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Date:   Fri, 17 Apr 2020 15:12:47 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     David Hildenbrand <david@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Pavel Tatashin <pasha.tatashin@soleen.com>,
        Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
        Baoquan He <bhe@redhat.com>,
        Shile Zhang <shile.zhang@linux.alibaba.com>,
        Michal Hocko <mhocko@suse.com>,
        Kirill Tkhai <ktkhai@virtuozzo.com>,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
        Michal Hocko <mhocko@kernel.org>,
        Alexander Duyck <alexander.duyck@gmail.com>,
        Oscar Salvador <osalvador@suse.de>
Subject: Re: [PATCH v2] mm/page_alloc: fix watchdog soft lockups during
 set_zone_contiguous()
Message-Id: <20200417151247.0068d5aa3f026ced2289ce31@linux-foundation.org>
In-Reply-To: <20200416073417.5003-1-david@redhat.com>
References: <20200416073417.5003-1-david@redhat.com>
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On Thu, 16 Apr 2020 09:34:17 +0200 David Hildenbrand <david@redhat.com> wrote:

> Without CONFIG_PREEMPT, it can happen that we get soft lockups detected,
> e.g., while booting up.
> 
> ...
> 
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1607,6 +1607,7 @@ void set_zone_contiguous(struct zone *zone)
>  		if (!__pageblock_pfn_to_page(block_start_pfn,
>  					     block_end_pfn, zone))
>  			return;
> +		cond_resched();
>  	}
>  
>  	/* We confirm that there is no hole */

I added cc:stable to this one.  Please let me know if that wasn't a
good idea.