Re: [PATCH 05/10] powerpc/hugetlb: Split the function 'huge_pte_alloc'
From: Balbir Singh <bsingharora@gmail.com>
Date: 2016-04-11 13:51:45
Also in:
linux-mm, lkml
On 07/04/16 15:37, Anshuman Khandual wrote:
quoted hunk ↗ jump to hunk
Currently the function 'huge_pte_alloc' has got two versions, one for the BOOK3S server and the other one for the BOOK3E embedded platforms. This change splits only the BOOK3S server version into two parts, one for the ARCH_WANT_GENERAL_HUGETLB config implementation and the other one for everything else. This change is one of the prerequisites towards enabling ARCH_WANT_GENERAL_HUGETLB config option on POWER platform. Signed-off-by: Anshuman Khandual <redacted> --- arch/powerpc/mm/hugetlbpage.c | 67 +++++++++++++++++++++++++++---------------- 1 file changed, 43 insertions(+), 24 deletions(-)diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index d991b9e..e453918 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c@@ -59,6 +59,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL, NULL); } +#ifndef CONFIG_ARCH_WANT_GENERAL_HUGETLB static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, unsigned long address, unsigned pdshift, unsigned pshift) {@@ -116,6 +117,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, spin_unlock(&mm->page_table_lock); return 0; } +#endif /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */ /* * These macros define how to determine which level of the page table holds@@ -130,6 +132,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, #endif #ifdef CONFIG_PPC_BOOK3S_64 +#ifndef CONFIG_ARCH_WANT_GENERAL_HUGETLB /* * At this point we do the placement change only for BOOK3S 64. This would * possibly work on other subarchs.@@ -145,32 +148,23 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz addr &= ~(sz-1); pg = pgd_offset(mm, addr); - - if (pshift == PGDIR_SHIFT) - /* 16GB huge page */ - return (pte_t *) pg; - else if (pshift > PUD_SHIFT) - /* - * We need to use hugepd table - */ + if (pshift > PUD_SHIFT) { hpdp = (hugepd_t *)pg; - else { - pdshift = PUD_SHIFT; - pu = pud_alloc(mm, pg, addr); - if (pshift == PUD_SHIFT) - return (pte_t *)pu; - else if (pshift > PMD_SHIFT) - hpdp = (hugepd_t *)pu; - else { - pdshift = PMD_SHIFT; - pm = pmd_alloc(mm, pu, addr); - if (pshift == PMD_SHIFT) - /* 16MB hugepage */ - return (pte_t *)pm; - else - hpdp = (hugepd_t *)pm; - } + goto hugepd_search; } + + pdshift = PUD_SHIFT; + pu = pud_alloc(mm, pg, addr); + if (pshift > PMD_SHIFT) { + hpdp = (hugepd_t *)pu; + goto hugepd_search; + } + + pdshift = PMD_SHIFT; + pm = pmd_alloc(mm, pu, addr); + hpdp = (hugepd_t *)pm; + +hugepd_search: if (!hpdp) return NULL;@@ -182,6 +176,31 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz return hugepte_offset(*hpdp, addr, pdshift); } +#else /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ +pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
This is confusing, aren't we using the one from mm/hugetlb.c?
+{
+ pgd_t *pg;
+ pud_t *pu;
+ pmd_t *pm;
+ unsigned pshift = __ffs(sz);
+
+ addr &= ~(sz-1);Am I reading this right? Shouldn't this be addr &= ~(1 << pshift - 1)
+ pg = pgd_offset(mm, addr); + + if (pshift == PGDIR_SHIFT) /* 16GB Huge Page */ + return (pte_t *)pg; + + pu = pud_alloc(mm, pg, addr); /* NA, skipped */ + if (pshift == PUD_SHIFT) + return (pte_t *)pu; + + pm = pmd_alloc(mm, pu, addr); /* 16MB Huge Page */ + if (pshift == PMD_SHIFT) + return (pte_t *)pm; + + return NULL; +} +#endif /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */ #else pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)