* [RFC][PATCH] Drop FOLL_GET in GUP when doing async_pf in kvm
@ 2013-10-10 13:20 chai wen
2013-10-10 15:15 ` Gleb Natapov
0 siblings, 1 reply; 4+ messages in thread
From: chai wen @ 2013-10-10 13:20 UTC (permalink / raw)
To: gleb
Cc: linux-kernel, pbonzini, tangchen, guz.fnst, zhangyanfei,
guijianfeng, chaiwen_0825, chai wen
Hi Gleb
Thanks for you explanation about async_pf in kvm.
Page pinning is not mandatory in kvm async_pf processing and probably should
be dropped later.this patch drops the FOLL_GET flag when doing GUP in async_pf
and uses a bool (marking result of GUP) to replace the *page in kvm_async_pf
structure to simplify some following async_pf check/clear processing.
Thanks.
Suggested-by: gleb@redhat.com
Signed-off-by: chai wen <chaiw.fnst@cn.fujitsu.com>
---
arch/x86/kvm/x86.c | 5 ++---
include/linux/kvm_host.h | 2 +-
virt/kvm/async_pf.c | 16 ++++++----------
3 files changed, 9 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e5ca72a..0ff7d02 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7282,8 +7282,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
{
int r;
- if ((vcpu->arch.mmu.direct_map != work->arch.direct_map) ||
- is_error_page(work->page))
+ if ((vcpu->arch.mmu.direct_map != work->arch.direct_map))
return;
r = kvm_mmu_reload(vcpu);
@@ -7393,7 +7392,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
struct x86_exception fault;
trace_kvm_async_pf_ready(work->arch.token, work->gva);
- if (is_error_page(work->page))
+ if (!work->got_page)
work->arch.token = ~0; /* broadcast wakeup */
else
kvm_del_async_pf_gfn(vcpu, work->arch.gfn);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 0fbbc7a..232a7d0 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -189,7 +189,7 @@ struct kvm_async_pf {
gva_t gva;
unsigned long addr;
struct kvm_arch_async_pf arch;
- struct page *page;
+ bool got_page;
bool done;
};
diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 8a39dda..0cafdc7 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -56,7 +56,7 @@ void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu)
static void async_pf_execute(struct work_struct *work)
{
- struct page *page = NULL;
+ long nrpages = 0;
struct kvm_async_pf *apf =
container_of(work, struct kvm_async_pf, work);
struct mm_struct *mm = apf->mm;
@@ -68,13 +68,13 @@ static void async_pf_execute(struct work_struct *work)
use_mm(mm);
down_read(&mm->mmap_sem);
- get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL);
+ nrpages = get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL);
up_read(&mm->mmap_sem);
unuse_mm(mm);
spin_lock(&vcpu->async_pf.lock);
list_add_tail(&apf->link, &vcpu->async_pf.done);
- apf->page = page;
+ apf->got_page = (1==nrpages);
apf->done = true;
spin_unlock(&vcpu->async_pf.lock);
@@ -114,8 +114,6 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
list_entry(vcpu->async_pf.done.next,
typeof(*work), link);
list_del(&work->link);
- if (!is_error_page(work->page))
- kvm_release_page_clean(work->page);
kmem_cache_free(async_pf_cache, work);
}
spin_unlock(&vcpu->async_pf.lock);
@@ -135,14 +133,12 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
list_del(&work->link);
spin_unlock(&vcpu->async_pf.lock);
- if (work->page)
+ if (work->got_page)
kvm_arch_async_page_ready(vcpu, work);
kvm_arch_async_page_present(vcpu, work);
list_del(&work->queue);
vcpu->async_pf.queued--;
- if (!is_error_page(work->page))
- kvm_release_page_clean(work->page);
kmem_cache_free(async_pf_cache, work);
}
}
@@ -165,7 +161,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
if (!work)
return 0;
- work->page = NULL;
+ work->got_page = false;
work->done = false;
work->vcpu = vcpu;
work->gva = gva;
@@ -206,7 +202,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
if (!work)
return -ENOMEM;
- work->page = KVM_ERR_PTR_BAD_PAGE;
+ work->got_page = false;
INIT_LIST_HEAD(&work->queue); /* for list_del to work */
spin_lock(&vcpu->async_pf.lock);
--
1.7.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [RFC][PATCH] Drop FOLL_GET in GUP when doing async_pf in kvm
2013-10-10 13:20 [RFC][PATCH] Drop FOLL_GET in GUP when doing async_pf in kvm chai wen
@ 2013-10-10 15:15 ` Gleb Natapov
2013-10-11 10:08 ` chai wen
0 siblings, 1 reply; 4+ messages in thread
From: Gleb Natapov @ 2013-10-10 15:15 UTC (permalink / raw)
To: chai wen
Cc: linux-kernel, pbonzini, tangchen, guz.fnst, zhangyanfei,
guijianfeng, chaiwen_0825
On Thu, Oct 10, 2013 at 09:20:15PM +0800, chai wen wrote:
> Hi Gleb
>
> Thanks for you explanation about async_pf in kvm.
> Page pinning is not mandatory in kvm async_pf processing and probably should
> be dropped later.this patch drops the FOLL_GET flag when doing GUP in async_pf
> and uses a bool (marking result of GUP) to replace the *page in kvm_async_pf
> structure to simplify some following async_pf check/clear processing.
Thanks, but the patch need to be on top of
git://git.kernel.org/pub/scm/virt/kvm/kvm.git queue branch.
Some more comment bellow.
> Thanks.
>
> Suggested-by: gleb@redhat.com
> Signed-off-by: chai wen <chaiw.fnst@cn.fujitsu.com>
> ---
> arch/x86/kvm/x86.c | 5 ++---
> include/linux/kvm_host.h | 2 +-
> virt/kvm/async_pf.c | 16 ++++++----------
> 3 files changed, 9 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index e5ca72a..0ff7d02 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -7282,8 +7282,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
> {
> int r;
>
> - if ((vcpu->arch.mmu.direct_map != work->arch.direct_map) ||
> - is_error_page(work->page))
> + if ((vcpu->arch.mmu.direct_map != work->arch.direct_map))
> return;
>
> r = kvm_mmu_reload(vcpu);
> @@ -7393,7 +7392,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
> struct x86_exception fault;
>
> trace_kvm_async_pf_ready(work->arch.token, work->gva);
> - if (is_error_page(work->page))
> + if (!work->got_page)
> work->arch.token = ~0; /* broadcast wakeup */
> else
> kvm_del_async_pf_gfn(vcpu, work->arch.gfn);
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 0fbbc7a..232a7d0 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -189,7 +189,7 @@ struct kvm_async_pf {
> gva_t gva;
> unsigned long addr;
> struct kvm_arch_async_pf arch;
> - struct page *page;
> + bool got_page;
I would call it wakeup_all.
> bool done;
> };
>
> diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
> index 8a39dda..0cafdc7 100644
> --- a/virt/kvm/async_pf.c
> +++ b/virt/kvm/async_pf.c
> @@ -56,7 +56,7 @@ void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu)
>
> static void async_pf_execute(struct work_struct *work)
> {
> - struct page *page = NULL;
> + long nrpages = 0;
> struct kvm_async_pf *apf =
> container_of(work, struct kvm_async_pf, work);
> struct mm_struct *mm = apf->mm;
> @@ -68,13 +68,13 @@ static void async_pf_execute(struct work_struct *work)
>
> use_mm(mm);
> down_read(&mm->mmap_sem);
> - get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL);
> + nrpages = get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL);
> up_read(&mm->mmap_sem);
> unuse_mm(mm);
>
> spin_lock(&vcpu->async_pf.lock);
> list_add_tail(&apf->link, &vcpu->async_pf.done);
> - apf->page = page;
> + apf->got_page = (1==nrpages);
Space before and after ==, but this is not needed at all. It does
not matter if GUP failed or not here. We need to wake up guest process
that is waiting on a page, so just set wakeup_all to false in kvm_setup_async_pf().
