##fn(pmd_t pmd) { pmd_val(pmd) op; return pmd; }

@@ -261,8 +268,67 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
        return __pmd(pmdval);
 }

+#else
+#define        HPAGE_SIZE      0

why this and the conditional define of _PMD_HUGE, you could just do
like in pgtable.h and put the #ifdef around the condition in
pmd_page(pmt_t pmd).

Thanks, I'll take a look at this.

quoted

quoted

 #endif /* CONFIG_SYS_SUPPORTS_HUGETLBFS */

+#define HPAGE_MASK              (~(HPAGE_SIZE - 1))
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#define pmd_mkhuge(pmd)                (__pmd((pmd_val(pmd) & ~PMD_TYPE_MASK) | PMD_TYPE_SECT))
+
+PMD_BIT_FUNC(mkold, &= ~PMD_DSECT_AF);
+PMD_BIT_FUNC(mksplitting, |= PMD_DSECT_SPLITTING);
+PMD_BIT_FUNC(mkdirty, |= PMD_DSECT_DIRTY);
+PMD_BIT_FUNC(mkyoung, |= PMD_DSECT_AF);
+PMD_BIT_FUNC(mkwrite, |= PMD_SECT_AP_WRITE);
+PMD_BIT_FUNC(mknotpresent, &= ~PMD_TYPE_MASK);
+
+#define pmd_trans_splitting(pmd)       (pmd_val(pmd) & PMD_DSECT_SPLITTING)
+#define pmd_young(pmd)                 (pmd_val(pmd) & PMD_DSECT_AF)
+#define pmd_write(pmd)                 (pmd_val(pmd) & PMD_SECT_AP_WRITE)
+#define pmd_trans_huge(pmd)            ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_SECT)
+
+static inline unsigned long pmd_pfn(pmd_t pmd)
+{
+       /*
+        * for a section, we need to mask off more of the pmd
+        * before looking up the pfn
+        */
+       if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_SECT)
+               return __phys_to_pfn(pmd_val(pmd) & HPAGE_MASK);
+       else
+               return __phys_to_pfn(pmd_val(pmd) & PHYS_MASK);
+}
+
+static inline pmd_t pfn_pmd(unsigned long pfn, pgprot_t prot)
+{
+       pmd_t pmd = __pmd(__pfn_to_phys(pfn) | PMD_SECT_AP_READ | PMD_SECT_nG);
+
+       return pmd_modify(pmd, prot);
+}
+
+#define mk_pmd(page,prot) pfn_pmd(page_to_pfn(page),prot);
+
+static inline int has_transparent_hugepage(void)
+{
+       return 1;
+}
+
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+static inline struct page *pmd_page(pmd_t pmd)
+{
+       /*
+        * for a section, we need to mask off more of the pmd
+        * before looking up the page as it is a section descriptor.
+        */
+       if (_PMD_HUGE(pmd))
+               return phys_to_page(pmd_val(pmd) & HPAGE_MASK);
+
+       return phys_to_page(pmd_val(pmd) & PHYS_MASK);
+}
+
 #endif /* __ASSEMBLY__ */

 #endif /* _ASM_PGTABLE_2LEVEL_H */

diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
index 31c071f..8360814 100644
--- a/arch/arm/include/asm/pgtable-3level.h
+++ b/arch/arm/include/asm/pgtable-3level.h

@@ -197,6 +197,8 @@ PMD_BIT_FUNC(mknotpresent, &= ~PMD_TYPE_MASK);
 #define pfn_pmd(pfn,prot)      (__pmd(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))
 #define mk_pmd(page,prot)      pfn_pmd(page_to_pfn(page),prot)

+#define pmd_page(pmd)           pfn_to_page(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK))
+
 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 {
        const pmdval_t mask = PMD_SECT_USER | PMD_SECT_XN | PMD_SECT_RDONLY;

diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 767aa7c..2d96381 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h

@@ -169,11 +169,14 @@ extern pgd_t swapper_pg_dir[PTRS_PER_PGD];

 static inline pte_t *pmd_page_vaddr(pmd_t pmd)
 {
+#ifdef SYS_SUPPORTS_HUGETLBFS
+       if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_SECT)
+               return __va(pmd_val(pmd) & HPAGE_MASK);
+#endif
+
        return __va(pmd_val(pmd) & PHYS_MASK & (s32)PAGE_MASK);
 }

-#define pmd_page(pmd)          pfn_to_page(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK))
-
 #ifndef CONFIG_HIGHPTE
 #define __pte_map(pmd)         pmd_page_vaddr(*(pmd))
 #define __pte_unmap(pte)       do { } while (0)
--

1.7.9.5

The whole series looks functionally correct to me:

Reviewed-by: Christoffer Dall <redacted>

A big thank you for going through this Christoffer.

I'm correcting/simplifying/testing the huge pages code and will send out another
version soon.

Great. This really makes a performance difference for running VMs, so
I'm happy to have the code for KVM/ARM. Please remember to cc me
and/or the kvmarm mailing list for a new version of this series.

-Christoffer