Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752410AbbHRIbi (ORCPT ); Tue, 18 Aug 2015 04:31:38 -0400 Received: from foss.arm.com ([217.140.101.70]:48141 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752315AbbHRIbc (ORCPT ); Tue, 18 Aug 2015 04:31:32 -0400 Date: Tue, 18 Aug 2015 09:31:27 +0100 From: Will Deacon To: "Zhang, Jonathan Zhixiong" Cc: "fu.wei@linaro.org" , "harba@codeaurora.org" , "linaro-acpi@lists.linaro.org" , "linux-kernel@vger.kernel.org" , "matt.fleming@intel.com" , "tekkamanninja@gmail.com" , "graeme.gregory@linaro.org" , "al.stone@linaro.org" , "hanjun.guo@linaro.org" , "jcm@redhat.com" , Mark Rutland , Catalin Marinas , "rjw@rjwysocki.net" , "bp@alien8.de" , Tomasz Nowicki Subject: Re: [PATCH] acpi, apei, arm64: APEI initial support for aarch64. Message-ID: <20150818083127.GB10301@arm.com> References: <=fu.wei@linaro.org> <1439555753-11974-1-git-send-email-fu.wei@linaro.org> <20150817100109.GE1688@arm.com> <55D26BF1.5090203@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55D26BF1.5090203@codeaurora.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2668 Lines: 62 On Tue, Aug 18, 2015 at 12:19:13AM +0100, Zhang, Jonathan Zhixiong wrote: > On 8/17/2015 3:01 AM, Will Deacon wrote: > > On Fri, Aug 14, 2015 at 01:35:53PM +0100, fu.wei@linaro.org wrote: > >> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > >> index a17b623..ced6e25 100644 > >> --- a/arch/arm64/include/asm/acpi.h > >> +++ b/arch/arm64/include/asm/acpi.h > >> @@ -22,6 +22,7 @@ > >> #ifdef CONFIG_ACPI_APEI > >> #include > >> #include > >> +#include > >> #endif > >> > >> /* Macros for consistency checks of the GICC subtable of MADT */ > >> @@ -52,6 +53,9 @@ typedef u64 phys_cpuid_t; > >> extern int acpi_disabled; > >> extern int acpi_noirq; > >> extern int acpi_pci_disabled; > >> +#ifdef CONFIG_ACPI_APEI > >> +extern int acpi_disable_cmcff; > >> +#endif > >> > >> static inline void disable_acpi(void) > >> { > >> @@ -89,6 +93,13 @@ static inline bool acpi_has_cpu_in_madt(void) > >> static inline void arch_fix_phys_package_id(int num, u32 slot) { } > >> void __init acpi_init_cpus(void); > >> > >> +#ifdef CONFIG_ACPI_APEI > >> +static inline void arch_apei_flush_tlb_one(unsigned long addr) > >> +{ > >> + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); > >> +} > >> +#endif > > > > Looking at the callers of this function, I suspect we could downgrade it > > to a local CPU invalidation if we wanted. However, this isn't a hot-path > > so it's fine to stay like it is for now. > I suppose if we run "tlbi vae1" instead of "tlbi vae1is", it will be > more efficient without side effect, since both ghes_ioremap_pfn_irq() > and ghes_iounmap_irq() happen in same atomic context. However, today > arch/arm64/include/asm/tlbflush.h does not have a function tailored for > such performance optimization. Does it make sense to add a parameter to > flush_tlb_kernel_range() to allow caller to make a choice? > static inline void flush_tlb_kernel_range(unsigned long start, > unsigned long end, bool local) > There are only two others callers of flush_tlb_kernel_range(). I've already got some patches to add things like local_flush_tlb_all, which I'll post after the merge window (I'm currently rewriting a bunch of the switch_mm code to try to reduce the TLBI traffic). If this isn't a hotpath (I don't think it is), then it's probably not worth making the optimisation without a system to benchmark it on. Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/