> apf->done = true;
> spin_unlock(&vcpu->async_pf.lock);
>
> @@ -114,8 +114,6 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
> list_entry(vcpu->async_pf.done.next,
> typeof(*work), link);
> list_del(&work->link);
> - if (!is_error_page(work->page))
> - kvm_release_page_clean(work->page);
> kmem_cache_free(async_pf_cache, work);
> }
> spin_unlock(&vcpu->async_pf.lock);
> @@ -135,14 +133,12 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
> list_del(&work->link);
> spin_unlock(&vcpu->async_pf.lock);
>
> - if (work->page)
> + if (work->got_page)
> kvm_arch_async_page_ready(vcpu, work);
> kvm_arch_async_page_present(vcpu, work);
>
> list_del(&work->queue);
> vcpu->async_pf.queued--;
> - if (!is_error_page(work->page))
> - kvm_release_page_clean(work->page);
> kmem_cache_free(async_pf_cache, work);
> }
> }
> @@ -165,7 +161,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
> if (!work)
> return 0;
>
> - work->page = NULL;
> + work->got_page = false;
Sp here do:
work->wakeup_all = false;
> work->done = false;
> work->vcpu = vcpu;
> work->gva = gva;
> @@ -206,7 +202,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
> if (!work)
> return -ENOMEM;
>
> - work->page = KVM_ERR_PTR_BAD_PAGE;
> + work->got_page = false;
And here:
work->wakeup_all = true;
> INIT_LIST_HEAD(&work->queue); /* for list_del to work */
>
> spin_lock(&vcpu->async_pf.lock);
> --
> 1.7.1
--
Gleb.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [RFC][PATCH] Drop FOLL_GET in GUP when doing async_pf in kvm
2013-10-10 15:15 ` Gleb Natapov
@ 2013-10-11 10:08 ` chai wen
2013-10-11 11:30 ` Gleb Natapov
0 siblings, 1 reply; 4+ messages in thread
From: chai wen @ 2013-10-11 10:08 UTC (permalink / raw)
To: Gleb Natapov
Cc: linux-kernel, pbonzini, tangchen, guz.fnst, zhangyanfei,
guijianfeng, chaiwen_0825
On 10/10/2013 11:15 PM, Gleb Natapov wrote:
> On Thu, Oct 10, 2013 at 09:20:15PM +0800, chai wen wrote:
>> Hi Gleb
>>
>> Thanks for you explanation about async_pf in kvm.
>> Page pinning is not mandatory in kvm async_pf processing and probably should
>> be dropped later.this patch drops the FOLL_GET flag when doing GUP in async_pf
>> and uses a bool (marking result of GUP) to replace the *page in kvm_async_pf
>> structure to simplify some following async_pf check/clear processing.
> Thanks, but the patch need to be on top of
> git://git.kernel.org/pub/scm/virt/kvm/kvm.git queue branch.
>
> Some more comment bellow.
>
>> Thanks.
>>
>> Suggested-by: gleb@redhat.com
>> Signed-off-by: chai wen <chaiw.fnst@cn.fujitsu.com>
>> ---
>> arch/x86/kvm/x86.c | 5 ++---
>> include/linux/kvm_host.h | 2 +-
>> virt/kvm/async_pf.c | 16 ++++++----------
>> 3 files changed, 9 insertions(+), 14 deletions(-)
>>
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index e5ca72a..0ff7d02 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -7282,8 +7282,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
>> {
>> int r;
>>
>> - if ((vcpu->arch.mmu.direct_map != work->arch.direct_map) ||
>> - is_error_page(work->page))
>> + if ((vcpu->arch.mmu.direct_map != work->arch.direct_map))
>> return;
>>
>> r = kvm_mmu_reload(vcpu);
>> @@ -7393,7 +7392,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
>> struct x86_exception fault;
>>
>> trace_kvm_async_pf_ready(work->arch.token, work->gva);
>> - if (is_error_page(work->page))
>> + if (!work->got_page)
>> work->arch.token = ~0; /* broadcast wakeup */
>> else
>> kvm_del_async_pf_gfn(vcpu, work->arch.gfn);
>> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
>> index 0fbbc7a..232a7d0 100644
>> --- a/include/linux/kvm_host.h
>> +++ b/include/linux/kvm_host.h
>> @@ -189,7 +189,7 @@ struct kvm_async_pf {
>> gva_t gva;
>> unsigned long addr;
>> struct kvm_arch_async_pf arch;
>> - struct page *page;
>> + bool got_page;
> I would call it wakeup_all.
