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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A60A0C6FD1D for ; Tue, 4 Apr 2023 12:19:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234428AbjDDMTl (ORCPT ); Tue, 4 Apr 2023 08:19:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234152AbjDDMTX (ORCPT ); Tue, 4 Apr 2023 08:19:23 -0400 Received: from mail-ed1-x52c.google.com (mail-ed1-x52c.google.com [IPv6:2a00:1450:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72C8A49C9 for ; Tue, 4 Apr 2023 05:14:03 -0700 (PDT) Received: by mail-ed1-x52c.google.com with SMTP id b20so129722494edd.1 for ; Tue, 04 Apr 2023 05:14:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dectris.com; s=google; t=1680610442; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=1FlXMDdCERweSivjHZ7/5B+1YGIBAwVG5BfESYtf7Lw=; b=YX8mzm+GaExr+LtZQZLQbjXBf1wS5hKRbNWLvbv1HjVUsM43EMylri0DSwQKzYdOPA niP9hMX/S7wflAS3uaIVpxFRjuTyNgSicuyHS4XSu+waAvO2edBguxqRD1aXbI5dP9mJ vDVmJ//mmpj6c0Mml6AJnkPMLTXJsMWBWxUpU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680610442; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=1FlXMDdCERweSivjHZ7/5B+1YGIBAwVG5BfESYtf7Lw=; b=Yjn4PI86+3lLZi/YsgwftGERnzw5ArhGuyNliF+JfL8Z7ca7sIaUpwKKKAWy/EJ43K +nXp/Z/wDSwDFMY0fahP6f8RazGgCVskv1lrL3WqPuEzAQiR/uESmD12es6i+yM9qEuQ ny0TWVpOv/+Odh7BntFZHt85VE8xHjxmVbUTxgPmAYFebvGOpiPGp78XW6oTnPbl0tfz c6cLp96jChEGMbxbPJMKrLbgS2+q9ink86qXKHrxM3KJbiSwNE3D8gtmqFBTIjTksZq2 mFzbqWi2pKkB10PLPi4b40VGvF8RWB9t2CJAP1MLeJWJVt7y6QbxAznYfUJgty7GgPmI 3Ysg== X-Gm-Message-State: AAQBX9cqNlUrfzQb/NimyLe3NHQjLcLklu6tImub4qBUL3W12RzJHt2Q X0i4gnIRQbYKd3UhfCwiE3ZYRRF7cObgsBz4gPaUYA== X-Google-Smtp-Source: AKy350Z8HlCm5B54b7UZJKHACU21DJz3ku5dfDAh0DEMnERB4q/wmKmLgfyJ3uyBvPJjFhCSf597wbTe7HicdKc0qaQ= X-Received: by 2002:a50:8d54:0:b0:4fb:7e7a:ebf1 with SMTP id t20-20020a508d54000000b004fb7e7aebf1mr1266924edt.6.1680610442009; Tue, 04 Apr 2023 05:14:02 -0700 (PDT) MIME-Version: 1.0 References: <20230329180502.1884307-1-kal.conley@dectris.com> <20230329180502.1884307-9-kal.conley@dectris.com> In-Reply-To: From: Kal Cutter Conley Date: Tue, 4 Apr 2023 14:18:42 +0200 Message-ID: Subject: Re: [PATCH bpf-next v2 08/10] xsk: Support UMEM chunk_size > PAGE_SIZE To: Magnus Karlsson Cc: =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Magnus Karlsson , Maciej Fijalkowski , Jonathan Lemon , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jonathan Corbet , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org > > > > > Is not the max 64K as you test against XDP_UMEM_MAX_CHUNK_SIZE in > > > > > xdp_umem_reg()? > > > > > > > > The absolute max is 64K. In the case of HPAGE_SIZE < 64K, then it > > > > would be HPAGE_SIZE. > > > > > > Is there such a case when HPAGE_SIZE would be less than 64K? If not, > > > then just write 64K. > > > > Yes. While most platforms have HPAGE_SIZE defined to a compile-time > > constant >= 64K (very often 2M) there are platforms (at least ia64 and > > powerpc) where the hugepage size is configured at boot. Specifically, > > in the case of Itanium (ia64), the hugepage size may be configured at > > boot to any valid page size > PAGE_SIZE (e.g. 8K). See: > > https://elixir.bootlin.com/linux/latest/source/arch/ia64/mm/hugetlbpage.c#L159 > > So for all practical purposes it is max 64K. Let us just write that then. What about when CONFIG_HUGETLB_PAGE is not defined? Should we keep it set to PAGE_SIZE in that case, or would you like it to be a fixed constant == 64K always? > > > > > > > > > > static int xdp_umem_pin_pages(struct xdp_umem *umem, unsigned long address) > > > > > > { > > > > > > +#ifdef CONFIG_HUGETLB_PAGE > > > > > > > > > > Let us try to get rid of most of these #ifdefs sprinkled around the > > > > > code. How about hiding this inside xdp_umem_is_hugetlb() and get rid > > > > > of these #ifdefs below? Since I believe it is quite uncommon not to > > > > > have this config enabled, we could simplify things by always using the > > > > > page_size in the pool, for example. And dito for the one in struct > > > > > xdp_umem. What do you think? > > > > > > > > I used #ifdef for `page_size` in the pool for maximum performance when > > > > huge pages are disabled. We could also not worry about optimizing this > > > > uncommon case though since the performance impact is very small. > > > > However, I don't find the #ifdefs excessive either. > > > > > > Keep them to a minimum please since there are few of them in the > > > current code outside of some header files. And let us assume that > > > CONFIG_HUGETLB_PAGE is the common case. > > > > > > > Would you be OK if I just remove the ones from xsk_buff_pool? I think > > the code in xdp_umem.c is quite readable and the #ifdefs are really > > only used in xdp_umem_pin_pages. > > Please make an effort to remove the ones in xdp_umem.c too. The more > ifdefs you add, the harder it will be to read. OK