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=-11.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham 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 8EA2AC282DD for ; Thu, 18 Apr 2019 20:06:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4FFA2214DA for ; Thu, 18 Apr 2019 20:06:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Mxwougxj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390120AbfDRUGJ (ORCPT ); Thu, 18 Apr 2019 16:06:09 -0400 Received: from mail-oi1-f194.google.com ([209.85.167.194]:42511 "EHLO mail-oi1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732589AbfDRUGI (ORCPT ); Thu, 18 Apr 2019 16:06:08 -0400 Received: by mail-oi1-f194.google.com with SMTP id w139so2552272oie.9 for ; Thu, 18 Apr 2019 13:06:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=a6psBRnFpB7DT4kJqxN1R2rbuZUxd3M/O30vwsyGIaQ=; b=MxwougxjhQcCTyKYfeGv+CT6C1LW/27c3RnEo5RB48icabS9MZuNIbfzLAdKFm9cg4 pUx2CL/lVJnirHDWUJNVkr0qYSSGsvwpl7863zjCXPdLnL4HBDSy9qjpOSlheODczUQq sd+PxYHPXb5h+vtiOGlbQjCahO9uKZ53r0q9j8i2Mi+v7wxwT6A9nEV5/hLZ4pyP1LUb SSWu3CizXPA45sQeFs8cCaLTtkYv9ws/lHoOLtXo4UM4eFODiRlvLSOHil3Pq1/8W3lS QLYoAxwPtG4KtZYML60KS0kdzbzSunUbB7+3SB9Gz+aqyA+QSiz4Q1VfaDI89A9cHLbq rwJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=a6psBRnFpB7DT4kJqxN1R2rbuZUxd3M/O30vwsyGIaQ=; b=QMbMEWWImszp91nemyI2566WjAWzdtl7jah2lcFQmSwqjtYWLry7JE1+I8ASlzj7ad Ig8VquJ19z1N4gg2mg34hjJM0oQXv9kcKnuRcbjplP4qd4IAX/9f5eMfC11eiKJ8mjlS qBUvX/cNUUaIc4ZLCA8WEHonQXOwp0zs5xdcmwtDcCBUZlaIvaJu9NpPIcf6n+X0HxKg SYsTR5C5NuxxNN/wCkPYmj2m4Vio2ndkXt2OhFI3YcW9Iw0nmrxDiPvH+ToOxSgNa4Yj LdMS4FHAwcjPLUfE9UVjzdX5AFLkRAxyWKI1R8p3XiaU7smX4O/CEIo8JAoUi2ZC4ZpH OsUQ== X-Gm-Message-State: APjAAAXFLypezD7H8B2ZffczNWSInwc0mUepfhUstTkPwF5cNyTOZKW0 Z58PNCLfoLlpWLuNLOnovKf9D/voqJPWMj69WdYjqQ== X-Google-Smtp-Source: APXvYqyk4amR67SqzEPJyzNej8ggsRvFq0vQ+XpcnpCGh+Gt+LDcWGHGbOpTd0FBTt/m3DAZjGuclb1S5HSyLQEe1GA= X-Received: by 2002:aca:f20b:: with SMTP id q11mr3206032oih.4.1555617967313; Thu, 18 Apr 2019 13:06:07 -0700 (PDT) MIME-Version: 1.0 References: <20190416025934.115252-1-khazhy@google.com> <20190418115326.GE28541@quack2.suse.cz> In-Reply-To: <20190418115326.GE28541@quack2.suse.cz> From: Khazhismel Kumykov Date: Thu, 18 Apr 2019 13:05:56 -0700 Message-ID: Subject: Re: [PATCH] ext4: add cond_resched() to ext4_mb_init_backend() To: Jan Kara Cc: "Theodore Ts'o" , adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, Linux Kernel Mailing List Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256; boundary="0000000000006269a80586d38844" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --0000000000006269a80586d38844 Content-Type: text/plain; charset="UTF-8" On Thu, Apr 18, 2019 at 4:53 AM Jan Kara wrote: > > On Mon 15-04-19 19:59:34, Khazhismel Kumykov wrote: > > on non-preempt kernels for filesystems with large number of groups we > > may take a long time (>50 ticks) initializing all the groups. > > > > Signed-off-by: Khazhismel Kumykov > > Thanks for the patch. I'm not opposed to this but I'm just wondering: Has > this caused any real issues to you? Or how have you come across this > particular loop? Because I'd think we have more similar loops in ext4 > codebase... > > Honza > We have some instrumentation to warn for these longer periods without scheduling, which admittedly does trigger relatively frequently from various places. This particular loop just so happens to be during system startup where it caught my eye. --0000000000006269a80586d38844 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIIS5wYJKoZIhvcNAQcCoIIS2DCCEtQCAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg ghBNMIIEXDCCA0SgAwIBAgIOSBtqDm4P/739RPqw/wcwDQYJKoZIhvcNAQELBQAwZDELMAkGA1UE BhMCQkUxGTAXBgNVBAoTEEdsb2JhbFNpZ24gbnYtc2ExOjA4BgNVBAMTMUdsb2JhbFNpZ24gUGVy c29uYWxTaWduIFBhcnRuZXJzIENBIC0gU0hBMjU2IC0gRzIwHhcNMTYwNjE1MDAwMDAwWhcNMjEw NjE1MDAwMDAwWjBMMQswCQYDVQQGEwJCRTEZMBcGA1UEChMQR2xvYmFsU2lnbiBudi1zYTEiMCAG A1UEAxMZR2xvYmFsU2lnbiBIViBTL01JTUUgQ0EgMTCCASIwDQYJKoZIhvcNAQEBBQADggEPADCC AQoCggEBALR23lKtjlZW/17kthzYcMHHKFgywfc4vLIjfq42NmMWbXkNUabIgS8KX4PnIFsTlD6F GO2fqnsTygvYPFBSMX4OCFtJXoikP2CQlEvO7WooyE94tqmqD+w0YtyP2IB5j4KvOIeNv1Gbnnes 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