From: Will Deacon <will.deacon@arm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: aneesh.kumar@linux.vnet.ibm.com, akpm@linux-foundation.org,
npiggin@gmail.com, linux-arch@vger.kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux@armlinux.org.uk, heiko.carstens@de.ibm.com,
riel@surriel.com
Subject: Re: [PATCH 05/18] asm-generic/tlb: Provide generic tlb_flush
Date: Wed, 26 Sep 2018 13:53:35 +0100 [thread overview]
Message-ID: <20180926125335.GG2979@brain-police> (raw)
In-Reply-To: <20180926114800.770817616@infradead.org>
On Wed, Sep 26, 2018 at 01:36:28PM +0200, Peter Zijlstra wrote:
> Provide a generic tlb_flush() implementation that relies on
> flush_tlb_range(). This is a little awkward because flush_tlb_range()
> assumes a VMA for range invalidation, but we no longer have one.
>
> Audit of all flush_tlb_range() implementations shows only vma->vm_mm
> and vma->vm_flags are used, and of the latter only VM_EXEC (I-TLB
> invalidates) and VM_HUGETLB (large TLB invalidate) are used.
>
> Therefore, track VM_EXEC and VM_HUGETLB in two more bits, and create a
> 'fake' VMA.
>
> This allows architectures that have a reasonably efficient
> flush_tlb_range() to not require any additional effort.
>
> Cc: Nick Piggin <npiggin@gmail.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> arch/arm64/include/asm/tlb.h | 1
> arch/powerpc/include/asm/tlb.h | 1
> arch/riscv/include/asm/tlb.h | 1
> arch/x86/include/asm/tlb.h | 1
> include/asm-generic/tlb.h | 80 +++++++++++++++++++++++++++++++++++------
> 5 files changed, 74 insertions(+), 10 deletions(-)
>
> --- a/arch/arm64/include/asm/tlb.h
> +++ b/arch/arm64/include/asm/tlb.h
> @@ -27,6 +27,7 @@ static inline void __tlb_remove_table(vo
> free_page_and_swap_cache((struct page *)_table);
> }
>
> +#define tlb_flush tlb_flush
> static void tlb_flush(struct mmu_gather *tlb);
>
> #include <asm-generic/tlb.h>
> --- a/arch/powerpc/include/asm/tlb.h
> +++ b/arch/powerpc/include/asm/tlb.h
> @@ -28,6 +28,7 @@
> #define tlb_end_vma(tlb, vma) do { } while (0)
> #define __tlb_remove_tlb_entry __tlb_remove_tlb_entry
>
> +#define tlb_flush tlb_flush
> extern void tlb_flush(struct mmu_gather *tlb);
>
> /* Get the generic bits... */
> --- a/arch/riscv/include/asm/tlb.h
> +++ b/arch/riscv/include/asm/tlb.h
> @@ -18,6 +18,7 @@ struct mmu_gather;
>
> static void tlb_flush(struct mmu_gather *tlb);
>
> +#define tlb_flush tlb_flush
> #include <asm-generic/tlb.h>
>
> static inline void tlb_flush(struct mmu_gather *tlb)
> --- a/arch/x86/include/asm/tlb.h
> +++ b/arch/x86/include/asm/tlb.h
> @@ -6,6 +6,7 @@
> #define tlb_end_vma(tlb, vma) do { } while (0)
> #define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0)
>
> +#define tlb_flush tlb_flush
> static inline void tlb_flush(struct mmu_gather *tlb);
>
> #include <asm-generic/tlb.h>
> --- a/include/asm-generic/tlb.h
> +++ b/include/asm-generic/tlb.h
> @@ -241,6 +241,12 @@ struct mmu_gather {
> unsigned int cleared_puds : 1;
> unsigned int cleared_p4ds : 1;
>
> + /*
> + * tracks VM_EXEC | VM_HUGETLB in tlb_start_vma
> + */
> + unsigned int vma_exec : 1;
> + unsigned int vma_huge : 1;
> +
> unsigned int batch_count;
>
> struct mmu_gather_batch *active;
> @@ -282,7 +288,35 @@ static inline void __tlb_reset_range(str
> tlb->cleared_pmds = 0;
> tlb->cleared_puds = 0;
> tlb->cleared_p4ds = 0;
> + /*
> + * Do not reset mmu_gather::vma_* fields here, we do not
> + * call into tlb_start_vma() again to set them if there is an
> + * intermediate flush.
> + */
> +}
> +
> +#ifndef tlb_flush
> +
> +#if defined(tlb_start_vma) || defined(tlb_end_vma)
> +#error Default tlb_flush() relies on default tlb_start_vma() and tlb_end_vma()
> +#endif
> +
> +#define tlb_flush tlb_flush
Do we need this #define?
