From patchwork Sun Nov 24 23:49:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 13884293 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2DBF21607A4; Sun, 24 Nov 2024 23:49:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732492173; cv=none; b=TP7GonF3cLvSDGk0n+Hg6Bb0j3GvTQ3kWc7wWpdgYHntMWNjvOpVCuKVyqvS3Eh2w7vA66wOMYfLv5XQrbxwXxYRiA8qbfUKi8z8cDc3CmyypqQS5Oy737hTpGgyKmJ3SbkZ474PhFmMxrhW81brL5+7kaEANQJDFR9A/+cY6dM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732492173; c=relaxed/simple; bh=yCUNkk6yShU8TZGlAY96O7m0lA5Zg/DBQJ7E8YVPT4w=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=kObRDymY3cxIfjPz4RSQ/f1nSpajimhmP0aiHcjM6ICu1uY7nPO9Dpb39A2W6YYEZM6byA5gv2SXTwIqbWUqaU6QFpqUHGRChh918pxUrsxMSpsLc+FzM74qh/ZJ1KvNmL+jKcIBlBjt9Kdd2YzVjFxvnND247xaH4JVLg8uweQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0BB8CC4CED3; Sun, 24 Nov 2024 23:49:33 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98) (envelope-from ) id 1tFMMt-00000006vke-140A; Sun, 24 Nov 2024 18:50:19 -0500 Message-ID: <20241124235019.106333158@goodmis.org> User-Agent: quilt/0.68 Date: Sun, 24 Nov 2024 18:49:44 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Linus Torvalds , Thomas Gleixner , Michael Jeanson , Peter Zijlstra , Alexei Starovoitov , Yonghong Song , "Paul E. McKenney" , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Namhyung Kim , Andrii Nakryiko , bpf@vger.kernel.org, Joel Fernandes , Jordan Rife , linux-trace-kernel@vger.kernel.org Subject: [for-next][PATCH 4/6] rcupdate_trace: Define rcu_tasks_trace lock guard References: <20241124234940.017394686@goodmis.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Mathieu Desnoyers Define a rcu_tasks_trace lock guard for use by the syscall enter/exit tracepoints. Cc: Linus Torvalds Cc: Thomas Gleixner Cc: Michael Jeanson Cc: Masami Hiramatsu Cc: Peter Zijlstra Cc: Alexei Starovoitov Cc: Yonghong Song Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Mark Rutland Cc: Alexander Shishkin Cc: Namhyung Kim Cc: Andrii Nakryiko Cc: bpf@vger.kernel.org Cc: Joel Fernandes Cc: Jordan Rife Cc: linux-trace-kernel@vger.kernel.org Link: https://lore.kernel.org/20241123153031.2884933-4-mathieu.desnoyers@efficios.com Signed-off-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt (Google) Reviewed-by: Paul E. McKenney --- include/linux/rcupdate_trace.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/linux/rcupdate_trace.h b/include/linux/rcupdate_trace.h index eda493200663..e6c44eb428ab 100644 --- a/include/linux/rcupdate_trace.h +++ b/include/linux/rcupdate_trace.h @@ -10,6 +10,7 @@ #include #include +#include extern struct lockdep_map rcu_trace_lock_map; @@ -98,4 +99,8 @@ static inline void rcu_read_lock_trace(void) { BUG(); } static inline void rcu_read_unlock_trace(void) { BUG(); } #endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ +DEFINE_LOCK_GUARD_0(rcu_tasks_trace, + rcu_read_lock_trace(), + rcu_read_unlock_trace()) + #endif /* __LINUX_RCUPDATE_TRACE_H */ From patchwork Sun Nov 24 23:49:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 13884294 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51D46188704; Sun, 24 Nov 2024 23:49:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732492173; cv=none; b=ASuxBGO2IjJwIhEVZyiL1akUrn9cu5Up4RQ17W0PUMNnt8CFgMrPubQWTDV2L7JphlEHhoQZZPUC+AdldaPczXnmxAbHJ7JQs6NNPLSdctL4P6qzfoSF9pOdgCKMtezKMY1isnruIVcYOb6+mywCXwbfp84AS64lmLMpmSa3hxs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732492173; c=relaxed/simple; bh=rVl59srqCL8+wmOTj6ciPu2sqqN4TSM7onriJ55rBgQ=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=JLkViFRmv35d/bNS1v6AqAZOkodVetuzlh1MFHMoRnm204+kX5MLYHKDLcYobnh7rCigb+k9LtHkd6RIBBGsqnhp6eLuzHeP7+YTvYv7G5BUfwbn3x9cBhV+fQrUDWcenOcZsKQAp9wU/IDoc7kOMgBYRQbNrm022ZNmq+mJO74= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FA1CC4CECC; Sun, 