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[209.132.180.67]) by mx.google.com with ESMTP id q199si40474533pfq.112.2019.08.04.02.25.13; Sun, 04 Aug 2019 02:26:15 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@gmx.net header.s=badeba3b8450 header.b=e5thmEDf; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726050AbfHDJXV (ORCPT + 99 others); Sun, 4 Aug 2019 05:23:21 -0400 Received: from mout.gmx.net ([212.227.17.20]:42269 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725987AbfHDJXV (ORCPT ); Sun, 4 Aug 2019 05:23:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1564910600; bh=Oi0qBKpS1zpZHZDbRB9bx40ZA2YAz8/lccg36x6bvPc=; h=X-UI-Sender-Class:To:From:Subject:Date; b=e5thmEDfpO8kWK7Jmax/X65Tb4o2QvDHjGjVo9n7n4AQsFI8e2KZQKKlfbS6q2ORG XVFPXY0dTX4k5C/eUtlxGmQWfO2ero51Qu1nPz1SYAc4t3nqg1PimdeFqcU2rRv9nh CnsSkwgwNFZaTaHNahIdjxlMAQYz86/8dj0UPdcg= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [10.94.10.6] ([196.52.84.45]) by mail.gmx.com (mrgmx101 [212.227.17.174]) with ESMTPSA (Nemesis) id 0MWwp6-1hokiJ3xhs-00Vuv9 for ; Sun, 04 Aug 2019 11:23:20 +0200 To: linux-kernel@vger.kernel.org From: "Artem S. Tashkinov" Subject: Let's talk about the elephant in the room - the Linux kernel's inability to gracefully handle low memory pressure Message-ID: Date: Sun, 4 Aug 2019 09:23:17 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:U4wRXzSlCtkm8rZ0+8o5Wpc4SJsu0+V9HYAcEx9jEZqrapstOM2 8OCTO4n2U/XRawDtcDPZ5zSFFGWqTsJKNynqXYjVU6M0Kcd0AxEFNF19m3o6DlC4IFAvXDJ iRgqbER8qi3vWRgL/V+3wd2Bg1t4pAvT7XBqjmPQ0ccPPHyzixpowsD/LRwEOc1df2TFrXs dsJwYx9xNHUdnFiHm2dMw== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:qpzRUryDTmw=:05lDcR6Xen2/KZkcJgskV2 D5ccfdiahpB1VbMzJ283uIsd97R8QxGtne33NBGtEhZEwo9FU7UsYZTLvIj+afbEUs6xaWvZ+ 4wjLzJ7OdgFsqCRGj13sJjzSvzM0sK8MDrBp8a9/QvsQAvKdRi6gilhM/ZQPrDXfEhCIUe8ix nmVG0XUoYgM7SA/pJjTVjwXH+kZLQ32IWYXusL96eaQ3oOYdoDsF6pe+aBedXwlyBuOoRjjgU Yfag8V6MHaOvk16L1m2HATk834cBm71HnjPKlPDskqjkXDHkZfOQDGbpX8rnMb/ZAeCdqc74n c9E2COHxKN4Ry9idtvvvGOyCLQvNR+D2j/ZiMAd4J86QWpQjuv92LQ/lUAcHRrc/oCwo0F9Rn y/K9wO4IIlUrnn40YTjYaLLbMsqivuA07NVT5K6JiPe6+CFviH+qoILo8ZRSFwO8P+ZlJTCFS iQykh4n6wN9abmh3LBpLK7J+WPa4JERQZn4H/MRfnbys+rG7T6EKNf3xqgu3neGAVqbAqAzq9 jUam1HxBRO/k2dpufDnUHTtrdInsHNPiLuPRg0+sx/O3CE9hCnBlKHEbsw+C9v7JQwXh77pd1 Rdaisd+BKoH+4HxntrvGxXZ+Au4E+VACCO32suTgG4/ygjpK4A1bu2HilmYzpY+TLCP39Y14f 6Mnbq5xJJFJjOBO3roh/bmtu/ZA+SKKtJ5+6BO0IA03sbqKDi+hgdh9F04w+qQDARM0C+oWAH hBt2GxZpv39Ea6Beaxip99sQBK8vhsgSis0J9dRaZugEQeLVfncpD42h+IhJ5gPzXi9vr1Uwv xseYP9zjzLRkxOVVwba3wTBvdx1R8WyGHEhpaPiNvPrWnpmyWhxxv9PYRX6+HmGBfxMgD1Ks8 lRAw60yN5wldQqvvVbihdsw4cg6A79TpB94vfhY6RznT8zHlihkMgopVrVp+Nx4Puu/iUBoo6 PFd9Yijh3C83/zq744WQN2+wKr6OGqCkZgCh49ce9wat/NZZR/eNnVpj3PgzBf4PRwYpaGZlV 1XveWyYEeWpNw0kp4Itp1sSIFEZbl6WfsBKdQKVYtmUtswLKxPEuNMilVZl39/HDvwBHdPHO/ ySs/G0cR7M1EOTFpfe0k3xJ7HWAyQW62y+EwJ+RfTw8tBdz453IedNDqGNwm4NxxJc4rszMvi aFbes= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, There's this bug which has been bugging many people for many years already and which is reproducible in less than a few minutes under the latest and greatest kernel, 5.2.6. All the kernel parameters are set to defaults. Steps to reproduce: 1) Boot with mem=3D4G 2) Disable swap to make everything faster (sudo swapoff -a) 3) Launch a web browser, e.g. Chrome/Chromium or/and Firefox 4) Start opening tabs in either of them and watch your free RAM decrease Once you hit a situation when opening a new tab requires more RAM than is currently available, the system will stall hard. You will barely be able to move the mouse pointer. Your disk LED will be flashing incessantly (I'm not entirely sure why). You will not be able to run new applications or close currently running ones. This little crisis may continue for minutes or even longer. I think that's not how the system should behave in this situation. I believe something must be done about that to avoid this stall. I'm almost sure some sysctl parameters could be changed to avoid this situation but something tells me this could be done for everyone and made default because some non tech-savvy users will just give up on Linux if they ever get in a situation like this and they won't be keen or even be able to Google for solutions. Best regards, Artem