linux-kernel - Re: [PATCH V2] mm/mprotect: Add a cond_resched() inside change_pmd

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Date:   Thu, 14 Dec 2017 12:29:28 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     Anshuman Khandual <khandual@...ux.vnet.ibm.com>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        akpm@...ux-foundation.org
Subject: Re: [PATCH V2] mm/mprotect: Add a cond_resched() inside
 change_pmd_range()

On Thu 14-12-17 16:44:26, Anshuman Khandual wrote:
> diff --git a/mm/mprotect.c b/mm/mprotect.c
> index ec39f73..43c29fa 100644
> --- a/mm/mprotect.c
> +++ b/mm/mprotect.c
> @@ -196,6 +196,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
>  		this_pages = change_pte_range(vma, pmd, addr, next, newprot,
>  				 dirty_accountable, prot_numa);
>  		pages += this_pages;
> +		cond_resched();
>  	} while (pmd++, addr = next, addr != end);
>  
>  	if (mni_start)

this is not exactly what I meant. See how change_huge_pmd does continue.
That's why I mentioned zap_pmd_range which does goto next...
-- 
Michal Hocko
SUSE Labs