linux-kernel - Re: [PATCH 11/11] KVM: MMU: improve write flooding detected

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]

Date:	Fri, 26 Aug 2011 07:53:28 -0300
From:	Marcelo Tosatti <mtosatti@...hat.com>
To:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
Cc:	Avi Kivity <avi@...hat.com>, LKML <linux-kernel@...r.kernel.org>,
	KVM <kvm@...r.kernel.org>
Subject: Re: [PATCH 11/11] KVM: MMU: improve write flooding detected

On Fri, Aug 26, 2011 at 11:18:01AM +0800, Xiao Guangrong wrote:
> On 08/25/2011 09:47 PM, Marcelo Tosatti wrote:
> 
> > I guess it is OK to be more trigger happy with zapping by ignoring
> > the accessed bit, clearing the flood counter on page fault.
> > 
> 
> Yeah, i like this way, is this patch good for you?

Looks fine, can you rerun kernbench?

> ================================
> Subject: [PATCH 11/11] KVM: MMU: improve write flooding detected
> 
> Detecting write-flooding does not work well, when we handle page written, if
> the last speculative spte is not accessed, we treat the page is
> write-flooding, however, we can speculative spte on many path, such as pte
> prefetch, page synced, that means the last speculative spte may be not point
> to the written page and the written page can be accessed via other sptes, so
> depends on the Accessed bit of the last speculative spte is not enough
> 
> Instead of detected page accessed, we can detect whether the spte is accessed
> after it is written, if the spte is not accessed but it is written frequently,
> we treat is not a page table or it not used for a long time
> 
> Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com>
--
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/