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To: "Mel Gorman" <mel@csn.ul.ie>
Cc: "Marek Szyprowski" <m.szyprowski@samsung.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
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        linaro-mm-sig@lists.linaro.org,
        "Kyungmin Park" <kyungmin.park@samsung.com>,
        "Russell King" <linux@arm.linux.org.uk>,
        "Andrew Morton" <akpm@linux-foundation.org>,
        "KAMEZAWA Hiroyuki" <kamezawa.hiroyu@jp.fujitsu.com>,
        "Daniel Walker" <dwalker@codeaurora.org>,
        "Arnd Bergmann" <arnd@arndb.de>,
        "Jesse Barker" <jesse.barker@linaro.org>,
        "Jonathan Corbet" <corbet@lwn.net>,
        "Shariq Hasnain" <shariq.hasnain@linaro.org>,
        "Chunsang Jeong" <chunsang.jeong@linaro.org>,
        "Dave Hansen" <dave@linux.vnet.ibm.com>,
        "Benjamin Gaignard" <benjamin.gaignard@linaro.org>
Subject: Re: [PATCH 04/11] mm: page_alloc: introduce alloc_contig_range()
References: <1325162352-24709-1-git-send-email-m.szyprowski@samsung.com>
 <1325162352-24709-5-git-send-email-m.szyprowski@samsung.com>
 <20120110141613.GB3910@csn.ul.ie> <op.v71gpt1b3l0zgt@mpn-glaptop>
 <20120116090110.GA2929@csn.ul.ie>
Date: Mon, 16 Jan 2012 13:48:11 +0100
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From: "Michal Nazarewicz" <mina86@mina86.com>
Message-ID: <op.v76giluf3l0zgt@mpn-glaptop>
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On Mon, 16 Jan 2012 10:01:10 +0100, Mel Gorman <mel@csn.ul.ie> wrote:

> On Fri, Jan 13, 2012 at 09:04:31PM +0100, Michal Nazarewicz wrote:
>> >On Thu, Dec 29, 2011 at 01:39:05PM +0100, Marek Szyprowski wrote:
>> >>From: Michal Nazarewicz <mina86@mina86.com>
>> >>+	/* Make sure all pages are isolated. */
>> >>+	if (!ret) {
>> >>+		lru_add_drain_all();
>> >>+		drain_all_pages();
>> >>+		if (WARN_ON(test_pages_isolated(start, end)))
>> >>+			ret = -EBUSY;
>> >>+	}
>>
>> On Tue, 10 Jan 2012 15:16:13 +0100, Mel Gorman <mel@csn.ul.ie> wrote:
>> >Another global IPI seems overkill. Drain pages only from the local CPU
>> >(drain_pages(get_cpu()); put_cpu()) and test if the pages are isolated.
>>
>> Is get_cpu() + put_cpu() required? Won't drain_local_pages() work?
>>
>
> drain_local_pages() calls smp_processor_id() without preemption
> disabled.

Thanks, I wasn't sure if preemption is an issue.

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo--