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Subject: Re: [RFC] /dev/ioasid uAPI proposal
To:     Jason Gunthorpe <jgg@nvidia.com>
Cc:     "Tian, Kevin" <kevin.tian@intel.com>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Liu Yi L <yi.l.liu@linux.intel.com>,
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        Jonathan Corbet <corbet@lwn.net>,
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        LKML <linux-kernel@vger.kernel.org>,
        "Alex Williamson (alex.williamson@redhat.com)\"\"" 
        <alex.williamson@redhat.com>, David Woodhouse <dwmw2@infradead.org>
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From:   Jason Wang <jasowang@redhat.com>
Message-ID: <f4d70f28-4bd6-5315-d7c7-0a509e4f1d1d@redhat.com>
Date:   Thu, 10 Jun 2021 10:00:01 +0800
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?? 2021/6/8 ????9:20, Jason Gunthorpe д??:
> On Tue, Jun 08, 2021 at 09:10:42AM +0800, Jason Wang wrote:
>
>> Well, this sounds like a re-invention of io_uring which has already worked
>> for multifds.
> How so? io_uring is about sending work to the kernel, not getting
> structued events back?


Actually it can. Userspace can poll multiple fds via preparing multiple 
sqes with IORING_OP_ADD flag.


>
> It is more like one of the perf rings


This means another ring and we need introduce ioctl() to add or remove 
ioasids from the poll. And it still need a kind of fallback like a list 
if the ring is full.

Thanks


>
> Jason
>