| Message ID | 1346360743-3628-8-git-send-email-paulmck@linux.vnet.ibm.com |
|---|---|
| State | Accepted |
| Commit | bf5a3c13b939813d28ce26c01425054c740d6731 |
| Headers | show |
On Thu, Aug 30, 2012 at 02:05:25PM -0700, Paul E. McKenney wrote: > From: Frederic Weisbecker <fweisbec@gmail.com> > > 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 <fweisbec@gmail.com> > Cc: Alessio Igor Bogani <abogani@kernel.org> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Avi Kivity <avi@redhat.com> > Cc: Chris Metcalf <cmetcalf@tilera.com> > Cc: Christoph Lameter <cl@linux.com> > Cc: Geoff Levand <geoff@infradead.org> > Cc: Gilad Ben Yossef <gilad@benyossef.com> > Cc: Hakan Akkan <hakanakkan@gmail.com> > Cc: H. Peter Anvin <hpa@zytor.com> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Josh Triplett <josh@joshtriplett.org> > Cc: Kevin Hilman <khilman@ti.com> > Cc: Max Krasnyansky <maxk@qualcomm.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Stephen Hemminger <shemminger@vyatta.com> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> This seems reasonable; presumably you plan to add something actually setting TIF_NOHZ in a subsequent patch series? Reviewed-by: Josh Triplett <josh@joshtriplett.org> > 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 <linux/signal.h> > #include <linux/perf_event.h> > #include <linux/hw_breakpoint.h> > +#include <linux/rcupdate.h> > > #include <asm/uaccess.h> > #include <asm/pgtable.h> > @@ -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 >
On Fri, Aug 31, 2012 at 04:59:10PM -0700, Josh Triplett wrote: > On Thu, Aug 30, 2012 at 02:05:25PM -0700, Paul E. McKenney wrote: > > From: Frederic Weisbecker <fweisbec@gmail.com> > > > > 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 <fweisbec@gmail.com> > > Cc: Alessio Igor Bogani <abogani@kernel.org> > > Cc: Andrew Morton <akpm@linux-foundation.org> > > Cc: Avi Kivity <avi@redhat.com> > > Cc: Chris Metcalf <cmetcalf@tilera.com> > > Cc: Christoph Lameter <cl@linux.com> > > Cc: Geoff Levand <geoff@infradead.org> > > Cc: Gilad Ben Yossef <gilad@benyossef.com> > > Cc: Hakan Akkan <hakanakkan@gmail.com> > > Cc: H. Peter Anvin <hpa@zytor.com> > > Cc: Ingo Molnar <mingo@kernel.org> > > Cc: Josh Triplett <josh@joshtriplett.org> > > Cc: Kevin Hilman <khilman@ti.com> > > Cc: Max Krasnyansky <maxk@qualcomm.com> > > Cc: Peter Zijlstra <peterz@infradead.org> > > Cc: Stephen Hemminger <shemminger@vyatta.com> > > Cc: Steven Rostedt <rostedt@goodmis.org> > > Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> > > Cc: Thomas Gleixner <tglx@linutronix.de> > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > > This seems reasonable; presumably you plan to add something actually > setting TIF_NOHZ in a subsequent patch series? Yes, currently this is set by the selftests, see the combination of: [PATCH tip/core/rcu 07/26] rcu: Switch task's syscall hooks on context switch [PATCH tip/core/rcu 14/26] rcu: Userspace RCU extended QS selftest Later this will be driven by the nohz subsystem.
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 <linux/signal.h> #include <linux/perf_event.h> #include <linux/hw_breakpoint.h> +#include <linux/rcupdate.h> #include <asm/uaccess.h> #include <asm/pgtable.h> @@ -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(); }