[PATCH 04/13] mm: pagewalk: Add p4d_entry() and pgd_entry()
From: Steven Price <steven.price@arm.com>
Date: 2019-02-15 17:03:24
Also in:
linux-mm, lkml
Subsystem:
memory management, memory management - core, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
pgd_entry() and pud_entry() were removed by commit 0b1fbfe50006c410
("mm/pagewalk: remove pgd_entry() and pud_entry()") because there were
no users. We're about to add users so reintroduce them, along with
p4d_entry() as we now have 5 levels of tables.
Note that commit a00cc7d9dd93d66a ("mm, x86: add support for
PUD-sized transparent hugepages") already re-added pud_entry() but with
different semantics to the other callbacks. Since there have never
been upstream users of this, revert the semantics back to match the
other callbacks. This means pud_entry() is called for all entries, not
just transparent huge pages.
Signed-off-by: Steven Price <steven.price@arm.com>
---
include/linux/mm.h | 9 ++++++---
mm/pagewalk.c | 27 ++++++++++++++++-----------
2 files changed, 22 insertions(+), 14 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 80bb6408fe73..1a4b1615d012 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -1412,10 +1412,9 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma, /** * mm_walk - callbacks for walk_page_range + * @pgd_entry: if set, called for each non-empty PGD (top-level) entry + * @p4d_entry: if set, called for each non-empty P4D (1st-level) entry * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry - * this handler should only handle pud_trans_huge() puds. - * the pmd_entry or pte_entry callbacks will be used for - * regular PUDs. * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry * this handler is required to be able to handle * pmd_trans_huge() pmds. They may simply choose to
@@ -1435,6 +1434,10 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma, * (see the comment on walk_page_range() for more details) */ struct mm_walk { + int (*pgd_entry)(pgd_t *pgd, unsigned long addr, + unsigned long next, struct mm_walk *walk); + int (*p4d_entry)(p4d_t *p4d, unsigned long addr, + unsigned long next, struct mm_walk *walk); int (*pud_entry)(pud_t *pud, unsigned long addr, unsigned long next, struct mm_walk *walk); int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index c3084ff2569d..98373a9f88b8 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c@@ -90,15 +90,9 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, } if (walk->pud_entry) { - spinlock_t *ptl = pud_trans_huge_lock(pud, walk->vma); - - if (ptl) { - err = walk->pud_entry(pud, addr, next, walk); - spin_unlock(ptl); - if (err) - break; - continue; - } + err = walk->pud_entry(pud, addr, next, walk); + if (err) + break; } split_huge_pud(walk->vma, pud, addr);
@@ -131,7 +125,12 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end, break; continue; } - if (walk->pmd_entry || walk->pte_entry) + if (walk->p4d_entry) { + err = walk->p4d_entry(p4d, addr, next, walk); + if (err) + break; + } + if (walk->pud_entry || walk->pmd_entry || walk->pte_entry) err = walk_pud_range(p4d, addr, next, walk); if (err) break;
@@ -157,7 +156,13 @@ static int walk_pgd_range(unsigned long addr, unsigned long end, break; continue; } - if (walk->pmd_entry || walk->pte_entry) + if (walk->pgd_entry) { + err = walk->pgd_entry(pgd, addr, next, walk); + if (err) + break; + } + if (walk->p4d_entry || walk->pud_entry || walk->pmd_entry || + walk->pte_entry) err = walk_p4d_range(pgd, addr, next, walk); if (err) break;
--
2.20.1
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