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 1537DC432C3 for ; Sat, 16 Nov 2019 10:51:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DC34D20723 for ; Sat, 16 Nov 2019 10:51:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ROMJcx61" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727378AbfKPKrZ (ORCPT ); Sat, 16 Nov 2019 05:47:25 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:32839 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727000AbfKPKrZ (ORCPT ); Sat, 16 Nov 2019 05:47:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573901244; 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=7gF0eJeuiZodSAhORXmoP5s14B2XONiOXpf6C0HyEY4=; b=ROMJcx61sSzZOE4Qwjt6RNvkEzJfMAkLZnyhFcN30/XQB1oc9Sxra6moSZdzq2JFJM2Xoc DeXH6umn643L2D8PA8KT/tl9ZCpvmv+6W9tgdRZJgJpgCDa6wXCGmK6/8x9Gv7DGn6YsVq FuZ5pmuckXQw2wjN5vx89ZHP9/2XGAc= 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-329-5Aq7myTPN0CNbvF4tTnNcQ-1; Sat, 16 Nov 2019 05:47:18 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8290E1005502; Sat, 16 Nov 2019 10:47:16 +0000 (UTC) Received: from carbon (ovpn-200-17.brq.redhat.com [10.40.200.17]) by smtp.corp.redhat.com (Postfix) with ESMTP id 16AF86055F; Sat, 16 Nov 2019 10:47:08 +0000 (UTC) Date: Sat, 16 Nov 2019 11:47:07 +0100 From: Jesper Dangaard Brouer To: "Jonathan Lemon" Cc: "Toke =?UTF-8?B?SMO4aWxhbmQtSsO4cmdlbnNlbg==?=" , netdev@vger.kernel.org, "Ilias Apalodimas" , "Saeed Mahameed" , "Matteo Croce" , "Lorenzo Bianconi" , "Tariq Toukan" , brouer@redhat.com Subject: Re: [net-next v1 PATCH 3/4] page_pool: block alloc cache during shutdown Message-ID: <20191116114707.0bfde142@carbon> In-Reply-To: <8FD50D75-44C3-4C67-984E-0B85ADE6BAA5@gmail.com> References: <157383032789.3173.11648581637167135301.stgit@firesoul> <157383036914.3173.12541360542055110975.stgit@firesoul> <8FD50D75-44C3-4C67-984E-0B85ADE6BAA5@gmail.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: 5Aq7myTPN0CNbvF4tTnNcQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 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 10:38:21 -0800 "Jonathan Lemon" wrote: > Case 1: > Now, if the driver screws up and tries to re-use the pool and allocate > another packet, it enters __page_pool_get_cached(), which will decrement > the alloc.count, and return NULL. This causes a fallback to > __get_alloc_pages_slow(), which bumps up the pool inflight count. I can see that I made a mistake, and cannot use NULL as the poison value. Let me drop this patch, so others (and yours) can go in before merge window. --=20 Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer