From: palmerdabbelt@google.com To: guoren@kernel.org Cc: guoren@kernel.org, Anup Patel <Anup.Patel@wdc.com>, Arnd Bergmann <arnd@arndb.de>, Christoph Hellwig <hch@lst.de>, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-sunxi@lists.linux.dev, guoren@linux.alibaba.com Subject: Re: [PATCH V4 1/2] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL Date: Sat, 29 May 2021 16:42:35 -0700 (PDT) [thread overview] Message-ID: <mhng-60806045-5ac7-4057-b596-a4d9cb79b7be@palmerdabbelt-glaptop> (raw) In-Reply-To: <1622008161-41451-2-git-send-email-guoren@kernel.org> On Tue, 25 May 2021 22:49:20 PDT (-0700), guoren@kernel.org wrote: > From: Guo Ren <guoren@linux.alibaba.com> > > Kernel virtual address translation should avoid to use ASIDs or it'll > cause more TLB-miss and TLB-refill. Because the current ASID in satp > belongs to the current process, but the target kernel va TLB entry's > ASID still belongs to the previous process. Sorry, I still can't quite figure out what this is trying to say. I went ahead and re-wrote the commit text to riscv: Use global mappings for kernel pages We map kernel pages into all addresses spages, so they can be marked as global. This allows hardware to avoid flushing the kernel mappings when moving between address spaces. LMK if I'm misunderstanding something here, it's on for-next. > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com> > Reviewed-by: Anup Patel <anup@brainfault.org> > Reviewed-by: Christoph Hellwig <hch@lst.de> > Cc: Palmer Dabbelt <palmerdabbelt@google.com> > --- > arch/riscv/include/asm/pgtable.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > index 9469f46..346a3c6 100644 > --- a/arch/riscv/include/asm/pgtable.h > +++ b/arch/riscv/include/asm/pgtable.h > @@ -134,7 +134,8 @@ > | _PAGE_WRITE \ > | _PAGE_PRESENT \ > | _PAGE_ACCESSED \ > - | _PAGE_DIRTY) > + | _PAGE_DIRTY \ > + | _PAGE_GLOBAL) > > #define PAGE_KERNEL __pgprot(_PAGE_KERNEL) > #define PAGE_KERNEL_READ __pgprot(_PAGE_KERNEL & ~_PAGE_WRITE)
WARNING: multiple messages have this Message-ID (diff)
From: palmerdabbelt@google.com To: guoren@kernel.org Cc: guoren@kernel.org, Anup Patel <Anup.Patel@wdc.com>, Arnd Bergmann <arnd@arndb.de>, Christoph Hellwig <hch@lst.de>, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-sunxi@lists.linux.dev, guoren@linux.alibaba.com Subject: Re: [PATCH V4 1/2] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL Date: Sat, 29 May 2021 16:42:35 -0700 (PDT) [thread overview] Message-ID: <mhng-60806045-5ac7-4057-b596-a4d9cb79b7be@palmerdabbelt-glaptop> (raw) In-Reply-To: <1622008161-41451-2-git-send-email-guoren@kernel.org> On Tue, 25 May 2021 22:49:20 PDT (-0700), guoren@kernel.org wrote: > From: Guo Ren <guoren@linux.alibaba.com> > > Kernel virtual address translation should avoid to use ASIDs or it'll > cause more TLB-miss and TLB-refill. Because the current ASID in satp > belongs to the current process, but the target kernel va TLB entry's > ASID still belongs to the previous process. Sorry, I still can't quite figure out what this is trying to say. I went ahead and re-wrote the commit text to riscv: Use global mappings for kernel pages We map kernel pages into all addresses spages, so they can be marked as global. This allows hardware to avoid flushing the kernel mappings when moving between address spaces. LMK if I'm misunderstanding something here, it's on for-next. > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com> > Reviewed-by: Anup Patel <anup@brainfault.org> > Reviewed-by: Christoph Hellwig <hch@lst.de> > Cc: Palmer Dabbelt <palmerdabbelt@google.com> > --- > arch/riscv/include/asm/pgtable.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > index 9469f46..346a3c6 100644 > --- a/arch/riscv/include/asm/pgtable.h > +++ b/arch/riscv/include/asm/pgtable.h > @@ -134,7 +134,8 @@ > | _PAGE_WRITE \ > | _PAGE_PRESENT \ > | _PAGE_ACCESSED \ > - | _PAGE_DIRTY) > + | _PAGE_DIRTY \ > + | _PAGE_GLOBAL) > > #define PAGE_KERNEL __pgprot(_PAGE_KERNEL) > #define PAGE_KERNEL_READ __pgprot(_PAGE_KERNEL & ~_PAGE_WRITE) _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2021-05-29 23:42 UTC|newest] Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-26 5:49 [PATCH V4 0/2] riscv: Fixup asid_allocator remaining issues guoren 2021-05-26 5:49 ` guoren 2021-05-26 5:49 ` [PATCH V4 1/2] riscv: Fixup _PAGE_GLOBAL in _PAGE_KERNEL guoren 2021-05-26 5:49 ` guoren 2021-05-29 23:42 ` palmerdabbelt [this message] 2021-05-29 23:42 ` palmerdabbelt 2021-05-30 5:33 ` Guo Ren 2021-05-30 5:33 ` Guo Ren 2021-05-30 5:33 ` Guo Ren 2021-05-26 5:49 ` [PATCH V4 2/2] riscv: Use use_asid_allocator flush TLB guoren 2021-05-26 5:49 ` guoren 2021-05-27 7:09 ` Christoph Hellwig 2021-05-27 7:09 ` Christoph Hellwig 2021-05-29 23:42 ` palmerdabbelt 2021-05-29 23:42 ` palmerdabbelt 2021-05-30 0:51 ` Guo Ren 2021-05-30 0:51 ` Guo Ren 2021-05-30 0:51 ` Guo Ren 2021-05-31 6:36 ` Christoph Hellwig 2021-05-31 6:36 ` Christoph Hellwig 2021-05-30 0:39 ` Guo Ren 2021-05-30 0:39 ` Guo Ren 2021-05-30 0:39 ` Guo Ren
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