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 picard.linux.it (picard.linux.it [213.254.12.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 87112C433EF for ; Thu, 16 Jun 2022 21:43:26 +0000 (UTC) Received: from picard.linux.it (localhost [IPv6:::1]) by picard.linux.it (Postfix) with ESMTP id 63AE43C7730 for ; Thu, 16 Jun 2022 23:43:23 +0200 (CEST) Received: from in-2.smtp.seeweb.it (in-2.smtp.seeweb.it [IPv6:2001:4b78:1:20::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by picard.linux.it (Postfix) with ESMTPS id 71C873C0611 for ; Thu, 16 Jun 2022 23:43:13 +0200 (CEST) Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by in-2.smtp.seeweb.it (Postfix) with ESMTPS id C4D546019BA for ; Thu, 16 Jun 2022 23:43:12 +0200 (CEST) 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-out2.suse.de (Postfix) with ESMTPS id A2E0B1F8BB; Thu, 16 Jun 2022 21:43:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1655415791; h=from:from:reply-to: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=JLyk2c8oTu74ZAH8zpRvLLf+udG2nn39qky28m7s72c=; b=X36tu04V5AQ2DZuvkVRYtYk4740Q4XDXW0/MyjFXTKvojnb4EDFJnXCAwkDHqgGyFxBfyS sSH5gWT2SSmAWo4sPoq3tF4x+rO+JmED2zFOS4vhLGEwLWpCPvUxX3y8Uu1I6nA3gLjNIp YsD94zExi1wvdkGxlWCTFV6Lq41SZZE= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1655415791; h=from:from:reply-to: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=JLyk2c8oTu74ZAH8zpRvLLf+udG2nn39qky28m7s72c=; b=3PcYd1ujAwNKPpB1hfnPkSFDqSBLBdaEN/KIbzTu20MfhpFaibh+OYxP5/U4EHR8/wbi+g HHyCuR4TWA92guDA== 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 8203C1344E; Thu, 16 Jun 2022 21:43:11 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id V3f5He+jq2JxPQAAMHmgww (envelope-from ); Thu, 16 Jun 2022 21:43:11 +0000 Date: Thu, 16 Jun 2022 23:43:10 +0200 From: Petr Vorel To: Cyril Hrubis Message-ID: References: <20220616134919.8248-1-chrubis@suse.cz> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220616134919.8248-1-chrubis@suse.cz> X-Virus-Scanned: clamav-milter 0.102.4 at in-2.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH] syscalls/fork13: Rewrite to new API + add .max_runtime X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Petr Vorel Cc: ltp@lists.linux.it Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" Hi Cyril, > This fixes a problem we had for years, the test can run for more than > half an hour on slow systems and it used to timeout quite often. +1 > This commit introduces a max_runtime with a 10 minute limit which is > more than enough for the test to complete on a modern hardware but at > the same time it limits the runtime to a sensible value on older > hardware and embedded. +1 Original implementation was quite nicely written (at least some parts were reused), which clearly demonstrates advantages of new LTP API. LGTM. Reviewed-by: Petr Vorel I'd just formatted the doc differently: /*\ * [Description] * * A race in pid generation that causes pids to be reused immediately * * From the mainline commit 5fdee8c4a5e1800489ce61963208f8cc55e42ea1: * * A program that repeatedly forks and waits is susceptible to having * the same pid repeated, especially when it competes with another * instance of the same program. This is really bad for bash * implementation. Furthermore, many shell scripts assume that pid * numbers will not be used for some length of time. * * [Race Description] * --------------------------------------------------------------------- * A B * * // pid == offset == n // pid == offset == n + 1 * test_and_set_bit(offset, map->page) * test_and_set_bit(offset, map->page); * pid_ns->last_pid = pid; * pid_ns->last_pid = pid; * // pid == n + 1 is freed (wait()) * * // Next fork()... * last = pid_ns->last_pid; // == n * pid = last + 1; * --------------------------------------------------------------------- */ Kind regards, Petr -- Mailing list info: https://lists.linux.it/listinfo/ltp