linux-kernel - Re: [PATCH 04/10] hugetlb: hugepage migration core

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20100922045907.GC2538@spritzera.linux.bs1.fc.nec.co.jp>
Date:	Wed, 22 Sep 2010 13:59:07 +0900
From:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
To:	Mel Gorman <mel@....ul.ie>
Cc:	Andi Kleen <andi@...stfloor.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Christoph Lameter <cl@...ux-foundation.org>,
	Wu Fengguang <fengguang.wu@...el.com>,
	"Jun'ichi Nomura" <j-nomura@...jp.nec.com>,
	linux-mm <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 04/10] hugetlb: hugepage migration core

On Mon, Sep 20, 2010 at 12:10:55PM +0100, Mel Gorman wrote:
> On Wed, Sep 08, 2010 at 10:19:35AM +0900, Naoya Horiguchi wrote:
...
> > @@ -95,26 +96,34 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma,
> >  	pte_t *ptep, pte;
> >   	spinlock_t *ptl;
> >  
> > - 	pgd = pgd_offset(mm, addr);
> > -	if (!pgd_present(*pgd))
> > -		goto out;
> > +	if (unlikely(PageHuge(new))) {
> > +		ptep = huge_pte_offset(mm, addr);
> > +		if (!ptep)
> > +			goto out;
> > +		ptl = &mm->page_table_lock;
> > +	} else {
> > +		pgd = pgd_offset(mm, addr);
> > +		if (!pgd_present(*pgd))
> > +			goto out;
> >  
> > -	pud = pud_offset(pgd, addr);
> > -	if (!pud_present(*pud))
> > -		goto out;
> > +		pud = pud_offset(pgd, addr);
> > +		if (!pud_present(*pud))
> > +			goto out;
> >  
> 
> Why are the changes to teh rest of the walkers necessary? Instead, why
> did you not identify which PTL lock you needed and then goto the point
> where spin_lock(ptl) is called? Similar to what page_check_address()
> does for example.

This is because Andi-san commented to avoid using goto sentense.
But honestly I'm not sure which is a clear way.

Thanks,
Naoya Horiguchi
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/