Again in proper SVA it should be quite unlikely to take a fault caused
by something like migration, on the same likelyhood as the CPU. If
things are faulting so much this is a problem then I think it is a
system level problem with doing too much page motion.
My point is that single one SVA appl
ubject: Re: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory
> pin
>
> On Tue, Feb 09, 2021 at 10:22:47PM +, Song Bao Hua (Barry Song) wrote:
>
> > The problem is that SVA declares we can use any memory of a process
> > to do I/O. And in real scenarios, we
On Tue, Feb 09, 2021 at 08:20:18PM +0800, Zhou Wang wrote:
> Agree, will add it in next version.
No, don't do another version. Jason is right, this approach is wrong.
The point of SVA is that it doesn't require the application to do
anything special. If jitter from too-frequent page migration is
On Tue, Feb 09, 2021 at 10:22:47PM +, Song Bao Hua (Barry Song) wrote:
> The problem is that SVA declares we can use any memory of a process
> to do I/O. And in real scenarios, we are unable to customize most
> applications to make them use the pool. So we are looking for some
> extension gene
ubject: Re: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory
> pin
>
> On Tue, Feb 09, 2021 at 03:01:42AM +, Song Bao Hua (Barry Song) wrote:
>
> > On the other hand, wouldn't it be the benefit of hardware accelerators
> > to have a lower and mo
On Tue, Feb 09, 2021 at 03:01:42AM +, Song Bao Hua (Barry Song) wrote:
> On the other hand, wouldn't it be the benefit of hardware accelerators
> to have a lower and more stable latency zip/encryption than CPU?
No, I don't think so.
If this is an important problem then it should apply equall
On 2021/2/9 20:01, Greg KH wrote:
> On Tue, Feb 09, 2021 at 07:58:15PM +0800, Zhou Wang wrote:
>> On 2021/2/9 17:37, Greg KH wrote:
>>> On Tue, Feb 09, 2021 at 05:17:46PM +0800, Zhou Wang wrote:
On 2021/2/8 6:02, Andy Lutomirski wrote:
>
>
>> On Feb 7, 2021, at 12:31 AM, Zhou Wang
On Tue, Feb 09, 2021 at 07:58:15PM +0800, Zhou Wang wrote:
> On 2021/2/9 17:37, Greg KH wrote:
> > On Tue, Feb 09, 2021 at 05:17:46PM +0800, Zhou Wang wrote:
> >> On 2021/2/8 6:02, Andy Lutomirski wrote:
> >>>
> >>>
> On Feb 7, 2021, at 12:31 AM, Zhou Wang wrote:
>
> SVA(share virt
On 2021/2/9 17:37, Greg KH wrote:
> On Tue, Feb 09, 2021 at 05:17:46PM +0800, Zhou Wang wrote:
>> On 2021/2/8 6:02, Andy Lutomirski wrote:
>>>
>>>
On Feb 7, 2021, at 12:31 AM, Zhou Wang wrote:
SVA(share virtual address) offers a way for device to share process
virtual
ad
On Tue, Feb 09, 2021 at 05:17:46PM +0800, Zhou Wang wrote:
> On 2021/2/8 6:02, Andy Lutomirski wrote:
> >
> >
> >> On Feb 7, 2021, at 12:31 AM, Zhou Wang wrote:
> >>
> >> SVA(share virtual address) offers a way for device to share process
> >> virtual
> >> address space safely, which makes mor
On 2021/2/8 5:51, Arnd Bergmann wrote:
> On Sun, Feb 7, 2021 at 9:18 AM Zhou Wang wrote:
>
>> diff --git a/arch/arm64/include/asm/unistd32.h
>> b/arch/arm64/include/asm/unistd32.h
>> index cccfbbe..3f49529 100644
>> --- a/arch/arm64/include/asm/unistd32.h
>> +++ b/arch/arm64/include/asm/unistd32
On 2021/2/8 6:02, Andy Lutomirski wrote:
>
>
>> On Feb 7, 2021, at 12:31 AM, Zhou Wang wrote:
>>
>> SVA(share virtual address) offers a way for device to share process virtual
>> address space safely, which makes more convenient for user space device
>> driver coding. However, IO page faults ma
gt; ;
> > > gre...@linuxfoundation.org; Song Bao Hua (Barry Song)
> > > ; kevin.t...@intel.com;
> > > jean-phili...@linaro.org; eric.au...@redhat.com; Liguozhu (Kenneth)
> > > ; zhangfei@linaro.org; chensihang (A)
> > >
> > > Subject: Re:
...@linaro.org; eric.au...@redhat.com; Liguozhu (Kenneth)
> > ; zhangfei....@linaro.org; chensihang (A)
> >
> > Subject: Re: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory
> > pin
> >
> > On Mon, Feb 08, 2021 at 09:14:28AM +0100, David Hildenbran
linux...@kvack.org;
> >> linux-arm-ker...@lists.infradead.org; linux-...@vger.kernel.org; Andrew
> >> Morton ; Alexander Viro
> ;
> >> gre...@linuxfoundation.org; j...@ziepe.ca; kevin.t...@intel.com;
> >> jean-phili...@linaro.org; eric.au...@redhat.com; Liguozhu (Ke
; Subject: Re: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory
> pin
>
> On Mon, Feb 08, 2021 at 09:14:28AM +0100, David Hildenbrand wrote:
>
> > People are constantly struggling with the effects of long term pinnings
> > under user space control, like we al
On Mon, Feb 08, 2021 at 09:14:28AM +0100, David Hildenbrand wrote:
> People are constantly struggling with the effects of long term pinnings
> under user space control, like we already have with vfio and RDMA.
