* [PATCH v2] KVM: cleanup {kvm_vm_ioctl, kvm}_get_dirty_log()
@ 2010-03-17 7:49 Xiao Guangrong
2010-03-17 8:17 ` Takuya Yoshikawa
2010-03-18 2:48 ` Marcelo Tosatti
0 siblings, 2 replies; 6+ messages in thread
From: Xiao Guangrong @ 2010-03-17 7:49 UTC (permalink / raw)
To: Avi Kivity; +Cc: Takuya Yoshikawa, KVM list, LKML
Using bitmap_empty() to see whether memslot->dirty_bitmap is empty
Changlog:
cleanup x86 specific kvm_vm_ioctl_get_dirty_log() and fix a local
parameter's type address Takuya Yoshikawa's suggestion
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
arch/x86/kvm/x86.c | 17 ++++-------------
virt/kvm/kvm_main.c | 7 ++-----
2 files changed, 6 insertions(+), 18 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bcf52d1..e6cbbd4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2644,22 +2644,17 @@ static int kvm_vm_ioctl_reinject(struct kvm *kvm,
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
struct kvm_dirty_log *log)
{
- int r, n, i;
+ int r, n, is_dirty = 0;
struct kvm_memory_slot *memslot;
- unsigned long is_dirty = 0;
unsigned long *dirty_bitmap = NULL;
mutex_lock(&kvm->slots_lock);
- r = -EINVAL;
- if (log->slot >= KVM_MEMORY_SLOTS)
+ r = kvm_get_dirty_log(kvm, log, &is_dirty);
+ if (r)
goto out;
memslot = &kvm->memslots->memslots[log->slot];
- r = -ENOENT;
- if (!memslot->dirty_bitmap)
- goto out;
-
n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
r = -ENOMEM;
@@ -2668,9 +2663,6 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
goto out;
memset(dirty_bitmap, 0, n);
- for (i = 0; !is_dirty && i < n/sizeof(long); i++)
- is_dirty = memslot->dirty_bitmap[i];
-
/* If nothing is dirty, don't bother messing with page tables. */
if (is_dirty) {
struct kvm_memslots *slots, *old_slots;
@@ -2694,8 +2686,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
}
r = 0;
- if (copy_to_user(log->dirty_bitmap, dirty_bitmap, n))
- r = -EFAULT;
+
out_free:
vfree(dirty_bitmap);
out:
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index bcd08b8..b08a7de 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -767,9 +767,7 @@ int kvm_get_dirty_log(struct kvm *kvm,
struct kvm_dirty_log *log, int *is_dirty)
{
struct kvm_memory_slot *memslot;
- int r, i;
- int n;
- unsigned long any = 0;
+ int r, n, any = 0;
r = -EINVAL;
if (log->slot >= KVM_MEMORY_SLOTS)
@@ -782,8 +780,7 @@ int kvm_get_dirty_log(struct kvm *kvm,
n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
- for (i = 0; !any && i < n/sizeof(long); ++i)
- any = memslot->dirty_bitmap[i];
+ any = !bitmap_empty(memslot->dirty_bitmap, memslot->npages);
r = -EFAULT;
if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
--
1.6.1.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH v2] KVM: cleanup {kvm_vm_ioctl, kvm}_get_dirty_log()
2010-03-17 7:49 [PATCH v2] KVM: cleanup {kvm_vm_ioctl, kvm}_get_dirty_log() Xiao Guangrong
@ 2010-03-17 8:17 ` Takuya Yoshikawa
2010-03-17 8:28 ` Xiao Guangrong
2010-03-18 2:48 ` Marcelo Tosatti
1 sibling, 1 reply; 6+ messages in thread
From: Takuya Yoshikawa @ 2010-03-17 8:17 UTC (permalink / raw)
To: Xiao Guangrong; +Cc: Avi Kivity, KVM list, LKML
Xiao Guangrong wrote:
> Using bitmap_empty() to see whether memslot->dirty_bitmap is empty
>
> Changlog:
> cleanup x86 specific kvm_vm_ioctl_get_dirty_log() and fix a local
> parameter's type address Takuya Yoshikawa's suggestion
Oh, for such a tiny comment.
>
> Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
> ---
> arch/x86/kvm/x86.c | 17 ++++-------------
> virt/kvm/kvm_main.c | 7 ++-----
> 2 files changed, 6 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index bcf52d1..e6cbbd4 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
What I said was just you may be able to use bitmap_empty() instead of
> - for (i = 0; !is_dirty && i < n/sizeof(long); i++)
> - is_dirty = memslot->dirty_bitmap[i];
for x86's code too, if your patch for kvm_get_dirty_log() was correct.
