Date: Tue, 17 Feb 2015 14:24:47 +0900
From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
To: Gioh Kim <gioh.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>,
        Johannes Weiner <hannes@cmpxchg.org>, Mel Gorman <mgorman@suse.de>,
        Laura Abbott <lauraa@codeaurora.org>, Minchan Kim <minchan@kernel.org>,
        Heesub Shin <heesub.shin@samsung.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Michal Nazarewicz <mina86@mina86.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Hui Zhu <zhuhui@xiaomi.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Ritesh Harjani <ritesh.list@gmail.com>,
        Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [RFC 07/16] mm/page_isolation: watch out zone range overlap
Message-ID: <20150217052446.GB15413@js1304-P5Q-DELUXE>
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On Fri, Feb 13, 2015 at 03:40:08PM +0900, Gioh Kim wrote:
> 
> > diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> > index c8778f7..883e78d 100644
> > --- a/mm/page_isolation.c
> > +++ b/mm/page_isolation.c
> > @@ -210,8 +210,8 @@ int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
> >    * Returns 1 if all pages in the range are isolated.
> >    */
> >   static int
> > -__test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
> > -				  bool skip_hwpoisoned_pages)
> > +__test_page_isolated_in_pageblock(struct zone *zone, unsigned long pfn,
> > +			unsigned long end_pfn, bool skip_hwpoisoned_pages)
> >   {
> >   	struct page *page;
> >   
> > @@ -221,6 +221,9 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
> >   			continue;
> >   		}
> >   		page = pfn_to_page(pfn);
> > +		if (page_zone(page) != zone)
> > +			break;
> > +
> >   		if (PageBuddy(page)) {
> >   			/*
> >   			 * If race between isolatation and allocation happens,
> > @@ -281,7 +284,7 @@ int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
> >   	/* Check all pages are free or marked as ISOLATED */
> >   	zone = page_zone(page);
> >   	spin_lock_irqsave(&zone->lock, flags);
> > -	ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
> > +	ret = __test_page_isolated_in_pageblock(zone, start_pfn, end_pfn,
> >   						skip_hwpoisoned_pages);
> >   	spin_unlock_irqrestore(&zone->lock, flags);
> >   	return ret ? 0 : -EBUSY;
> > 
> 
> What about checking zone at test_pages_isolated?
> It might be a little bit early and without locking zone.

Hello,

Will do in next spin.

Thanks.

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