From: Vishal Moola <vishal.moola@gmail.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org,
linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev,
linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
linux-openrisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
linux-um@lists.infradead.org, xen-devel@lists.xenproject.org,
kvm@vger.kernel.org, Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH v4 04/34] pgtable: Create struct ptdesc
Date: Tue, 20 Jun 2023 16:10:22 -0700 [thread overview]
Message-ID: <CAOzc2pwNc-9bRbAV8=_yROU5uq96q6v-dEfcYuzJyDrRygNsbA@mail.gmail.com> (raw)
In-Reply-To: <ZJIwpO68kc3zMB/c@nvidia.com>
On Tue, Jun 20, 2023 at 4:05 PM Jason Gunthorpe <jgg@nvidia.com> wrote:
>
> On Tue, Jun 20, 2023 at 01:01:39PM -0700, Vishal Moola wrote:
> > On Fri, Jun 16, 2023 at 5:38 AM Jason Gunthorpe <jgg@nvidia.com> wrote:
> > >
> > > On Mon, Jun 12, 2023 at 02:03:53PM -0700, Vishal Moola (Oracle) wrote:
> > > > Currently, page table information is stored within struct page. As part
> > > > of simplifying struct page, create struct ptdesc for page table
> > > > information.
> > > >
> > > > Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
> > > > ---
> > > > include/linux/pgtable.h | 51 +++++++++++++++++++++++++++++++++++++++++
> > > > 1 file changed, 51 insertions(+)
> > > >
> > > > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> > > > index c5a51481bbb9..330de96ebfd6 100644
> > > > --- a/include/linux/pgtable.h
> > > > +++ b/include/linux/pgtable.h
> > > > @@ -975,6 +975,57 @@ static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
> > > > #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
> > > > #endif /* CONFIG_MMU */
> > > >
> > > > +
> > > > +/**
> > > > + * struct ptdesc - Memory descriptor for page tables.
> > > > + * @__page_flags: Same as page flags. Unused for page tables.
> > > > + * @pt_list: List of used page tables. Used for s390 and x86.
> > > > + * @_pt_pad_1: Padding that aliases with page's compound head.
> > > > + * @pmd_huge_pte: Protected by ptdesc->ptl, used for THPs.
> > > > + * @_pt_s390_gaddr: Aliases with page's mapping. Used for s390 gmap only.
> > > > + * @pt_mm: Used for x86 pgds.
> > > > + * @pt_frag_refcount: For fragmented page table tracking. Powerpc and s390 only.
> > > > + * @ptl: Lock for the page table.
> > > > + *
> > > > + * This struct overlays struct page for now. Do not modify without a good
> > > > + * understanding of the issues.
> > > > + */
> > > > +struct ptdesc {
> > > > + unsigned long __page_flags;
> > > > +
> > > > + union {
> > > > + struct list_head pt_list;
> > > > + struct {
> > > > + unsigned long _pt_pad_1;
> > > > + pgtable_t pmd_huge_pte;
> > > > + };
> > > > + };
> > > > + unsigned long _pt_s390_gaddr;
> > > > +
> > > > + union {
> > > > + struct mm_struct *pt_mm;
> > > > + atomic_t pt_frag_refcount;
> > > > + };
> > > > +
> > > > +#if ALLOC_SPLIT_PTLOCKS
> > > > + spinlock_t *ptl;
> > > > +#else
> > > > + spinlock_t ptl;
> > > > +#endif
> > > > +};
> > >
> > > I think you should include the memcg here too? It needs to be valid
> > > for a ptdesc, even if we don't currently deref it through the ptdesc
> > > type.
> >
> > Yes, thanks for catching that! I'll add it to v5.
> >
> > > Also, do you see a way to someday put a 'struct rcu_head' into here?
> >
> > Eventually, when they're being dynamically allocated independent of
> > struct page. Although at that point I'm not sure if we'll need one.
>
> Sooner than dynamic struct page?
>
> Probably it can overlap pt_list in alot of arches?
Ah yes, there will be one if v5 overlapping with pt_list
(it already does in struct page anyways).
