linux-kernel - Re: [PATCH v3 16/19] KVM: MMU: lockless walking shadow page table

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:	Thu, 7 Jul 2011 05:18:35 -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 v3 16/19] KVM: MMU: lockless walking shadow page table

On Thu, Jul 07, 2011 at 03:26:14AM +0800, Xiao Guangrong wrote:
> On 07/07/2011 02:08 AM, Marcelo Tosatti wrote:
> 
> >> +static void free_pages_rcu(struct rcu_head *head)
> >> +{
> >> +	struct kvm_mmu_page *next, *sp;
> >> +
> >> +	sp = container_of(head, struct kvm_mmu_page, rcu);
> >> +	while (sp) {
> >> +		if (!list_empty(&sp->link))
> >> +			next = list_first_entry(&sp->link,
> >> +				      struct kvm_mmu_page, link);
> >> +		else
> >> +			next = NULL;
> >> +		kvm_mmu_free_page(sp);
> >> +		sp = next;
> >> +	}
> >> +}
> > 
> > There is no need for this while loop.
> > 
> 
> The while loop is needed, since many shadow pages can be freed together in
> the rcu context, on commit_zap_page path, we only remove the list head, and
> the shadow page is still listed.

Right.

--
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/