> @@ -353,19 +387,45 @@ static inline unsigned long tlb_get_unma
> * the vmas are adjusted to only cover the region to be torn down.
> */
> #ifndef tlb_start_vma
> -#define tlb_start_vma(tlb, vma) \
> -do { \
> - if (!tlb->fullmm) \
> - flush_cache_range(vma, vma->vm_start, vma->vm_end); \
> -} while (0)
> +#define tlb_start_vma tlb_start_vma
Or this one?
> +static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
> +{
> + if (tlb->fullmm)
> + return;
> +
> + /*
> + * flush_tlb_range() implementations that look at VM_HUGETLB (tile,
> + * mips-4k) flush only large pages.
> + *
> + * flush_tlb_range() implementations that flush I-TLB also flush D-TLB
> + * (tile, xtensa, arm), so it's ok to just add VM_EXEC to an existing
> + * range.
> + *
> + * We rely on tlb_end_vma() to issue a flush, such that when we reset
> + * these values the batch is empty.
> + */
> + tlb->vma_huge = !!(vma->vm_flags & VM_HUGETLB);
> + tlb->vma_exec = !!(vma->vm_flags & VM_EXEC);
Hmm, does this result in code generation for archs that don't care about the
vm_flags?
> + flush_cache_range(vma, vma->vm_start, vma->vm_end);
> +}
> #endif
>
> #ifndef tlb_end_vma
> -#define tlb_end_vma(tlb, vma) \
> -do { \
> - if (!tlb->fullmm) \
> - tlb_flush_mmu_tlbonly(tlb); \
> -} while (0)
> +#define tlb_end_vma tlb_end_vma
Another #define we can drop?
Will
next prev parent reply other threads:[~2018-09-26 12:53 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-26 11:36 [PATCH 00/18] my generic mmu_gather patches Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 01/18] asm-generic/tlb: Provide a comment Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 02/18] asm-generic/tlb: Provide HAVE_MMU_GATHER_PAGE_SIZE Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 03/18] x86/mm: Page size aware flush_tlb_mm_range() Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 04/18] asm-generic/tlb: Provide generic VIPT cache flush Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 05/18] asm-generic/tlb: Provide generic tlb_flush Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 12:53 ` Will Deacon [this message]
2018-09-26 12:53 ` Will Deacon
2018-09-26 13:11 ` Peter Zijlstra
2018-09-26 13:11 ` Peter Zijlstra
2018-09-26 18:07 ` Peter Zijlstra
2018-09-26 18:07 ` Peter Zijlstra
2018-09-27 12:14 ` Will Deacon
2018-09-27 12:14 ` Will Deacon
2018-09-26 11:36 ` [PATCH 06/18] asm-generic/tlb: Conditionally provide tlb_migrate_finish() Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 12:53 ` Will Deacon
2018-09-26 12:53 ` Will Deacon
2018-09-26 11:36 ` [PATCH 07/18] asm-generic/tlb: Invert HAVE_RCU_TABLE_INVALIDATE Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 08/18] arm/tlb: Convert to generic mmu_gather Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 12:54 ` Will Deacon
2018-09-26 12:54 ` Will Deacon
2018-09-26 11:36 ` [PATCH 09/18] ia64/tlb: Conver " Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 10/18] sh/tlb: Convert SH " Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 11/18] um/tlb: Convert " Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 12/18] arch/tlb: Clean up simple architectures Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-10-03 17:03 ` Vineet Gupta
2018-10-03 17:03 ` Vineet Gupta
2018-10-11 15:04 ` Peter Zijlstra
2018-10-11 15:04 ` Peter Zijlstra
2018-10-12 19:40 ` Vineet Gupta
2018-10-12 19:40 ` Vineet Gupta
2018-10-15 14:14 ` Peter Zijlstra
2018-10-15 14:14 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 13/18] asm-generic/tlb: Introduce HAVE_MMU_GATHER_NO_GATHER Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-12-11 5:43 ` Aneesh Kumar K.V
2018-12-11 5:43 ` Aneesh Kumar K.V
2018-09-26 11:36 ` [PATCH 14/18] s390/tlb: convert to generic mmu_gather Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 15/18] asm-generic/tlb: Remove arch_tlb*_mmu() Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 16/18] asm-generic/tlb: Remove HAVE_GENERIC_MMU_GATHER Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 17/18] asm-generic/tlb: Remove tlb_flush_mmu_free() Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 11:36 ` [PATCH 18/18] asm-generic/tlb: Remove tlb_table_flush() Peter Zijlstra
2018-09-26 11:36 ` Peter Zijlstra
2018-09-26 12:47 ` [PATCH 00/18] my generic mmu_gather patches Will Deacon
2018-09-26 12:47 ` Will Deacon
2018-12-11 5:50 ` Aneesh Kumar K.V
2018-12-11 5:50 ` Aneesh Kumar K.V
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