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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=ham 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 50557C0044C for ; Thu, 1 Nov 2018 23:34:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8F9E22513 for ; Thu, 1 Nov 2018 23:34:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="tNvAvqYF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D8F9E22513 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728395AbeKBIjD (ORCPT ); Fri, 2 Nov 2018 04:39:03 -0400 Received: from mail-qk1-f194.google.com ([209.85.222.194]:45581 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728134AbeKBIjD (ORCPT ); Fri, 2 Nov 2018 04:39:03 -0400 Received: by mail-qk1-f194.google.com with SMTP id d135so272564qkc.12 for ; Thu, 01 Nov 2018 16:33:59 -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=HCsOkoK9O1mFqWcI9m6G2BHQPpgSD/MSas0vVvPAEL0=; b=tNvAvqYFFkAUQWQ2jC3PuyXWoUDFFNsPYwF18tP6uT8vt/udSAwpJWspX20YjCU5dg kat++mAirNzZvNBknEDZ1/lcZdGt+y+xiRbzstioEry+q7hLDuqzMhcOS9szsczk/x3n o3j2cHCYXhzDX77NolKe5fqIG0BWl/dPuRrWqZinZ9Bsxo+2U4z4TlIdc7qm3wf1MWxO uKQRnh9tUzgz5VlNIoC5nCNI03jPASSbxGu2IiHp8i5QN/gPLcEDzFpVKfekZd2rP6oy gaCLJy9Rsap+Qp5SSC2O6LHWVeggP5VOwfTfH6AH2gmbas0RG7U2SVanI5M3QDchBqgB C3gA== 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=HCsOkoK9O1mFqWcI9m6G2BHQPpgSD/MSas0vVvPAEL0=; b=ppadvjlpUNqaQx4dlUBrY1i13d6zaWj4anNpJAjMyizMO2KEQT4ZRXr+4PPQBbtlSF f5hiCqogRf1B4uf51LxsEklzkBmWnDkNZaTSgdiyATXj6aMsF3aAjlmefNTDbaMJcDol /43qbZX8ZBnP6tbqZOQMxbksgjKkxnYV40gjmrqvN1gRgeCF8tHPUKYoI+NOodpna/J3 KDObKUuOVDCQQajkYijJQfHVXvtgi7L8HnDDlfmsevgMfdG+JODxQWqLxgdVsWTesNmt +aOfhNrkmYTyfLJ4/v3qdqjMCUM+TQagQ6okvX/N8M7sDhdmP2UpZ778ieP2860ft77s jShg== X-Gm-Message-State: AGRZ1gIysV55RpdRO9VOvkKyJ8OWdlEQMwINTA5lSL9trEmA570DPowa 16vgChuy+88ciBum8TYzQgFKbdklsPdXYPzVb4QTdGwHjwc= X-Google-Smtp-Source: AJdET5fQlbBTUCnTxUKy225Ry1u6UEXu6atOtK7yCmgbVOghlxvCBd3+SIQ42g4xXrmiqhpACu0RCMX9JBVBfH7fJ3E= X-Received: by 2002:a37:12a1:: with SMTP id 33mr8133358qks.189.1541115238356; Thu, 01 Nov 2018 16:33:58 -0700 (PDT) MIME-Version: 1.0 References: <60988959.4070.1541112982406.JavaMail.zimbra@efficios.com> In-Reply-To: <60988959.4070.1541112982406.JavaMail.zimbra@efficios.com> From: Joel Fernandes Date: Thu, 1 Nov 2018 16:33:47 -0700 Message-ID: Subject: Re: [diamon-discuss] [RELEASE] LTTng-modules 2.9.11, 2.10.8, 2.11.0-rc2 (Linux kernel tracer) To: Mathieu Desnoyers Cc: lttng-dev@lists.lttng.org, diamon-discuss@lists.linuxfoundation.org, LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 1, 2018 at 3:56 PM Mathieu Desnoyers wrote: > > Hi, > > This is a set of bugfix releases of the LTTng modules kernel tracer. > It covers the three currently active lttng-modules branches: the > 2.9 and 2.10 stable branches, as well as the 2.11 branch in release > candidate cycle. > > Those releases add support for kernel 4.19. > > One important improvement is to prevent allocation of buffers larger > than the available memory, which can cause the OOM killer to trigger. > Even if the OOM killer end up having to trigger, the current OOM kill > target is set to the current thread while allocating buffers. This is interesting. Me and Steve were looking at exactly this issue with the ftrace ring buffer a few months ago. Turns out that even setting the OOM kill target may not be enough to prevent all OOMs. I don't remember the reason why not, I'll have to dig out those threads but that's what the -mm folks said at the time. I did remember vaguely that I tested it and the kill target doesn't always get killed.. its possible that something *other* parallel allocation can be victimized AFAIR, even though the culprit is the kill target. - Joel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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=HCsOkoK9O1mFqWcI9m6G2BHQPpgSD/MSas0vVvPAEL0=; b=tNvAvqYFFkAUQWQ2jC3PuyXWoUDFFNsPYwF18tP6uT8vt/udSAwpJWspX20YjCU5dg kat++mAirNzZvNBknEDZ1/lcZdGt+y+xiRbzstioEry+q7hLDuqzMhcOS9szsczk/x3n o3j2cHCYXhzDX77NolKe5fqIG0BWl/dPuRrWqZinZ9Bsxo+2U4z4TlIdc7qm3wf1MWxO uKQRnh9tUzgz5VlNIoC5nCNI03jPASSbxGu2IiHp8i5QN/gPLcEDzFpVKfekZd2rP6oy gaCLJy9Rsap+Qp5SSC2O6LHWVeggP5VOwfTfH6AH2gmbas0RG7U2SVanI5M3QDchBqgB C3gA== MIME-Version: 1.0 References: <60988959.4070.1541112982406.JavaMail.zimbra@efficios.com> In-Reply-To: <60988959.4070.1541112982406.JavaMail.zimbra@efficios.com> From: Joel Fernandes Date: Thu, 1 Nov 2018 16:33:47 -0700 Message-ID: Content-Type: text/plain; charset="UTF-8" Subject: Re: [diamon-discuss] [RELEASE] LTTng-modules 2.9.11, 2.10.8, 2.11.0-rc2 (Linux kernel tracer) List-Id: DiaMon diagnostic and monitoring workgroup general discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Mathieu Desnoyers Cc: diamon-discuss@lists.linuxfoundation.org, lttng-dev@lists.lttng.org, LKML On Thu, Nov 1, 2018 at 3:56 PM Mathieu Desnoyers wrote: > > Hi, > > This is a set of bugfix releases of the LTTng modules kernel tracer. > It covers the three currently active lttng-modules branches: the > 2.9 and 2.10 stable branches, as well as the 2.11 branch in release > candidate cycle. > > Those releases add support for kernel 4.19. > > One important improvement is to prevent allocation of buffers larger > than the available memory, which can cause the OOM killer to trigger. > Even if the OOM killer end up having to trigger, the current OOM kill > target is set to the current thread while allocating buffers. This is interesting. Me and Steve were looking at exactly this issue with the ftrace ring buffer a few months ago. Turns out that even setting the OOM kill target may not be enough to prevent all OOMs. I don't remember the reason why not, I'll have to dig out those threads but that's what the -mm folks said at the time. I did remember vaguely that I tested it and the kill target doesn't always get killed.. its possible that something *other* parallel allocation can be victimized AFAIR, even though the culprit is the kill target. - Joel