20347fca71
Traditionally swiotlb was not performance critical because it was only used for slow devices. But in some setups, like TDX/SEV confidential guests, all IO has to go through swiotlb. Currently swiotlb only has a single lock. Under high IO load with multiple CPUs this can lead to significat lock contention on the swiotlb lock. This patch splits the swiotlb bounce buffer pool into individual areas which have their own lock. Each CPU tries to allocate in its own area first. Only if that fails does it search other areas. On freeing the allocation is freed into the area where the memory was originally allocated from. Area number can be set via swiotlb kernel parameter and is default to be possible cpu number. If possible cpu number is not power of 2, area number will be round up to the next power of 2. This idea from Andi Kleen patch(https://github.com/intel/tdx/commit/ 4529b5784c141782c72ec9bd9a92df2b68cb7d45). Based-on-idea-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Signed-off-by: Christoph Hellwig <hch@lst.de> |
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| .. | ||
| coherent.c | ||
| contiguous.c | ||
| debug.c | ||
| debug.h | ||
| direct.c | ||
| direct.h | ||
| dummy.c | ||
| Kconfig | ||
| Makefile | ||
| map_benchmark.c | ||
| mapping.c | ||
| ops_helpers.c | ||
| pool.c | ||
| remap.c | ||
| swiotlb.c | ||