linux-kernel - Re: [v2 PATCH] RISC-V: Optimize tlb flush path.

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Message-ID: <mvmh86cl1o3.fsf@linux-m68k.org>
Date:   Tue, 20 Aug 2019 09:46:20 +0200
From:   Andreas Schwab <schwab@...ux-m68k.org>
To:     Atish Patra <atish.patra@....com>
Cc:     linux-kernel@...r.kernel.org, Albert Ou <aou@...s.berkeley.edu>,
        Allison Randal <allison@...utok.net>,
        Anup Patel <anup@...infault.org>,
        linux-riscv@...ts.infradead.org,
        Palmer Dabbelt <palmer@...ive.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        "hch\@infradead.org" <hch@...radead.org>
Subject: Re: [v2 PATCH] RISC-V: Optimize tlb flush path.

On Aug 19 2019, Atish Patra <atish.patra@....com> wrote:

> @@ -42,20 +43,44 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
>  
>  #include <asm/sbi.h>
>  
> -static inline void remote_sfence_vma(struct cpumask *cmask, unsigned long start,
> -				     unsigned long size)
> +static void __riscv_flush_tlb(struct cpumask *cmask, unsigned long start,
> +			      unsigned long size)

cmask can be const.

>  {
>  	struct cpumask hmask;
> +	unsigned int hartid;
> +	unsigned int cpuid;
>  
>  	cpumask_clear(&hmask);
> +
> +	if (!cmask) {
> +		riscv_cpuid_to_hartid_mask(cpu_online_mask, &hmask);
> +		goto issue_sfence;
> +	}

Wouldn't it make sense to fall through to doing a local flush here?

	if (!cmask)
		cmask = cpu_online_mask;

Andreas.

-- 
Andreas Schwab, schwab@...ux-m68k.org
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