>
> And here we are, adding yet another, easier way to mess with core MM in the
> same
(Kenneth)
; zhangfei@linaro.org; chensihang (A)
Subject: Re: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory
pin
On 08.02.21 03:27, Song Bao Hua (Barry Song) wrote:
-Original Message-
From: owner-linux...@kvack.org [mailto:owner-linux...@kvack.org] On Behalf
Of
Matthew
Kenneth)
> ; zhangfei@linaro.org; chensihang (A)
>
> Subject: Re: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory
> pin
>
> On 08.02.21 03:27, Song Bao Hua (Barry Song) wrote:
> >
> >
> >> -Original Message-
> >> From: ow
@linaro.org; chensihang (A)
Subject: Re: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory
pin
On Sun, Feb 07, 2021 at 10:24:28PM +, Song Bao Hua (Barry Song) wrote:
In high-performance I/O cases, accelerators might want to perform
I/O on a memory without IO page faults which can
On 07.02.21 09:18, Zhou Wang wrote:
SVA(share virtual address) offers a way for device to share process virtual
address space safely, which makes more convenient for user space device
driver coding. However, IO page faults may happen when doing DMA
operations. As the latency of IO page fault is r
(A)
>
> Subject: RE: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory
> pin
>
> On Sun, 7 Feb 2021, Song Bao Hua (Barry Song) wrote:
>
> > NUMA balancer is just one of many reasons for page migration. Even one
> > simple alloc_pages() can cause memory
angfei@linaro.org; chensihang (A)
>
> Subject: Re: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory
> pin
>
> On Sun, Feb 07, 2021 at 10:24:28PM +, Song Bao Hua (Barry Song) wrote:
> > > > In high-performance I/O cases, accelerators might want to perform
On Sun, 7 Feb 2021, Song Bao Hua (Barry Song) wrote:
> NUMA balancer is just one of many reasons for page migration. Even one
> simple alloc_pages() can cause memory migration in just single NUMA
> node or UMA system.
>
> The other reasons for page migration include but are not limited to:
> * me
On Sun, Feb 07, 2021 at 10:24:28PM +, Song Bao Hua (Barry Song) wrote:
> > > In high-performance I/O cases, accelerators might want to perform
> > > I/O on a memory without IO page faults which can result in dramatically
> > > increased latency. Current memory related APIs could not achieve thi
> On Feb 7, 2021, at 12:31 AM, Zhou Wang wrote:
>
> SVA(share virtual address) offers a way for device to share process virtual
> address space safely, which makes more convenient for user space device
> driver coding. However, IO page faults may happen when doing DMA
> operations. As the late
ubject: Re: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory
> pin
>
> On Sun, Feb 07, 2021 at 04:18:03PM +0800, Zhou Wang wrote:
> > SVA(share virtual address) offers a way for device to share process virtual
> > address space safely, which makes more convenient for
On Sun, Feb 7, 2021 at 9:18 AM Zhou Wang wrote:
> diff --git a/arch/arm64/include/asm/unistd32.h
> b/arch/arm64/include/asm/unistd32.h
> index cccfbbe..3f49529 100644
> --- a/arch/arm64/include/asm/unistd32.h
> +++ b/arch/arm64/include/asm/unistd32.h
> @@ -891,6 +891,8 @@ __SYSCALL(__NR_faccessa
On Sun, Feb 07, 2021 at 04:18:03PM +0800, Zhou Wang wrote:
> SVA(share virtual address) offers a way for device to share process virtual
> address space safely, which makes more convenient for user space device
> driver coding. However, IO page faults may happen when doing DMA
> operations. As the
SVA(share virtual address) offers a way for device to share process virtual
address space safely, which makes more convenient for user space device
driver coding. However, IO page faults may happen when doing DMA
operations. As the latency of IO page fault is relatively big, DMA
performance will be
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