linux-kernel - Re: [PATCH] MIPS: smp: optimization for flush_tlb

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Message-ID: <20220512161127.GF14475@alpha.franken.de>
Date:   Thu, 12 May 2022 18:11:27 +0200
From:   Thomas Bogendoerfer <tsbogend@...ha.franken.de>
To:     Mao Bibo <maobibo@...ngson.cn>
Cc:     linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] MIPS: smp: optimization for flush_tlb_mm when exiting

On Tue, May 10, 2022 at 07:44:41PM +0800, Mao Bibo wrote:
> When process exits or execute new binary, it will call function
> exit_mmap with old mm, there is such function call trace:
>   exit_mmap(struct mm_struct *mm)
>       --> tlb_finish_mmu(&tlb, 0, -1)
>          --> arch_tlb_finish_mmu(tlb, start, end, force)
> 	    --> tlb_flush_mmu(tlb);
>                --> tlb_flush(struct mmu_gather *tlb)
>                   --> flush_tlb_mm(tlb->mm)
> 
> It is not necessary to flush tlb since oldmm is not used anymore
> by the process, there is similar operations on IA64/ARM64 etc,
> this patch adds such optimization on MIPS.
> 
> Signed-off-by: Mao Bibo <maobibo@...ngson.cn>
> ---
>  arch/mips/kernel/smp.c | 6 ++++++
>  1 file changed, 6 insertions(+)

applied to mips-next.

Thomas.

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