From patchwork Tue Nov 10 11:18:30 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 56297 Delivered-To: patch@linaro.org Received: by 10.112.155.196 with SMTP id vy4csp707188lbb; Tue, 10 Nov 2015 03:18:31 -0800 (PST) X-Received: by 10.66.153.166 with SMTP id vh6mr4778040pab.83.1447154311803; Tue, 10 Nov 2015 03:18:31 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id yk2si4540056pac.192.2015.11.10.03.18.31; Tue, 10 Nov 2015 03:18:31 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752627AbbKJLSa (ORCPT + 28 others); Tue, 10 Nov 2015 06:18:30 -0500 Received: from foss.arm.com ([217.140.101.70]:55276 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752484AbbKJLS2 (ORCPT ); Tue, 10 Nov 2015 06:18:28 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6F08C49; Tue, 10 Nov 2015 03:18:15 -0800 (PST) Received: from arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A80AD3F308; Tue, 10 Nov 2015 03:18:26 -0800 (PST) Date: Tue, 10 Nov 2015 11:18:30 +0000 From: Will Deacon To: Heiko Carstens Cc: yalin wang , Catalin Marinas , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: add HAVE_LATENCYTOP_SUPPORT config Message-ID: <20151110111829.GD31947@arm.com> References: <1446825478-24824-1-git-send-email-yalin.wang2010@gmail.com> <20151106160501.GR6087@arm.com> <247F438B-3EEA-4550-970E-A649D0E604ED@gmail.com> <20151106162109.GT6087@arm.com> <20151110074124.GB6672@osiris> <20151110100547.GC31947@arm.com> <20151110110145.GE6672@osiris> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20151110110145.GE6672@osiris> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 10, 2015 at 12:01:45PM +0100, Heiko Carstens wrote: > On Tue, Nov 10, 2015 at 10:05:48AM +0000, Will Deacon wrote: > > Hi Heiko, > > > > On Tue, Nov 10, 2015 at 08:41:24AM +0100, Heiko Carstens wrote: > > > On Fri, Nov 06, 2015 at 04:21:10PM +0000, Will Deacon wrote: > > > > On Sat, Nov 07, 2015 at 12:11:16AM +0800, yalin wang wrote: > > > > > i just enable it on ARM64, > > > > > and it can work, > > > > > i don’t see some special requirement to enable this config . > > > > > > > > Right, so why does HAVE_LATENCYTOP_SUPPORT exist? > [...] > > > And looking through the kernel there is at least avr32 which would break > > > at build time if the config option would be removed completely. > > > > > > So.. renaming it to STACKTRACE_TSK_SUPPORT would be a good idea. > > > > ftrace has a similar issue and solves it by having architectures define > > a `config STACKTRACE_SUPPORT' symbol. Over in kernel/trace/Kconfig, > > there's a `select STACKTRACE if STACKTRACE_SUPPORT', which means > > that kernel/stacktrace.c gets built and a dummy (weak symbol) version of > > save_stack_trace_tsk appears. > > Ah, I wasn't aware of the weak symbol. > > > I don't think adding another STACKTRACE-related Kconfig option is > > necessarily the best thing to do. Maybe we should instead have LATENCYTOP > > depend on STACKTRACE_SUPPORT (already the case) and select STACKTRACE? > > LATENCYTOP also already selects STACKTRACE. So it looks like > HAVE_LATENCYTOP_SUPPORT could simply be removed. Ha, so it does! Patch below. The only non-trivial part was arch/arm/, which has a dependency on !SMP which I believe is no longer required as of d5996b2ff0e2 ("ARM: fix /proc/$PID/stack on SMP"). Will --->8 >From 8dfb40e92ac322cbd68bf9f16cbb11fc5e210269 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 10 Nov 2015 11:10:04 +0000 Subject: [PATCH] Kconfig: remove HAVE_LATENCYTOP_SUPPORT As illustrated by a3afe70b83fd ("[S390] latencytop s390 support."), HAVE_LATENCYTOP_SUPPORT is defined by an architecture to advertise an implementation of save_stack_trace_tsk. However, as of 9212ddb5eada ("stacktrace: provide save_stack_trace_tsk() weak alias") a dummy implementation is provided if STACKTRACE=y. Given that LATENCYTOP already depends on STACKTRACE_SUPPORT and selects STACKTRACE, we can remove HAVE_LATENCYTOP_SUPPORT altogether. Signed-off-by: Will Deacon --- arch/arc/Kconfig | 3 --- arch/arm/Kconfig | 5 ----- arch/metag/Kconfig | 3 --- arch/microblaze/Kconfig | 3 --- arch/parisc/Kconfig | 3 --- arch/powerpc/Kconfig | 3 --- arch/s390/Kconfig | 3 --- arch/sh/Kconfig | 3 --- arch/sparc/Kconfig | 4 ---- arch/unicore32/Kconfig | 3 --- arch/x86/Kconfig | 3 --- lib/Kconfig.debug | 1 - 12 files changed, 37 deletions(-) -- 2.1.4 -- 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/ diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 2c2ac3f3ff80..6dc312fd6480 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -73,9 +73,6 @@ config STACKTRACE_SUPPORT def_bool y select STACKTRACE -config HAVE_LATENCYTOP_SUPPORT - def_bool y - config HAVE_ARCH_TRANSPARENT_HUGEPAGE def_bool y depends on ARC_MMU_V4 diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 35854e8d97ff..94eff0c6b0f8 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -162,11 +162,6 @@ config STACKTRACE_SUPPORT bool default y -config HAVE_LATENCYTOP_SUPPORT - bool - depends on !SMP - default y - config LOCKDEP_SUPPORT bool default y diff --git a/arch/metag/Kconfig b/arch/metag/Kconfig index 0b389a81c43a..a0fa88da3e31 100644 --- a/arch/metag/Kconfig +++ b/arch/metag/Kconfig @@ -36,9 +36,6 @@ config STACKTRACE_SUPPORT config LOCKDEP_SUPPORT def_bool y -config HAVE_LATENCYTOP_SUPPORT - def_bool y - config RWSEM_GENERIC_SPINLOCK def_bool y diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig index 0bce820428fc..5ecd0287a874 100644 --- a/arch/microblaze/Kconfig +++ b/arch/microblaze/Kconfig @@ -67,9 +67,6 @@ config STACKTRACE_SUPPORT config LOCKDEP_SUPPORT def_bool y -config HAVE_LATENCYTOP_SUPPORT - def_bool y - source "init/Kconfig" source "kernel/Kconfig.freezer" diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index c36546959e86..16276d505cd6 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -79,9 +79,6 @@ config TIME_LOW_RES depends on SMP default y -config HAVE_LATENCYTOP_SUPPORT - def_bool y - # unless you want to implement ACPI on PA-RISC ... ;-) config PM bool diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index db49e0d796b1..89210bfdfc7a 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -47,9 +47,6 @@ config STACKTRACE_SUPPORT bool default y -config HAVE_LATENCYTOP_SUPPORT - def_bool y - config TRACE_IRQFLAGS_SUPPORT bool default y diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 3a55f493c7da..69e22b502d09 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -10,9 +10,6 @@ config LOCKDEP_SUPPORT config STACKTRACE_SUPPORT def_bool y -config HAVE_LATENCYTOP_SUPPORT - def_bool y - config RWSEM_GENERIC_SPINLOCK bool diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index d514df7e04dd..6c391a5d3e5c 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -130,9 +130,6 @@ config STACKTRACE_SUPPORT config LOCKDEP_SUPPORT def_bool y -config HAVE_LATENCYTOP_SUPPORT - def_bool y - config ARCH_HAS_ILOG2_U32 def_bool n diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 56442d2d7bbc..3203e42190dd 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -101,10 +101,6 @@ config LOCKDEP_SUPPORT bool default y if SPARC64 -config HAVE_LATENCYTOP_SUPPORT - bool - default y if SPARC64 - config ARCH_HIBERNATION_POSSIBLE def_bool y if SPARC64 diff --git a/arch/unicore32/Kconfig b/arch/unicore32/Kconfig index c9faddc61100..910aaaaed969 100644 --- a/arch/unicore32/Kconfig +++ b/arch/unicore32/Kconfig @@ -33,9 +33,6 @@ config NO_IOPORT_MAP config STACKTRACE_SUPPORT def_bool y -config HAVE_LATENCYTOP_SUPPORT - def_bool y - config LOCKDEP_SUPPORT def_bool y diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index db3622f22b61..9574f7d1fe97 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -177,9 +177,6 @@ config LOCKDEP_SUPPORT config STACKTRACE_SUPPORT def_bool y -config HAVE_LATENCYTOP_SUPPORT - def_bool y - config MMU def_bool y diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 16bf3bc25e3e..6984710e75c9 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1547,7 +1547,6 @@ config FAULT_INJECTION_STACKTRACE_FILTER config LATENCYTOP bool "Latency measuring infrastructure" - depends on HAVE_LATENCYTOP_SUPPORT depends on DEBUG_KERNEL depends on STACKTRACE_SUPPORT depends on PROC_FS