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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 376DCC433EF for ; Wed, 6 Jul 2022 18:26:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 82E4A6B0072; Wed, 6 Jul 2022 14:26:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7B73F6B0073; Wed, 6 Jul 2022 14:26:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 658196B0074; Wed, 6 Jul 2022 14:26:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 51AAD6B0072 for ; Wed, 6 Jul 2022 14:26:40 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 2534C206CF for ; Wed, 6 Jul 2022 18:26:40 +0000 (UTC) X-FDA: 79657505760.14.9060B4B Received: from mail-pg1-f177.google.com (mail-pg1-f177.google.com [209.85.215.177]) by imf15.hostedemail.com (Postfix) with ESMTP id C0EFCA002F for ; Wed, 6 Jul 2022 18:26:39 +0000 (UTC) Received: by mail-pg1-f177.google.com with SMTP id s27so14615292pga.13 for ; Wed, 06 Jul 2022 11:26:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=fEv55no+mDNdpRv2Yii2FTtzxzsaoXBUMlMWPyySZaw=; b=XajZao5oUGH9jMUhI6INvwovP3CVCShuJT6+ix93Htg6Lou44Ay60vc5AToPhwI6ze DLgizKv3+4u1lhHjR3yYWoYar4zYnV6rDQhKECQLjIGuWyIbqyUD89kAgfLH/0kh4bU6 rI7ecOBpP0lfv6p8L/tIzT9abcA+Mtagq7aNFgrxhuZvqgKd7Vi2XoIWl/YeUSp37PHZ dx3NyAZkIzPxh+5wr5tKE1Y34dtsFemVqmic5OOn01Ij9omlNa/cOiCUOXtQr7Ll95Kv da4q5/AZf1yAQTMhFTZi7ZLaYtkOTF3ROQTy8GD1bKuq6/FFT46+Rv9dmM+k+bm17qR2 GZrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=fEv55no+mDNdpRv2Yii2FTtzxzsaoXBUMlMWPyySZaw=; b=V5WrBwdO54RNZS73CRWdSlc6n4JEGs58vqT2tgrnkj2Sl7tToy6VYoEr/2lryO78MG b71fEmGxigm7oy4RwOoJzjIjsXB77tu3WzJOX6+xp9thQTM2LPTAfym0PPATMy94BYUc kQPfOgNhXkoLBQIdXl1EEq6We07gGtYFEUWeaaY0DxYLcNhnE3KkYl4LDhMYH4cAXqYQ 1yQgCDeaQ7ImldSuimE/On/5VIddm6lJvrG0GDef4uXhW6aB8NQgjH/b5qYq5egi+7K4 E4z+GHZjK0aPgyuDu/mdoqLuBbWGL+FM85tMDI22UsmZBDy28pva+ffguRGVWgub9cw+ msLQ== X-Gm-Message-State: AJIora89tCidm2qL/W88ksJrkbX+a7cqfCOWBfA5BHxC9UiQPzjTOMzo juiGlV3QiBOaQGOsqfTCuB/SrdtXbPE= X-Google-Smtp-Source: AGRyM1taEbkT7dBbGdXMfEz1oWYmL7t0q00r5lMLCbN2HQZWofL3h86+NOQ/uwxUISNwGkjVQ4BCxw== X-Received: by 2002:a65:6e4d:0:b0:411:c102:397e with SMTP id be13-20020a656e4d000000b00411c102397emr29425157pgb.271.1657131998716; Wed, 06 Jul 2022 11:26:38 -0700 (PDT) Received: from MacBook-Pro-3.local ([2620:10d:c090:500::2:8597]) by smtp.gmail.com with ESMTPSA id z26-20020a634c1a000000b0040dd052ab11sm20857296pga.58.2022.07.06.11.26.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Jul 2022 11:26:38 -0700 (PDT) Date: Wed, 6 Jul 2022 11:26:35 -0700 From: Alexei Starovoitov To: Matthew Wilcox Cc: Christoph Hellwig , davem@davemloft.net, daniel@iogearbox.net, andrii@kernel.org, tj@kernel.org, kafai@fb.com, bpf@vger.kernel.org, kernel-team@fb.com, linux-mm@kvack.org, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka Subject: Re: [PATCH bpf-next 0/5] bpf: BPF specific memory allocator. Message-ID: <20220706182635.ccgt6zcr6bkd3rjc@MacBook-Pro-3.local> References: <20220623003230.37497-1-alexei.starovoitov@gmail.com> <20220706175034.y4hw5gfbswxya36z@MacBook-Pro-3.local> <20220706180525.ozkxnbifgd4vzxym@MacBook-Pro-3.local.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657131999; a=rsa-sha256; cv=none; b=ILmr1g/tzh2sZyh1a6wkNdfoc//Xaat1lkXPphsTaXGVjN4GL8sxle0e/rEIj7+Q0pBC+R 0yw/XBWfZJJBsGsl+4nZcKtrUItLeplq1Q639i+zSyCf9/c9e0Nvpu2cePBdnpb8qIcKn6 8v2nxZaMqV5ArHhGSdjmSoOtObsKMrY= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=XajZao5o; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf15.hostedemail.com: domain of alexei.starovoitov@gmail.com designates 209.85.215.177 as permitted sender) smtp.mailfrom=alexei.starovoitov@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1657131999; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=fEv55no+mDNdpRv2Yii2FTtzxzsaoXBUMlMWPyySZaw=; b=LeAJC/dR8QQUfPT6JArcXCRKXs7sHDSsp7ujf31A1wcgVmz0ypNUNdzYAsVK2l+Vkb8oBq 5q9N8k3zoX1nZHCmbtRqWE7908lJPfcxKfX0HOS83r5vMwAa9NWgWUGyX3VEc20rd2Pd/3 xjlDM2jEpRrqhB/dgT9g0yYXkg7mcow= X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: C0EFCA002F Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=XajZao5o; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf15.hostedemail.com: domain of alexei.starovoitov@gmail.com designates 209.85.215.177 as permitted sender) smtp.mailfrom=alexei.starovoitov@gmail.com X-Stat-Signature: iojs9sj7b8q1jmg4zibac6tjjyfdtfib X-HE-Tag: 1657131999-986206 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jul 06, 2022 at 07:21:29PM +0100, Matthew Wilcox wrote: > On Wed, Jul 06, 2022 at 11:05:25AM -0700, Alexei Starovoitov wrote: > > On Wed, Jul 06, 2022 at 06:55:36PM +0100, Matthew Wilcox wrote: > > > For example, I assume that a BPF program > > > has a fairly tight limit on how much memory it can cause to be allocated. > > > Right? > > > > No. It's constrained by memcg limits only. It can allocate gigabytes. > > I'm confused. A BPF program is limited to executing 4096 insns and > using a maximum of 512 bytes of stack space, but it can allocate an > unlimited amount of heap? That seems wrong. 4k insn limit was lifted years ago. bpf progs are pretty close to be at parity with kernel modules. Except that they are safe, portable, and users have full visibility into them. It's not a blob of bytes unlike .ko.