From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 1B48AA04A3 for ; Tue, 16 Jun 2020 10:13:36 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id D26331BC25; Tue, 16 Jun 2020 10:13:35 +0200 (CEST) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) by dpdk.org (Postfix) with ESMTP id 850271BC25 for ; Tue, 16 Jun 2020 10:13:34 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592295213; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=/r9AnAO70p9qzWd5Z4BTpj3KduPVJSzcI2cldcj2aGQ=; b=P1S5BAL+dVs0diZwDIvM7hBr77xZbgzGqDhTNXUMlsDKt76+tfjCG1VUkvzQpRYMazZdwt V4dIgXQSH7ee7hq3Xy/u66VqLJxT8YAUG62SNCzgTA6GD5u6ISrLzDWpdcFhrvvwsfE4fD VkCb757+zfpWItTyMFxGhdBafgAYsb0= Received: from mail-vk1-f199.google.com (mail-vk1-f199.google.com [209.85.221.199]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-28-BvdYn2RMNYaCGnqX7TFSHA-1; Tue, 16 Jun 2020 04:13:26 -0400 X-MC-Unique: BvdYn2RMNYaCGnqX7TFSHA-1 Received: by mail-vk1-f199.google.com with SMTP id g21so4881852vkk.15 for ; Tue, 16 Jun 2020 01:13:26 -0700 (PDT) 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=/r9AnAO70p9qzWd5Z4BTpj3KduPVJSzcI2cldcj2aGQ=; b=lBgnaldZvsNUKH7CM/GRBqjfZj7+ZQQIZvVdSj/wlv2Iich4m1Totx5ygBzIS7qO7Y gX12KUyPa9Q9N8sGZRiW4XLK/Zbq1poOfF+QRDKZzp7GGNIxDfLZMd2obQ7RQ6yWndad cwt3KesWgkkQnbAvG3EDQ+JB0N3B1JSEmhDrWDwo6eXpE2f1LeWcma7fnL3tzukrEiHx gybUbfRZzZIg2cMBouZWkbw/8sjnaM3PvKBbBojl6/ytrh7eo1O+2zuQrE61M0m1CAh7 d0SuDZjpvjl0KS5TT6/exmeQ25i0T+FV2/as8NZ55wrpiD2s3P2ozs2KDB2lmSqcSuhz jK8Q== X-Gm-Message-State: AOAM530w3uHt+3GHg+RPjQhBr7uopFIHGEvxNSY3w684KboknvSZOu1P ENkLHxtMbOkOobRaaRu3IPeUvmdn60G4kn7pEa9DzoGiY8dBq23Fbv9EMxMiWeW5R0fGZ0VUZsl YBgqODTe3UORtVtdlKArvI98= X-Received: by 2002:a9f:31c6:: with SMTP id w6mr918504uad.86.1592295206136; Tue, 16 Jun 2020 01:13:26 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyfpvoM8jSiDieeSHkobqs9C7W2ibvLX+W5wvbDocmPbK9M3YBiBqp+0tUm0YL0aK2EQAPmAI/adhgzuEcKI4g= X-Received: by 2002:a9f:31c6:: with SMTP id w6mr918496uad.86.1592295205874; Tue, 16 Jun 2020 01:13:25 -0700 (PDT) MIME-Version: 1.0 References: <20200519125804.104349-1-luca.boccassi@gmail.com> <20200519125804.104349-11-luca.boccassi@gmail.com> <06e1bc7c-d41d-e575-2460-b2cb4ff0cda9@redhat.com> <39a62e6f200444d3386504ab27f14d916fdb4ece.camel@debian.org> In-Reply-To: From: David Marchand Date: Tue, 16 Jun 2020 10:13:14 +0200 Message-ID: To: Luca Boccassi Cc: Kevin Traynor , Andrea Arcangeli , Maxime Coquelin , Aaron Conole , Anatoly Burakov , dpdk stable , Li Feng Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dmarchan@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Subject: Re: [dpdk-stable] patch 'mem: mark pages as not accessed when reserving VA' has been queued to stable release 19.11.3 X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches for DPDK stable branches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: stable-bounces@dpdk.org Sender: "stable" Hello Luca, On Fri, Jun 12, 2020 at 10:00 AM Luca Boccassi wrote: > On Tue, 2020-06-09 at 15:14 +0100, Luca Boccassi wrote: > > On Tue, 2020-06-09 at 14:45 +0100, Kevin Traynor wrote: > > > Hi, discussed this patch for 18.11 with David and he pointed out that > > > there is a fix for it on master: > > > > Uh, I wonder how it got left behind, strange - how critical is it? And > > how safe is it to pick up now, when validation has already started? > - On the reason of why it was left behind, iiuc, Kevin thought it was because of how the git-log-fixes.sh script works and this patch was not marked as a fix in master. - This first patch fixed the way we mark anonymous pages used by the dpdk memory allocator. At initialisation, the dpdk memory allocator reserves anonymous mappings for later uses. Before this patch, it was instructing the kernel the mapping was used for reading with PROT_READ (which has some side effects, for applications calling mlockall()). The dpdk memory allocator has no actual need at the time of the reservation, it switches to the right memory protection when using the mapping. So the first patch switched the memory protection to PROT_NONE when reserving. Later when the dpdk memory allocator frees some memory and does not use a mapping, the memory protection on this mapping is left untouched as I forgot to set it back to PROT_NONE: this is what the 2nd patch from Li Feng addresses. The first patch landed in master at the start of 20.05 and we lived in this state for a month. The second patch got merged just before tagging 20.05-rc1. "Real" validation happened with both patches applied. I can understand your reluctance at touching the memory allocator now that validation for 19.11.3 started, but with only the first patch, we end up with an intermediate behavior in the dpdk memory allocator. I would go with backporting the second patch. -- David Marchand