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 B1DA4C433F5 for ; Fri, 4 Mar 2022 18:15:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 47A3E8D0005; Fri, 4 Mar 2022 13:15:23 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 401EC8D0001; Fri, 4 Mar 2022 13:15:23 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2CB298D0005; Fri, 4 Mar 2022 13:15:23 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0069.hostedemail.com [216.40.44.69]) by kanga.kvack.org (Postfix) with ESMTP id 1C14A8D0001 for ; Fri, 4 Mar 2022 13:15:23 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id CD93B96766 for ; Fri, 4 Mar 2022 18:15:22 +0000 (UTC) X-FDA: 79207506084.22.0581278 Received: from mail-yw1-f179.google.com (mail-yw1-f179.google.com [209.85.128.179]) by imf24.hostedemail.com (Postfix) with ESMTP id 628F2180022 for ; Fri, 4 Mar 2022 18:15:22 +0000 (UTC) Received: by mail-yw1-f179.google.com with SMTP id 00721157ae682-2dbd8777564so100970127b3.0 for ; Fri, 04 Mar 2022 10:15:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=KUxn8JdSU+FAiz+Yz45U+PNiIfEjVkTsbOETITn3KvI=; b=n0vwTpqyGaSeYU+QRRntw2mfKbgAEHYrx8YQnH8YGsbg4ge9sCog/6QN4ThJOAVrZ6 0kj2ftdppdOZya/3BITeo1aOBkAbSA2WjA2/NNeg6lsu5hvwpe6e0wRvUQCyeZfs2Isj mKyDDw5r64ERuPobZkoNF5at2vYncMMBY2S9u4LCij/oJzuAJPDzyIRQilVpuYrzCKaP 1D67t0mU6BPrqnjCU487jIe2eS0648F8whYX1KEF9DBj+zGGXzEAnBpnqq0px/4zFk1g HP1V9Tb0S1skyDE7NshToa7WOYx3Iu5Q5SbS4CbbyyJ8zGdMcyz5ybmhKBAjcVu3UNJ+ 1Vew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=KUxn8JdSU+FAiz+Yz45U+PNiIfEjVkTsbOETITn3KvI=; b=aurWUnLvBIFhJwzxRDVkymVmMnk55sLfer/3toOSsPZaIM1+Y/eP+PLpxH7MDOGYyi 33zAkNgK/4LiWHk5+AbgGoiGWJJZLz4m/Eyq2nQTK9sJnUgQ002fzVcwWDZLMmmTnoUf fzmCW5CnY9rGV+ff1Gp1JwrnAvSAJVVacCn6c3Joen4iizqAbqIMDuVmtRcReZfTDPv/ CqvMk5+f9+MkPeXP2sRWjRpzUVPHniS60hYMa7an8r9PJoP6WRb7zRlBgFdwc6m25Bov vjc2EC04vqjJ6DJSIsSQbL7v37VRPt1zMQfiO1TSxEhF/E/v+A5PMlZtdQLTgnbKs+lV 4jaA== X-Gm-Message-State: AOAM532n9wgOjrC9KViYFpH8QdFOyJetIpmy/rjs4godc4u0uv8I5aNM naKVQF5G9XOwlV7pd7UeB46xRX/LRnX8m6hqQTZ27w== X-Google-Smtp-Source: ABdhPJxQ2cgTJae7kgiyUkeyJI57pYDeXpLqxHnVy712muMu1WjRdTNkJqGl6VTaB0njyjc21Ubww8pqNhE5xQsiykc= X-Received: by 2002:a81:5549:0:b0:2dc:2826:e6ee with SMTP id j70-20020a815549000000b002dc2826e6eemr11829422ywb.327.1646417721537; Fri, 04 Mar 2022 10:15:21 -0800 (PST) MIME-Version: 1.0 References: <20220303031505.28495-1-dtcccc@linux.alibaba.com> <7c14bb40-1e7b-9819-1634-e9e9051726fa@linux.alibaba.com> In-Reply-To: <7c14bb40-1e7b-9819-1634-e9e9051726fa@linux.alibaba.com> From: Marco Elver Date: Fri, 4 Mar 2022 19:14:45 +0100 Message-ID: Subject: Re: [RFC PATCH 0/2] Alloc kfence_pool after system startup To: Tianchen Ding Cc: Alexander Potapenko , Dmitry Vyukov , Andrew Morton , kasan-dev , Linux Memory Management List , LKML Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 628F2180022 X-Stat-Signature: kbsrpde1xwcg6fp57iwbuimue6jeharg Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=n0vwTpqy; spf=pass (imf24.hostedemail.com: domain of elver@google.com designates 209.85.128.179 as permitted sender) smtp.mailfrom=elver@google.com; dmarc=pass (policy=reject) header.from=google.com X-HE-Tag: 1646417722-498312 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 Fri, 4 Mar 2022 at 03:25, Tianchen Ding wrote= : > > On 2022/3/3 17:30, Marco Elver wrote: > > Thanks for your replies. > I do see setting a large sample_interval means almost disabling KFENCE. > In fact, my point is to provide a more =E2=80=9Cflexible=E2=80=9D way. Si= nce some Ops > may be glad to use something like on/off switch than 10000ms interval. :-= ) Have you already successfully caught bugs by turning KFENCE on _in reaction_ to some suspected issues? We really do not think that switching on KFENCE _after_ having observed a bug, especially on a completely different machine, is at all reliable. While your patches are appreciated, I think your usecase doesn't make sense to us (based on our experience). I think this flexibility is nice-to-have, so I think the justification just needs changing, to avoid misleading other folks. Please see comments on the other patches. Thanks, -- Marco