24 Nov 2024 23:49:33 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98) (envelope-from ) id 1tFMMt-00000006vl8-1mBI; Sun, 24 Nov 2024 18:50:19 -0500 Message-ID: <20241124235019.274562787@goodmis.org> User-Agent: quilt/0.68 Date: Sun, 24 Nov 2024 18:49:45 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Linus Torvalds , Thomas Gleixner , Michael Jeanson , Peter Zijlstra , Alexei Starovoitov , Yonghong Song , "Paul E. McKenney" , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Namhyung Kim , Andrii Nakryiko , bpf@vger.kernel.org, Joel Fernandes , Jordan Rife , linux-trace-kernel@vger.kernel.org Subject: [for-next][PATCH 5/6] tracing: Remove conditional locking from __DO_TRACE() References: <20241124234940.017394686@goodmis.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Mathieu Desnoyers Remove conditional locking by moving the __DO_TRACE() code into trace_##name(). When the faultable syscall tracepoints were implemented, __DO_TRACE() had a rcuidle argument which selected between SRCU and preempt disable. Therefore, the RCU tasks trace protection for faultable syscall tracepoints was introduced using the same pattern. At that point, it did not appear obvious that this feedback from Linus [1] applied here as well, because the __DO_TRACE() modification was extending a pre-existing pattern. Shortly before pulling the faultable syscall tracepoints modifications, Steven removed the rcuidle argument and SRCU protection scheme entirely from tracepoint.h: commit 48bcda684823 ("tracing: Remove definition of trace_*_rcuidle()") This required a rebase of the faultable syscall tracepoints series, which missed a perfect opportunity to integrate the prior recommendation from Linus. In response to the pull request, Linus pointed out [2] that he was not pleased by the implementation, expecting this to be fixed in a follow up patch series. Move __DO_TRACE() code into trace_##name() within each of __DECLARE_TRACE() and __DECLARE_TRACE_SYSCALL(). Use a scoped guard to guard the preempt disable notrace and RCU tasks trace critical sections. Link: https://lore.kernel.org/all/CAHk-=wggDLDeTKbhb5hh--x=-DQd69v41137M72m6NOTmbD-cw@mail.gmail.com/ [1] Link: https://lore.kernel.org/lkml/CAHk-=witPrLcu22dZ93VCyRQonS7+-dFYhQbna=KBa-TAhayMw@mail.gmail.com/ [2] Fixes: a363d27cdbc2 ("tracing: Allow system call tracepoints to handle page faults") Cc: Linus Torvalds Cc: Thomas Gleixner Cc: Michael Jeanson Cc: Masami Hiramatsu Cc: Peter Zijlstra Cc: Alexei Starovoitov Cc: Yonghong Song Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Mark Rutland Cc: Alexander Shishkin Cc: Namhyung Kim Cc: Andrii Nakryiko Cc: bpf@vger.kernel.org Cc: Joel Fernandes Cc: Jordan Rife Cc: linux-trace-kernel@vger.kernel.org Link: https://lore.kernel.org/20241123153031.2884933-5-mathieu.desnoyers@efficios.com Signed-off-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt (Google) --- include/linux/tracepoint.h | 45 ++++++++++---------------------------- 1 file changed, 12 insertions(+), 33 deletions(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 867f3c1ac7dc..832f49b56b1f 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -209,31 +209,6 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #define __DO_TRACE_CALL(name, args) __traceiter_##name(NULL, args) #endif /* CONFIG_HAVE_STATIC_CALL */ -/* - * With @syscall=0, the tracepoint callback array dereference is - * protected by disabling preemption. - * With @syscall=1, the tracepoint callback array dereference is - * protected by Tasks Trace RCU, which allows probes to handle page - * faults. - */ -#define __DO_TRACE(name, args, cond, syscall) \ - do { \ - if (!(cond)) \ - return; \ - \ - if (syscall) \ - rcu_read_lock_trace(); \ - else \ - preempt_disable_notrace(); \ - \ - __DO_TRACE_CALL(name, TP_ARGS(args)); \ - \ - if (syscall) \ - rcu_read_unlock_trace(); \ - else \ - preempt_enable_notrace(); \ - } while (0) - /* * Make sure the alignment of the structure in the __tracepoints section will * not add unwanted padding between the beginning of the section and the @@ -282,10 +257,12 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), cond, PARAMS(data_proto)) \ static inline void trace_##name(proto) \ { \ - if (static_branch_unlikely(&__tracepoint_##name.key)) \ - __DO_TRACE(name, \ - TP_ARGS(args), \ - TP_CONDITION(cond), 0); \ + if (static_branch_unlikely(&__tracepoint_##name.key)) { \ + if (cond) { \ + scoped_guard(preempt_notrace) \ + __DO_TRACE_CALL(name, TP_ARGS(args)); \ + } \ + } \ if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ WARN_ONCE(!rcu_is_watching(), \ "RCU not watching for tracepoint"); \ @@ -297,10 +274,12 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) static inline void trace_##name(proto) \ { \ might_fault(); \ - if (static_branch_unlikely(&__tracepoint_##name.key)) \ - __DO_TRACE(name, \ - TP_ARGS(args), \ - TP_CONDITION(cond), 1); \ + if (static_branch_unlikely(&__tracepoint_##name.key)) { \ + if (cond) { \ + scoped_guard(rcu_tasks_trace) \ + __DO_TRACE_CALL(name, TP_ARGS(args)); \ + } \ + } \ if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ WARN_ONCE(!rcu_is_watching(), \ "RCU not watching for tracepoint"); \ From patchwork Sun Nov 24 23:49:46 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 13884295 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8F58418C031; Sun, 24 Nov 2024 23:49:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732492173; cv=none; b=qwem52Jl8M/MpBxNagThwKNa76zmNZdFfLjq8/uRNaJ6c13bE4CyOBtbms+Cjg1LGXki7LifzrOIipdj8jI48GiVmTz0joiPvvjSwVCeEY2mlaYNdemxOfdUB/nOeBUsRlzQmuj9TchhkM8koyzinmgNGUKH+obCW/7i/eyVPKw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732492173; c=relaxed/simple; bh=BlBwOL/w3gx0AUldIPoarft+PBQzsa3kJ+PTEt5vlKs=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=OJy0JfOW37emKdp6FUBhcrP669S2z7NVCiUGz4rI5TsTv/Y97nDYTkMteXqLxejopv4YpYS15O2BdPeNkzk/s8nrtt7aphIHqvtSJ4Dv8/qeiKhg1O1QzjGdiHUUCCxCDDLzUBiv8L3hObzpP1pxhsYVNqrh6ga0mSCqggGDm/8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BF72C4CED9; Sun, 24 Nov 2024 23:49:33 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.98) (envelope-from ) id 1tFMMt-00000006vlc-2UW9; Sun, 24 Nov 2024 18:50:19 -0500 Message-ID: <20241124235019.444613315@goodmis.org> User-Agent: quilt/0.68 Date: Sun, 24 Nov 2024 18:49:46 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Linus Torvalds , Thomas Gleixner , Michael Jeanson , Peter Zijlstra , Alexei Starovoitov , Yonghong Song , "Paul E. McKenney" , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Namhyung Kim , Andrii Nakryiko , bpf@vger.kernel.org, Joel Fernandes , Jordan Rife , linux-trace-kernel@vger.kernel.org Subject: [for-next][PATCH 6/6] tracing: Remove cond argument from __DECLARE_TRACE_SYSCALL References: <20241124234940.017394686@goodmis.