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Subject: Re: [PATCH] x86/mm/tlb: avoid reading mm_tlb_gen when possible
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To:     Nadav Amit <nadav.amit@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>
Cc:     linux-kernel@vger.kernel.org, Nadav Amit <namit@vmware.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Ingo Molnar <mingo@kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>, x86@kernel.org
References: <20220322220757.8607-1-namit@vmware.com>
From:   Dave Hansen <dave.hansen@intel.com>
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On 3/22/22 15:07, Nadav Amit wrote:
> +	if (f->new_tlb_gen <= local_tlb_gen) {
> +		/*
> +		 * We are already up to date in respect to f->new_tlb_gen.
> +		 * While the core might be still behind mm_tlb_gen, checking
> +		 * mm_tlb_gen unnecessarily would have negative caching effects
> +		 * so avoid it.
> +		 */
> +		return;
> +	}
> +

Nit: There's at least one "we" in here that needs to get fixed up.  I'll
plan to do that when I apply it, but a v2 with that fixed and Peter's
ack added might save me five minutes.