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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88850C48BE5 for ; Wed, 16 Jun 2021 01:03:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6FDD961351 for ; Wed, 16 Jun 2021 01:03:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231290AbhFPBGA (ORCPT ); Tue, 15 Jun 2021 21:06:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:36954 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230488AbhFPBF7 (ORCPT ); Tue, 15 Jun 2021 21:05:59 -0400 Received: from rorschach.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EADD361246; Wed, 16 Jun 2021 01:03:53 +0000 (UTC) Date: Tue, 15 Jun 2021 21:03:51 -0400 From: Steven Rostedt To: Masami Hiramatsu Cc: "Naveen N. Rao" , Anton Blanchard , linux-kernel@vger.kernel.org, Peter Zijlstra Subject: Re: [PATCH 2/2] trace/kprobe: Remove limit on kretprobe maxactive Message-ID: <20210615210351.602bc03e@rorschach.local.home> In-Reply-To: <20210616094622.c8bd37840898c67dddde1053@kernel.org> References: <20210615183527.9068ef2f70fdd2a45fea78f0@kernel.org> <1623777582.jsiokbdey1.naveen@linux.ibm.com> <20210616094622.c8bd37840898c67dddde1053@kernel.org> X-Mailer: Claws Mail 3.17.8 (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 Wed, 16 Jun 2021 09:46:22 +0900 Masami Hiramatsu wrote: > To avoid such trouble, I had set the 4096 limitation for the maxactive > parameter. Of course 4096 may not enough for some use-cases. I'm welcome > to expand it (e.g. 32k, isn't it enough?), but removing the limitation > may cause OOM trouble easily. What if you just made the max as 10 * number of possible cpus, or 4096, which ever is greater? Why would a user need more? I'd still like to get a wrapper around function graph tracing so that kretprobes could use it. I think that would get rid of the requirement of maxactive, because isn't that just used to have a way to know the original return value? -- Steve