From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Zi Yan <ziy@nvidia.com>
Cc: linux-mm@kvack.org, Roman Gushchin <guro@fb.com>,
Rik van Riel <riel@surriel.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>,
Shakeel Butt <shakeelb@google.com>,
Yang Shi <yang.shi@linux.alibaba.com>,
David Nellans <dnellans@nvidia.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 05/16] mm: thp: handling 1GB THP reference bit.
Date: Wed, 9 Sep 2020 17:09:12 +0300 [thread overview]
Message-ID: <20200909140912.g2s4y22li2xwfttr@box> (raw)
In-Reply-To: <20200902180628.4052244-6-zi.yan@sent.com>
On Wed, Sep 02, 2020 at 02:06:17PM -0400, Zi Yan wrote:
> From: Zi Yan <ziy@nvidia.com>
>
> Add PUD-level TLB flush ops and teach page_vma_mapped_talk about 1GB
> THPs.
>
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> ---
> arch/x86/include/asm/pgtable.h | 3 +++
> arch/x86/mm/pgtable.c | 13 +++++++++++++
> include/linux/mmu_notifier.h | 13 +++++++++++++
> include/linux/pgtable.h | 14 ++++++++++++++
> include/linux/rmap.h | 1 +
> mm/page_vma_mapped.c | 33 +++++++++++++++++++++++++++++----
> mm/rmap.c | 12 +++++++++---
> 7 files changed, 82 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index 26255cac78c0..15334f5ba172 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -1127,6 +1127,9 @@ extern int pudp_test_and_clear_young(struct vm_area_struct *vma,
> extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
> unsigned long address, pmd_t *pmdp);
>
> +#define __HAVE_ARCH_PUDP_CLEAR_YOUNG_FLUSH
> +extern int pudp_clear_flush_young(struct vm_area_struct *vma,
> + unsigned long address, pud_t *pudp);
>
> #define pmd_write pmd_write
> static inline int pmd_write(pmd_t pmd)
> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
> index 7be73aee6183..e4a2dffcc418 100644
> --- a/arch/x86/mm/pgtable.c
> +++ b/arch/x86/mm/pgtable.c
> @@ -633,6 +633,19 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
>
> return young;
> }
> +int pudp_clear_flush_young(struct vm_area_struct *vma,
> + unsigned long address, pud_t *pudp)
> +{
> + int young;
> +
> + VM_BUG_ON(address & ~HPAGE_PUD_MASK);
> +
> + young = pudp_test_and_clear_young(vma, address, pudp);
> + if (young)
> + flush_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
> +
> + return young;
> +}
> #endif
>
> /**
> diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
> index b8200782dede..4ffa179e654f 100644
> --- a/include/linux/mmu_notifier.h
> +++ b/include/linux/mmu_notifier.h
> @@ -557,6 +557,19 @@ static inline void mmu_notifier_range_init_migrate(
> __young; \
> })
>
> +#define pudp_clear_flush_young_notify(__vma, __address, __pudp) \
> +({ \
> + int __young; \
> + struct vm_area_struct *___vma = __vma; \
> + unsigned long ___address = __address; \
> + __young = pudp_clear_flush_young(___vma, ___address, __pudp); \
> + __young |= mmu_notifier_clear_flush_young(___vma->vm_mm, \
> + ___address, \
> + ___address + \
> + PUD_SIZE); \
> + __young; \
> +})
> +
> #define ptep_clear_young_notify(__vma, __address, __ptep) \
> ({ \
> int __young; \
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 255275d5b73e..8ef358c386af 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -240,6 +240,20 @@ static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
> #endif
>
> +#ifndef __HAVE_ARCH_PUDP_CLEAR_YOUNG_FLUSH
> +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
> +extern int pudp_clear_flush_young(struct vm_area_struct *vma,
> + unsigned long address, pud_t *pudp);
> +#else
> +int pudp_clear_flush_young(struct vm_area_struct *vma,
> + unsigned long address, pud_t *pudp)
> +{
> + BUILD_BUG();
> + return 0;
> +}
> +#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
> +#endif
> +
> #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
> static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
> unsigned long address,
> diff --git a/include/linux/rmap.h b/include/linux/rmap.h
> index 3a6adfa70fb0..0af61dd193d2 100644
> --- a/include/linux/rmap.h
> +++ b/include/linux/rmap.h
> @@ -206,6 +206,7 @@ struct page_vma_mapped_walk {
> struct page *page;
> struct vm_area_struct *vma;
> unsigned long address;
> + pud_t *pud;
> pmd_t *pmd;
> pte_t *pte;
> spinlock_t *ptl;
> diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
> index 5e77b269c330..d9d39ec06e21 100644
> --- a/mm/page_vma_mapped.c
> +++ b/mm/page_vma_mapped.c
> @@ -145,9 +145,12 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
> struct page *page = pvmw->page;
> pgd_t *pgd;
> p4d_t *p4d;
> - pud_t *pud;
> + pud_t pude;
> pmd_t pmde;
>
> + if (!pvmw->pte && !pvmw->pmd && pvmw->pud)
> + return not_found(pvmw);
> +
> /* The only possible pmd mapping has been handled on last iteration */
> if (pvmw->pmd && !pvmw->pte)
> return not_found(pvmw);
> @@ -174,10 +177,31 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
> p4d = p4d_offset(pgd, pvmw->address);
> if (!p4d_present(*p4d))
> return false;
> - pud = pud_offset(p4d, pvmw->address);
> - if (!pud_present(*pud))
> + pvmw->pud = pud_offset(p4d, pvmw->address);
> +
> + /*
> + * Make sure the pud value isn't cached in a register by the
> + * compiler and used as a stale value after we've observed a
> + * subsequent update.
