From: Minchan Kim <minchan@kernel.org>
To: Wen Congyang <wency@cn.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
mgorman@suse.de,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
hughd@google.com, linux-mm@kvack.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] memory hotplug: reset pgdat->kswapd to NULL if creating kernel thread fails
Date: Tue, 21 Aug 2012 16:37:38 +0900 [thread overview]
Message-ID: <20120821073738.GA24667@bbox> (raw)
In-Reply-To: <50332B37.2000500@cn.fujitsu.com>
On Tue, Aug 21, 2012 at 02:31:19PM +0800, Wen Congyang wrote:
> If kthread_run() fails, pgdat->kswapd contains errno. When we stop
> this thread, we only check whether pgdat->kswapd is NULL and access
> it. If it contains errno, it will cause page fault. Reset pgdat->kswapd
> to NULL when creating kernel thread fails can avoid this problem.
>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Nitpick: Why doesn't online_pages check kswapd_run's return value?
I hope memory-hotplug can handle this error rightly without
relying on this patch in the future.
--
Kind regards,
Minchan Kim
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WARNING: multiple messages have this Message-ID (diff)
From: Minchan Kim <minchan@kernel.org>
To: Wen Congyang <wency@cn.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
mgorman@suse.de,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
hughd@google.com, linux-mm@kvack.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] memory hotplug: reset pgdat->kswapd to NULL if creating kernel thread fails
Date: Tue, 21 Aug 2012 16:37:38 +0900 [thread overview]
Message-ID: <20120821073738.GA24667@bbox> (raw)
In-Reply-To: <50332B37.2000500@cn.fujitsu.com>
On Tue, Aug 21, 2012 at 02:31:19PM +0800, Wen Congyang wrote:
> If kthread_run() fails, pgdat->kswapd contains errno. When we stop
> this thread, we only check whether pgdat->kswapd is NULL and access
> it. If it contains errno, it will cause page fault. Reset pgdat->kswapd
> to NULL when creating kernel thread fails can avoid this problem.
>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Nitpick: Why doesn't online_pages check kswapd_run's return value?
I hope memory-hotplug can handle this error rightly without
relying on this patch in the future.
--
Kind regards,
Minchan Kim
next prev parent reply other threads:[~2012-08-21 7:37 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-21 6:31 [PATCH] memory hotplug: reset pgdat->kswapd to NULL if creating kernel thread fails Wen Congyang
2012-08-21 6:31 ` Wen Congyang
2012-08-21 7:37 ` Minchan Kim [this message]
2012-08-21 7:37 ` Minchan Kim
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