linux-kernel - Re: [RFC][PATCH 6/8] mm: handle_speculative

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] [day] [month] [year] [list]

Date:	Sun, 10 Jan 2010 10:57:34 +0530
From:	Nitin Gupta <ngupta@...are.org>
To:	Ed Tomlinson <edt@....ca>
CC:	Peter Zijlstra <peterz@...radead.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Minchan Kim <minchan.kim@...il.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>, cl@...ux-foundation.org,
	"hugh.dickins" <hugh.dickins@...cali.co.uk>,
	Nick Piggin <nickpiggin@...oo.com.au>,
	Ingo Molnar <mingo@...e.hu>
Subject: Re: [RFC][PATCH 6/8] mm: handle_speculative_fault()

On 01/09/2010 08:17 PM, Ed Tomlinson wrote:
> On Friday 08 January 2010 11:53:30 Peter Zijlstra wrote:
>> On Tue, 2010-01-05 at 20:20 -0800, Linus Torvalds wrote:
>>>
>>> On Wed, 6 Jan 2010, KAMEZAWA Hiroyuki wrote:
>>>>>
>>>>> Of course, your other load with MADV_DONTNEED seems to be horrible, and 
>>>>> has some nasty spinlock issues, but that looks like a separate deal (I 
>>>>> assume that load is just very hard on the pgtable lock).
>>>>
>>>> It's zone->lock, I guess. My test program avoids pgtable lock problem.
>>>
>>> Yeah, I should have looked more at your callchain. That's nasty. Much 
>>> worse than the per-mm lock. I thought the page buffering would avoid the 
>>> zone lock becoming a huge problem, but clearly not in this case.
>>
>> Right, so I ran some numbers on a multi-socket (2) machine as well:
>>
>>                                pf/min
>>
>> -tip                          56398626
>> -tip + xadd                  174753190
>> -tip + speculative           189274319
>> -tip + xadd + speculative    200174641
> 
> Has anyone tried these patches with ramzswap?  Nitin do they help with the locking
> issues you mentioned?
> 

Locking problem with ramzswap seems completely unrelated to what is being discussed here.

Thanks,
Nitin
--
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/