Messages in this thread | | | Subject | Re: [PATCH] Documentation/features: mark BATCHED_UNMAP_TLB_FLUSH doesn't apply to ARM64 | From | Anshuman Khandual <> | Date | Tue, 23 Feb 2021 11:40:09 +0530 |
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On 2/23/21 6:02 AM, Barry Song wrote: > BATCHED_UNMAP_TLB_FLUSH is used on x86 to do batched tlb shootdown by > sending one IPI to TLB flush all entries after unmapping pages rather > than sending an IPI to flush each individual entry. > On arm64, tlb shootdown is done by hardware. Flush instructions are > innershareable. The local flushes are limited to the boot (1 per CPU) > and when a task is getting a new ASID.
Is there any previous discussion around this ?
> So marking this feature as "TODO" is not proper. ".." isn't good as > well. So this patch adds a "N/A" for this kind of features which are > not needed on some architectures. > > Cc: Mel Gorman <mgorman@suse.de> > Cc: Andy Lutomirski <luto@kernel.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> > --- > Documentation/features/arch-support.txt | 1 + > Documentation/features/vm/TLB/arch-support.txt | 2 +- > 2 files changed, 2 insertions(+), 1 deletion(-) > > diff --git a/Documentation/features/arch-support.txt b/Documentation/features/arch-support.txt > index d22a1095e661..118ae031840b 100644 > --- a/Documentation/features/arch-support.txt > +++ b/Documentation/features/arch-support.txt > @@ -8,4 +8,5 @@ The meaning of entries in the tables is: > | ok | # feature supported by the architecture > |TODO| # feature not yet supported by the architecture > | .. | # feature cannot be supported by the hardware > + | N/A| # feature doesn't apply to the architecture
NA might be better here. s/doesn't apply/not applicable/ in order to match NA. Still wondering if NA is really needed when there is already ".." ? Regardless either way should be fine.
> > diff --git a/Documentation/features/vm/TLB/arch-support.txt b/Documentation/features/vm/TLB/arch-support.txt > index 30f75a79ce01..0d070f9f98d8 100644 > --- a/Documentation/features/vm/TLB/arch-support.txt > +++ b/Documentation/features/vm/TLB/arch-support.txt > @@ -9,7 +9,7 @@ > | alpha: | TODO | > | arc: | TODO | > | arm: | TODO | > - | arm64: | TODO | > + | arm64: | N/A | > | c6x: | .. | > | csky: | TODO | > | h8300: | .. | >
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