linux-kernel - Re: [RFC 2/2] x86_64, mm: Reinsert the absent memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <51C88400.7090907@zytor.com>
Date:	Mon, 24 Jun 2013 10:38:08 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Ingo Molnar <mingo@...nel.org>
CC:	Nathan Zimmer <nzimmer@....com>, holt@....com, travis@....com,
	rob@...dley.net, tglx@...utronix.de, mingo@...hat.com,
	yinghai@...nel.org, akpm@...ux-foundation.org,
	gregkh@...uxfoundation.org, x86@...nel.org,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [RFC 2/2] x86_64, mm: Reinsert the absent memory

On 06/23/2013 02:32 AM, Ingo Molnar wrote:
> 
> * Ingo Molnar <mingo@...nel.org> wrote:
> 
>> Yet another thing to consider would be to implement an initialization 
>> speedup of 3 orders of magnitude: initialize on the large page (2MB) 
>> grandularity and on-demand delay the initialization of the 4K granular 
>> struct pages [but still allocating them] - which I suspect are a good 
>> chunk of the overhead? That way we could initialize in 2MB steps and speed 
>> up the 2 hours bootup of 32 TB of RAM to 14 seconds...
>>
>> [ The cost would be one more branch in the buddy allocator, to detect
>>   not-yet-initialized 2 MB chunks as we encounter them. Acceptable I 
>>   think. ]
> 
> One advantage of this scheme would be that we could use it on pretty much 
> any box, it would provide instant boot time speedups everywhere [a couple 
> of hundred msecs on a small 4GB box - significant I think] - and would 
> spread out and parallelize initialization to later stages.
> 

Even better if we could start at the 1 GB level, which most of these
really huge machines will have hardware support for.

	-hpa


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/