From: Cody P Schafer <cody@linux.vnet.ibm.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] mmzone: make holding lock_memory_hotplug() a requirement for updating pgdat size
Date: Wed, 01 May 2013 15:32:02 -0700 [thread overview]
Message-ID: <518197E2.7050004@linux.vnet.ibm.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1305011525580.8804@chino.kir.corp.google.com>
On 05/01/2013 03:26 PM, David Rientjes wrote:
> On Wed, 1 May 2013, Cody P Schafer wrote:
>
>> All updaters of pgdat size (spanned_pages, start_pfn, and
>> present_pages) currently also hold lock_memory_hotplug() (in addition
>> to pgdat_resize_lock()).
>>
>> Document this and make holding of that lock a requirement on the update
>> side for now, but keep the pgdat_resize_lock() around for readers that
>> can't lock a mutex.
>>
>> Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
>
> Nack, these fields are initialized at boot without lock_memory_hotplug(),
> so you're statement is wrong, and all you need is pgdat_resize_lock().
They are also initialized at boot without pgdat_resize_lock(), if we
consider boot time, quite a few of the statements on when locking is
required are wrong.
That said, you are correct that it is not strictly required to hold
lock_memory_hotplug() when updating the fields in question because
pgdat_resize_lock() is used.
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WARNING: multiple messages have this Message-ID (diff)
From: Cody P Schafer <cody@linux.vnet.ibm.com>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] mmzone: make holding lock_memory_hotplug() a requirement for updating pgdat size
Date: Wed, 01 May 2013 15:32:02 -0700 [thread overview]
Message-ID: <518197E2.7050004@linux.vnet.ibm.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1305011525580.8804@chino.kir.corp.google.com>
On 05/01/2013 03:26 PM, David Rientjes wrote:
> On Wed, 1 May 2013, Cody P Schafer wrote:
>
>> All updaters of pgdat size (spanned_pages, start_pfn, and
>> present_pages) currently also hold lock_memory_hotplug() (in addition
>> to pgdat_resize_lock()).
>>
>> Document this and make holding of that lock a requirement on the update
>> side for now, but keep the pgdat_resize_lock() around for readers that
>> can't lock a mutex.
>>
>> Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
>
> Nack, these fields are initialized at boot without lock_memory_hotplug(),
> so you're statement is wrong, and all you need is pgdat_resize_lock().
They are also initialized at boot without pgdat_resize_lock(), if we
consider boot time, quite a few of the statements on when locking is
required are wrong.
That said, you are correct that it is not strictly required to hold
lock_memory_hotplug() when updating the fields in question because
pgdat_resize_lock() is used.
next prev parent reply other threads:[~2013-05-01 22:32 UTC|newest]
Thread overview: 36+ 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 ` 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 22:17 ` Cody P Schafer
2013-05-01 22:26 ` David Rientjes
2013-05-01 22:26 ` David Rientjes
2013-05-01 22:32 ` Cody P Schafer [this message]
2013-05-01 22:32 ` Cody P Schafer
2013-05-01 22:39 ` David Rientjes
2013-05-01 22:39 ` David Rientjes
2013-05-01 22:45 ` Cody P Schafer
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 22:17 ` Cody P Schafer
2013-05-01 22:27 ` David Rientjes
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 22:17 ` Cody P Schafer
2013-05-01 22:29 ` David Rientjes
2013-05-01 22:29 ` David Rientjes
2013-05-01 22:36 ` Cody P Schafer
2013-05-01 22:36 ` Cody P Schafer
2013-05-01 22:42 ` David Rientjes
2013-05-01 22:42 ` David Rientjes
2013-05-01 22:47 ` Cody P Schafer
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 22:17 ` Cody P Schafer
2013-05-01 22:30 ` David Rientjes
2013-05-01 22:30 ` David Rientjes
2013-05-01 22:41 ` Cody P Schafer
2013-05-01 22:41 ` Cody P Schafer
2013-05-01 22:48 ` David Rientjes
2013-05-01 22:48 ` David Rientjes
2013-05-01 22:51 ` Cody P Schafer
2013-05-01 22:51 ` Cody P Schafer
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