From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 895B41E103F; Mon, 21 Oct 2024 08:01:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729497691; cv=none; b=qJHy+POa7uh2V4LWXgwS6jOZ5FYV3Rt1B86ZCjr+PXI+jqnkD6t3DsAG+qIFA5idczKg9eq98eJLIUSfi0gUK2u/oNoo6drC9vl9BkBynJAR6sGj7gQIZ82Opm2TQSD4tbXkKTG5VYd6vwe/S3biZYAW7Ute40Pj6hAppS6sbFs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729497691; c=relaxed/simple; bh=qYaluKYeXjK/vxavp1QyHP7JhfNcOYobyCl7MtCijIk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=gQe5pWVMvi+f2+IL1auu6jHdVsjB7fzrETNjGiETAZa9qzllsRlioDcaRuYSiK/BpWXmJuLhTW/0nhcIwxkz+PZP8HXzYYc6+dfU61fosrwfbFOBDtV5BFCJxGT6TjaWk1BvhtEBqdaD0hhNV8WXbbGPRdygGhPj4CMg025OX5g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8EB09DA7; Mon, 21 Oct 2024 01:01:58 -0700 (PDT) Received: from [10.57.87.148] (unknown [10.57.87.148]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BB05C3F71E; Mon, 21 Oct 2024 01:01:27 -0700 (PDT) Message-ID: <218a79b3-8bf1-4a2a-a137-092920830b91@arm.com> Date: Mon, 21 Oct 2024 09:01:25 +0100 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] fgraph: Separate size of ret_stack from PAGE_SIZE Content-Language: en-GB To: Steven Rostedt , LKML , Linux trace kernel Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers References: <20241019152951.053f9646@rorschach.local.home> From: Ryan Roberts In-Reply-To: <20241019152951.053f9646@rorschach.local.home> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 19/10/2024 20:29, Steven Rostedt wrote: > From: Steven Rostedt > > 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 > Signed-off-by: Steven Rostedt (Google) LGTM! Reviewed-by: Ryan Roberts > --- > 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 \