From: Christoph Hellwig <hch@lst.de>
To: Robin Murphy <robin.murphy@arm.com>
Cc: "Petr Tesařík" <petr@tesarici.cz>,
"Alexander Lobakin" <aleksander.lobakin@intel.com>,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Christoph Hellwig" <hch@lst.de>,
"Marek Szyprowski" <m.szyprowski@samsung.com>,
"Joerg Roedel" <joro@8bytes.org>, "Will Deacon" <will@kernel.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"Magnus Karlsson" <magnus.karlsson@intel.com>,
"Maciej Fijalkowski" <maciej.fijalkowski@intel.com>,
"Alexander Duyck" <alexanderduyck@fb.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 2/7] dma: avoid expensive redundant calls for sync operations
Date: Mon, 29 Jan 2024 07:09:47 +0100 [thread overview]
Message-ID: <20240129060947.GC19258@lst.de> (raw)
In-Reply-To: <1c62d388-a600-40d8-b386-15841cb1af95@arm.com>
On Fri, Jan 26, 2024 at 07:13:05PM +0000, Robin Murphy wrote:
>> Can we have a comment that states this assumption along with the flag?
>> Because when it breaks, it will keep someone cursing for days why DMA
>> sometimes fails on their device before they find out it's not synced.
>> And then wondering why the code makes such silly assumptions...
>
> Indeed, apologies if it wasn't totally clear, but I really was implying a
> literal "may skip sync if coherent and not using SWIOTLB (which matches
> dma-direct)" flag, documented as such, and not trying to dress it up as
> anything more generic. I just can't suggest a suitably concise name for
> that of the top of my head... :)
Yes, that seems like the right way to go.
next prev parent reply other threads:[~2024-01-29 6:09 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-26 13:54 [PATCH net-next 0/7] dma: skip calling no-op sync ops when possible Alexander Lobakin
2024-01-26 13:54 ` [PATCH net-next 1/7] dma: compile-out DMA sync op calls when not used Alexander Lobakin
2024-01-29 6:11 ` Christoph Hellwig
2024-01-29 11:07 ` Alexander Lobakin
2024-01-29 12:15 ` Robin Murphy
2024-01-31 16:52 ` Simon Horman
2024-01-31 17:14 ` Robin Murphy
2024-01-26 13:54 ` [PATCH net-next 2/7] dma: avoid expensive redundant calls for sync operations Alexander Lobakin
2024-01-26 15:48 ` Robin Murphy
2024-01-26 16:45 ` Alexander Lobakin
2024-01-26 17:21 ` Robin Murphy
2024-01-26 18:48 ` Petr Tesařík
2024-01-26 19:13 ` Robin Murphy
2024-01-29 6:09 ` Christoph Hellwig [this message]
2024-01-29 14:36 ` Alexander Lobakin
2024-01-29 16:15 ` Petr Tesařík
2024-01-29 14:07 ` Alexander Lobakin
2024-01-29 14:29 ` Robin Murphy
2024-01-29 14:34 ` Alexander Lobakin
2024-01-26 13:54 ` [PATCH net-next 3/7] iommu/dma: avoid expensive indirect " Alexander Lobakin
2024-01-26 13:54 ` [PATCH net-next 4/7] page_pool: make sure frag API fields don't span between cachelines Alexander Lobakin
2024-01-26 13:54 ` [PATCH net-next 5/7] page_pool: don't use driver-set flags field directly Alexander Lobakin
2024-01-26 13:54 ` [PATCH net-next 6/7] page_pool: check for DMA sync shortcut earlier Alexander Lobakin
2024-01-26 13:54 ` [PATCH net-next 7/7] xsk: use generic DMA sync shortcut instead of a custom one Alexander Lobakin
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