diff mbox

[03/11] mm: hugetlb: Copy general hugetlb code from x86 to mm.

Message ID 1369328878-11706-4-git-send-email-steve.capper@linaro.org
State Accepted
Commit 9e5fc74c30250566ff9154effdb17d6d18952052
Headers show

Commit Message

Steve Capper May 23, 2013, 5:07 p.m. UTC 
The huge_pte_alloc, huge_pte_offset and follow_huge_p[mu]d
functions in x86/mm/hugetlbpage.c do not rely on any architecture
specific knowledge other than the fact that pmds and puds can be
treated as huge ptes.

To allow other architectures to use this code (and reduce the need
for code duplication), this patch copies these functions into mm,
replaces the use of pud_large with pud_huge and provides a config
flag to activate them:
CONFIG_ARCH_WANT_GENERAL_HUGETLB

If CONFIG_ARCH_WANT_HUGE_PMD_SHARE is also active then the
huge_pmd_share code will be called by huge_pte_alloc (othewise we
call pmd_alloc and skip the sharing code).

Signed-off-by: Steve Capper <steve.capper@linaro.org>
---
 mm/hugetlb.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 88 insertions(+), 9 deletions(-)

Comments

Catalin Marinas May 24, 2013, 11:14 a.m. UTC | #1 
On Thu, May 23, 2013 at 06:07:50PM +0100, Steve Capper wrote:
> The huge_pte_alloc, huge_pte_offset and follow_huge_p[mu]d
> functions in x86/mm/hugetlbpage.c do not rely on any architecture
> specific knowledge other than the fact that pmds and puds can be
> treated as huge ptes.
> 
> To allow other architectures to use this code (and reduce the need
> for code duplication), this patch copies these functions into mm,
> replaces the use of pud_large with pud_huge and provides a config
> flag to activate them:
> CONFIG_ARCH_WANT_GENERAL_HUGETLB
> 
> If CONFIG_ARCH_WANT_HUGE_PMD_SHARE is also active then the
> huge_pmd_share code will be called by huge_pte_alloc (othewise we
> call pmd_alloc and skip the sharing code).
> 
> Signed-off-by: Steve Capper <steve.capper@linaro.org>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Catalin Marinas May 24, 2013, 11:18 a.m. UTC | #2 
On Thu, May 23, 2013 at 06:07:50PM +0100, Steve Capper wrote:
> The huge_pte_alloc, huge_pte_offset and follow_huge_p[mu]d
> functions in x86/mm/hugetlbpage.c do not rely on any architecture
> specific knowledge other than the fact that pmds and puds can be
> treated as huge ptes.
> 
> To allow other architectures to use this code (and reduce the need
> for code duplication), this patch copies these functions into mm,
> replaces the use of pud_large with pud_huge and provides a config
> flag to activate them:
> CONFIG_ARCH_WANT_GENERAL_HUGETLB

BTW, I think it's worth mentioning that pud_large is inline while
pud_huge is not.
diff mbox

Patch

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b0bfb29..6321726 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2931,15 +2931,6 @@  out_mutex:
 	return ret;
 }
 
-/* Can be overriden by architectures */
-__attribute__((weak)) struct page *
-follow_huge_pud(struct mm_struct *mm, unsigned long address,
-	       pud_t *pud, int write)
-{
-	BUG();
-	return NULL;
-}
-
 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
 			 struct page **pages, struct vm_area_struct **vmas,
 			 unsigned long *position, unsigned long *nr_pages,
@@ -3289,8 +3280,96 @@  int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
 	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
 	return 1;
 }
+#define want_pmd_share()	(1)
+#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
+pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
+{
+	return NULL;
+}
+#define want_pmd_share()	(0)
 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
 
+#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+			unsigned long addr, unsigned long sz)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pte_t *pte = NULL;
+
+	pgd = pgd_offset(mm, addr);
+	pud = pud_alloc(mm, pgd, addr);
+	if (pud) {
+		if (sz == PUD_SIZE) {
+			pte = (pte_t *)pud;
+		} else {
+			BUG_ON(sz != PMD_SIZE);
+			if (want_pmd_share() && pud_none(*pud))
+				pte = huge_pmd_share(mm, addr, pud);
+			else
+				pte = (pte_t *)pmd_alloc(mm, pud, addr);
+		}
+	}
+	BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
+
+	return pte;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd = NULL;
+
+	pgd = pgd_offset(mm, addr);
+	if (pgd_present(*pgd)) {
+		pud = pud_offset(pgd, addr);
+		if (pud_present(*pud)) {
+			if (pud_huge(*pud))
+				return (pte_t *)pud;
+			pmd = pmd_offset(pud, addr);
+		}
+	}
+	return (pte_t *) pmd;
+}
+
+struct page *
+follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+		pmd_t *pmd, int write)
+{
+	struct page *page;
+
+	page = pte_page(*(pte_t *)pmd);
+	if (page)
+		page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
+	return page;
+}
+
+struct page *
+follow_huge_pud(struct mm_struct *mm, unsigned long address,
+		pud_t *pud, int write)
+{
+	struct page *page;
+
+	page = pte_page(*(pte_t *)pud);
+	if (page)
+		page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
+	return page;
+}
+
+#else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
+
+/* Can be overriden by architectures */
+__attribute__((weak)) struct page *
+follow_huge_pud(struct mm_struct *mm, unsigned long address,
+	       pud_t *pud, int write)
+{
+	BUG();
+	return NULL;
+}
+
+#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
+
 #ifdef CONFIG_MEMORY_FAILURE
 
 /* Should be called in hugetlb_lock */