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| author | Xiongfeng Wang <wangxiongfeng2@huawei.com> | 2021-12-21 04:55:56 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-12-22 11:44:53 +0100 |
| commit | d5624bb29f49b849ac8d1e9783dbf9c65cf33457 (patch) | |
| tree | 15c4737e7664df0afd23cbca92a32e7ed7c47a0d /Documentation/doc-guide | |
| parent | arm64: remove __dma_*_area() aliases (diff) | |
| download | linux-d5624bb29f49b849ac8d1e9783dbf9c65cf33457.tar.xz linux-d5624bb29f49b849ac8d1e9783dbf9c65cf33457.zip | |
asm-generic: introduce io_stop_wc() and add implementation for ARM64
For memory accesses with write-combining attributes (e.g. those returned
by ioremap_wc()), the CPU may wait for prior accesses to be merged with
subsequent ones. But in some situation, such wait is bad for the
performance.
We introduce io_stop_wc() to prevent the merging of write-combining
memory accesses before this macro with those after it.
We add implementation for ARM64 using DGH instruction and provide NOP
implementation for other architectures.
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Suggested-by: Will Deacon <will@kernel.org>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20211221035556.60346-1-wangxiongfeng2@huawei.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'Documentation/doc-guide')
0 files changed, 0 insertions, 0 deletions