> + */
> + pude = READ_ONCE(*pvmw->pud);
> + if (pud_trans_huge(pude)) {
> + pvmw->ptl = pud_lock(mm, pvmw->pud);
> + if (likely(pud_trans_huge(*pvmw->pud))) {
> + if (pvmw->flags & PVMW_MIGRATION)
> + return not_found(pvmw);
> + if (pud_page(*pvmw->pud) != page)
> + return not_found(pvmw);
> + return true;
> + } else {
> + /* THP pud was split under us: handle on pmd level */
> + spin_unlock(pvmw->ptl);
> + pvmw->ptl = NULL;
Hm. What makes you sure the pmd table is established here?
I have not looked at PUD THP handling of MADV_DONTNEED yet, but for PMD
THP can became pmd_none() at any point (unless ptl is locked).
> + }
> + } else if (!pud_present(pude))
> return false;
> - pvmw->pmd = pmd_offset(pud, pvmw->address);
> +
> + pvmw->pmd = pmd_offset(pvmw->pud, pvmw->address);
> /*
> * Make sure the pmd value isn't cached in a register by the
> * compiler and used as a stale value after we've observed a
> @@ -213,6 +237,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
> } else if (!pmd_present(pmde)) {
> return false;
> }
> +
> if (!map_pte(pvmw))
> goto next_pte;
> while (1) {
> diff --git a/mm/rmap.c b/mm/rmap.c
Why?
> index 10195a2421cf..77cec0658b76 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -803,9 +803,15 @@ static bool page_referenced_one(struct page *page, struct vm_area_struct *vma,
> referenced++;
> }
> } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
> - if (pmdp_clear_flush_young_notify(vma, address,
> - pvmw.pmd))
> - referenced++;
> + if (pvmw.pmd) {
> + if (pmdp_clear_flush_young_notify(vma, address,
> + pvmw.pmd))
> + referenced++;
> + } else if (pvmw.pud) {
> + if (pudp_clear_flush_young_notify(vma, address,
> + pvmw.pud))
> + referenced++;
> + }
> } else {
> /* unexpected pmd-mapped page? */
> WARN_ON_ONCE(1);
> --
> 2.28.0
>
>
--
Kirill A. Shutemov
next prev parent reply other threads:[~2020-09-09 14:09 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-02 18:06 [RFC PATCH 00/16] 1GB THP support on x86_64 Zi Yan
2020-09-02 18:06 ` [RFC PATCH 01/16] mm: add pagechain container for storing multiple pages Zi Yan
2020-09-02 20:29 ` Randy Dunlap
2020-09-02 20:48 ` Zi Yan
2020-09-03 3:15 ` Matthew Wilcox
2020-09-07 12:22 ` Kirill A. Shutemov
2020-09-07 15:11 ` Zi Yan
2020-09-09 13:46 ` Kirill A. Shutemov
2020-09-09 14:15 ` Zi Yan
2020-09-02 18:06 ` [RFC PATCH 02/16] mm: thp: 1GB anonymous page implementation Zi Yan
2020-09-02 18:06 ` [RFC PATCH 03/16] mm: proc: add 1GB THP kpageflag Zi Yan
2020-09-09 13:46 ` Kirill A. Shutemov
2020-09-02 18:06 ` [RFC PATCH 04/16] mm: thp: 1GB THP copy on write implementation Zi Yan
2020-09-02 18:06 ` [RFC PATCH 05/16] mm: thp: handling 1GB THP reference bit Zi Yan
2020-09-09 14:09 ` Kirill A. Shutemov [this message]
2020-09-09 14:36 ` Zi Yan
2020-09-02 18:06 ` [RFC PATCH 06/16] mm: thp: add 1GB THP split_huge_pud_page() function Zi Yan
