On Fri, Sep 9, 2022 at 4:26 PM Anshuman Khandual <anshuman.khandual@xxxxxxx> wrote: > > > > On 8/22/22 13:51, Yicong Yang wrote: > > From: Barry Song <v-songbaohua@xxxxxxxx> > > > > This reverts commit 6bfef171d0d74cb050112e0e49feb20bfddf7f42. > > > > I was wrong. Though ARM64 has hardware TLB flush, but it is not free > > and it is still expensive. > > We still have a good chance to enable batched and deferred TLB flush > > on ARM64 for memory reclamation. A possible way is that we only queue > > tlbi instructions in hardware's queue. When we have to broadcast TLB, > > we broadcast it by dsb. We just need to get adapted the existing > > BATCHED_UNMAP_TLB_FLUSH. > > > > Tested-by: Xin Hao <xhao@xxxxxxxxxxxxxxxxx> > > Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx> > > Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx> > > --- > > Documentation/features/arch-support.txt | 1 - > > Documentation/features/vm/TLB/arch-support.txt | 2 +- > > 2 files changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/Documentation/features/arch-support.txt b/Documentation/features/arch-support.txt > > index 118ae031840b..d22a1095e661 100644 > > --- a/Documentation/features/arch-support.txt > > +++ b/Documentation/features/arch-support.txt > > @@ -8,5 +8,4 @@ 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 > > > > diff --git a/Documentation/features/vm/TLB/arch-support.txt b/Documentation/features/vm/TLB/arch-support.txt > > index 039e4e91ada3..1c009312b9c1 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: | N/A | > > + | arm64: | TODO | > > | csky: | TODO | > > | hexagon: | TODO | > > | ia64: | TODO | > > I believe this patch is not needed, which explicitly reverts an > older commit. Instead when ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH > framework gets enabled on arm64, the same patch could just drop > 'NA' as possible values for arch support for a give feature in > file Documentation/features/arch-support.txt. Sure. it is certainly ok to fix this in arm64: support batched/deferred tlb shootdown during page reclamation By a separate patch, I was trying to highlight that my previous patch was wrong. but, yes. it is not fundamentally necessary. Thanks Barry
