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 8806AC10F0E for ; Thu, 18 Apr 2019 20:06:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48559214DA for ; Thu, 18 Apr 2019 20:06:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ab/J3/zi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388389AbfDRUGJ (ORCPT ); Thu, 18 Apr 2019 16:06:09 -0400 Received: from mail-oi1-f193.google.com ([209.85.167.193]:34839 "EHLO mail-oi1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729198AbfDRUGI (ORCPT ); Thu, 18 Apr 2019 16:06:08 -0400 Received: by mail-oi1-f193.google.com with SMTP id j132so2587667oib.2 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=eYVY8xUy275P6afs3lzaQMq2QB6cf+FsIkCoguEGNSY=; b=ab/J3/ziVHGeK6AZ7ZI9U/D4FIcK5uHT3rtphl0e2TNACroS1dOdeoDeYm+sNXODUu XKjrSQ84lOw3+m1Hg3dezwBcUCCDslxvu2LFBlNKpQX/BQ/1xSiP1TUDJA+J8HigzQ3K 5dq64bB818IJzyvEA6HaSfa6q6j823+gD6D4Jjz+JRoEx9DwX2v6BSZT/KYJBhnhzP47 NMQRQix3RKjBuU9JyR9ILLpcI4WVIIgcjXOnKDAIDBFL/s86ljQNBGxLhySzM1sRSEvh oymj0rsHEp+HdxTvFpuqDRufMQMxqqsGmUnlUh8/HZ7FqzuWc9sQb8EUNpqzksju6jVo YqGQ== 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=eYVY8xUy275P6afs3lzaQMq2QB6cf+FsIkCoguEGNSY=; b=gqmQde9KwWm9w3ZsEW6DPOyOx0rWR0i7Iif1+kh62dp8eZSHFMTSHbC0cmHLnFglIB s93E7OC4DyqpEssUmgMZqEaizFhtnTX30CzofiBxWJLtnPWOUkAKF6A8q/Z5o/5F6OFn EwzicG6z+bxmT4aIpIP2ZeRkW7ekR0rgG54Nmj6FVa77cr8faD2mMb3EOlWimVkOacDo f4Ph7tT5lnV3V2Pn7dixePidOZu5tfp4DLV0860vzLXl6bkAW8ITjRp4lgpboD7TPW8j fzjB70yXJQWURwgjudCamqzZqoXx06xaOnJVAVCFZcKhns6Zzl4+9YV8PHu/NS9is9Wo QyvA== X-Gm-Message-State: APjAAAXgv+KlReGAMNx2S+Yhk2zn/XP/9aJqb190uUrQNm8Yaguhn4Pu GTToO0cyUS3TPeCUe6ZiNTt/HKDxUh7PynC6zkglBoaP 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="0000000000006264b50586d38831" Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org --0000000000006264b50586d38831 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. --0000000000006264b50586d38831 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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