From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: Re: [RFC PATCH v4 0/6] arm64: tlb: add support for TTL feature Date: Wed, 25 Mar 2020 14:32:01 +0100 Message-ID: <20200325133201.GI20713@hirez.programming.kicks-ass.net> References: <20200324134534.1570-1-yezhenyu2@huawei.com> <20200324150155.GH20713@hirez.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane-mx.org@lists.infradead.org To: Zhenyu Ye Cc: mark.rutland@arm.com, catalin.marinas@arm.com, linux-mm@kvack.org, guohanjun@huawei.com, will@kernel.org, linux-arch@vger.kernel.org, yuzhao@google.com, maz@kernel.org, steven.price@arm.com, arm@kernel.org, Dave.Martin@arm.com, arnd@arndb.de, suzuki.poulose@arm.com, npiggin@gmail.com, zhangshaokun@hisilicon.com, broonie@kernel.org, rostedt@goodmis.org, prime.zeng@hisilicon.com, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, xiexiangyou@huawei.com, linux-kernel@vger.kernel.org, aneesh.kumar@linux.ibm.com, akpm@linux-foundation.org List-Id: linux-arch.vger.kernel.org On Wed, Mar 25, 2020 at 12:49:45PM +0800, Zhenyu Ye wrote: > Hi Peter, > > On 2020/3/24 23:01, Peter Zijlstra wrote: > > On Tue, Mar 24, 2020 at 09:45:28PM +0800, Zhenyu Ye wrote: > >> In order to reduce the cost of TLB invalidation, the ARMv8.4 TTL > >> feature allows TLBs to be issued with a level allowing for quicker > >> invalidation. This series provide support for this feature. > >> > >> Patch 1 and Patch 2 was provided by Marc on his NV series[1] patches, > >> which detect the TTL feature and add __tlbi_level interface. > > > > I realy hate how it makes vma->vm_flags more important for tlbi. > > > > Thanks for your review. > > The tlbi interfaces only have two parameters: vma and addr. If we > try to not use vma->vm_flags, we may should have to add a parameter > to some of these interfaces(such as flush_tlb_range), which are > common to all architectures. > > I'm not sure if this is feasible, because this feature is only > supported by ARM64 currently. Power (p9-radix) also has level dependent invalidation instructions, so at the very least you can hook them up as well. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 25 Mar 2020 14:32:01 +0100 From: Peter Zijlstra Subject: Re: Re: [RFC PATCH v4 0/6] arm64: tlb: add support for TTL feature Message-ID: <20200325133201.GI20713@hirez.programming.kicks-ass.net> References: <20200324134534.1570-1-yezhenyu2@huawei.com> <20200324150155.GH20713@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Zhenyu Ye Cc: mark.rutland@arm.com, catalin.marinas@arm.com, linux-mm@kvack.org, guohanjun@huawei.com, will@kernel.org, linux-arch@vger.kernel.org, yuzhao@google.com, maz@kernel.org, steven.price@arm.com, arm@kernel.org, Dave.Martin@arm.com, arnd@arndb.de, suzuki.poulose@arm.com, npiggin@gmail.com, zhangshaokun@hisilicon.com, broonie@kernel.org, rostedt@goodmis.org, prime.zeng@hisilicon.com, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, xiexiangyou@huawei.com, linux-kernel@vger.kernel.org, aneesh.kumar@linux.ibm.com, akpm@linux-foundation.org List-ID: Message-ID: <20200325133201.th2k7M87pfM9OkvXS3qZehcWFthExKgikiJta45gWls@z> On Wed, Mar 25, 2020 at 12:49:45PM +0800, Zhenyu Ye wrote: > Hi Peter, > > On 2020/3/24 23:01, Peter Zijlstra wrote: > > On Tue, Mar 24, 2020 at 09:45:28PM +0800, Zhenyu Ye wrote: > >> In order to reduce the cost of TLB invalidation, the ARMv8.4 TTL > >> feature allows TLBs to be issued with a level allowing for quicker > >> invalidation. This series provide support for this feature. > >> > >> Patch 1 and Patch 2 was provided by Marc on his NV series[1] patches, > >> which detect the TTL feature and add __tlbi_level interface. > > > > I realy hate how it makes vma->vm_flags more important for tlbi. > > > > Thanks for your review. > > The tlbi interfaces only have two parameters: vma and addr. If we > try to not use vma->vm_flags, we may should have to add a parameter > to some of these interfaces(such as flush_tlb_range), which are > common to all architectures. > > I'm not sure if this is feasible, because this feature is only > supported by ARM64 currently. Power (p9-radix) also has level dependent invalidation instructions, so at the very least you can hook them up as well.