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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 1F6A8C433E8 for ; Tue, 28 Jul 2020 18:26:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB564207F5 for ; Tue, 28 Jul 2020 18:26:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595960797; bh=aXTVVd/PUq8HmC+vBJeiVp8AV7G5PpSGCFiIIoApAkI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Z5MstlPVjANJkKsf4NYvZDMrymrxwScXDNNpw2MVBwjvloW4fumZBmYNBeETTKV2G vA/siP0nWumhk7ihApCG6Xy/okbAR03aYePh9YpnTMZ4dOaMkKUP9kBq2Avg4swkRz R5RLrPA+Bod/snhZBGlMEQiqzRxCFeFYuJ0Das/A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732377AbgG1S0g (ORCPT ); Tue, 28 Jul 2020 14:26:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:42214 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728401AbgG1S0f (ORCPT ); Tue, 28 Jul 2020 14:26:35 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E4C9F20714; Tue, 28 Jul 2020 18:26:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595960795; bh=aXTVVd/PUq8HmC+vBJeiVp8AV7G5PpSGCFiIIoApAkI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=odHdzjzuQYx+MPDxNKNSDwptoi/CNSJvKhnXrdaeAXof1G5zuITqzK2dsq1SBzzOv oNzXdSyOscyi5V7fyLbWH6BgNmjw89ChZAgq2RqDY1f8SjVL3kb/qWVAHqFgFwynyP V4UjLdDbXA6jJwR/bw5sw3KDSpZ6c+c5JsYAfqAE= Date: Tue, 28 Jul 2020 20:26:28 +0200 From: Greg KH To: Jonathan Lemon Cc: netdev@vger.kernel.org, kernel-team@fb.com Subject: Re: [RFC PATCH v2 11/21] core/skbuff: add page recycling logic for netgpu pages Message-ID: <20200728182628.GB328787@kroah.com> References: <20200727224444.2987641-1-jonathan.lemon@gmail.com> <20200727224444.2987641-12-jonathan.lemon@gmail.com> <20200728162825.GC4181352@kroah.com> <20200728180040.az3xgwzmuz6grv32@bsd-mbp.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200728180040.az3xgwzmuz6grv32@bsd-mbp.dhcp.thefacebook.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Jul 28, 2020 at 11:00:40AM -0700, Jonathan Lemon wrote: > On Tue, Jul 28, 2020 at 06:28:25PM +0200, Greg KH wrote: > > On Mon, Jul 27, 2020 at 03:44:34PM -0700, Jonathan Lemon wrote: > > > From: Jonathan Lemon > > > > > > netgpu pages will always have a refcount of at least one (held by > > > the netgpu module). If the skb is marked as containing netgpu ZC > > > pages, recycle them back to netgpu. > > > > What??? > > Yes, this is page refcount elevation. ZONE_DEVICE pages do this also, > which is hidden in put_devmap_managed_page(). I would really like to > find a generic solution for this, as it has come up in other cases as > well (page recycling for page_pool, for example). Some way to say "this > page is different", and a separate routine to release refcounts. > > Can we have a discussion on this possibility? Then propose a generic solution, not a "solution" like this. greg k-h