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Date: Fri, 9 Jun 2023 10:11:56 +0200
From: Petr =?UTF-8?B?VGVzYcWZw61r?= <petr@tesarici.cz>
To: Isaac Manjarres <isaacmanjarres@google.com>
Cc: Ard Biesheuvel <ardb@kernel.org>, Catalin Marinas
 <catalin.marinas@arm.com>, Linus Torvalds <torvalds@linux-foundation.org>,
 Christoph Hellwig <hch@lst.de>, Robin Murphy <robin.murphy@arm.com>, Arnd
 Bergmann <arnd@arndb.de>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
 Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>, Andrew Morton
 <akpm@linux-foundation.org>, Herbert Xu <herbert@gondor.apana.org.au>,
 Saravana Kannan <saravanak@google.com>, Alasdair Kergon <agk@redhat.com>,
 Daniel Vetter <daniel@ffwll.ch>, Joerg Roedel <joro@8bytes.org>, Mark Brown
 <broonie@kernel.org>, Mike Snitzer <snitzer@kernel.org>, "Rafael J.
 Wysocki" <rafael@kernel.org>, Jonathan Cameron <jic23@kernel.org>,
 linux-mm@kvack.org, iommu@lists.linux.dev,
 linux-arm-kernel@lists.infradead.org, FUJITA Tomonori
 <fujita.tomonori@lab.ntt.co.jp>, Konrad Rzeszutek Wilk
 <konrad.wilk@oracle.com>
Subject: Re: [PATCH v6 00/17] mm, dma, arm64: Reduce ARCH_KMALLOC_MINALIGN
 to 8
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On Thu, 8 Jun 2023 14:29:45 -0700
Isaac Manjarres <isaacmanjarres@google.com> wrote:

>[...]
> P.S. I noticed that the trace_swiotlb_bounced() tracepoint may not be
> invoked even though bouncing occurs. For example, in the dma-iommu path,
> swiotlb_tbl_map_single() is called when bouncing, instead of
> swiotlb_map(), which is what ends up calling trace_swiotlb_bounced().
> 
> Would it make sense to move the call to trace_swiotlb_bounced() to
> swiotlb_tbl_map_single() since that function is always invoked?

Definitely, if you ask me. I believe the change was merely forgotten in
commit eb605a5754d0 ("swiotlb: add swiotlb_tbl_map_single library
function").

Let me take the author into Cc. Plus Konrad, who built further on that
commit, may also have an opinion.

Petr T