2020-09-09 14:18 ` Kirill A. Shutemov
2020-09-09 14:19 ` Zi Yan
2020-09-02 18:06 ` [RFC PATCH 07/16] mm: stats: make smap stats understand PUD THPs Zi Yan
2020-09-02 18:06 ` [RFC PATCH 08/16] mm: page_vma_walk: teach it about PMD-mapped PUD THP Zi Yan
2020-09-02 18:06 ` [RFC PATCH 09/16] mm: thp: 1GB THP support in try_to_unmap() Zi Yan
2020-09-02 18:06 ` [RFC PATCH 10/16] mm: thp: split 1GB THPs at page reclaim Zi Yan
2020-09-02 18:06 ` [RFC PATCH 11/16] mm: thp: 1GB THP follow_p*d_page() support Zi Yan
2020-09-02 18:06 ` [RFC PATCH 12/16] mm: support 1GB THP pagemap support Zi Yan
2020-09-02 18:06 ` [RFC PATCH 13/16] mm: thp: add a knob to enable/disable 1GB THPs Zi Yan
2020-09-02 18:06 ` [RFC PATCH 14/16] mm: page_alloc: >=MAX_ORDER pages allocation an deallocation Zi Yan
2020-09-02 18:06 ` [RFC PATCH 15/16] hugetlb: cma: move cma reserve function to cma.c Zi Yan
2020-09-02 18:06 ` [RFC PATCH 16/16] mm: thp: use cma reservation for pud thp allocation Zi Yan
2020-09-02 18:40 ` [RFC PATCH 00/16] 1GB THP support on x86_64 Jason Gunthorpe
2020-09-02 18:45 ` Zi Yan
2020-09-02 18:48 ` Jason Gunthorpe
2020-09-02 19:05 ` Zi Yan
2020-09-02 19:57 ` Jason Gunthorpe
2020-09-02 20:29 ` Zi Yan
2020-09-03 16:40 ` Jason Gunthorpe
2020-09-03 16:55 ` Matthew Wilcox
2020-09-03 17:08 ` Jason Gunthorpe
2020-09-03 7:32 ` Michal Hocko
2020-09-03 16:25 ` Roman Gushchin
2020-09-03 16:50 ` Jason Gunthorpe
2020-09-03 17:01 ` Matthew Wilcox
2020-09-03 17:18 ` Jason Gunthorpe
2020-09-03 20:57 ` Mike Kravetz
2020-09-03 21:06 ` Roman Gushchin
2020-09-04 7:42 ` Michal Hocko
2020-09-04 21:10 ` Roman Gushchin
2020-09-07 7:20 ` Michal Hocko
2020-09-08 15:09 ` Zi Yan
2020-09-08 19:58 ` Roman Gushchin
2020-09-09 4:01 ` John Hubbard
2020-09-09 7:15 ` Michal Hocko
2020-09-03 14:23 ` Kirill A. Shutemov
2020-09-03 16:30 ` Roman Gushchin
2020-09-08 11:57 ` David Hildenbrand
2020-09-08 14:05 ` Zi Yan
2020-09-08 14:22 ` David Hildenbrand
2020-09-08 15:36 ` Zi Yan
2020-09-08 14:27 ` Matthew Wilcox
2020-09-08 15:50 ` Zi Yan
2020-09-09 12:11 ` Jason Gunthorpe
2020-09-09 12:32 ` Matthew Wilcox
2020-09-09 13:14 ` Jason Gunthorpe
2020-09-09 13:27 ` David Hildenbrand
2020-09-10 10:02 ` William Kucharski
2020-09-08 14:35 ` Michal Hocko
2020-09-08 14:41 ` Rik van Riel
2020-09-08 15:02 ` David Hildenbrand
2020-09-09 7:04 ` Michal Hocko
2020-09-09 13:19 ` Rik van Riel
2020-09-09 13:43 ` David Hildenbrand
2020-09-09 13:49 ` Rik van Riel
2020-09-09 13:54 ` David Hildenbrand
2020-09-10 7:32 ` Michal Hocko
2020-09-10 8:27 ` David Hildenbrand
2020-09-10 14:21 ` Zi Yan
2020-09-10 14:34 ` David Hildenbrand
2020-09-10 14:41 ` Zi Yan
2020-09-10 15:15 ` David Hildenbrand
2020-09-10 13:32 ` Rik van Riel
2020-09-10 14:30 ` Zi Yan
2020-09-09 13:59 ` Michal Hocko
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