[PATCH v6 5/9] arm64: hugetlb: Handle swap entries in huge_pte_offset() for contiguous hugepages
From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2017-08-18 11:20:23
Also in:
linux-mm
On Thu, Aug 10, 2017 at 06:09:02PM +0100, Punit Agrawal wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index d3a6713048a2..09e79785c019 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c@@ -210,6 +210,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, pgd_t *pgd; pud_t *pud; pmd_t *pmd; + pte_t *pte; pgd = pgd_offset(mm, addr); pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd);@@ -217,19 +218,29 @@ pte_t *huge_pte_offset(struct mm_struct *mm, return NULL; pud = pud_offset(pgd, addr); - if (pud_none(*pud)) + if (pud_none(*pud) && sz != PUD_SIZE) return NULL; /* swap or huge page */ if (!pud_present(*pud) || pud_huge(*pud)) return (pte_t *)pud; /* table; check the next level */
So if sz == PUD_SIZE and we have pud_none(*pud) == true, it returns the pud. Isn't this different from what you proposed for the generic huge_pte_offset()? [1]
+ if (sz == CONT_PMD_SIZE) + addr &= CONT_PMD_MASK; + pmd = pmd_offset(pud, addr); - if (pmd_none(*pmd)) + if (pmd_none(*pmd) && + !(sz == PMD_SIZE || sz == CONT_PMD_SIZE)) return NULL;
Again, if sz == PMD_SIZE, you no longer return NULL. The generic proposal in [1] looks like: if (pmd_none(*pmd)) return NULL; and that's even when sz == PMD_SIZE. Anyway, I think we need to push for [1] again to be accepted before we go ahead with these changes. [1] http://lkml.kernel.org/r/20170725154114.24131-2-punit.agrawal at arm.com -- Catalin