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Date: Sat, 05 Mar 2011 17:20:02 -0800
From: Yinghai Lu <yinghai@kernel.org>
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To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@elte.hu>,
        Thomas Gleixner <tglx@linutronix.de>, linux-mm@kvack.org,
        Russell King <linux@arm.linux.org.uk>
Subject: Re: [RFC] memblock; Properly handle overlaps
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On 03/05/2011 04:49 PM, Benjamin Herrenschmidt wrote:
> On Sat, 2011-03-05 at 15:20 -0800, Yinghai Lu wrote:
>>
>> maybe we can omit rgn->size == 0 checking here.
>> with that case, dummy array will go though to some extra checking.
>>
>> if (rgn->base <= base && rend >= end)
>> if (base < rgn->base && end >= rgn->base) {
>> if (base <= rend && end >= rend) {
>>
>> but we can spare more checking regarding
>>         rgn->size == 0
> 
> Well, the array can be collasped to dummy by the removal of the last
> block when doing a top overlap, then on the next loop around, we can
> potentially hit the if (base <= rend && end >= rend) test, and loop
> again no ?
> 
> I'd rather keep the test in .. won't hurt.

ok.