linux-kernel - Re: [RFC][PATCH 03/11] x86/mm: Page size aware flush_tlb_mm

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Message-ID: <20180913184836.GN24142@hirez.programming.kicks-ass.net>
Date:   Thu, 13 Sep 2018 20:48:36 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Dave Hansen <dave.hansen@...ux.intel.com>
Cc:     will.deacon@....com, aneesh.kumar@...ux.vnet.ibm.com,
        akpm@...ux-foundation.org, npiggin@...il.com,
        linux-arch@...r.kernel.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, linux@...linux.org.uk,
        heiko.carstens@...ibm.com
Subject: Re: [RFC][PATCH 03/11] x86/mm: Page size aware flush_tlb_mm_range()

On Thu, Sep 13, 2018 at 08:46:32PM +0200, Peter Zijlstra wrote:
> On Thu, Sep 13, 2018 at 08:42:30PM +0200, Peter Zijlstra wrote:
> > > > +#define flush_tlb_range(vma, start, end)			\
> > > > +		flush_tlb_mm_range((vma)->vm_mm, start, end,	\
> > > > +				(vma)->vm_flags & VM_HUGETLB ? PMD_SHIFT : PAGE_SHIFT)
> > > 
> > > This is safe.  But, Couldn't this PMD_SHIFT also be PUD_SHIFT for a 1G
> > > hugetlb page?
> > 
> > It could be, but can we tell at that point?
> 
> I had me a look in higetlb.h, would something like so work?
> 
> #define flush_tlb_range(vma, start, end)			\
> 	flush_tlb_mm_range((vma)->vm_mm, start, end,		\
> 			   huge_page_shift(hstate_vma(vma)))
> 

D'uh

#define flush_tlb_range(vma, start, end)			\
	flush_tlb_mm_range((vma)->vm_mm, start, end,		\
	   (vma)->vm_flags & VM_HUGETLB ? huge_page_shift(hstate_vma(vma)) : PAGE_SHIFT)