Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755289Ab2HaX7V (ORCPT ); Fri, 31 Aug 2012 19:59:21 -0400 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:54977 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754706Ab2HaX7U (ORCPT ); Fri, 31 Aug 2012 19:59:20 -0400 X-Originating-IP: 217.70.178.148 X-Originating-IP: 173.246.103.110 Date: Fri, 31 Aug 2012 16:59:10 -0700 From: Josh Triplett To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, patches@linaro.org, Alessio Igor Bogani , Avi Kivity , Chris Metcalf , Christoph Lameter , Geoff Levand , Gilad Ben Yossef , Hakan Akkan , "H. Peter Anvin" , Ingo Molnar , Kevin Hilman , Max Krasnyansky , Stephen Hemminger , Sven-Thorsten Dietrich Subject: Re: [PATCH tip/core/rcu 08/26] x86: Syscall hooks for userspace RCU extended QS Message-ID: <20120831235909.GM11771@jtriplet-mobl1> References: <20120830210520.GA2824@linux.vnet.ibm.com> <1346360743-3628-1-git-send-email-paulmck@linux.vnet.ibm.com> <1346360743-3628-8-git-send-email-paulmck@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1346360743-3628-8-git-send-email-paulmck@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4583 Lines: 119 On Thu, Aug 30, 2012 at 02:05:25PM -0700, Paul E. McKenney wrote: > From: Frederic Weisbecker > > Add syscall slow path hooks to notify syscall entry > and exit on CPUs that want to support userspace RCU > extended quiescent state. > > Signed-off-by: Frederic Weisbecker > Cc: Alessio Igor Bogani > Cc: Andrew Morton > Cc: Avi Kivity > Cc: Chris Metcalf > Cc: Christoph Lameter > Cc: Geoff Levand > Cc: Gilad Ben Yossef > Cc: Hakan Akkan > Cc: H. Peter Anvin > Cc: Ingo Molnar > Cc: Josh Triplett > Cc: Kevin Hilman > Cc: Max Krasnyansky > Cc: Peter Zijlstra > Cc: Stephen Hemminger > Cc: Steven Rostedt > Cc: Sven-Thorsten Dietrich > Cc: Thomas Gleixner > Signed-off-by: Paul E. McKenney This seems reasonable; presumably you plan to add something actually setting TIF_NOHZ in a subsequent patch series? Reviewed-by: Josh Triplett > arch/x86/include/asm/thread_info.h | 10 +++++++--- > arch/x86/kernel/ptrace.c | 5 +++++ > 2 files changed, 12 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h > index 89f794f..c535d84 100644 > --- a/arch/x86/include/asm/thread_info.h > +++ b/arch/x86/include/asm/thread_info.h > @@ -89,6 +89,7 @@ struct thread_info { > #define TIF_NOTSC 16 /* TSC is not accessible in userland */ > #define TIF_IA32 17 /* IA32 compatibility process */ > #define TIF_FORK 18 /* ret_from_fork */ > +#define TIF_NOHZ 19 /* in adaptive nohz mode */ > #define TIF_MEMDIE 20 /* is terminating due to OOM killer */ > #define TIF_DEBUG 21 /* uses debug registers */ > #define TIF_IO_BITMAP 22 /* uses I/O bitmap */ > @@ -114,6 +115,7 @@ struct thread_info { > #define _TIF_NOTSC (1 << TIF_NOTSC) > #define _TIF_IA32 (1 << TIF_IA32) > #define _TIF_FORK (1 << TIF_FORK) > +#define _TIF_NOHZ (1 << TIF_NOHZ) > #define _TIF_DEBUG (1 << TIF_DEBUG) > #define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP) > #define _TIF_FORCED_TF (1 << TIF_FORCED_TF) > @@ -126,12 +128,13 @@ struct thread_info { > /* work to do in syscall_trace_enter() */ > #define _TIF_WORK_SYSCALL_ENTRY \ > (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \ > - _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT) > + _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT | \ > + _TIF_NOHZ) > > /* work to do in syscall_trace_leave() */ > #define _TIF_WORK_SYSCALL_EXIT \ > (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP | \ > - _TIF_SYSCALL_TRACEPOINT) > + _TIF_SYSCALL_TRACEPOINT | _TIF_NOHZ) > > /* work to do on interrupt/exception return */ > #define _TIF_WORK_MASK \ > @@ -141,7 +144,8 @@ struct thread_info { > > /* work to do on any return to user space */ > #define _TIF_ALLWORK_MASK \ > - ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT) > + ((0x0000FFFF & ~_TIF_SECCOMP) | _TIF_SYSCALL_TRACEPOINT | \ > + _TIF_NOHZ) > > /* Only used for 64 bit */ > #define _TIF_DO_NOTIFY_MASK \ > diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c > index c4c6a5c..9f94f8e 100644 > --- a/arch/x86/kernel/ptrace.c > +++ b/arch/x86/kernel/ptrace.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -1463,6 +1464,8 @@ long syscall_trace_enter(struct pt_regs *regs) > { > long ret = 0; > > + rcu_user_exit(); > + > /* > * If we stepped into a sysenter/syscall insn, it trapped in > * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP. > @@ -1526,4 +1529,6 @@ void syscall_trace_leave(struct pt_regs *regs) > !test_thread_flag(TIF_SYSCALL_EMU); > if (step || test_thread_flag(TIF_SYSCALL_TRACE)) > tracehook_report_syscall_exit(regs, step); > + > + rcu_user_enter(); > } > -- > 1.7.8 > -- 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/