From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Avi Kivity <avi@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH v2 5/5] KVM: MMU: lower the aduit frequency
Date: Tue, 31 Aug 2010 10:27:09 +0800 [thread overview]
Message-ID: <4C7C687D.2000401@cn.fujitsu.com> (raw)
In-Reply-To: <20100830154719.GB12707@amt.cnet>
On 08/30/2010 11:47 PM, Marcelo Tosatti wrote:
> On Mon, Aug 30, 2010 at 06:26:33PM +0800, Xiao Guangrong wrote:
>> The audit is very high overhead, so we need lower the frequency to assure the guest running
>>
>> Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
>> ---
>> arch/x86/kvm/mmu_audit.c | 7 +++++++
>> 1 files changed, 7 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
>> index 3bde186..bd2b1be 100644
>> --- a/arch/x86/kvm/mmu_audit.c
>> +++ b/arch/x86/kvm/mmu_audit.c
>> @@ -17,6 +17,8 @@
>> *
>> */
>>
>> +#include <linux/ratelimit.h>
>> +
>> static const char *audit_msg;
>>
>> typedef void (*inspect_spte_fn) (struct kvm_vcpu *vcpu, u64 *sptep, int level);
>> @@ -228,6 +230,11 @@ static void audit_vcpu_spte(struct kvm_vcpu *vcpu)
>>
>> static void kvm_mmu_audit(void *ignore, struct kvm_vcpu *vcpu, int audit_point)
>> {
>> + static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
>> +
>> + if (!__ratelimit(&ratelimit_state))
>> + return;
>> +
>> audit_msg = audit_point_name[audit_point];
>> audit_all_active_sps(vcpu->kvm);
>> audit_vcpu_spte(vcpu);
>> --
>> 1.7.0.4
>
> Well, as Avi said this makes it difficult to trace back to offender (the
> audit points are placed around modifications to the shadow page tree
> for that reason).
>
Yeah. it's the best way that not rate limit it, but...
> I've always seen progress from the guest while running with audit
> enabled (its slow, but its not supposed to be fast anyway).
>
> Did you experience a freeze?
>
There is a simply test in the guest if it's not rate limit:
# time ls
anaconda-ks.cfg Documents install.log Music Public Videos
Desktop Downloads install.log.syslog Pictures Templates
real 1m26.053s
user 0m0.311s
sys 0m1.813s
'ls' command cost about 1.5 minute, if we run the memory test program, i think
the time/delay is unacceptable...... :-(
next prev parent reply other threads:[~2010-08-31 2:27 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-28 11:58 [PATCH 0/4] KVM: MMU: mmu audit code improved Xiao Guangrong
2010-08-28 12:00 ` [PATCH 1/4] KVM: MMU: support disable/enable mmu audit dynamicly Xiao Guangrong
2010-08-29 9:16 ` Avi Kivity
2010-08-30 1:58 ` Xiao Guangrong
2010-08-28 12:01 ` [PATCH 2/4] KVM: MMU: improve active sp audit Xiao Guangrong
2010-08-28 12:02 ` [PATCH 3/4] KVM: MMU: improve spte audit Xiao Guangrong
2010-08-28 12:03 ` [PATCH 4/4] KVM: MMU: lower the aduit frequency Xiao Guangrong
2010-08-29 9:19 ` Avi Kivity
2010-08-30 2:16 ` Xiao Guangrong
2010-08-30 6:59 ` Avi Kivity
2010-08-30 10:22 ` [PATCH v2 1/5] KVM: MMU: support disable/enable mmu audit dynamicly Xiao Guangrong
2010-08-30 10:24 ` [PATCH v2 2/5] KVM: MMU: move audit to a separate file Xiao Guangrong
2010-08-30 10:25 ` [PATCH v2 3/5] KVM: MMU: improve active sp audit Xiao Guangrong
2010-08-30 10:25 ` [PATCH v2 4/5] KVM: MMU: improve spte audit Xiao Guangrong
2010-08-30 10:26 ` [PATCH v2 5/5] KVM: MMU: lower the aduit frequency Xiao Guangrong
2010-08-30 15:47 ` Marcelo Tosatti
2010-08-31 2:27 ` Xiao Guangrong [this message]
2010-09-01 9:06 ` Avi Kivity
2010-09-01 16:27 ` Marcelo Tosatti
2010-09-02 8:30 ` Avi Kivity
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4C7C687D.2000401@cn.fujitsu.com \
--to=xiaoguangrong@cn.fujitsu.com \
--cc=avi@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mtosatti@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).