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From:   Andreas Schwab <schwab@linux-m68k.org>
To:     Atish Patra <atish.patra@wdc.com>
Cc:     linux-kernel@vger.kernel.org, Albert Ou <aou@eecs.berkeley.edu>,
        Alexios Zavras <alexios.zavras@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Palmer Dabbelt <palmer@sifive.com>,
        Anup Patel <anup.patel@wdc.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        linux-riscv@lists.infradead.org,
        Allison Randal <allison@lohutok.net>
Subject: Re: [PATCH] RISC-V: Issue a local tlb flush if possible.
References: <20190810014309.20838-1-atish.patra@wdc.com>
Date:   Sat, 10 Aug 2019 08:37:21 +0200
In-Reply-To: <20190810014309.20838-1-atish.patra@wdc.com> (Atish Patra's
        message of "Fri, 9 Aug 2019 18:43:09 -0700")
Message-ID: <m2r25t8r1a.fsf@linux-m68k.org>
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On Aug 09 2019, Atish Patra <atish.patra@wdc.com> wrote:

> @@ -46,14 +47,38 @@ static inline void remote_sfence_vma(struct cpumask *cmask, unsigned long start,
>  				     unsigned long size)
>  {
>  	struct cpumask hmask;
> +	struct cpumask tmask;
> +	int cpuid = smp_processor_id();
>  
>  	cpumask_clear(&hmask);
> -	riscv_cpuid_to_hartid_mask(cmask, &hmask);
> -	sbi_remote_sfence_vma(hmask.bits, start, size);
> +	cpumask_clear(&tmask);
> +
> +	if (cmask)
> +		cpumask_copy(&tmask, cmask);
> +	else
> +		cpumask_copy(&tmask, cpu_online_mask);
> +
> +	if (cpumask_test_cpu(cpuid, &tmask)) {
> +		/* Save trap cost by issuing a local tlb flush here */
> +		if ((start == 0 && size == -1) || (size > PAGE_SIZE))
> +			local_flush_tlb_all();
> +		else if (size == PAGE_SIZE)
> +			local_flush_tlb_page(start);
> +		cpumask_clear_cpu(cpuid, &tmask);
> +	} else if (cpumask_empty(&tmask)) {
> +		/* cpumask is empty. So just do a local flush */
> +		local_flush_tlb_all();
> +		return;
> +	}
> +
> +	if (!cpumask_empty(&tmask)) {
> +		riscv_cpuid_to_hartid_mask(&tmask, &hmask);
> +		sbi_remote_sfence_vma(hmask.bits, start, size);
> +	}
>  }

I think it's becoming too big to be inline.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
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