> @@ -2644,22 +2644,17 @@ static int kvm_vm_ioctl_reinject(struct kvm *kvm,
> int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
> struct kvm_dirty_log *log)
> {
> - int r, n, i;
> + int r, n, is_dirty = 0;
> struct kvm_memory_slot *memslot;
> - unsigned long is_dirty = 0;
> unsigned long *dirty_bitmap = NULL;
>
> mutex_lock(&kvm->slots_lock);
>
> - r = -EINVAL;
> - if (log->slot >= KVM_MEMORY_SLOTS)
> + r = kvm_get_dirty_log(kvm, log, &is_dirty);
> + if (r)
> goto out;
>
> memslot = &kvm->memslots->memslots[log->slot];
> - r = -ENOENT;
> - if (!memslot->dirty_bitmap)
> - goto out;
> -
> n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
>
> r = -ENOMEM;
> @@ -2668,9 +2663,6 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
> goto out;
> memset(dirty_bitmap, 0, n);
>
> - for (i = 0; !is_dirty && i < n/sizeof(long); i++)
> - is_dirty = memslot->dirty_bitmap[i];
> -
> /* If nothing is dirty, don't bother messing with page tables. */
> if (is_dirty) {
> struct kvm_memslots *slots, *old_slots;
> @@ -2694,8 +2686,7 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
> }
>
> r = 0;
> - if (copy_to_user(log->dirty_bitmap, dirty_bitmap, n))
> - r = -EFAULT;
> +
> out_free:
> vfree(dirty_bitmap);
> out:
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index bcd08b8..b08a7de 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -767,9 +767,7 @@ int kvm_get_dirty_log(struct kvm *kvm,
> struct kvm_dirty_log *log, int *is_dirty)
> {
> struct kvm_memory_slot *memslot;
> - int r, i;
> - int n;
> - unsigned long any = 0;
> + int r, n, any = 0;
>
> r = -EINVAL;
> if (log->slot >= KVM_MEMORY_SLOTS)
> @@ -782,8 +780,7 @@ int kvm_get_dirty_log(struct kvm *kvm,
>
> n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
>
> - for (i = 0; !any && i < n/sizeof(long); ++i)
> - any = memslot->dirty_bitmap[i];
> + any = !bitmap_empty(memslot->dirty_bitmap, memslot->npages);
>
> r = -EFAULT;
> if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] KVM: cleanup {kvm_vm_ioctl, kvm}_get_dirty_log()
2010-03-17 8:17 ` Takuya Yoshikawa
@ 2010-03-17 8:28 ` Xiao Guangrong
2010-03-17 8:41 ` Takuya Yoshikawa
0 siblings, 1 reply; 6+ messages in thread
From: Xiao Guangrong @ 2010-03-17 8:28 UTC (permalink / raw)
To: Takuya Yoshikawa; +Cc: Avi Kivity, KVM list, LKML
Takuya Yoshikawa wrote:
>
> Oh, for such a tiny comment.
Your comment is valuable although it's tiny :-)
>
>
> What I said was just you may be able to use bitmap_empty() instead of
>
>> - for (i = 0; !is_dirty && i < n/sizeof(long); i++)
>> - is_dirty = memslot->dirty_bitmap[i];
>
> for x86's code too, if your patch for kvm_get_dirty_log() was correct.
While i look into x86's code, i found we can direct call kvm_get_dirty_log()
in kvm_vm_ioctl_get_dirty_log() to remove some unnecessary code, this is a
better cleanup way
Thanks,
Xiao
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] KVM: cleanup {kvm_vm_ioctl, kvm}_get_dirty_log()
2010-03-17 8:28 ` Xiao Guangrong
@ 2010-03-17 8:41 ` Takuya Yoshikawa
2010-03-17 10:13 ` Xiao Guangrong
0 siblings, 1 reply; 6+ messages in thread
From: Takuya Yoshikawa @ 2010-03-17 8:41 UTC (permalink / raw)
To: Xiao Guangrong; +Cc: Avi Kivity, KVM list, LKML
Xiao Guangrong wrote:
>
> Takuya Yoshikawa wrote:
>
>> Oh, for such a tiny comment.
>
> Your comment is valuable although it's tiny :-)
>
>
>> What I said was just you may be able to use bitmap_empty() instead of
>>
>>> - for (i = 0; !is_dirty && i < n/sizeof(long); i++)
>>> - is_dirty = memslot->dirty_bitmap[i];
>> for x86's code too, if your patch for kvm_get_dirty_log() was correct.
>
> While i look into x86's code, i found we can direct call kvm_get_dirty_log()
> in kvm_vm_ioctl_get_dirty_log() to remove some unnecessary code, this is a
> better cleanup way
Ah, probably checking the git log will explain you why it is like that!
