From: Christoph Hellwig <hch@lst.de>
To: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: netdev@vger.kernel.org, iommu@lists.linux-foundation.org,
"Björn Töpel" <bjorn.topel@intel.com>,
"Christoph Hellwig" <hch@lst.de>
Subject: Re: the XSK buffer pool needs be to reverted
Date: Sat, 27 Jun 2020 09:02:36 +0200 [thread overview]
Message-ID: <20200627070236.GA11854@lst.de> (raw)
In-Reply-To: <20200626205412.xfe4lywdbmh3kmri@bsd-mbp>
On Fri, Jun 26, 2020 at 01:54:12PM -0700, Jonathan Lemon wrote:
> On Fri, Jun 26, 2020 at 09:47:25AM +0200, Christoph Hellwig wrote:
> >
> > Note that this is somewhat urgent, as various of the APIs that the code
> > is abusing are slated to go away for Linux 5.9, so this addition comes
> > at a really bad time.
>
> Could you elaborate on what is upcoming here?
Moving all these calls out of line, and adding a bypass flag to avoid
the indirect function call for IOMMUs in direct mapped mode.
> Also, on a semi-related note, are there limitations on how many pages
> can be left mapped by the iommu? Some of the page pool work involves
> leaving the pages mapped instead of constantly mapping/unmapping them.
There are, but I think for all modern IOMMUs they are so big that they
don't matter. Maintaines of the individual IOMMU drivers might know
more.
> On a heavily loaded box with iommu enabled, it seems that quite often
> there is contention on the iova_lock. Are there known issues in this
> area?
I'll have to defer to the IOMMU maintainers, and for that you'll need
to say what code you are using. Current mainlaine doesn't even have
an iova_lock anywhere.
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WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: "Christoph Hellwig" <hch@lst.de>,
"Björn Töpel" <bjorn.topel@intel.com>,
"Alexander Duyck" <alexander.duyck@gmail.com>,
netdev@vger.kernel.org, iommu@lists.linux-foundation.org
Subject: Re: the XSK buffer pool needs be to reverted
Date: Sat, 27 Jun 2020 09:02:36 +0200 [thread overview]
Message-ID: <20200627070236.GA11854@lst.de> (raw)
In-Reply-To: <20200626205412.xfe4lywdbmh3kmri@bsd-mbp>
On Fri, Jun 26, 2020 at 01:54:12PM -0700, Jonathan Lemon wrote:
> On Fri, Jun 26, 2020 at 09:47:25AM +0200, Christoph Hellwig wrote:
> >
> > Note that this is somewhat urgent, as various of the APIs that the code
> > is abusing are slated to go away for Linux 5.9, so this addition comes
> > at a really bad time.
>
> Could you elaborate on what is upcoming here?
Moving all these calls out of line, and adding a bypass flag to avoid
the indirect function call for IOMMUs in direct mapped mode.
> Also, on a semi-related note, are there limitations on how many pages
> can be left mapped by the iommu? Some of the page pool work involves
> leaving the pages mapped instead of constantly mapping/unmapping them.
There are, but I think for all modern IOMMUs they are so big that they
don't matter. Maintaines of the individual IOMMU drivers might know
more.
> On a heavily loaded box with iommu enabled, it seems that quite often
> there is contention on the iova_lock. Are there known issues in this
> area?
I'll have to defer to the IOMMU maintainers, and for that you'll need
to say what code you are using. Current mainlaine doesn't even have
an iova_lock anywhere.
next prev parent reply other threads:[~2020-06-27 7:02 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-26 7:47 the XSK buffer pool needs be to reverted Christoph Hellwig
2020-06-26 7:47 ` Christoph Hellwig
2020-06-26 12:22 ` Björn Töpel
2020-06-26 12:22 ` Björn Töpel
2020-06-26 12:41 ` Christoph Hellwig
2020-06-26 12:41 ` Christoph Hellwig
2020-06-26 12:45 ` Björn Töpel
2020-06-26 12:45 ` Björn Töpel
2020-06-26 20:54 ` Jonathan Lemon
2020-06-26 20:54 ` Jonathan Lemon
2020-06-27 7:02 ` Christoph Hellwig [this message]
2020-06-27 7:02 ` Christoph Hellwig
2020-06-29 13:15 ` Robin Murphy
2020-06-29 13:15 ` Robin Murphy
2020-06-30 19:08 ` Jonathan Lemon
2020-06-30 19:08 ` Jonathan Lemon
2020-07-01 9:46 ` Robin Murphy
2020-07-01 9:46 ` Robin Murphy
2020-07-06 19:59 ` Jonathan Lemon
2020-07-06 19:59 ` Jonathan Lemon
2020-07-07 17:35 ` Robin Murphy
2020-07-07 17:35 ` Robin Murphy
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