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 BD24536C; Sun, 21 Apr 2024 02:41:01 +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=1713667261; cv=none; b=lFjItgsmk3kFaU6wZaM2m4F4tZgajnj6JZ4Gl/6eEIXdqalocOXCdXFKM5wNxKVN2Mx4txdBpiNwkd0R2gWLFVsJ8FGOMYqGIrJyDwF3ZJCPpPSGi8C/VI6doo8SZBvH2nxRkcNLhX2B0324iYc4GHGZHQHpB4Utjo32dTxyAYo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713667261; c=relaxed/simple; bh=eKFTXERSllwBgJNh3yoEBQ9eO+rzF2j9SfTsRgXU5Fs=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=aKB1nUc2isMOON0D+XEh8zKXLw+x/43Ob4badio7ydgwsYysNxRPGEErSQlxnUnZdlA0suSSQWBAy3izf5OIMYnUvTTV1kv7kzwJ7Tgxm4fXCMXcc5X3d3DcP5tG1yedsX69EtAxMozGhSCowOVju+oo5BAU63fxIJhQt2l8Y1k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ObFqBZr1; 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="ObFqBZr1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3500DC072AA; Sun, 21 Apr 2024 02:40:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713667261; bh=eKFTXERSllwBgJNh3yoEBQ9eO+rzF2j9SfTsRgXU5Fs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ObFqBZr1KZxHJO1L4w7pVipOJOZcnEf7FvQuzq5h5E+IrB4WDkpMD6hh3floo5NwV PMVOneVPs7X2GVbKt7anSU6ZE30SRhx7Yky3+cZK6OvjH/1OTbvC8tpD1gfxpr4xT1 ZSYT/QCIrYBbm2zivr+xqbRwD9gttU+TAMlN8EWs2syAfCJthmhlt6HjS9DnTMiGO7 4QsGKnGkhS30KxbpchKu6V20NjMjiA8KBo+GhopHauj2nRNcq9GbyP0Q64NGSDzWVr fS0pDKlKfThF8AgSUVqF4sRPbuaibFGDEa53/mInaXpud38Nzzt/fr32i5JJAwzOiC qT+VoEI21yv+w== Date: Sun, 21 Apr 2024 11:40:56 +0900 From: Masami Hiramatsu (Google) To: Andrii Nakryiko Cc: Andrii Nakryiko , 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: <20240421114056.a5150b8c9736b390367b38b8@kernel.org> In-Reply-To: References: <20240418190909.704286-1-andrii@kernel.org> <20240418190909.704286-2-andrii@kernel.org> <20240419100041.87152aa873cbf25e52b8bd4f@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=UTF-8 Content-Transfer-Encoding: 8bit On Fri, 19 Apr 2024 10:59:09 -0700 Andrii Nakryiko wrote: > On Thu, Apr 18, 2024 at 6:00 PM Masami Hiramatsu wrote: > > > > 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. > > Thanks, Masami! Will you take it through your tree, or you'd like to > route it through bpf-next? OK, let me take it through linux-trace tree. Thank you! > > > > > 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) -- Masami Hiramatsu (Google)