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 09DC3C2BA4C for ; Wed, 26 Jan 2022 18:25:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237445AbiAZSY7 (ORCPT ); Wed, 26 Jan 2022 13:24:59 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:56426 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237412AbiAZSY6 (ORCPT ); Wed, 26 Jan 2022 13:24:58 -0500 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 CCA371F3AF; Wed, 26 Jan 2022 18:24:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1643221497; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IoNCbcwyxnv6CxKL/uuKLe5hgsTrflJcuZ0lUaBY4Xw=; b=CDJ8SJfqLfzlJvW887PQ9qXRLTfNiRoSGkqof4hsIyOB2EYkjuIi9V5XZywCF64oXefHFF xBjlLLKSITIWSaJhCGB7EkA6s9ERjHj6HEMvyWVgn2oJSxxwUAJWrrhKudQPibPr7i9ByF l48J8JZmB8ytxfSOc2rnmHH98ogAhU4= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1643221497; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IoNCbcwyxnv6CxKL/uuKLe5hgsTrflJcuZ0lUaBY4Xw=; b=IVflkwyY72ut2OljZVidqhMoUJZEZEN2SyFj+QE3uB04AVewm9TWjOe3VMAuD5X/u8tzHY kv+tOLvcWU44HMDQ== 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 6F77013E2C; Wed, 26 Jan 2022 18:24:57 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id qDbAGPmR8WGddgAAMHmgww (envelope-from ); Wed, 26 Jan 2022 18:24:57 +0000 Date: Wed, 26 Jan 2022 19:24:55 +0100 From: Petr Vorel To: Shuah Khan Cc: "xuyang2018.jy@fujitsu.com" , "linux-kselftest@vger.kernel.org" , "shuah@kernel.org" , "linux-kernel@vger.kernel.org" , "naresh.kamboju@linaro.org" , "aleksei.kodanev@bell-sw.com" Subject: Re: [PATCH 1/3] selftests/zram: Remove obsolete max_comp_streams interface Message-ID: Reply-To: Petr Vorel References: <1639562171-4434-1-git-send-email-xuyang2018.jy@fujitsu.com> <1146337d-718e-a369-1012-224f06bc9c2f@linuxfoundation.org> <61F0D9F7.1080200@fujitsu.com> <590c1f1c-2da1-583a-d055-83c15969cf80@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <590c1f1c-2da1-583a-d055-83c15969cf80@linuxfoundation.org> Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org > On 1/26/22 12:13 AM, Petr Vorel wrote: > > Hi all, > > > on 2022/1/26 4:33, Shuah Khan wrote : > > > > On 12/15/21 2:56 AM, Yang Xu wrote: > > > > > Since kernel commit 43209ea2d17a ("zram: remove max_comp_streams > > > > > internals"), zram has > > > > > switched to per-cpu streams. Even kernel still keep this interface for > > > > > some reasons, but > > > > > writing to max_comp_stream doesn't take any effect. So remove it. > > > > I get that max_comp_stream doesn't do anything since this referenced > > > > commit. Don't we need this test on older kernels since older kernels > > > > still support max_comp_stream? > > > I read the following info from kernel selftest documentation > > > https://www.kernel.org/doc/html/latest/dev-tools/kselftest.html > > > "The kernel contains a set of “self tests” under the > > > tools/testing/selftests/ directory. These are intended to be small tests > > > to exercise individual code paths in the kernel. Tests are intended to > > > be run after building, installing and booting a kernel." > > > So, we can build older kernel(use older kernel source) if we want to > > > test older kernel. > > > IMO, kernel selftest is different from other testsuit(ie ltp, this > > > shuould think about api changes because ltp may test on different kernel). > > Yes, that's how I understand the difference with approach of in kselftest - the > > kernel tree testsuite and LTP - the out-of-tree testsuite. > Removing max_comp_stream test appears to be motivated by the fact it isn't > needed on newer kernels. > Kselftest from mainline can be run on older stable kernels. This is a use-case > for a lot test rings. The idea is that when a new test gets added for older > code to regression test a bug, we should be able to run that test on an older > kernel. This is the reason why we don't remove code that can still test an older > kernel and make sure it skips gracefully. Thanks for clarifying this approach. It might be worth of documenting it in dev-tools/kselftest.rst. Kind regards, Petr > Hence, I won't be taking this patch. > thanks, > -- Shuah