Messages in this thread | | | Date | Tue, 21 Dec 2021 11:32:41 +0000 | From | Catalin Marinas <> | Subject | Re: [PATCH v2] asm-generic: introduce io_stop_wc() and add implementation for ARM64 |
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On Tue, Dec 21, 2021 at 10:17:27AM +0100, Arnd Bergmann wrote: > On Tue, Dec 21, 2021 at 4:55 AM Xiongfeng Wang > <wangxiongfeng2@huawei.com> wrote: > > > > 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> > > --- > > v1->v2: change 'Normal-Non Cacheable' to 'write-combining' > > For asm-generic: > > Acked-by: Arnd Bergmann <arnd@arndb.de> > > Will, Catalin: if you are happy with this version, please merge it through the > arm64 tree.
Thanks for the ack Arnd. I'll queue this through the arm64 tree.
-- Catalin
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