>
>> bool done;
>> };
>>
>> diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
>> index 8a39dda..0cafdc7 100644
>> --- a/virt/kvm/async_pf.c
>> +++ b/virt/kvm/async_pf.c
>> @@ -56,7 +56,7 @@ void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu)
>>
>> static void async_pf_execute(struct work_struct *work)
>> {
>> - struct page *page = NULL;
>> + long nrpages = 0;
>> struct kvm_async_pf *apf =
>> container_of(work, struct kvm_async_pf, work);
>> struct mm_struct *mm = apf->mm;
>> @@ -68,13 +68,13 @@ static void async_pf_execute(struct work_struct *work)
>>
>> use_mm(mm);
>> down_read(&mm->mmap_sem);
>> - get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL);
>> + nrpages = get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL);
>> up_read(&mm->mmap_sem);
>> unuse_mm(mm);
>>
>> spin_lock(&vcpu->async_pf.lock);
>> list_add_tail(&apf->link, &vcpu->async_pf.done);
>> - apf->page = page;
>> + apf->got_page = (1==nrpages);
> Space before and after ==, but this is not needed at all. It does
> not matter if GUP failed or not here. We need to wake up guest process
> that is waiting on a page, so just set wakeup_all to false in kvm_setup_async_pf().
Hi Gleb
Thanks for you reply.
It does not matter if GUP failed or not here. But in the original logic of
kvm_arch_async_page_ready and kvm_arch_async_page_present, there is
is_error_page
checking in them. I am not sure wheher this ‘logic’ should be dropped.
And in kvm_async_pf_wakeup_all we used a dummy bad page pointer to generate
boradcast wakeup before. if wakeup_all(bool) is marking the result of
gup should it be false in this function ?
thanks
>
>> apf->done = true;
>> spin_unlock(&vcpu->async_pf.lock);
>>
>> @@ -114,8 +114,6 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
>> list_entry(vcpu->async_pf.done.next,
>> typeof(*work), link);
>> list_del(&work->link);
>> - if (!is_error_page(work->page))
>> - kvm_release_page_clean(work->page);
>> kmem_cache_free(async_pf_cache, work);
>> }
>> spin_unlock(&vcpu->async_pf.lock);
>> @@ -135,14 +133,12 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
>> list_del(&work->link);
>> spin_unlock(&vcpu->async_pf.lock);
>>
>> - if (work->page)
>> + if (work->got_page)
>> kvm_arch_async_page_ready(vcpu, work);
>> kvm_arch_async_page_present(vcpu, work);
>>
>> list_del(&work->queue);
>> vcpu->async_pf.queued--;
>> - if (!is_error_page(work->page))
>> - kvm_release_page_clean(work->page);
>> kmem_cache_free(async_pf_cache, work);
>> }
>> }
>> @@ -165,7 +161,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
>> if (!work)
>> return 0;
>>
>> - work->page = NULL;
>> + work->got_page = false;
> Sp here do:
> work->wakeup_all = false;
>
>> work->done = false;
>> work->vcpu = vcpu;
>> work->gva = gva;
>> @@ -206,7 +202,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
>> if (!work)
>> return -ENOMEM;
>>
>> - work->page = KVM_ERR_PTR_BAD_PAGE;
>> + work->got_page = false;
> And here:
> work->wakeup_all = true;
>> INIT_LIST_HEAD(&work->queue); /* for list_del to work */
>>
>> spin_lock(&vcpu->async_pf.lock);
>> --
>> 1.7.1
> --
> Gleb.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
--
Regards
chai wen
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [RFC][PATCH] Drop FOLL_GET in GUP when doing async_pf in kvm
2013-10-11 10:08 ` chai wen
@ 2013-10-11 11:30 ` Gleb Natapov
0 siblings, 0 replies; 4+ messages in thread
From: Gleb Natapov @ 2013-10-11 11:30 UTC (permalink / raw)
To: chai wen
Cc: linux-kernel, pbonzini, tangchen, guz.fnst, zhangyanfei,
guijianfeng, chaiwen_0825
On Fri, Oct 11, 2013 at 06:08:16PM +0800, chai wen wrote:
> On 10/10/2013 11:15 PM, Gleb Natapov wrote:
> > On Thu, Oct 10, 2013 at 09:20:15PM +0800, chai wen wrote:
> >> Hi Gleb
> >>
> >> Thanks for you explanation about async_pf in kvm.
