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Date: Sun, 5 May 2024 17:29:18 -0700
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Subject: Re: [RFC PATCH net-next v8 07/14] page_pool: devmem support
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To: Christoph Hellwig <hch@infradead.org>
Cc: Mina Almasry <almasrymina@google.com>, netdev@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
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References: <20240403002053.2376017-1-almasrymina@google.com>
 <20240403002053.2376017-8-almasrymina@google.com>
 <8357256a-f0e9-4640-8fec-23341fc607db@davidwei.uk>
 <ZjH1hO8qJgOqNKub@infradead.org>
From: David Wei <dw@davidwei.uk>
In-Reply-To: <ZjH1hO8qJgOqNKub@infradead.org>
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On 2024-05-01 00:55, Christoph Hellwig wrote:
> On Fri, Apr 26, 2024 at 05:17:52PM -0700, David Wei wrote:
>> On 2024-04-02 5:20 pm, Mina Almasry wrote:
>>> @@ -69,20 +106,26 @@ net_iov_binding(const struct net_iov *niov)
>>>   */
>>>  typedef unsigned long __bitwise netmem_ref;
>>>  
>>> +static inline bool netmem_is_net_iov(const netmem_ref netmem)
>>> +{
>>> +#if defined(CONFIG_PAGE_POOL) && defined(CONFIG_DMA_SHARED_BUFFER)
>>
>> I am guessing you added this to try and speed up the fast path? It's
>> overly restrictive for us since we do not need dmabuf necessarily. I
>> spent a bit too much time wondering why things aren't working only to
>> find this :(
> 
> So what else do you need?  I was assured last round that nothing but
> dmabuf and potentially the huge page case (that really just is the page
> provider) would get added.

I'm using userspace memory so having this gated behind
CONFIG_DMA_SHARED_BUFFER doesn't make sense for us.

> 
>>
> ---end quoted text---