| Message ID | 20191018101248.33727-12-steven.price@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Generic page walk and ptdump | expand |
Steven Price <steven.price@arm.com> 於 2019年10月19日 週六 下午4:14寫道： > > 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/pagewalk.h | 19 +++++++++++++------ > mm/pagewalk.c | 27 ++++++++++++++++----------- > 2 files changed, 29 insertions(+), 17 deletions(-) > > diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h > index bddd9759bab9..12004b097eae 100644 > --- a/include/linux/pagewalk.h > +++ b/include/linux/pagewalk.h > @@ -8,15 +8,15 @@ struct mm_walk; > > /** > * mm_walk_ops - 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 > @@ -24,8 +24,15 @@ struct mm_walk; > * "do page table walk over the current vma", returning > * a negative value means "abort current page table walk > * right now" and returning 1 means "skip the current vma" > + * > + * p?d_entry callbacks are called even if those levels are folded on a > + * particular architecture/configuration. > */ > struct mm_walk_ops { > + 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 d48c2a986ea3..fc4d98a3a5a0 100644 > --- a/mm/pagewalk.c > +++ b/mm/pagewalk.c > @@ -93,15 +93,9 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, > } > > if (ops->pud_entry) { > - spinlock_t *ptl = pud_trans_huge_lock(pud, walk->vma); > - > - if (ptl) { > - err = ops->pud_entry(pud, addr, next, walk); > - spin_unlock(ptl); > - if (err) > - break; > - continue; > - } > + err = ops->pud_entry(pud, addr, next, walk); > + if (err) > + break; > } > > split_huge_pud(walk->vma, pud, addr); > @@ -135,7 +129,12 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end, > break; > continue; > } > - if (ops->pmd_entry || ops->pte_entry) > + if (ops->p4d_entry) { > + err = ops->p4d_entry(p4d, addr, next, walk); > + if (err) > + break; > + } > + if (ops->pud_entry || ops->pmd_entry || ops->pte_entry) > err = walk_pud_range(p4d, addr, next, walk); > if (err) > break; > @@ -162,7 +161,13 @@ static int walk_pgd_range(unsigned long addr, unsigned long end, > break; > continue; > } > - if (ops->pmd_entry || ops->pte_entry) > + if (ops->pgd_entry) { > + err = ops->pgd_entry(pgd, addr, next, walk); > + if (err) > + break; > + } > + if (ops->p4d_entry || ops->pud_entry || ops->pmd_entry || > + ops->pte_entry) > err = walk_p4d_range(pgd, addr, next, walk); > if (err) > break; > -- > 2.20.1 > It's good to me. Tested-by: Zong Li <zong.li@sifive.com>
diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h index bddd9759bab9..12004b097eae 100644 --- a/include/linux/pagewalk.h +++ b/include/linux/pagewalk.h @@ -8,15 +8,15 @@ struct mm_walk; /** * mm_walk_ops - 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 @@ -24,8 +24,15 @@ struct mm_walk; * "do page table walk over the current vma", returning * a negative value means "abort current page table walk * right now" and returning 1 means "skip the current vma" + * + * p?d_entry callbacks are called even if those levels are folded on a + * particular architecture/configuration. */ struct mm_walk_ops { + 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 d48c2a986ea3..fc4d98a3a5a0 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -93,15 +93,9 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, } if (ops->pud_entry) { - spinlock_t *ptl = pud_trans_huge_lock(pud, walk->vma); - - if (ptl) { - err = ops->pud_entry(pud, addr, next, walk); - spin_unlock(ptl); - if (err) - break; - continue; - } + err = ops->pud_entry(pud, addr, next, walk); + if (err) + break; } split_huge_pud(walk->vma, pud, addr); @@ -135,7 +129,12 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end, break; continue; } - if (ops->pmd_entry || ops->pte_entry) + if (ops->p4d_entry) { + err = ops->p4d_entry(p4d, addr, next, walk); + if (err) + break; + } + if (ops->pud_entry || ops->pmd_entry || ops->pte_entry) err = walk_pud_range(p4d, addr, next, walk); if (err) break; @@ -162,7 +161,13 @@ static int walk_pgd_range(unsigned long addr, unsigned long end, break; continue; } - if (ops->pmd_entry || ops->pte_entry) + if (ops->pgd_entry) { + err = ops->pgd_entry(pgd, addr, next, walk); + if (err) + break; + } + if (ops->p4d_entry || ops->pud_entry || ops->pmd_entry || + ops->pte_entry) err = walk_p4d_range(pgd, addr, next, walk); if (err) break;
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/pagewalk.h | 19 +++++++++++++------ mm/pagewalk.c | 27 ++++++++++++++++----------- 2 files changed, 29 insertions(+), 17 deletions(-)