From: Mark Rutland <mark.rutland@arm.com>
To: madvenka@linux.microsoft.com
Cc: broonie@kernel.org, jpoimboe@redhat.com, ardb@kernel.org,
nobuta.keiya@fujitsu.com, sjitindarsingh@gmail.com,
catalin.marinas@arm.com, will@kernel.org, jmorris@namei.org,
linux-arm-kernel@lists.infradead.org,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 02/11] arm64: Make perf_callchain_kernel() use arch_stack_walk()
Date: Fri, 22 Oct 2021 19:11:54 +0100 [thread overview]
Message-ID: <20211022181154.GM86184@C02TD0UTHF1T.local> (raw)
In-Reply-To: <20211015025847.17694-3-madvenka@linux.microsoft.com>
On Thu, Oct 14, 2021 at 09:58:38PM -0500, madvenka@linux.microsoft.com wrote:
> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
>
> Currently, perf_callchain_kernel() in ARM64 code walks the stack using
> start_backtrace() and walk_stackframe(). Make it use arch_stack_walk()
> instead. This makes maintenance easier.
>
> Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
This looks good to me; bailing out when perf_callchain_store() can't
accept any more entries absolutely makes sense.
I gave this a spin with:
| # perf record -g -c1 ls
| # perf report
... and the recorded callchains look sane.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
As mentioned on patch 1, I'd like to get this rebased atop Peter's
untangling of ARCH_STACKWALK from STACKTRACE.
Thanks,
Mark.
> ---
> arch/arm64/kernel/perf_callchain.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c
> index 4a72c2727309..f173c448e852 100644
> --- a/arch/arm64/kernel/perf_callchain.c
> +++ b/arch/arm64/kernel/perf_callchain.c
> @@ -140,22 +140,18 @@ void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
> static bool callchain_trace(void *data, unsigned long pc)
> {
> struct perf_callchain_entry_ctx *entry = data;
> - perf_callchain_store(entry, pc);
> - return true;
> + return perf_callchain_store(entry, pc) == 0;
> }
>
> void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
> struct pt_regs *regs)
> {
> - struct stackframe frame;
> -
> if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
> /* We don't support guest os callchain now */
> return;
> }
>
> - start_backtrace(&frame, regs->regs[29], regs->pc);
> - walk_stackframe(current, &frame, callchain_trace, entry);
> + arch_stack_walk(callchain_trace, entry, current, regs);
> }
>
> unsigned long perf_instruction_pointer(struct pt_regs *regs)
> --
> 2.25.1
>
next prev parent reply other threads:[~2021-10-22 18:12 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <c05ce30dcc9be1bd6b5e24a2ca8fe1d66246980b>
2021-10-15 2:34 ` [PATCH v9 00/11] arm64: Reorganize the unwinder and implement stack trace reliability checks madvenka
2021-10-15 2:34 ` [PATCH v9 01/11] arm64: Select STACKTRACE in arch/arm64/Kconfig madvenka
2021-10-15 2:34 ` [PATCH v9 10/11] arm64: Introduce stack trace reliability checks in the unwinder madvenka
2021-10-15 2:34 ` [PATCH v9 11/11] arm64: Create a list of SYM_CODE functions, check return PC against list madvenka
2021-10-15 2:34 ` [PATCH v9 02/11] arm64: Make perf_callchain_kernel() use arch_stack_walk() madvenka
2021-10-15 2:34 ` [PATCH v9 03/11] arm64: Make get_wchan() " madvenka
2021-10-15 2:34 ` [PATCH v9 04/11] arm64: Make return_address() " madvenka
2021-10-15 2:34 ` [PATCH v9 05/11] arm64: Make dump_stacktrace() " madvenka
2021-10-15 2:34 ` [PATCH v9 06/11] arm64: Make profile_pc() " madvenka
2021-10-15 2:34 ` [PATCH v9 07/11] arm64: Call stack_backtrace() only from within walk_stackframe() madvenka
2021-10-15 2:34 ` [PATCH v9 08/11] arm64: Rename unwinder functions, prevent them from being traced and kprobed madvenka
2021-10-15 2:34 ` [PATCH v9 09/11] arm64: Make the unwind loop in unwind() similar to other architectures madvenka
2021-10-15 2:53 ` [PATCH v9 00/11] arm64: Reorganize the unwinder and implement stack trace reliability checks Madhavan T. Venkataraman
2021-10-15 2:58 ` [PATCH v10 " madvenka
2021-10-15 2:58 ` [PATCH v10 01/11] arm64: Select STACKTRACE in arch/arm64/Kconfig madvenka
2021-10-15 18:28 ` Mark Brown
2021-10-21 12:28 ` Madhavan T. Venkataraman
2021-10-22 18:02 ` Mark Rutland
2021-11-12 17:44 ` Mark Rutland
2021-11-14 16:15 ` Madhavan T. Venkataraman
2021-10-15 2:58 ` [PATCH v10 02/11] arm64: Make perf_callchain_kernel() use arch_stack_walk() madvenka
2021-10-20 14:59 ` Mark Brown
2021-10-21 12:28 ` Madhavan T. Venkataraman
2021-10-22 18:11 ` Mark Rutland [this message]
2021-10-23 12:49 ` Madhavan T. Venkataraman
2021-10-15 2:58 ` [PATCH v10 03/11] arm64: Make get_wchan() " madvenka
2021-10-20 16:10 ` Mark Brown
2021-10-21 12:30 ` Madhavan T. Venkataraman
2021-10-15 2:58 ` [PATCH v10 04/11] arm64: Make return_address() " madvenka
2021-10-20 15:03 ` Mark Brown
2021-10-21 12:29 ` Madhavan T. Venkataraman
2021-10-22 18:51 ` Mark Rutland
2021-10-23 12:51 ` Madhavan T. Venkataraman
2021-10-15 2:58 ` [PATCH v10 05/11] arm64: Make dump_stacktrace() " madvenka
2021-10-25 16:49 ` Mark Rutland
2021-10-26 12:05 ` Mark Rutland
2021-10-27 16:09 ` Madhavan T. Venkataraman
2021-10-15 2:58 ` [PATCH v10 06/11] arm64: Make profile_pc() " madvenka
2021-10-25 2:18 ` nobuta.keiya
2021-10-27 16:10 ` Madhavan T. Venkataraman
2021-10-27 13:32 ` Mark Rutland
2021-10-27 16:15 ` Madhavan T. Venkataraman
2021-10-15 2:58 ` [PATCH v10 07/11] arm64: Call stack_backtrace() only from within walk_stackframe() madvenka
2021-10-15 2:58 ` [PATCH v10 08/11] arm64: Rename unwinder functions, prevent them from being traced and kprobed madvenka
2021-10-27 17:53 ` Mark Rutland
2021-10-27 20:07 ` Madhavan T. Venkataraman
2021-10-15 2:58 ` [PATCH v10 09/11] arm64: Make the unwind loop in unwind() similar to other architectures madvenka
2021-10-15 2:58 ` [PATCH v10 10/11] arm64: Introduce stack trace reliability checks in the unwinder madvenka
2021-11-04 12:39 ` nobuta.keiya
2021-11-10 3:13 ` Madhavan T. Venkataraman
2021-10-15 2:58 ` [PATCH v10 11/11] arm64: Create a list of SYM_CODE functions, check return PC against list madvenka
2021-10-15 17:00 ` [PATCH v10 00/11] arm64: Reorganize the unwinder and implement stack trace reliability checks Madhavan T. Venkataraman
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