> >> Page pinning is not mandatory in kvm async_pf processing and probably should
> >> be dropped later.this patch drops the FOLL_GET flag when doing GUP in async_pf
> >> and uses a bool (marking result of GUP) to replace the *page in kvm_async_pf
> >> structure to simplify some following async_pf check/clear processing.
> > Thanks, but the patch need to be on top of
> > git://git.kernel.org/pub/scm/virt/kvm/kvm.git queue branch.
> >
> > Some more comment bellow.
> >
> >> Thanks.
> >>
> >> Suggested-by: gleb@redhat.com
> >> Signed-off-by: chai wen <chaiw.fnst@cn.fujitsu.com>
> >> ---
> >> arch/x86/kvm/x86.c | 5 ++---
> >> include/linux/kvm_host.h | 2 +-
> >> virt/kvm/async_pf.c | 16 ++++++----------
> >> 3 files changed, 9 insertions(+), 14 deletions(-)
> >>
> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> >> index e5ca72a..0ff7d02 100644
> >> --- a/arch/x86/kvm/x86.c
> >> +++ b/arch/x86/kvm/x86.c
> >> @@ -7282,8 +7282,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
> >> {
> >> int r;
> >>
> >> - if ((vcpu->arch.mmu.direct_map != work->arch.direct_map) ||
> >> - is_error_page(work->page))
> >> + if ((vcpu->arch.mmu.direct_map != work->arch.direct_map))
> >> return;
> >>
> >> r = kvm_mmu_reload(vcpu);
> >> @@ -7393,7 +7392,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
> >> struct x86_exception fault;
> >>
> >> trace_kvm_async_pf_ready(work->arch.token, work->gva);
> >> - if (is_error_page(work->page))
> >> + if (!work->got_page)
> >> work->arch.token = ~0; /* broadcast wakeup */
> >> else
> >> kvm_del_async_pf_gfn(vcpu, work->arch.gfn);
> >> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> >> index 0fbbc7a..232a7d0 100644
> >> --- a/include/linux/kvm_host.h
> >> +++ b/include/linux/kvm_host.h
> >> @@ -189,7 +189,7 @@ struct kvm_async_pf {
> >> gva_t gva;
> >> unsigned long addr;
> >> struct kvm_arch_async_pf arch;
> >> - struct page *page;
> >> + bool got_page;
> > I would call it wakeup_all.
