From: Jan Kiszka <jan.kiszka@siemens.com>
To: Avi Kivity <avi@redhat.com>
Cc: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>,
mtosatti@redhat.com, laijs@cn.fujitsu.com, kvm@vger.kernel.org,
takuya.yoshikawa@gmail.com
Subject: Re: [RFC PATCH 1/2] KVM: count the number of dirty bits for each memslot
Date: Thu, 18 Nov 2010 14:10:20 +0100 [thread overview]
Message-ID: <4CE525BC.7020906@siemens.com> (raw)
In-Reply-To: <4CE521FF.5010509@redhat.com>
Am 18.11.2010 13:54, Avi Kivity wrote:
> On 11/18/2010 07:14 AM, Takuya Yoshikawa wrote:
>> This patch introduces the counter to hold the number of dirty bits in
>> each
>> memslot. We will use this to optimize dirty logging later.
>>
>>
>> @@ -3217,11 +3216,8 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
>>
>> n = kvm_dirty_bitmap_bytes(memslot);
>>
>> - for (i = 0; !is_dirty&& i< n/sizeof(long); i++)
>> - is_dirty = memslot->dirty_bitmap[i];
>> -
>
> This can already be an improvement.
/Me wonders if it wouldn't make sense to expand this optimization to the
user space interface as well, i.e. signaling "there are no dirty pages"
via some flag instead of writing zeros in a bitmap. Of course, this
means supporting both interfaces for a longer period.
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
next prev parent reply other threads:[~2010-11-18 13:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-18 5:12 [RFC PATCH 0/2] KVM: dirty logging optimization Takuya Yoshikawa
2010-11-18 5:14 ` [RFC PATCH 1/2] KVM: count the number of dirty bits for each memslot Takuya Yoshikawa
2010-11-18 12:54 ` Avi Kivity
2010-11-18 13:10 ` Jan Kiszka [this message]
2010-11-18 13:14 ` Avi Kivity
2010-11-18 5:15 ` [RFC PATCH 2/2] KVM: selective write protection using dirty bitmap Takuya Yoshikawa
2010-11-18 13:06 ` Avi Kivity
2010-11-19 8:30 ` Takuya Yoshikawa
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