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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 AE830C433ED for ; Sat, 10 Apr 2021 17:42:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74C24611C9 for ; Sat, 10 Apr 2021 17:42:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234680AbhDJRnA (ORCPT ); Sat, 10 Apr 2021 13:43:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41534 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234392AbhDJRnA (ORCPT ); Sat, 10 Apr 2021 13:43:00 -0400 Received: from mail-lj1-x235.google.com (mail-lj1-x235.google.com [IPv6:2a00:1450:4864:20::235]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45913C06138A for ; Sat, 10 Apr 2021 10:42:45 -0700 (PDT) Received: by mail-lj1-x235.google.com with SMTP id u20so10207776lja.13 for ; Sat, 10 Apr 2021 10:42:45 -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=YQRCaZgP2UefM3Ubw17zbmZirkjkTDsaBGQG+axJ5kQ=; b=mjbnE9JRYwo/fH61O7Xyg2aVRfgPRGJsm4XORh9xQMVPMxNp+zDIb9pMaFMV3ATQt1 +M6LrxvuT5e9oDB0rkXB3wmBvNR5UTP6ndLcJvIlUC/C6YqLmzFDpNWr6yxOzloHsibA tBA385gGi2e6vbt5P0I+lZ4/gLnEsvg1MMxBJz/poKMw42gMCkjCZeJAsSPJtDpkVpmL h4P0hfiQhLFbhxUpMMAUkID0aSo/qqJaKEmrSEfzJ2rIKAOhoLyFc+USxeCPa8Cy817P zqEMX41eeVSLoHDtC8131M4jumJazcD+PQis77VUdbRdVU4X/JjbmLmGylWWbsV/pbX4 HxRw== 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=YQRCaZgP2UefM3Ubw17zbmZirkjkTDsaBGQG+axJ5kQ=; b=A4O3YqDDzde9g3NQ3xuLcX06jOyA0+jpKjKEXJh+1HR66tiilwl9Oiqcpy6gTueuTI A8N2W7KaSAhXtmN1v4A831j/hP6J9Z2MgskTSe/Mw6vPa6+E9Seobkk7WjeJhvfIiSWJ jz+oJpFWUZboV46doWu5QtpJXyCM+0USrQicipLbqZ1BfdVc4NFzrDKbUW0XP4+USWFm 82eMTyJY/BoofOa+fZr31hEwjDlJ95aqjZTjJv8QlZzNZJ/co2VKzPSmRetcYq1xlDuc jzwfUl8sEzU3XwFzxBCFkW/12MV41NwdKG/KGn6GUjMwrThS2fzxwsgqUqbSoYgfmlsC Te7w== X-Gm-Message-State: AOAM530TloU40CfxptZn6KN7EwhRjwDOTmqXzVASGTl/mJFFK3sZXHGi dTe75KVvbgwVlv45dDpr5tKqiD6YF8SoK75Qnqn5gw== X-Google-Smtp-Source: ABdhPJz54PyIV6KeuDGJx6pxTDDePDj+YPgyrhMW/RNrlHb4Plp9GyuL8iOp7iVgh+YTm/eAuEaH7X7lzhVg+2SHD4E= X-Received: by 2002:a2e:9cc4:: with SMTP id g4mr12781684ljj.34.1618076563428; Sat, 10 Apr 2021 10:42:43 -0700 (PDT) MIME-Version: 1.0 References: <20210409223801.104657-1-mcroce@linux.microsoft.com> <20210409223801.104657-3-mcroce@linux.microsoft.com> <20210410154824.GZ2531743@casper.infradead.org> In-Reply-To: From: Shakeel Butt Date: Sat, 10 Apr 2021 10:42:30 -0700 Message-ID: Subject: Re: [PATCH net-next v3 2/5] mm: add a signature in struct page To: Ilias Apalodimas Cc: Matthew Wilcox , Matteo Croce , netdev , Linux MM , Ayush Sawal , Vinay Kumar Yadav , Rohit Maheshwari , "David S. Miller" , Jakub Kicinski , Thomas Petazzoni , Marcin Wojtas , Russell King , Mirko Lindner , Stephen Hemminger , Tariq Toukan , Jesper Dangaard Brouer , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Boris Pismenny , Arnd Bergmann , Andrew Morton , "Peter Zijlstra (Intel)" , Vlastimil Babka , Yu Zhao , Will Deacon , Michel Lespinasse , Fenghua Yu , Roman Gushchin , Hugh Dickins , Peter Xu , Jason Gunthorpe , Guoqing Jiang , Jonathan Lemon , Alexander Lobakin , Cong Wang , wenxu , Kevin Hao , Aleksandr Nogikh , Jakub Sitnicki , Marco Elver , Willem de Bruijn , Miaohe Lin , Yunsheng Lin , Guillaume Nault , LKML , linux-rdma@vger.kernel.org, bpf , Eric Dumazet , David Ahern , Lorenzo Bianconi , Saeed Mahameed , Andrew Lunn , Paolo Abeni Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Sat, Apr 10, 2021 at 9:16 AM Ilias Apalodimas wrote: > > Hi Matthew > > On Sat, Apr 10, 2021 at 04:48:24PM +0100, Matthew Wilcox wrote: > > On Sat, Apr 10, 2021 at 12:37:58AM +0200, Matteo Croce wrote: > > > This is needed by the page_pool to avoid recycling a page not allocated > > > via page_pool. > > > > Is the PageType mechanism more appropriate to your needs? It wouldn't > > be if you use page->_mapcount (ie mapping it to userspace). > > Interesting! > Please keep in mind this was written ~2018 and was stale on my branches for > quite some time. So back then I did try to use PageType, but had not free > bits. Looking at it again though, it's cleaned up. So yes I think this can > be much much cleaner. Should we go and define a new PG_pagepool? > > Can this page_pool be used for TCP RX zerocopy? If yes then PageType can not be used. There is a recent discussion [1] on memcg accounting of TCP RX zerocopy and I am wondering if this work can somehow help in that regard. I will take a look at the series. [1] https://lore.kernel.org/linux-mm/20210316013003.25271-1-arjunroy.kdev@gmail.com/