From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Shi Subject: Re: [PATCH v8 8/8] x86/tlb: do flush_tlb_kernel_range by 'invlpg' Date: Thu, 14 Jun 2012 09:26:31 +0800 Message-ID: <4FD93DC7.8020501@intel.com> References: <1339492005-20241-1-git-send-email-alex.shi@intel.com> <1339492005-20241-9-git-send-email-alex.shi@intel.com> <20120613145656.GB32604@tassilo.jf.intel.com> <4FD939F2.3090605@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FD939F2.3090605@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Andi Kleen , linux-tegra@vger.kernel.org, linux-omap@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, arnd@arndb.de, rostedt@goodmis.org, fweisbec@gmail.com, jeremy@goop.org, seto.hidetoshi@jp.fujitsu.com, borislav.petkov@amd.com, tony.luck@intel.com, luto@mit.edu, riel@redhat.com, avi@redhat.com, len.brown@intel.com, tj@kernel.org, akpm@linux-foundation.org, cl@gentwo.org, jbeulich@suse.com, eric.dumazet@gmail.com, akinobu.mita@gmail.com, cpw@sgi.com, penberg@kernel.org, steiner@sgi.com, viro@zeniv.linux.org.uk, kamezawa.hiroyu@jp.fujitsu.com, aarcange@redhat.com, rientjes@google.com, linux-kernel@vger.kernel.org List-Id: linux-tegra@vger.kernel.org On 06/14/2012 09:10 AM, Alex Shi wrote: > On 06/13/2012 10:56 PM, Andi Kleen wrote: > >> On Tue, Jun 12, 2012 at 05:06:45PM +0800, Alex Shi wrote: >>> This patch do flush_tlb_kernel_range by 'invlpg'. The performance pay >>> and gain was analysed in my patch (x86/flush_tlb: try flush_tlb_single >>> one by one in flush_tlb_range). Now we move this logical into kernel >>> part. The pay is multiple 'invlpg' execution cost, that is same. but >>> the gain(cost reducing of TLB entries refilling) is absolutely >>> increased. >> >> The subtle point is whether INVLPG flushes global pages or not. >> After some digging I found a sentence in the SDM that says it does. >> So it may be safe. > > > Many thanks for your time! > >> >> What does it improve? > > > I have not specific benchmark for this. partly due to the gain theory > was proved since it is same as previous user process's page table flush. > > The user of tlb kernel flush in kernel is vmalloc. and Android binder > IPC subsystem is using it(drivers/staging/android/binder.c) > > I am wondering if it can help Andriod on this? > So, add cc to android-kernel@googlegroups.com Sorry, Andriod reject posting without register, so cc to linux-omap@vger.kernel.org and linux-tegra@vger.kernel.org instead. > >> -Andi > >