linux-kernel - Re: [RFC 2/2] mm: skip HWPoisoned pages when onlining pages

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Message-ID: <20170425080052.GB18194@hori1.linux.bs1.fc.nec.co.jp>
Date:   Tue, 25 Apr 2017 08:00:53 +0000
From:   Naoya Horiguchi <n-horiguchi@...jp.nec.com>
To:     Laurent Dufour <ldufour@...ux.vnet.ibm.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>
Subject: Re: [RFC 2/2] mm: skip HWPoisoned pages when onlining pages

On Thu, Apr 20, 2017 at 11:26:02AM +0200, Laurent Dufour wrote:
> The commit b023f46813cd ("memory-hotplug: skip HWPoisoned page when
> offlining pages") skip the HWPoisoned pages when offlining pages, but
> this should be skipped when onlining the pages too.
>
> Signed-off-by: Laurent Dufour <ldufour@...ux.vnet.ibm.com>
> ---
>  mm/memory_hotplug.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 6fa7208bcd56..20e1fadc2369 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -942,6 +942,8 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
>  	if (PageReserved(pfn_to_page(start_pfn)))
>  		for (i = 0; i < nr_pages; i++) {
>  			page = pfn_to_page(start_pfn + i);
> +			if (PageHWPoison(page))
> +				continue;

Is it OK that PageReserved (set by __offline_isolated_pages for non-buddy
hwpoisoned pages) still remains in this path?
If online_pages_range() is the reverse operation of __offline_isolated_pages(),
ClearPageReserved seems needed here.

Thanks,
Naoya Horiguchi

>  			(*online_page_callback)(page);
>  			onlined_pages++;
>  		}
> --
> 2.7.4
>
>