linux-kernel - Re: [patch] mm: node-setup agnostic free

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Date:	Wed, 30 Apr 2008 12:52:48 +0200
From:	Johannes Weiner <hannes@...urebad.de>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>, Yinghai Lu <yinghai.lu@....com>,
	Yinghai Lu <yhlu.kernel@...il.com>, jbarnes@...tuousgeek.org
Subject: Re: [patch] mm: node-setup agnostic free_bootmem()

Hi,

Ingo Molnar <mingo@...e.hu> writes:

> * Johannes Weiner <hannes@...urebad.de> wrote:
>
>> >  void __init free_bootmem(unsigned long addr, unsigned long size)
>> >  {
>> >  	bootmem_data_t *bdata;
>> > -	list_for_each_entry(bdata, &bdata_list, list)
>> > -		free_bootmem_core(bdata, addr, size);
>> > +	unsigned long pos = addr;
>> > +	unsigned long partsize = size;
>> > +
>> > +	list_for_each_entry(bdata, &bdata_list, list) {
>> > +		unsigned long remainder = 0;
>> > +
>> > +		if (pos < bdata->node_boot_start)
>> > +			continue;
>> > +
>> > +		if (PFN_DOWN(pos + partsize) > bdata->node_low_pfn) {
>> > +			remainder = PFN_DOWN(pos + partsize) - bdata->node_low_pfn;
>> > +			partsize -= remainder;
>> > +		}
>> > +
>> > +		free_bootmem_core(bdata, pos, partsize);
>> > +
>> > +		if (!remainder)
>> > +			return;
>> > +
>> > +		pos = PFN_PHYS(bdata->node_low_pfn + 1);
>> > +	}
>> > +	printk(KERN_ERR "free_bootmem: request: addr=%lx, size=%lx, "
>> > +			"state: pos=%lx, partsize=%lx\n", addr, size,
>> > +			pos, partsize);
>> > +	BUG();
>> >  }
>> >  
>> >  unsigned long __init free_all_bootmem(void)
>> 
>> Yes, looks good.  But needs explicit testing, I guess.
>
> yep, but as Yinghai Lu has pointed it out, this removes a cross-node 
> allocation fix. That fix has to be preserved in any cleanup, agreed?

Yes, if Yinghai is right, my patch should be dropped, of course.

> in general bootmem should assume the weirdest of NUMA topologies and be 
> defensive about them. Topologies will only become more complex, never 
> less complex.

Okay.

	Hannes
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