linux-kernel - Re: [PATCH 2 of 4] hotplug-memory: adding non-section-aligned memory is bad

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: <47ED36AC.9000807@goop.org>
Date:	Fri, 28 Mar 2008 11:19:24 -0700
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
CC:	Yasunori Goto <y-goto@...fujitsu.com>, Ingo Molnar <mingo@...e.hu>,
	LKML <linux-kernel@...r.kernel.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Christoph Lameter <clameter@....com>,
	Dave Hansen <dave@...ux.vnet.ibm.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 2 of 4] hotplug-memory: adding non-section-aligned memory
 is bad

KAMEZAWA Hiroyuki wrote:
>> What would happen if I did online_pages(pfn, 1) on each page as I 
>> populate it?
>>
>>     
> I think (hope) it works well. But it seems no one tries to do that.

Well I had immediate problems because I try to use it under spinlock and 
it calls online_pages -> build_all_zonelists -> stop_machine_run.  I can 
easily rearrange to fix that, but it seems to me that stop_machine_run() 
is probably too expensive to call thousands of times (one for each page, 
rather than once per section).

I'm just looking at how I can refactor online_pages() into a function 
which does the general zone setup stuff, and one for actually onlining 
pages.  The function of online_pages() would remain unchanged for 
existing users, but I could call the pieces separately at the 
appropriate times.

    J
--
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/