All of lore.kernel.org
 help / color / mirror / Atom feed
From: Leon Romanovsky <leon@kernel.org>
To: Mostafa Saleh <smostafa@google.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Easwar Hariharan <eahariha@linux.microsoft.com>,
	linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
	Jason Gunthorpe <jgg@nvidia.com>
Subject: Re: [PATCH v2 2/2] dma: add IOMMU static calls with clear default ops
Date: Mon, 29 Jul 2024 17:07:36 +0300	[thread overview]
Message-ID: <20240729140736.GC5669@unreal> (raw)
In-Reply-To: <ZqeN6MP4o2JNLcUz@google.com>

On Mon, Jul 29, 2024 at 12:41:12PM +0000, Mostafa Saleh wrote:
> Hi Leon,
> 
> On Wed, Jul 17, 2024 at 03:37:11PM +0300, Leon Romanovsky wrote:
> > From: Leon Romanovsky <leonro@nvidia.com>
> > 
> > Most of the arch DMA ops (which often, but not  always, involve
> > some sort of IOMMU) are using the same DMA operations. These DMA
> > operations are default ones implemented in drivers/iomem/dma-iommu.c.
> > 
> > So let's make sure to call them directly without need to perform function
> > pointers dereference.
> 
> Just out of curiosity, is there any observed improvement from that?
> As from my experience the DMA-IOMMU path is quite dense so it won't
> be senstive to such micro-optimizations.

DMA-IOMMU no, but NVMe driver which uses DMA-API in datapath will
potentially benefit from this change.

I personally used this change to simplify my "DMA split ... " series [1].

[1] https://git.kernel.org/pub/scm/linux/kernel/git/leon/linux-rdma.git/log/?h=dma-split-v2

Thanks

  reply	other threads:[~2024-07-29 14:07 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-17 12:37 [PATCH v2 0/2] DMA IOMMU static calls Leon Romanovsky
2024-07-17 12:37 ` [PATCH v2 1/2] dma: call unconditionally to unmap_page and unmap_sg callbacks Leon Romanovsky
2024-07-18  3:49   ` Christoph Hellwig
2024-07-18  6:33     ` Leon Romanovsky
2024-07-17 12:37 ` [PATCH v2 2/2] dma: add IOMMU static calls with clear default ops Leon Romanovsky
2024-07-18  3:48   ` Christoph Hellwig
2024-07-18  7:04     ` Leon Romanovsky
2024-07-18 12:30       ` Christoph Hellwig
2024-07-18 13:26         ` Leon Romanovsky
2024-07-29 12:41   ` Mostafa Saleh
2024-07-29 14:07     ` Leon Romanovsky [this message]
2024-07-29 17:15     ` Christoph Hellwig
2024-07-30  8:16       ` Leon Romanovsky
2024-07-30 15:26         ` Christoph Hellwig

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=20240729140736.GC5669@unreal \
    --to=leon@kernel.org \
    --cc=eahariha@linux.microsoft.com \
    --cc=hch@lst.de \
    --cc=iommu@lists.linux.dev \
    --cc=jgg@nvidia.com \
    --cc=joro@8bytes.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=m.szyprowski@samsung.com \
    --cc=robin.murphy@arm.com \
    --cc=smostafa@google.com \
    --cc=will@kernel.org \
    /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.