From mboxrd@z Thu Jan 1 00:00:00 1970 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 1ACFD387; Fri, 19 Apr 2024 01:00:45 +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=1713488447; cv=none; b=KSxucfK8OBovkd2HWVsldtGj1TEFVzN7TYXGxH4aK2LqzF5NxDaj3YEIUdvhoCuETFqzII9DlhZts5tkQwa1++8uyioQacS9W+CcINqHsWtoWOefqn25gdHSTFOfFOvsJh8Bd25aUtFbFANsuwxjmvBQjiTyW9WiLJbxYmGGmbc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713488447; c=relaxed/simple; bh=XFzhEyqV5YsqpLwt4BrqCkFpF2S281XGzoHpYGcHyHY=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=N3V9rSbSmUqVa7ofPar6l446WF44ZQasxs3+o3Z+/2sDh9A//pvCSGJJj2xBHsPLJ57Y/VOg8pBgm25OmwKHZc9hwA7kf5EvxwdXcIckUiWxdN5/u7uPI+auNow22D5CFGJXNx4rT+sVuEo+VaE812LJhDQaEDnL4kANYOJpDec= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oppxipOF; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oppxipOF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3033C113CC; Fri, 19 Apr 2024 01:00:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713488445; bh=XFzhEyqV5YsqpLwt4BrqCkFpF2S281XGzoHpYGcHyHY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=oppxipOFse5GDwNE649jX4M8R55x4t+JEpvOcxdXYx0DVQEckHLqNjSM/MkzEJ+Jl wlK0IXurU+kgpYBTUor4vMzemNj7lI7osK+42pSL/taipdQUZ7d5+1vV4+qL/p1Sgt D3DGlkdBGu+LX1DoXZHuRmCrGm/YBqofwaNKraNm7wiXw+WJtVOfxM7vY8WrjMTsM+ +WSoNIfMHRUvxRUH4HDbXkdPnlfxuTWifw/xOU+aFgk0MSkzsS8ZvattAlZz/9PMcC +Wvxh3JrY8GRz6qHo6RUIit0qXThziTPXFHdFhJCzFvdwF9YTqrbqeReRdi8pcMeOh V7lZQ1Uv7NZQA== Date: Fri, 19 Apr 2024 10:00:41 +0900 From: Masami Hiramatsu (Google) To: Andrii Nakryiko Cc: linux-trace-kernel@vger.kernel.org, rostedt@goodmis.org, bpf@vger.kernel.org, jolsa@kernel.org, "Paul E . McKenney" Subject: Re: [PATCH v4 2/2] rethook: honor CONFIG_FTRACE_VALIDATE_RCU_IS_WATCHING in rethook_try_get() Message-Id: <20240419100041.87152aa873cbf25e52b8bd4f@kernel.org> In-Reply-To: <20240418190909.704286-2-andrii@kernel.org> References: <20240418190909.704286-1-andrii@kernel.org> <20240418190909.704286-2-andrii@kernel.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 18 Apr 2024 12:09:09 -0700 Andrii Nakryiko wrote: > Take into account CONFIG_FTRACE_VALIDATE_RCU_IS_WATCHING when validating > that RCU is watching when trying to setup rethooko on a function entry. > > One notable exception when we force rcu_is_watching() check is > CONFIG_KPROBE_EVENTS_ON_NOTRACE=y case, in which case kretprobes will use > old-style int3-based workflow instead of relying on ftrace, making RCU > watching check important to validate. > > This further (in addition to improvements in the previous patch) > improves BPF multi-kretprobe (which rely on rethook) runtime throughput > by 2.3%, according to BPF benchmarks ([0]). > > [0] https://lore.kernel.org/bpf/CAEf4BzauQ2WKMjZdc9s0rBWa01BYbgwHN6aNDXQSHYia47pQ-w@mail.gmail.com/ > > Signed-off-by: Andrii Nakryiko Thanks for update! This looks good to me. Acked-by: Masami Hiramatsu (Google) Thanks, > --- > kernel/trace/rethook.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/trace/rethook.c b/kernel/trace/rethook.c > index fa03094e9e69..a974605ad7a5 100644 > --- a/kernel/trace/rethook.c > +++ b/kernel/trace/rethook.c > @@ -166,6 +166,7 @@ struct rethook_node *rethook_try_get(struct rethook *rh) > if (unlikely(!handler)) > return NULL; > > +#if defined(CONFIG_FTRACE_VALIDATE_RCU_IS_WATCHING) || defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE) > /* > * This expects the caller will set up a rethook on a function entry. > * When the function returns, the rethook will eventually be reclaimed > @@ -174,6 +175,7 @@ struct rethook_node *rethook_try_get(struct rethook *rh) > */ > if (unlikely(!rcu_is_watching())) > return NULL; > +#endif > > return (struct rethook_node *)objpool_pop(&rh->pool); > } > -- > 2.43.0 > -- Masami Hiramatsu (Google)