From: Barry Song <21cnbao@gmail.com>
To: Yicong Yang <yangyicong@huawei.com>
Cc: wangkefeng.wang@huawei.com, prime.zeng@hisilicon.com,
anshuman.khandual@arm.com, linux-doc@vger.kernel.org,
peterz@infradead.org, catalin.marinas@arm.com,
yangyicong@hisilicon.com, linux-mm@kvack.org, guojian@oppo.com,
linux-riscv@lists.infradead.org, will@kernel.org,
Anshuman Khandual <khandual@linux.vnet.ibm.com>,
linux-s390@vger.kernel.org, zhangshiming@oppo.com,
lipeifeng@oppo.com, corbet@lwn.net, x86@kernel.org,
linux-mips@vger.kernel.org, arnd@arndb.de, realmz6@gmail.com,
openrisc@lists.librecores.org, darren@os.amperecomputing.com,
linux-arm-kernel@lists.infradead.org, xhao@linux.alibaba.com,
linux-kernel@vger.kernel.org, huzhanyuan@oppo.com,
akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v4 1/2] mm/tlbbatch: Introduce arch_tlbbatch_should_defer()
Date: Wed, 21 Sep 2022 20:54:35 +1200 [thread overview]
Message-ID: <CAGsJ_4ydO=CegfrAF=jYmhOffXd7zKaFp_YxhdMgnoNGA8mBQQ@mail.gmail.com> (raw)
In-Reply-To: <20220921084302.43631-2-yangyicong@huawei.com>
On Wed, Sep 21, 2022 at 8:45 PM Yicong Yang <yangyicong@huawei.com> wrote:
>
> From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
>
> The entire scheme of deferred TLB flush in reclaim path rests on the
> fact that the cost to refill TLB entries is less than flushing out
> individual entries by sending IPI to remote CPUs. But architecture
> can have different ways to evaluate that. Hence apart from checking
> TTU_BATCH_FLUSH in the TTU flags, rest of the decision should be
> architecture specific.
>
> Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
> [https://lore.kernel.org/linuxppc-dev/20171101101735.2318-2-khandual@linux.vnet.ibm.com/]
> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
> [Rebase and fix incorrect return value type]
> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
Reviewed-by: Barry Song <baohua@kernel.org>
> arch/x86/include/asm/tlbflush.h | 12 ++++++++++++
> mm/rmap.c | 9 +--------
> 2 files changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
> index cda3118f3b27..8a497d902c16 100644
> --- a/arch/x86/include/asm/tlbflush.h
> +++ b/arch/x86/include/asm/tlbflush.h
> @@ -240,6 +240,18 @@ static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long a)
> flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, PAGE_SHIFT, false);
> }
>
> +static inline bool arch_tlbbatch_should_defer(struct mm_struct *mm)
> +{
> + bool should_defer = false;
> +
> + /* If remote CPUs need to be flushed then defer batch the flush */
> + if (cpumask_any_but(mm_cpumask(mm), get_cpu()) < nr_cpu_ids)
> + should_defer = true;
> + put_cpu();
> +
> + return should_defer;
> +}
> +
> static inline u64 inc_mm_tlb_gen(struct mm_struct *mm)
> {
> /*
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 93d5a6f793d2..cd8cf5cb0b01 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -690,17 +690,10 @@ static void set_tlb_ubc_flush_pending(struct mm_struct *mm, bool writable)
> */
> static bool should_defer_flush(struct mm_struct *mm, enum ttu_flags flags)
> {
> - bool should_defer = false;
> -
> if (!(flags & TTU_BATCH_FLUSH))
> return false;
>
> - /* If remote CPUs need to be flushed then defer batch the flush */
> - if (cpumask_any_but(mm_cpumask(mm), get_cpu()) < nr_cpu_ids)
> - should_defer = true;
> - put_cpu();
> -
> - return should_defer;
> + return arch_tlbbatch_should_defer(mm);
> }
>
> /*
> --
> 2.24.0
>
next prev parent reply other threads:[~2022-09-21 8:55 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-21 8:43 [PATCH v4 0/2] mm: arm64: bring up BATCHED_UNMAP_TLB_FLUSH Yicong Yang
2022-09-21 8:43 ` [PATCH v4 1/2] mm/tlbbatch: Introduce arch_tlbbatch_should_defer() Yicong Yang
2022-09-21 8:54 ` Barry Song [this message]
2022-09-21 8:43 ` [PATCH v4 2/2] arm64: support batched/deferred tlb shootdown during page reclamation Yicong Yang
2022-09-27 6:16 ` Anshuman Khandual
2022-09-27 9:15 ` Yicong Yang
2022-09-28 0:23 ` Barry Song
2022-10-27 10:41 ` Anshuman Khandual
2022-10-27 14:19 ` Punit Agrawal
2022-10-27 21:55 ` Barry Song
2022-10-28 2:14 ` Anshuman Khandual
2022-10-28 13:12 ` Punit Agrawal
2022-10-28 1:20 ` Yicong Yang
2022-10-28 13:11 ` Punit Agrawal
2022-10-28 21:40 ` Barry Song
2022-10-31 18:36 ` Punit Agrawal
2022-10-27 22:07 ` Barry Song
2022-10-28 1:56 ` Anshuman Khandual
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