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 2E822CD4F5B for ; Fri, 22 Sep 2023 11:42:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233787AbjIVLmv (ORCPT ); Fri, 22 Sep 2023 07:42:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233769AbjIVLmt (ORCPT ); Fri, 22 Sep 2023 07:42:49 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C067100 for ; Fri, 22 Sep 2023 04:42:43 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id EC2E621A9E; Fri, 22 Sep 2023 11:42:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1695382961; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=65+lm7d+dGRTiOMAyApVmU/Xt+Gy4JHwF9IUeIK1m1Q=; b=yJPzw4jKA78/KuVPeDtJPzXDAGBL5vPvSoxnuXVCM8RAh2RYriDdPP+yZAKS1CutJLntVi FFh4Iud6erKaiL6VZAjIt13auEAuC/Ru/cFgGCnz0KDuU75TY/uTVxI288PcND9Fv3aST4 gkCLkcAXbu43vZ1RiVGQ5jRQknt5Ec0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1695382961; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=65+lm7d+dGRTiOMAyApVmU/Xt+Gy4JHwF9IUeIK1m1Q=; b=fLpi/29qParzWJqJjq1VQuYRYSpCWpAK2Bu9U9mzTnpOu+5h7/MOI5YeDEWFf+l3OCP1Wd cS4+u8sAD88kp2DQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id D311113478; Fri, 22 Sep 2023 11:42:41 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id w6kLL7F9DWXnJAAAMHmgww (envelope-from ); Fri, 22 Sep 2023 11:42:41 +0000 Date: Fri, 22 Sep 2023 13:43:26 +0200 From: Cyril Hrubis To: Ingo Molnar Cc: Petr Vorel , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , linux-kernel@vger.kernel.org, ltp@lists.linux.it Subject: Re: [LTP] [PATCH] sched/rt: Disallow writing invalid values to sched_rt_period_us Message-ID: References: <20230901154355.5351-1-chrubis@suse.cz> <20230901174529.GB364687@pevik> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > Documentation/scheduller/sched-rt-group.rst [1] specifies this as values from -1 to > > > (INT_MAX - 1), I guess due int range. Looking into proc_dointvec_minmax() [2] > > > even INT_MAX would pass the check. I suppose we can do nothing about that, > > > because there is no value in sysctl_vals[] which would represent INT_MAX - 1. > > > > > > And you specify in LTP test range: from -1 to INT_MAX. > > > > > > But even much shorter value than INT_MAX fails: > > > > > > $ echo 1234567 > /proc/sys/kernel/sched_rt_runtime_us > > > sh: echo: write error: Invalid argument > > > > That is because runtime_us must be < period_us by definition, since > > runtime_us defines how much time is allocated from the period_us. I > > guess that this is not described good enough in the kernel docs. > > Mind adding a second patch to your series, clarifying > Documentation/scheduler/sched-rt-group.rst? Yes, that is the plan. I've been working on LTP release for past two weeks so this has been postponed. I will get to it hopefully next week. -- Cyril Hrubis chrubis@suse.cz