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Mathieu Desnoyers Syscall tracepoints do not require a "cond" argument, because they are meant to be used only for sys_enter and sys_exit instrumentation, which don't require condition evaluation. Cc: Linus Torvalds Cc: Thomas Gleixner Cc: Michael Jeanson Cc: Masami Hiramatsu Cc: Peter Zijlstra Cc: Alexei Starovoitov Cc: Yonghong Song Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Mark Rutland Cc: Alexander Shishkin Cc: Namhyung Kim Cc: Andrii Nakryiko Cc: bpf@vger.kernel.org Cc: Joel Fernandes Cc: Jordan Rife Cc: linux-trace-kernel@vger.kernel.org Link: https://lore.kernel.org/20241123153031.2884933-6-mathieu.desnoyers@efficios.com Signed-off-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt (Google) --- include/linux/tracepoint.h | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 832f49b56b1f..b2633a72e871 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -220,7 +220,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) * site if it is not watching, as it will need to be active when the * tracepoint is enabled. */ -#define __DECLARE_TRACE_COMMON(name, proto, args, cond, data_proto) \ +#define __DECLARE_TRACE_COMMON(name, proto, args, data_proto) \ extern int __traceiter_##name(data_proto); \ DECLARE_STATIC_CALL(tp_func_##name, __traceiter_##name); \ extern struct tracepoint __tracepoint_##name; \ @@ -254,7 +254,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) } #define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ - __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), cond, PARAMS(data_proto)) \ + __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), PARAMS(data_proto)) \ static inline void trace_##name(proto) \ { \ if (static_branch_unlikely(&__tracepoint_##name.key)) { \ @@ -269,18 +269,16 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) } \ } -#define __DECLARE_TRACE_SYSCALL(name, proto, args, cond, data_proto) \ - __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), cond, PARAMS(data_proto)) \ +#define __DECLARE_TRACE_SYSCALL(name, proto, args, data_proto) \ + __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), PARAMS(data_proto)) \ static inline void trace_##name(proto) \ { \ might_fault(); \ if (static_branch_unlikely(&__tracepoint_##name.key)) { \ - if (cond) { \ - scoped_guard(rcu_tasks_trace) \ - __DO_TRACE_CALL(name, TP_ARGS(args)); \ - } \ + scoped_guard(rcu_tasks_trace) \ + __DO_TRACE_CALL(name, TP_ARGS(args)); \ } \ - if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ + if (IS_ENABLED(CONFIG_LOCKDEP)) { \ WARN_ONCE(!rcu_is_watching(), \ "RCU not watching for tracepoint"); \ } \ @@ -363,7 +361,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #else /* !TRACEPOINTS_ENABLED */ -#define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ +#define __DECLARE_TRACE_COMMON(name, proto, args, data_proto) \ static inline void trace_##name(proto) \ { } \ static inline int \ @@ -387,7 +385,11 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) return false; \ } -#define __DECLARE_TRACE_SYSCALL __DECLARE_TRACE +#define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ + __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), PARAMS(data_proto)) + +#define __DECLARE_TRACE_SYSCALL(name, proto, args, data_proto) \ + __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), PARAMS(data_proto)) #define DEFINE_TRACE_FN(name, reg, unreg, proto, args) #define DEFINE_TRACE_SYSCALL(name, reg, unreg, proto, args) @@ -453,7 +455,6 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #define DECLARE_TRACE_SYSCALL(name, proto, args) \ __DECLARE_TRACE_SYSCALL(name, PARAMS(proto), PARAMS(args), \ - cpu_online(raw_smp_processor_id()), \ PARAMS(void *__data, proto)) #define TRACE_EVENT_FLAGS(event, flag)