linux-kernel - Re: [PATCH 2/8] x86/mm/cpa: Move flush_tlb

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Message-ID: <5ab3ee67-a29b-0f4c-d7cf-2bdedd192ad6@intel.com>
Date:   Fri, 21 Sep 2018 14:34:32 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org,
        Bin Yang <bin.yang@...el.com>,
        Mark Gross <mark.gross@...el.com>
Subject: Re: [PATCH 2/8] x86/mm/cpa: Move flush_tlb_all()

On 09/19/2018 01:50 AM, Peter Zijlstra wrote:
> @@ -1528,28 +1538,8 @@ static int __change_page_attr(struct cpa
>  	 * We have to split the large page:
>  	 */
>  	err = split_large_page(cpa, kpte, address);
> -	if (!err) {
...
> -		flush_tlb_all();
> +	if (!err)
>  		goto repeat;
> -	}

I _think_ this is the only use of split_large_page()'s error code.  We
can just make it return void now, right?

BTW, I also really like doing the "final" TLB flush as close as possible
to the actual PTE manipulation.  Makes it much less likely that we break it.