next prev parent reply other threads:[~2023-06-20 23:10 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-12 21:03 [PATCH v4 00/34] Split ptdesc from struct page Vishal Moola (Oracle)
2023-06-12 21:03 ` [PATCH v4 01/34] mm: Add PAGE_TYPE_OP folio functions Vishal Moola (Oracle)
2023-06-14 13:02 ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 02/34] s390: Use _pt_s390_gaddr for gmap address tracking Vishal Moola (Oracle)
2023-06-14 13:14 ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 03/34] s390: Use pt_frag_refcount for pagetables Vishal Moola (Oracle)
2023-06-14 13:21 ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 04/34] pgtable: Create struct ptdesc Vishal Moola (Oracle)
2023-06-14 13:34 ` Mike Rapoport
2023-06-15 7:57 ` Hugh Dickins
2023-06-16 20:38 ` Matthew Wilcox
2023-06-16 21:28 ` Vishal Moola
2023-06-16 12:38 ` Jason Gunthorpe
2023-06-20 20:01 ` Vishal Moola
2023-06-20 23:05 ` Jason Gunthorpe
2023-06-20 23:10 ` Vishal Moola [this message]
2023-06-12 21:03 ` [PATCH v4 05/34] mm: add utility functions for ptdesc Vishal Moola (Oracle)
2023-06-14 13:48 ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 06/34] mm: Convert pmd_pgtable_page() to pmd_ptdesc() Vishal Moola (Oracle)
2023-06-14 13:51 ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 07/34] mm: Convert ptlock_alloc() to use ptdescs Vishal Moola (Oracle)
2023-06-14 13:51 ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 08/34] mm: Convert ptlock_ptr() " Vishal Moola (Oracle)
2023-06-14 13:52 ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 09/34] mm: Convert pmd_ptlock_init() " Vishal Moola (Oracle)
2023-06-14 13:52 ` Mike Rapoport
2023-06-12 21:03 ` [PATCH v4 10/34] mm: Convert ptlock_init() " Vishal Moola (Oracle)
2023-06-14 13:57 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 11/34] mm: Convert pmd_ptlock_free() " Vishal Moola (Oracle)
2023-06-14 13:59 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 12/34] mm: Convert ptlock_free() " Vishal Moola (Oracle)
2023-06-14 13:59 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 13/34] mm: Create ptdesc equivalents for pgtable_{pte,pmd}_page_{ctor,dtor} Vishal Moola (Oracle)
2023-06-14 14:10 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 14/34] powerpc: Convert various functions to use ptdescs Vishal Moola (Oracle)
2023-06-14 14:19 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 15/34] x86: " Vishal Moola (Oracle)
2023-06-14 14:27 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 16/34] s390: Convert various gmap " Vishal Moola (Oracle)
2023-06-14 14:28 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 17/34] s390: Convert various pgalloc " Vishal Moola (Oracle)
2023-06-14 14:46 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 18/34] mm: Remove page table members from struct page Vishal Moola (Oracle)
2023-06-14 14:53 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 19/34] pgalloc: Convert various functions to use ptdescs Vishal Moola (Oracle)
2023-06-14 14:59 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 20/34] arm: " Vishal Moola (Oracle)
2023-06-14 15:03 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 21/34] arm64: " Vishal Moola (Oracle)
2023-06-14 15:05 ` Mike Rapoport
2023-06-14 16:41 ` Catalin Marinas
2023-06-12 21:04 ` [PATCH v4 22/34] csky: Convert __pte_free_tlb() " Vishal Moola (Oracle)
2023-06-14 15:07 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 23/34] hexagon: " Vishal Moola (Oracle)
2023-06-14 15:07 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 24/34] loongarch: Convert various functions " Vishal Moola (Oracle)
2023-06-14 15:09 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 25/34] m68k: " Vishal Moola (Oracle)
2023-06-13 7:28 ` Geert Uytterhoeven
2023-06-14 15:12 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 26/34] mips: " Vishal Moola (Oracle)
2023-06-14 15:16 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 27/34] nios2: Convert __pte_free_tlb() " Vishal Moola (Oracle)
2023-06-13 22:16 ` Dinh Nguyen
2023-06-14 9:30 ` Geert Uytterhoeven
2023-06-14 21:23 ` Dinh Nguyen
2023-06-14 15:16 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 28/34] openrisc: " Vishal Moola (Oracle)
2023-06-14 15:17 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 29/34] riscv: Convert alloc_{pmd, pte}_late() " Vishal Moola (Oracle)
2023-06-14 15:18 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 30/34] sh: Convert pte_free_tlb() " Vishal Moola (Oracle)
2023-06-14 15:19 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 31/34] sparc64: Convert various functions " Vishal Moola (Oracle)
2023-06-14 15:20 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 32/34] sparc: Convert pgtable_pte_page_{ctor, dtor}() to ptdesc equivalents Vishal Moola (Oracle)
2023-06-14 15:20 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 33/34] um: Convert {pmd, pte}_free_tlb() to use ptdescs Vishal Moola (Oracle)
2023-06-14 15:21 ` Mike Rapoport
2023-06-12 21:04 ` [PATCH v4 34/34] mm: Remove pgtable_{pmd, pte}_page_{ctor, dtor}() wrappers Vishal Moola (Oracle)
2023-06-14 15:23 ` Mike Rapoport
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