From: Ryan Roberts <ryan.roberts@arm.com>
To: Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux trace kernel <linux-trace-kernel@vger.kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [PATCH] fgraph: Separate size of ret_stack from PAGE_SIZE
Date: Mon, 21 Oct 2024 09:01:25 +0100 [thread overview]
Message-ID: <218a79b3-8bf1-4a2a-a137-092920830b91@arm.com> (raw)
In-Reply-To: <20241019152951.053f9646@rorschach.local.home>
On 19/10/2024 20:29, Steven Rostedt wrote:
> From: Steven Rostedt <rostedt@goodmis.org>
>
> The ret_stack (shadow stack used by function graph infrastructure) is
> currently defined as PAGE_SIZE. But some architectures which have 64K
> PAGE_SIZE, this is way overkill. Also there's an effort to allow the
> PAGE_SIZE to be defined at boot up.
>
> Hard code it for now to 4096. In the future, this size may change and even
> be dependent on specific architectures.
>
> Link: https://lore.kernel.org/all/e5067bb8-0fcd-4739-9bca-0e872037d5a1@arm.com/
>
> Suggested-by: Ryan Roberts <ryan.roberts@arm.com>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
LGTM!
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
> ---
> kernel/trace/fgraph.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
> index ee829d65f301..51e81b299a0d 100644
> --- a/kernel/trace/fgraph.c
> +++ b/kernel/trace/fgraph.c
> @@ -153,7 +153,7 @@ enum {
> * SHADOW_STACK_OFFSET: The size in long words of the shadow stack
> * SHADOW_STACK_MAX_OFFSET: The max offset of the stack for a new frame to be added
> */
> -#define SHADOW_STACK_SIZE (PAGE_SIZE)
> +#define SHADOW_STACK_SIZE (4096)
> #define SHADOW_STACK_OFFSET (SHADOW_STACK_SIZE / sizeof(long))
> /* Leave on a buffer at the end */
> #define SHADOW_STACK_MAX_OFFSET \
next prev parent reply other threads:[~2024-10-21 8:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-19 19:29 [PATCH] fgraph: Separate size of ret_stack from PAGE_SIZE Steven Rostedt
2024-10-21 8:01 ` Ryan Roberts [this message]
2024-10-21 14:58 ` Masami Hiramatsu
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