Re: [PATCH 05/16] iommu/io-pgtable-arm-v7s: use page allocation function provided by iommu-pages.h

From: Robin Murphy
Date: Tue Nov 28 2023 - 18:08:05 EST


On 2023-11-28 10:55 pm, Pasha Tatashin wrote:
kmem_cache_free(data->l2_tables, table);

We only account page allocations, not subpages, however, this is
something I was surprised about this particular architecture of why do
we allocate l2 using kmem ? Are the second level tables on arm v7s
really sub-page in size?

Yes, L2 tables are 1KB, so the kmem_cache could still quite easily end up consuming significantly more memory than the L1 table, which is usually 16KB (but could potentially be smaller depending on the config, or up to 64KB with the Mediatek hacks).

Thanks,
Robin.