Re: [PATCH net] octeontx2-af: Fix memory scaling limitation in SR-IOV mode

[Leon Romanovsky]

On Wed, Sep 16, 2026 at 07:51:11AM +0530, Ratheesh Kannoth wrote:
> The original code used DMA_ATTR_FORCE_CONTIGUOUS, which could exhaust
> the CMA pool when a large number of VFs were requested.
> 
> Fix this by switching to the DMA streaming API. This is equivalent on
> Octeon platforms, which provide full I/O coherency via the SMMU.
> 
> Cc: Leon Romanovsky <leon@xxxxxxxxxx>
> Fixes: 73d33dbc0723 ("octeontx2-af: Use DMA_ATTR_FORCE_CONTIGUOUS attribute in DMA alloc")
> Signed-off-by: Ratheesh Kannoth <rkannoth@xxxxxxxxxxx>
> 
> ---
> v9 -> v10: Updated commit message as suggested by Leon
> 
> v8 -> v9: Addressed Leon comment.
> - Used kzalloc instead of kmalloc.
> 
> v7 -> v8: Addressed Leon comments.
> - Replace __get_free_pages() and __GFP_COMP with kmalloc()
> - Drop GFP_DMA32 retry loop and dma_capable()/phys_to_dma() mask probing
> - Use dma_map_single()/dma_unmap_single() instead of dma_map_page_attrs()
>   with DMA_ATTR_REQUIRE_COHERENT
> - Remove defensive parameter checks and dma_max_mapping_size() from the
>   allocator helper
> - Move MAX_PAGE_ORDER validation to qmem_alloc()
> 
> v6 -> v7: Addressed Sashiko comments.
> 	https://lore.kernel.org/netdev/178863855246.219967.10510865726694393307@xxxxxxxxxx/
> 
> v5 -> v6: Addressed review comments.
> 	https://lore.kernel.org/netdev/20260901015621.2708182-1-rkannoth@xxxxxxxxxxx/
> 
> v4 -> v5: Fixed compilation issues.
> 	https://lore.kernel.org/netdev/20260831024210.208447-1-rkannoth@xxxxxxxxxxx/
> 
> v3 -> v4: Fixed compilation issues.
> 	https://lore.kernel.org/netdev/apTpKcN_S1xIwRbZ@rkannoth-OptiPlex-7090/
> 
> v2 -> v3: Addressed sashiko comments.
> 	https://sashiko.dev/#/patchset/20260825045616.3723078-1-rkannoth%40marvell.com
> 
> v1 -> v2: Rewrote patch as per sashiko comment.
> ---
>  .../ethernet/marvell/octeontx2/af/common.h    | 45 ++++++++++++++++---
>  1 file changed, 39 insertions(+), 6 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leon@xxxxxxxxxx>