From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 187FAC04A95 for ; Tue, 25 Oct 2022 15:33:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232877AbiJYPdW (ORCPT ); Tue, 25 Oct 2022 11:33:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231313AbiJYPdU (ORCPT ); Tue, 25 Oct 2022 11:33:20 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC7CD57E30 for ; Tue, 25 Oct 2022 08:33:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6A86A61997 for ; Tue, 25 Oct 2022 15:33:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A8DA2C433C1; Tue, 25 Oct 2022 15:33:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666711998; bh=eRDzSkJF+LWtgGnt1Y7/1Uo+B6YVNqwBobA9N504LRg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=mQR3f6Dwufxe4Yf0D995wgyrQuAC91zY39ZO5tkh8PN2QQzWkXT+7SO3GI5bXCJAD +ggfsnK0+dC9cYC9nCrNNOYjcP47l04XFaEgh83QLU2SRzUQRwsPKEZW4RsZHR6d00 PhggN4lrnX5aeUV5LqTlAfrpN4yo/v1qnY6ppdpKW9YaS2BNKk0BHf5xvROxU+tzJ0 FmtGgsfB8j1fBRi1eMoeKGvRO9wG6jeMzBcmBquHFLSiuJ2s6kfULx6QIQ46Unhpli MX7rsCwwfktzXdI89pr1LZcvsOGwoSN0Z9SCYDmdQUnb69M1zBwFlWoQQX7Sop6Tqf sYOyZnDglCo1A== Date: Wed, 26 Oct 2022 00:33:15 +0900 From: Masami Hiramatsu (Google) To: wuqiang Cc: davem@davemloft.net, anil.s.keshavamurthy@intel.com, naveen.n.rao@linux.ibm.com, linux-kernel@vger.kernel.org, mattwu@163.com Subject: Re: [PATCH] kretprobe events missing on 2-core KVM guest Message-Id: <20221026003315.266d59d5c0780c2817be3a0d@kernel.org> In-Reply-To: <20221025100117.18667-1-wuqiang.matt@bytedance.com> References: <20221025100117.18667-1-wuqiang.matt@bytedance.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 25 Oct 2022 18:01:17 +0800 wuqiang wrote: > Default value of maxactive is set as num_possible_cpus() for nonpreemptable > systems. For a 2-core system, only 2 kretprobe instances would be allocated > in default, then these 2 instances for execve kretprobe are very likely to > be used up with a pipelined command. > > This patch increases the minimum of maxactive to 10. > This looks reasonable to me. Acked-by: Masami Hiramatsu (Google) Thank you! > Signed-off-by: wuqiang > --- > kernel/kprobes.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 3220b0a2fb4a..b781dee3f552 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -2211,7 +2211,7 @@ int register_kretprobe(struct kretprobe *rp) > #ifdef CONFIG_PREEMPTION > rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus()); > #else > - rp->maxactive = num_possible_cpus(); > + rp->maxactive = max_t(unsigned int, 10, num_possible_cpus()); > #endif > } > #ifdef CONFIG_KRETPROBE_ON_RETHOOK > -- > 2.34.1 > -- Masami Hiramatsu (Google)