> >
> >> bool done;
> >> };
> >>
> >> diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
> >> index 8a39dda..0cafdc7 100644
> >> --- a/virt/kvm/async_pf.c
> >> +++ b/virt/kvm/async_pf.c
> >> @@ -56,7 +56,7 @@ void kvm_async_pf_vcpu_init(struct kvm_vcpu *vcpu)
> >>
> >> static void async_pf_execute(struct work_struct *work)
> >> {
> >> - struct page *page = NULL;
> >> + long nrpages = 0;
> >> struct kvm_async_pf *apf =
> >> container_of(work, struct kvm_async_pf, work);
> >> struct mm_struct *mm = apf->mm;
> >> @@ -68,13 +68,13 @@ static void async_pf_execute(struct work_struct *work)
> >>
> >> use_mm(mm);
> >> down_read(&mm->mmap_sem);
> >> - get_user_pages(current, mm, addr, 1, 1, 0, &page, NULL);
> >> + nrpages = get_user_pages(current, mm, addr, 1, 1, 0, NULL, NULL);
> >> up_read(&mm->mmap_sem);
> >> unuse_mm(mm);
> >>
> >> spin_lock(&vcpu->async_pf.lock);
> >> list_add_tail(&apf->link, &vcpu->async_pf.done);
> >> - apf->page = page;
> >> + apf->got_page = (1==nrpages);
> > Space before and after ==, but this is not needed at all. It does
> > not matter if GUP failed or not here. We need to wake up guest process
> > that is waiting on a page, so just set wakeup_all to false in kvm_setup_async_pf().
> Hi Gleb
> Thanks for you reply.
> It does not matter if GUP failed or not here. But in the original logic of
> kvm_arch_async_page_ready and kvm_arch_async_page_present, there is
> is_error_page
> checking in them. I am not sure wheher this ‘logic’ should be dropped.
> And in kvm_async_pf_wakeup_all we used a dummy bad page pointer to generate
> boradcast wakeup before. if wakeup_all(bool) is marking the result of
> gup should it be false in this function ?
>
is_error_page() does not consider NULL as error value.
> thanks
> >
> >> apf->done = true;
> >> spin_unlock(&vcpu->async_pf.lock);
> >>
> >> @@ -114,8 +114,6 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
> >> list_entry(vcpu->async_pf.done.next,
> >> typeof(*work), link);
> >> list_del(&work->link);
> >> - if (!is_error_page(work->page))
> >> - kvm_release_page_clean(work->page);
> >> kmem_cache_free(async_pf_cache, work);
> >> }
> >> spin_unlock(&vcpu->async_pf.lock);
> >> @@ -135,14 +133,12 @@ void kvm_check_async_pf_completion(struct kvm_vcpu *vcpu)
> >> list_del(&work->link);
> >> spin_unlock(&vcpu->async_pf.lock);
> >>
> >> - if (work->page)
> >> + if (work->got_page)
> >> kvm_arch_async_page_ready(vcpu, work);
> >> kvm_arch_async_page_present(vcpu, work);
> >>
> >> list_del(&work->queue);
> >> vcpu->async_pf.queued--;
> >> - if (!is_error_page(work->page))
> >> - kvm_release_page_clean(work->page);
> >> kmem_cache_free(async_pf_cache, work);
> >> }
> >> }
> >> @@ -165,7 +161,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
> >> if (!work)
> >> return 0;
> >>
> >> - work->page = NULL;
> >> + work->got_page = false;
> > Sp here do:
> > work->wakeup_all = false;
> >
> >> work->done = false;
> >> work->vcpu = vcpu;
> >> work->gva = gva;
> >> @@ -206,7 +202,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
> >> if (!work)
> >> return -ENOMEM;
> >>
> >> - work->page = KVM_ERR_PTR_BAD_PAGE;
> >> + work->got_page = false;
> > And here:
> > work->wakeup_all = true;
> >> INIT_LIST_HEAD(&work->queue); /* for list_del to work */
> >>
> >> spin_lock(&vcpu->async_pf.lock);
> >> --
> >> 1.7.1
> > --
> > Gleb.
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at http://www.tux.org/lkml/
> >
>
>
> --
> Regards
>
> chai wen
>
--
Gleb.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2013-10-11 11:30 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-10-10 13:20 [RFC][PATCH] Drop FOLL_GET in GUP when doing async_pf in kvm chai wen
2013-10-10 15:15 ` Gleb Natapov
2013-10-11 10:08 ` chai wen
2013-10-11 11:30 ` Gleb Natapov
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