From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
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.
Patch 1 is to introduce swiotlb area concept and split up single swiotlb
lock.
Patch 2 set swiotlb area number with lapic number
Tianyu Lan (2):
swiotlb: Split up single swiotlb lock
x86/ACPI: Set swiotlb area according to the number of lapic entry in
MADT
.../admin-guide/kernel-parameters.txt | 4 +-
arch/x86/kernel/acpi/boot.c | 3 +
include/linux/swiotlb.h | 27 +++
kernel/dma/swiotlb.c | 202 ++++++++++++++----
4 files changed, 197 insertions(+), 39 deletions(-)
--
2.25.1
