From: Andrew Morton <akpm@linux-foundation.org>
To: Vladimir Davydov <vdavydov@parallels.com>
Cc: cl@linux-foundation.org, penberg@kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
devel@openvz.org, Tang Chen <tangchen@cn.fujitsu.com>,
Zhang Yanfei <zhangyanfei@cn.fujitsu.com>,
Toshi Kani <toshi.kani@hp.com>, Xishi Qiu <qiuxishi@huawei.com>,
Jiang Liu <liuj97@gmail.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
David Rientjes <rientjes@google.com>,
Wen Congyang <wency@cn.fujitsu.com>,
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>
Subject: Re: [PATCH -mm v2 1/2] mem-hotplug: implement get/put_online_mems
Date: Fri, 18 Apr 2014 13:18:28 -0700 [thread overview]
Message-ID: <20140418131828.804a181e5b4364a704d786cc@linux-foundation.org> (raw)
In-Reply-To: <b65ff63d5805c86fa288bc09db4f378492c6c543.1396857765.git.vdavydov@parallels.com>
On Mon, 7 Apr 2014 13:45:34 +0400 Vladimir Davydov <vdavydov@parallels.com> wrote:
> {un}lock_memory_hotplug, which is used to synchronize against memory
> hotplug, is currently backed by a mutex, which makes it a bit of a
> hammer - threads that only want to get a stable value of online nodes
> mask won't be able to proceed concurrently. Also, it imposes some strong
> locking ordering rules on it, which narrows down the set of its usage
> scenarios.
>
> This patch introduces get/put_online_mems, which are the same as
> get/put_online_cpus, but for memory hotplug, i.e. executing a code
> inside a get/put_online_mems section will guarantee a stable value of
> online nodes, present pages, etc.
Well that seems a nice change. I added the important paragraph
"lock_memory_hotplug()/unlock_memory_hotplug() are removed altogether."
I'll Cc a large number of people who have recently worked on the memory
hotplug code. Hopefully some of them will have time to review and test
these patches, thanks.
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next prev parent reply other threads:[~2014-04-18 20:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-07 9:45 [PATCH -mm v2 0/2] slab: cleanup mem hotplug synchronization Vladimir Davydov
2014-04-07 9:45 ` [PATCH -mm v2 1/2] mem-hotplug: implement get/put_online_mems Vladimir Davydov
2014-04-18 20:18 ` Andrew Morton [this message]
2014-04-07 9:45 ` [PATCH -mm v2 2/2] slab: get_online_mems for kmem_cache_{create,destroy,shrink} Vladimir Davydov
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