All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jason Gunthorpe <jgg@nvidia.com>
To: Pranjal Shrivastava <praan@google.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	asahi@lists.linux.dev,
	Baolin Wang <baolin.wang@linux.alibaba.com>,
	iommu@lists.linux.dev, Janne Grunau <j@jannau.net>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Joerg Roedel <joro@8bytes.org>,
	Jean-Philippe Brucker <jpb@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	linux-riscv@lists.infradead.org, linux-sunxi@lists.linux.dev,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Neal Gompa <neal@gompa.dev>, Orson Zhai <orsonzhai@gmail.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <pjw@kernel.org>,
	Samuel Holland <samuel@sholland.org>,
	Sven Peter <sven@kernel.org>,
	virtualization@lists.linux.dev, Chen-Yu Tsai <wens@kernel.org>,
	Will Deacon <will@kernel.org>, Yong Wu <yong.wu@mediatek.com>,
	Chunyan Zhang <zhang.lyra@gmail.com>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>,
	Joerg Roedel <joerg.roedel@amd.com>,
	Jon Hunter <jonathanh@nvidia.com>,
	patches@lists.linux.dev, Robin Murphy <robin.murphy@arm.com>,
	Samiullah Khawaja <skhawaja@google.com>,
	stable@vger.kernel.org, Vasant Hegde <vasant.hegde@amd.com>
Subject: Re: [PATCH] iommu: Always fill in gather when unmapping
Date: Wed, 1 Apr 2026 09:58:50 -0300	[thread overview]
Message-ID: <20260401125850.GZ310919@nvidia.com> (raw)
In-Reply-To: <ac0AKyvHMYHlqL5i@google.com>

On Wed, Apr 01, 2026 at 11:23:23AM +0000, Pranjal Shrivastava wrote:

> I was wondering if, as a longer-term direction, having an explicit flag
> for these drivers to indicate they always require a sync would be a
> cleaner way to handle this than the trivial population?

My first thought was to just set the gather to start=0,end=ULONG_MAX
but it turned out to be trivial to just set the right gather parameters
and it looks like it is basically the same cost..

Adding a flag would mean we have to test the flag on the other case
where we don't use this flow, which doesn't seem good either.

Jason

WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@nvidia.com>
To: Pranjal Shrivastava <praan@google.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	asahi@lists.linux.dev,
	Baolin Wang <baolin.wang@linux.alibaba.com>,
	iommu@lists.linux.dev, Janne Grunau <j@jannau.net>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Joerg Roedel <joro@8bytes.org>,
	Jean-Philippe Brucker <jpb@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	linux-riscv@lists.infradead.org, linux-sunxi@lists.linux.dev,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Neal Gompa <neal@gompa.dev>, Orson Zhai <orsonzhai@gmail.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <pjw@kernel.org>,
	Samuel Holland <samuel@sholland.org>,
	Sven Peter <sven@kernel.org>,
	virtualization@lists.linux.dev, Chen-Yu Tsai <wens@kernel.org>,
	Will Deacon <will@kernel.org>, Yong Wu <yong.wu@mediatek.com>,
	Chunyan Zhang <zhang.lyra@gmail.com>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>,
	Joerg Roedel <joerg.roedel@amd.com>,
	Jon Hunter <jonathanh@nvidia.com>,
	patches@lists.linux.dev, Robin Murphy <robin.murphy@arm.com>,
	Samiullah Khawaja <skhawaja@google.com>,
	stable@vger.kernel.org, Vasant Hegde <vasant.hegde@amd.com>
Subject: Re: [PATCH] iommu: Always fill in gather when unmapping
Date: Wed, 1 Apr 2026 09:58:50 -0300	[thread overview]
Message-ID: <20260401125850.GZ310919@nvidia.com> (raw)
In-Reply-To: <ac0AKyvHMYHlqL5i@google.com>

On Wed, Apr 01, 2026 at 11:23:23AM +0000, Pranjal Shrivastava wrote:

> I was wondering if, as a longer-term direction, having an explicit flag
> for these drivers to indicate they always require a sync would be a
> cleaner way to handle this than the trivial population?

My first thought was to just set the gather to start=0,end=ULONG_MAX
but it turned out to be trivial to just set the right gather parameters
and it looks like it is basically the same cost..

Adding a flag would mean we have to test the flag on the other case
where we don't use this flow, which doesn't seem good either.

Jason

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply	other threads:[~2026-04-01 12:58 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-31 19:56 [PATCH] iommu: Always fill in gather when unmapping Jason Gunthorpe
2026-03-31 19:56 ` Jason Gunthorpe
2026-04-01 10:40 ` Jon Hunter
2026-04-01 10:40   ` Jon Hunter
2026-04-01 11:23 ` Pranjal Shrivastava
2026-04-01 11:23   ` Pranjal Shrivastava
2026-04-01 12:58   ` Jason Gunthorpe [this message]
2026-04-01 12:58     ` Jason Gunthorpe
2026-04-01 16:33 ` Robin Murphy
2026-04-01 16:33   ` Robin Murphy
2026-04-01 17:36   ` Jason Gunthorpe
2026-04-01 17:36     ` Jason Gunthorpe
2026-04-02 18:11     ` Robin Murphy
2026-04-02 18:11       ` Robin Murphy
2026-04-02 22:51       ` Jason Gunthorpe
2026-04-02 22:51         ` Jason Gunthorpe
2026-04-08  8:42         ` Jon Hunter
2026-04-08  8:42           ` Jon Hunter
2026-04-08 13:34           ` Jon Hunter
2026-04-08 13:34             ` Jon Hunter

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260401125850.GZ310919@nvidia.com \
    --to=jgg@nvidia.com \
    --cc=alex@ghiti.fr \
    --cc=angelogioacchino.delregno@collabora.com \
    --cc=aou@eecs.berkeley.edu \
    --cc=asahi@lists.linux.dev \
    --cc=baolin.wang@linux.alibaba.com \
    --cc=baolu.lu@linux.intel.com \
    --cc=iommu@lists.linux.dev \
    --cc=j@jannau.net \
    --cc=janusz.krzysztofik@linux.intel.com \
    --cc=jernej.skrabec@gmail.com \
    --cc=joerg.roedel@amd.com \
    --cc=jonathanh@nvidia.com \
    --cc=joro@8bytes.org \
    --cc=jpb@kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=linux-sunxi@lists.linux.dev \
    --cc=matthias.bgg@gmail.com \
    --cc=neal@gompa.dev \
    --cc=orsonzhai@gmail.com \
    --cc=palmer@dabbelt.com \
    --cc=patches@lists.linux.dev \
    --cc=pjw@kernel.org \
    --cc=praan@google.com \
    --cc=robin.murphy@arm.com \
    --cc=samuel@sholland.org \
    --cc=skhawaja@google.com \
    --cc=stable@vger.kernel.org \
    --cc=sven@kernel.org \
    --cc=vasant.hegde@amd.com \
    --cc=virtualization@lists.linux.dev \
    --cc=wens@kernel.org \
    --cc=will@kernel.org \
    --cc=yong.wu@mediatek.com \
    --cc=zhang.lyra@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.