linux-kernel - Re: [PATCH] mm: Introduce GFP

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Date:   Sat, 12 Jan 2019 04:12:31 -0800
From:   Matthew Wilcox <willy@...radead.org>
To:     Anshuman Khandual <anshuman.khandual@....com>
Cc:     linux-mm@...ck.org, akpm@...ux-foundation.org,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-arm-kernel@...ts.infradead.org, linux-sh@...r.kernel.org,
        kvmarm@...ts.cs.columbia.edu, linux@...linux.org.uk,
        catalin.marinas@....com, will.deacon@....com, mpe@...erman.id.au,
        tglx@...utronix.de, mingo@...hat.com, dave.hansen@...ux.intel.com,
        peterz@...radead.org, christoffer.dall@....com,
        marc.zyngier@....com, kirill@...temov.name,
        rppt@...ux.vnet.ibm.com, mhocko@...e.com,
        ard.biesheuvel@...aro.org, mark.rutland@....com,
        steve.capper@....com, james.morse@....com, robin.murphy@....com,
        aneesh.kumar@...ux.ibm.com, vbabka@...e.cz, shakeelb@...gle.com,
        rientjes@...gle.com
Subject: Re: [PATCH] mm: Introduce GFP_PGTABLE

On Sat, Jan 12, 2019 at 03:56:38PM +0530, Anshuman Khandual wrote:
> All architectures have been defining their own PGALLOC_GFP as (GFP_KERNEL |
> __GFP_ZERO) and using it for allocating page table pages.

Except that's not true.

> +++ b/arch/x86/mm/pgtable.c
> @@ -13,19 +13,17 @@ phys_addr_t physical_mask __ro_after_init = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
>  EXPORT_SYMBOL(physical_mask);
>  #endif
>  
> -#define PGALLOC_GFP (GFP_KERNEL_ACCOUNT | __GFP_ZERO)
> -
>  #ifdef CONFIG_HIGHPTE

...

>  pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
>  {
> -	return (pte_t *)__get_free_page(PGALLOC_GFP & ~__GFP_ACCOUNT);
> +	return (pte_t *)__get_free_page(GFP_PGTABLE & ~__GFP_ACCOUNT);
>  }

I think x86 was the only odd one out here, but you'll need to try again ...