linux-kernel - Re: [RFC PATCH 09/11] asm-generic/tlb: Track which levels of the page tables have been cleared

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Message-ID: <20180827075341.GY24124@hirez.programming.kicks-ass.net>
Date:   Mon, 27 Aug 2018 09:53:41 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Will Deacon <will.deacon@....com>
Cc:     linux-kernel@...r.kernel.org, benh@....ibm.com,
        torvalds@...ux-foundation.org, npiggin@...il.com,
        catalin.marinas@....com, linux-arm-kernel@...ts.infradead.org
Subject: Re: [RFC PATCH 09/11] asm-generic/tlb: Track which levels of the
 page tables have been cleared

On Fri, Aug 24, 2018 at 04:52:44PM +0100, Will Deacon wrote:
> +static inline unsigned long tlb_get_unmap_granule(struct mmu_gather *tlb)
> +{
> +	if (tlb->cleared_ptes)
> +		return PAGE_SIZE;
> +	if (tlb->cleared_pmds)
> +		return PMD_SIZE;
> +	if (tlb->cleared_puds)
> +		return PUD_SIZE;
> +	if (tlb->cleared_p4ds)
> +		return P4D_SIZE;
> +
> +	return PAGE_SIZE;
> +}

When doing the x86 patch; I found _SHIFT more useful than _SIZE.