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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 01A6DC432C3 for ; Sat, 16 Nov 2019 10:57:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C236F20723 for ; Sat, 16 Nov 2019 10:57:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YK5NNCmr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727395AbfKPK5C (ORCPT ); Sat, 16 Nov 2019 05:57:02 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:30134 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726794AbfKPK5C (ORCPT ); Sat, 16 Nov 2019 05:57:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573901821; h=from:from:reply-to:subject:subject: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=idEemdPMBikcwuqbCnV2wwyYeIIR9t0wn5/qWR2cpWU=; b=YK5NNCmr8BnXjA+RbAfLvs1s75duJYcjvVN6MMviKSxDigLD9+j4QjfSdv/e+7yV/ZASJg TQioe2bNkpy0gYCXexogmb74GuyG8/AEs/xc1fordC6GTW8VdmB4Q5dPEPgWl4U2xiOU8T naEpXwvsxS+XvADSKt8abjAqHiGvZJ4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-400-jKyod6iMM0SwVOgU_NKzbw-1; Sat, 16 Nov 2019 05:57:00 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C3631800EBA; Sat, 16 Nov 2019 10:56:58 +0000 (UTC) Received: from carbon (ovpn-200-17.brq.redhat.com [10.40.200.17]) by smtp.corp.redhat.com (Postfix) with ESMTP id 849AD1019611; Sat, 16 Nov 2019 10:56:50 +0000 (UTC) Date: Sat, 16 Nov 2019 11:56:49 +0100 From: Jesper Dangaard Brouer To: Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?= Cc: netdev@vger.kernel.org, Ilias Apalodimas , Saeed Mahameed , Matteo Croce , Jonathan Lemon , Lorenzo Bianconi , Tariq Toukan , brouer@redhat.com Subject: Re: [net-next v1 PATCH 2/4] page_pool: add destroy attempts counter and rename tracepoint Message-ID: <20191116115649.25567878@carbon> In-Reply-To: <87h835kskx.fsf@toke.dk> References: <157383032789.3173.11648581637167135301.stgit@firesoul> <157383036409.3173.14386381829936652438.stgit@firesoul> <87h835kskx.fsf@toke.dk> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-MC-Unique: jKyod6iMM0SwVOgU_NKzbw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, 15 Nov 2019 17:33:18 +0100 Toke H=C3=B8iland-J=C3=B8rgensen wrote: > Jesper Dangaard Brouer writes: >=20 > > When Jonathan change the page_pool to become responsible to its > > own shutdown via deferred work queue, then the disconnect_cnt > > counter was removed from xdp memory model tracepoint. > > > > This patch change the page_pool_inflight tracepoint name to > > page_pool_release, because it reflects the new responsability > > better. And it reintroduces a counter that reflect the number of > > times page_pool_release have been tried. > > > > The counter is also used by the code, to only empty the alloc > > cache once. With a stuck work queue running every second and > > counter being 64-bit, it will overrun in approx 584 billion > > years. For comparison, Earth lifetime expectancy is 7.5 billion > > years, before the Sun will engulf, and destroy, the Earth. =20 >=20 > I love how you just casually threw that last bit in there; and now I'm > thinking about under which conditions that would not be enough. Maybe > someone will put this code on a space probe bound for interstellar > space, which will escape the death of our solar system only to be > destined to increment this counter forever in the cold, dead void of > space? Like with performance numbers, when ever presenting a number, I always strive to relate it some something else, as without that the number is just a number. > I think that is a risk we can live with, so: >=20 > Acked-by: Toke H=C3=B8iland-J=C3=B8rgensen Thx --=20 Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer