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From: David Rientjes <rientjes@google.com>
To: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Linux MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/4] memory_hotplug: use pgdat_resize_lock() when updating node_present_pages
Date: Wed, 1 May 2013 15:30:52 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.02.1305011530050.8804@chino.kir.corp.google.com> (raw)
In-Reply-To: <1367446635-12856-5-git-send-email-cody@linux.vnet.ibm.com>

On Wed, 1 May 2013, Cody P Schafer wrote:

> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index a221fac..0bdca10 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -915,6 +915,7 @@ static void node_states_set_node(int node, struct memory_notify *arg)
>  
>  int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
>  {
> +	unsigned long flags;
>  	unsigned long onlined_pages = 0;
>  	struct zone *zone;
>  	int need_zonelists_rebuild = 0;
> @@ -993,7 +994,11 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
>  
>  	zone->managed_pages += onlined_pages;
>  	zone->present_pages += onlined_pages;
> +
> +	pgdat_resize_lock(zone->zone_pgdat, &flags);
>  	zone->zone_pgdat->node_present_pages += onlined_pages;
> +	pgdat_resize_unlock(zone->zone_pgdat, &flags);
> +
>  	if (onlined_pages) {
>  		node_states_set_node(zone_to_nid(zone), &arg);
>  		if (need_zonelists_rebuild)

Why?  You can't get a partial read of a word-sized data structure.

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  reply	other threads:[~2013-05-01 22:30 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-01 22:17 [PATCH 0/4] misc patches related to resizing nodes & zones Cody P Schafer
2013-05-01 22:17 ` [PATCH 1/4] mmzone: make holding lock_memory_hotplug() a requirement for updating pgdat size Cody P Schafer
2013-05-01 22:26   ` David Rientjes
2013-05-01 22:32     ` Cody P Schafer
2013-05-01 22:39       ` David Rientjes
2013-05-01 22:45         ` Cody P Schafer
2013-05-01 22:17 ` [PATCH 2/4] mm: fix comment referring to non-existent size_seqlock, change to span_seqlock Cody P Schafer
2013-05-01 22:27   ` David Rientjes
2013-05-01 22:17 ` [PATCH 3/4] mmzone: note that node_size_lock should be manipulated via pgdat_resize_lock() Cody P Schafer
2013-05-01 22:29   ` David Rientjes
2013-05-01 22:36     ` Cody P Schafer
2013-05-01 22:42       ` David Rientjes
2013-05-01 22:47         ` Cody P Schafer
2013-05-01 22:17 ` [PATCH 4/4] memory_hotplug: use pgdat_resize_lock() when updating node_present_pages Cody P Schafer
2013-05-01 22:30   ` David Rientjes [this message]
2013-05-01 22:41     ` Cody P Schafer
2013-05-01 22:48       ` David Rientjes
2013-05-01 22:51         ` Cody P Schafer

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