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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 0DF78C433E6 for ; Thu, 18 Mar 2021 21:32:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B39A964F30 for ; Thu, 18 Mar 2021 21:32:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233230AbhCRVbr (ORCPT ); Thu, 18 Mar 2021 17:31:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33984 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233237AbhCRVbX (ORCPT ); Thu, 18 Mar 2021 17:31:23 -0400 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:191:4433::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9744C06174A; Thu, 18 Mar 2021 14:31:23 -0700 (PDT) Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.94) (envelope-from ) id 1lN0E2-000JE2-TW; Thu, 18 Mar 2021 22:30:39 +0100 Message-ID: <90d11ebdb1f9e13387aa7699702da7e7fecec27d.camel@sipsolutions.net> Subject: Re: [PATCH 4/6] um: split up CONFIG_GCOV From: Johannes Berg To: Brendan Higgins Cc: Linux Kernel Mailing List , linux-um , Jessica Yu , Alexander Viro , linux-fsdevel Date: Thu, 18 Mar 2021 22:30:38 +0100 In-Reply-To: (sfid-20210318_222737_121554_AD23102C) References: <20210312095526.197739-1-johannes@sipsolutions.net> <20210312104627.927fb4c7d36f.Idb980393c41c2129ee592de4ed71e7a5518212f9@changeid> (sfid-20210318_222737_121554_AD23102C) Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.4 (3.38.4-1.fc33) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-malware-bazaar: not-scanned Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hi Brendan, > Hey, thanks for doing this! I was looking into this a few weeks ago > and root caused part of the issue in GCC and in the kernel, but I did > not have a fix put together. > > Anyway, most of the patches make sense to me, but I am not able to > apply this patch on torvalds/master. Do you mind sending a rebase so I > can test it? Well, if you see my other replies in the thread, I gave up for various reasons, see https://lore.kernel.org/r/d36ea54d8c0a8dd706826ba844a6f27691f45d55.camel@sipsolutions.net Personally, I ended up switching to CONFIG_GCOV_KERNEL instead because it actually works for modules, but then it was _really_ slow (think 30s to copy data for a few modules), but I root-caused this and ultimately sent these patches instead: https://patchwork.ozlabs.org/project/linux-um/patch/20210315233804.d3e52f6a3422.I9672eef7dfa7ce6c3de1ccf7ab8d9aad1fa7f3a6@changeid/ https://patchwork.ozlabs.org/project/linux-um/patch/20210315234731.2e03184a344b.I04f1816296f04c5aa7d7d88b33bd4a14dd458da8@changeid/ johannes