[PATCH v7 00/17] mm, dma, arm64: Reduce ARCH_KMALLOC_MINALIGN to 8

[Amit Pundir]

Hi Catalin,

On Wed, 5 Jul 2023 at 18:17, Catalin Marinas <catalin.marinas at arm.com> wrote:
>
> Hi,
>
> That's v7 of the series reducing the kmalloc() minimum alignment on
> arm64 to 8 (from 128). There's no new/different functionality, mostly
> cosmetic changes and acks/tested-bys.
>
> Andrew, if there are no further comments or objections to this version,
> are you ok to take the series through the mm tree? The arm64 changes are
> fairly small. Alternatively, I can push it into linux-next now to give
> it some wider exposure and decide whether to upstream it when the
> merging window opens. Thanks.

This patch series broke Dragonboard 845c (SDM845) running AOSP.
With this series I run into random oops at __kmem_cache_alloc_node().
Here is one such boot log https://bugs.linaro.org/attachment.cgi?id=1146

Reverting "arm64: Enable ARCH_WANT_KMALLOC_DMA_BOUNCE for arm64"
fixes it for the time being.

Regards,
Amit Pundir


>
> The updated patches are also available on this branch:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux devel/kmalloc-minalign
>
> Changes since v6
> (https://lore.kernel.org/r/20230531154836.1366225-1-catalin.marinas@arm.com):
>
> - Moved ARCH_DMA_MINALIGN to include/linux/cache.h from slab.h (it
>   matches the asm/cache.h where most architectures defining this macro
>   place it).
>
> - Single body for __kmalloc_minalign() with an #ifdef.
>
> - Renamed the sg_dma_use_swiotlb() to sg_dma_is_swiotlb() (Robin's
>   suggestion).
>
> - Added acks/tested-by.
>
> Catalin Marinas (15):
>   mm/slab: Decouple ARCH_KMALLOC_MINALIGN from ARCH_DMA_MINALIGN
>   dma: Allow dma_get_cache_alignment() to be overridden by the arch code
>   mm/slab: Simplify create_kmalloc_cache() args and make it static
>   mm/slab: Limit kmalloc() minimum alignment to
>     dma_get_cache_alignment()
>   drivers/base: Use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN
>   drivers/gpu: Use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN
>   drivers/usb: Use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN
>   drivers/spi: Use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN
>   dm-crypt: Use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN
>   iio: core: Use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN
>   arm64: Allow kmalloc() caches aligned to the smaller cache_line_size()
>   dma-mapping: Force bouncing if the kmalloc() size is not
>     cache-line-aligned
>   iommu/dma: Force bouncing if the size is not cacheline-aligned
>   mm: slab: Reduce the kmalloc() minimum alignment if DMA bouncing
>     possible
>   arm64: Enable ARCH_WANT_KMALLOC_DMA_BOUNCE for arm64
>
> Robin Murphy (2):
>   scatterlist: Add dedicated config for DMA flags
>   dma-mapping: Name SG DMA flag helpers consistently
>
>  arch/arm64/Kconfig             |  1 +
>  arch/arm64/include/asm/cache.h |  3 ++
>  arch/arm64/mm/init.c           |  7 +++-
>  drivers/base/devres.c          |  6 ++--
>  drivers/gpu/drm/drm_managed.c  |  6 ++--
>  drivers/iommu/Kconfig          |  1 +
>  drivers/iommu/dma-iommu.c      | 58 ++++++++++++++++++++++++--------
>  drivers/iommu/iommu.c          |  2 +-
>  drivers/md/dm-crypt.c          |  2 +-
>  drivers/pci/Kconfig            |  1 +
>  drivers/spi/spidev.c           |  2 +-
>  drivers/usb/core/buffer.c      |  8 ++---
>  include/linux/cache.h          |  6 ++++
>  include/linux/dma-map-ops.h    | 61 ++++++++++++++++++++++++++++++++++
>  include/linux/dma-mapping.h    |  5 ++-
>  include/linux/iio/iio.h        |  2 +-
>  include/linux/scatterlist.h    | 60 ++++++++++++++++++++++++++-------
>  include/linux/slab.h           | 14 +++++---
>  kernel/dma/Kconfig             |  7 ++++
>  kernel/dma/direct.c            |  2 +-
>  kernel/dma/direct.h            |  3 +-
>  mm/slab.c                      |  6 +---
>  mm/slab.h                      |  5 ++-
>  mm/slab_common.c               | 41 +++++++++++++++++------
>  24 files changed, 244 insertions(+), 65 deletions(-)
>