Re: [RESEND PATCH v3 0/4] iommu/iova: Solve longterm IOVA issue

[John Garry]

On 03/12/2020 06:04, Dmitry Safonov wrote:
> On Tue, 1 Dec 2020 at 21:50, Will Deacon<will@xxxxxxxxxx>  wrote:
> > On Tue, 17 Nov 2020 18:25:30 +0800, John Garry wrote:
> > > This series contains a patch to solve the longterm IOVA issue which
> > > leizhen originally tried to address at [0].
> > >
> > > A sieved kernel log is at the following, showing periodic dumps of IOVA
> > > sizes, per CPU and per depot bin, per IOVA size granule:
> > > https://raw.githubusercontent.com/hisilicon/kernel-dev/topic-iommu-5.10-iova-debug-v3/aging_test
> > >
> > > [...]
> > Applied the final patch to arm64 (for-next/iommu/iova), thanks!
> >
> > [4/4] iommu: avoid taking iova_rbtree_lock twice
> >        https://git.kernel.org/arm64/c/3a651b3a27a1
> Glad it made in next, 2 years ago I couldn't convince iommu maintainer
> it's worth it (but with a different justification):
> https://lore.kernel.org/linux-iommu/20180621180823.805-3-dima@xxxxxxxxxx/

Hi Dmitry,

I was unaware of your series, and it’s unfortunate that your 
optimization never made it. However I was having a quick look there, 
and, in case you did not notice, that the code which you were proposing 
changing in patch #1 for intel-iommu.c was removed in e70b081c6f37 
("iommu/vt-d: Remove IOVA handling code from the non-dma_ops path").

BTW, split_and_remove_iova() has no in-tree users anymore, so I can send 
a patch to delete if nobody else wants to.

BTW2, there's some more patches in my series which could use a review if 
you're feeling very helpful :)

Cheers,
John