The patch titled
Subject: mm: pagewalk: add p4d_entry() and pgd_entry()
has been added to the -mm tree. Its filename is
mm-pagewalk-add-p4d_entry-and-pgd_entry.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-pagewalk-add-p4d_entry-and-pgd_entry.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-pagewalk-add-p4d_entry-and-pgd_entry.patch
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------------------------------------------------------
From: Steven Price <steven.price@xxxxxxx>
Subject: mm: pagewalk: add p4d_entry() and pgd_entry()
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.
Link: http://lkml.kernel.org/r/20190731154603.41797-12-steven.price@xxxxxxx
Signed-off-by: Steven Price <steven.price@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 18 ++++++++++++------
mm/pagewalk.c | 27 ++++++++++++++++-----------
2 files changed, 28 insertions(+), 17 deletions(-)
--- a/include/linux/mm.h~mm-pagewalk-add-p4d_entry-and-pgd_entry
+++ a/include/linux/mm.h
@@ -1451,15 +1451,14 @@ void unmap_vmas(struct mmu_gather *tlb,
/**
* mm_walk - callbacks for walk_page_range
- * @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
+ * @pgd_entry: if set, called for each non-empty PGD (top-level) entry
+ * @p4d_entry: if set, called for each non-empty P4D entry
+ * @pud_entry: if set, called for each non-empty PUD entry
+ * @pmd_entry: if set, called for each non-empty PMD entry
* this handler is required to be able to handle
* pmd_trans_huge() pmds. They may simply choose to
* split_huge_page() instead of handling it explicitly.
- * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
+ * @pte_entry: if set, called for each non-empty PTE (lowest-level) entry
* @pte_hole: if set, called for each hole at all levels
* @hugetlb_entry: if set, called for each hugetlb entry
* @test_walk: caller specific callback function to determine whether
@@ -1472,8 +1471,15 @@ void unmap_vmas(struct mmu_gather *tlb,
* @private: private data for callbacks' usage
*
* (see the comment on walk_page_range() for more details)
+ *
+ * p?d_entry callbacks are called even if those levels are folded on a partial
+ * architecture/configuration.
*/
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,
--- a/mm/pagewalk.c~mm-pagewalk-add-p4d_entry-and-pgd_entry
+++ a/mm/pagewalk.c
@@ -90,15 +90,9 @@ static int walk_pud_range(p4d_t *p4d, un
}
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, un
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
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;
_
Patches currently in -mm which might be from steven.price@xxxxxxx are
mm-add-generic-pd_leaf-macros.patch
arc-mm-add-pd_leaf-definitions.patch
arm-mm-add-pd_leaf-definitions.patch
arm64-mm-add-pd_leaf-definitions.patch
mips-mm-add-pd_leaf-definitions.patch
powerpc-mm-add-pd_leaf-definitions.patch
riscv-mm-add-pd_leaf-definitions.patch
s390-mm-add-pd_leaf-definitions.patch
sparc-mm-add-pd_leaf-definitions.patch
x86-mm-add-pd_leaf-definitions.patch
mm-pagewalk-add-p4d_entry-and-pgd_entry.patch
mm-pagewalk-allow-walking-without-vma.patch
mm-pagewalk-add-test_pd-callbacks.patch
mm-pagewalk-add-depth-parameter-to-pte_hole.patch
x86-mm-point-to-struct-seq_file-from-struct-pg_state.patch
x86-mmefi-convert-ptdump_walk_pgd_level-to-take-a-mm_struct.patch
x86-mm-convert-ptdump_walk_pgd_level_debugfs-to-take-an-mm_struct.patch
x86-mm-convert-ptdump_walk_pgd_level_core-to-take-an-mm_struct.patch
mm-add-generic-ptdump.patch
x86-mm-convert-dump_pagetables-to-use-walk_page_range.patch
arm64-mm-convert-mm-dumpc-to-use-walk_page_range.patch
arm64-mm-display-non-present-entries-in-ptdump.patch