Marcelo's work? IIRC.
>
> Thanks,
> Xiao
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v2] KVM: cleanup {kvm_vm_ioctl, kvm}_get_dirty_log()
2010-03-17 8:41 ` Takuya Yoshikawa
@ 2010-03-17 10:13 ` Xiao Guangrong
0 siblings, 0 replies; 6+ messages in thread
From: Xiao Guangrong @ 2010-03-17 10:13 UTC (permalink / raw)
To: Takuya Yoshikawa; +Cc: Avi Kivity, KVM list, LKML, Marcelo Tosatti
Takuya Yoshikawa wrote:
>
> Ah, probably checking the git log will explain you why it is like that!
> Marcelo's work? IIRC.
Oh, i find this commit:
commit 706831a7faec7ac0d3057d20df8234c45bbbc3c5
Author: Marcelo Tosatti <mtosatti@redhat.com>
Date: Wed Dec 23 14:35:22 2009 -0200
KVM: use SRCU for dirty log
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
But i don't know why Marcelo separates kvm_get_dirty_log()'s code
into kvm_vm_ioctl_get_dirty_log(). :-(
Thanks,
Xiao
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] KVM: cleanup {kvm_vm_ioctl, kvm}_get_dirty_log()
2010-03-17 7:49 [PATCH v2] KVM: cleanup {kvm_vm_ioctl, kvm}_get_dirty_log() Xiao Guangrong
2010-03-17 8:17 ` Takuya Yoshikawa
@ 2010-03-18 2:48 ` Marcelo Tosatti
1 sibling, 0 replies; 6+ messages in thread
From: Marcelo Tosatti @ 2010-03-18 2:48 UTC (permalink / raw)
To: Xiao Guangrong; +Cc: Avi Kivity, Takuya Yoshikawa, KVM list, LKML
On Wed, Mar 17, 2010 at 03:49:19PM +0800, Xiao Guangrong wrote:
> Using bitmap_empty() to see whether memslot->dirty_bitmap is empty
>
> Changlog:
> cleanup x86 specific kvm_vm_ioctl_get_dirty_log() and fix a local
> parameter's type address Takuya Yoshikawa's suggestion
>
> Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
> ---
> arch/x86/kvm/x86.c | 17 ++++-------------
> virt/kvm/kvm_main.c | 7 ++-----
> 2 files changed, 6 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index bcf52d1..e6cbbd4 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -2644,22 +2644,17 @@ static int kvm_vm_ioctl_reinject(struct kvm *kvm,
> int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
> struct kvm_dirty_log *log)
> {
> - int r, n, i;
> + int r, n, is_dirty = 0;
> struct kvm_memory_slot *memslot;
> - unsigned long is_dirty = 0;
> unsigned long *dirty_bitmap = NULL;
>
> mutex_lock(&kvm->slots_lock);
>
> - r = -EINVAL;
> - if (log->slot >= KVM_MEMORY_SLOTS)
> + r = kvm_get_dirty_log(kvm, log, &is_dirty);
> + if (r)
> goto out;
>
> memslot = &kvm->memslots->memslots[log->slot];
> - r = -ENOENT;
> - if (!memslot->dirty_bitmap)
> - goto out;
> -
Its different because the user copy must be done after the
SRCU assignment.
> index bcd08b8..b08a7de 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -767,9 +767,7 @@ int kvm_get_dirty_log(struct kvm *kvm,
> struct kvm_dirty_log *log, int *is_dirty)
> {
> struct kvm_memory_slot *memslot;
> - int r, i;
> - int n;
> - unsigned long any = 0;
> + int r, n, any = 0;
>
> r = -EINVAL;
> if (log->slot >= KVM_MEMORY_SLOTS)
> @@ -782,8 +780,7 @@ int kvm_get_dirty_log(struct kvm *kvm,
>
> n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
>
> - for (i = 0; !any && i < n/sizeof(long); ++i)
> - any = memslot->dirty_bitmap[i];
> + any = !bitmap_empty(memslot->dirty_bitmap, memslot->npages);
The opencoded version should be faster in comparison to __bitmap_empty
because the dirty bitmaps are always unsigned long aligned (and also
there's a function call).
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2010-03-18 2:50 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2010-03-17 7:49 [PATCH v2] KVM: cleanup {kvm_vm_ioctl, kvm}_get_dirty_log() Xiao Guangrong
2010-03-17 8:17 ` Takuya Yoshikawa
2010-03-17 8:28 ` Xiao Guangrong
2010-03-17 8:41 ` Takuya Yoshikawa
2010-03-17 10:13 ` Xiao Guangrong
2010-03-18 2:48 ` Marcelo Tosatti
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