+ linux-scsi (see https://lore.kernel.org/linux-iommu/1607538189-237944-4-git-send-email-john....)

On 17/11/2020 10:25, 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...

Notice, for example, the following logs: [13175.355584] print_iova1 cpu_total=40135 depot_total=3866 total=44001 [83483.457858] print_iova1 cpu_total=62532 depot_total=24476 total=87008

Where total IOVA rcache size has grown from 44K->87K over a long time.

JFYI, I am able to reproduce this aging issue on another storage card, an LSI SAS 3008, so now it's harder to say it's an issue specific to a (buggy) single driver.

A log of the IOVA size dumps is here: https://raw.githubusercontent.com/hisilicon/kernel-dev/064c4dc8869b3f2ad07ed...

Notice again how the total IOVA size goes up over time, like: [ 68.176914] print_iova1 cpu_total=23663 depot_total=256 total=23919 [ 2337.008194] print_iova1 cpu_total=67361 depot_total=9088 total=76449 [17141.860078] print_iova1 cpu_total=73397 depot_total=10368 total=83765 [27087.850830] print_iova1 cpu_total=73386 depot_total=10624 total=84010 [10434.042877] print_iova1 cpu_total=90652 depot_total=12928 total=103580

I had to change some settings for that storage card to reproduce, though [0]. Could explain why no other reports.

So please consider this issue again...

Thanks, john

[0] https://lore.kernel.org/linux-scsi/dd8e6fdc-397d-b6ad-3371-0b65d1932ad1@huaw...

Along with this patch, I included the following:

• A smaller helper to clear all IOVAs for a domain
• Change polarity of the IOVA magazine helpers
• Small optimisation from Cong Wang included, which was never applied [1]. There was some debate of the other patches in that series, but this one is quite straightforward.

Differnces to v2:

• Update commit message for patch 3/4