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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 D8534C3524A for ; Tue, 4 Feb 2020 08:29:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7BA5A20730 for ; Tue, 4 Feb 2020 08:29:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cgIr7ESu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7BA5A20730 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EDD576B0003; Tue, 4 Feb 2020 03:29:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E8EC56B0005; Tue, 4 Feb 2020 03:29:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D2E726B0006; Tue, 4 Feb 2020 03:29:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0117.hostedemail.com [216.40.44.117]) by kanga.kvack.org (Postfix) with ESMTP id B7F5C6B0003 for ; Tue, 4 Feb 2020 03:29:40 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 69A718248047 for ; Tue, 4 Feb 2020 08:29:40 +0000 (UTC) X-FDA: 76451770920.02.table27_8e808f8d4ff60 X-HE-Tag: table27_8e808f8d4ff60 X-Filterd-Recvd-Size: 7862 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.81]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Tue, 4 Feb 2020 08:29:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580804978; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=ohrGTwmAT76eQeRzpJLCczh4G62uQiHZfZm4f0n/tDo=; b=cgIr7ESuMkDOam4cSaJLFSAHMLI+L6oH0WQmcvNCaMG3ZmLa75EWJf6/9iLujAfw7xBiqM mZsp2kvyGu7vmWpgd8eckKeKnqmZuubLLo5fo0vQMF9djYE8YVPhdM8IUrjPQHux+I7C+o KcEV0MdOzZZfT5bEnJpwsTpnpxEm6EM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-377-pe0dRV0-NPiOlyTrm-R10Q-1; Tue, 04 Feb 2020 03:29:31 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 55EBB19251DF; Tue, 4 Feb 2020 08:29:30 +0000 (UTC) Received: from [10.36.117.121] (ovpn-117-121.ams2.redhat.com [10.36.117.121]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3C6F060BFB; Tue, 4 Feb 2020 08:29:25 +0000 (UTC) Subject: Re: Balloon pressuring page cache To: Tyler Sanderson , "Michael S. Tsirkin" Cc: Alexander Duyck , "Wang, Wei W" , "virtualization@lists.linux-foundation.org" , David Rientjes , "linux-mm@kvack.org" , Michal Hocko References: <91270a68-ff48-88b0-219c-69801f0c252f@redhat.com> <75d4594f-0864-5172-a0f8-f97affedb366@redhat.com> <286AC319A985734F985F78AFA26841F73E3F8A02@shsmsx102.ccr.corp.intel.com> <20200203080520-mutt-send-email-mst@kernel.org> <5ac131de8e3b7fc1fafd05a61feb5f6889aeb917.camel@linux.intel.com> <20200203120225-mutt-send-email-mst@kernel.org> From: David Hildenbrand Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAlgEEwEIAEICGwMFCQlmAYAGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl3pImkCGQEACgkQTd4Q 9wD/g1o+VA//SFvIHUAvul05u6wKv/pIR6aICPdpF9EIgEU448g+7FfDgQwcEny1pbEzAmiw zAXIQ9H0NZh96lcq+yDLtONnXk/bEYWHHUA014A1wqcYNRY8RvY1+eVHb0uu0KYQoXkzvu+s Dncuguk470XPnscL27hs8PgOP6QjG4jt75K2LfZ0eAqTOUCZTJxA8A7E9+XTYuU0hs7QVrWJ jQdFxQbRMrYz7uP8KmTK9/Cnvqehgl4EzyRaZppshruKMeyheBgvgJd5On1wWq4ZUV5PFM4x II3QbD3EJfWbaJMR55jI9dMFa+vK7MFz3rhWOkEx/QR959lfdRSTXdxs8V3zDvChcmRVGN8U Vo93d1YNtWnA9w6oCW1dnDZ4kgQZZSBIjp6iHcA08apzh7DPi08jL7M9UQByeYGr8KuR4i6e RZI6xhlZerUScVzn35ONwOC91VdYiQgjemiVLq1WDDZ3B7DIzUZ4RQTOaIWdtXBWb8zWakt/ ztGhsx0e39Gvt3391O1PgcA7ilhvqrBPemJrlb9xSPPRbaNAW39P8ws/UJnzSJqnHMVxbRZC Am4add/SM+OCP0w3xYss1jy9T+XdZa0lhUvJfLy7tNcjVG/sxkBXOaSC24MFPuwnoC9WvCVQ ZBxouph3kqc4Dt5X1EeXVLeba+466P1fe1rC8MbcwDkoUo65Ag0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAGJAiUEGAECAA8FAlXLn5ECGwwFCQlmAYAACgkQTd4Q 9wD/g1qA6w/+M+ggFv+JdVsz5+ZIc6MSyGUozASX+bmIuPeIecc9UsFRatc91LuJCKMkD9Uv GOcWSeFpLrSGRQ1Z7EMzFVU//qVs6uzhsNk0RYMyS0B6oloW3FpyQ+zOVylFWQCzoyyf227y GW8HnXunJSC+4PtlL2AY4yZjAVAPLK2l6mhgClVXTQ/S7cBoTQKP+jvVJOoYkpnFxWE9pn4t H5QIFk7Ip8TKr5k3fXVWk4lnUi9MTF/5L/mWqdyIO1s7cjharQCstfWCzWrVeVctpVoDfJWp 4LwTuQ5yEM2KcPeElLg5fR7WB2zH97oI6/Ko2DlovmfQqXh9xWozQt0iGy5tWzh6I0JrlcxJ ileZWLccC4XKD1037Hy2FLAjzfoWgwBLA6ULu0exOOdIa58H4PsXtkFPrUF980EEibUp0zFz GotRVekFAceUaRvAj7dh76cToeZkfsjAvBVb4COXuhgX6N4pofgNkW2AtgYu1nUsPAo+NftU CxrhjHtLn4QEBpkbErnXQyMjHpIatlYGutVMS91XTQXYydCh5crMPs7hYVsvnmGHIaB9ZMfB njnuI31KBiLUks+paRkHQlFcgS2N3gkRBzH7xSZ+t7Re3jvXdXEzKBbQ+dC3lpJB0wPnyMcX FOTT3aZT7IgePkt5iC/BKBk3hqKteTnJFeVIT7EC+a6YUFg= Organization: Red Hat GmbH Message-ID: <74cc25a6-cefb-c580-8e59-5b76fb680bf4@redhat.com> Date: Tue, 4 Feb 2020 09:29:24 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: pe0dRV0-NPiOlyTrm-R10Q-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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 03.02.20 21:32, Tyler Sanderson wrote: > There were apparently good reasons for moving away from OOM notifier > callback: > https://lkml.org/lkml/2018/7/12/314 > https://lkml.org/lkml/2018/8/2/322 >=20 > In particular the OOM notifier is worse than the shrinker because: The issue is that DEFLATE_ON_OOM is under-specified. >=20 > 1. It is last-resort, which means the system has already gone through > heroics to prevent OOM. Those heroic reclaim efforts are expensive > and impact application performance. That's *exactly* what "deflate on OOM" suggests. Assume you are using virtio-balloon for some weird way of memory hotunplug (which is what some people do) and you want to minimize the footprint of your guest. Then you really only want to give the guest more memory (or rather, let it take back memory automatically in this case) in case it really needs more memory. It should try to reclaim first. Under-specified. > 2. It lacks understanding of NUMA or other OOM constraints. Ballooning in general lacks the understanding of NUMA. > 3. It has a higher potential for bugs due to the subtlety=C2=A0of the > callback context. While that is a valid point, it doesn't explain why existing functionality is changed. Personally, I think DEFLATE_ON_OOM should never have been introduced (at least not in this form). --=20 Thanks, David / dhildenb From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: Re: Balloon pressuring page cache Date: Tue, 4 Feb 2020 09:29:24 +0100 Message-ID: <74cc25a6-cefb-c580-8e59-5b76fb680bf4@redhat.com> References: <91270a68-ff48-88b0-219c-69801f0c252f@redhat.com> <75d4594f-0864-5172-a0f8-f97affedb366@redhat.com> <286AC319A985734F985F78AFA26841F73E3F8A02@shsmsx102.ccr.corp.intel.com> <20200203080520-mutt-send-email-mst@kernel.org> <5ac131de8e3b7fc1fafd05a61feb5f6889aeb917.camel@linux.intel.com> <20200203120225-mutt-send-email-mst@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" To: Tyler Sanderson , "Michael S. Tsirkin" Cc: Michal Hocko , "linux-mm@kvack.org" , David Rientjes , Alexander Duyck , "virtualization@lists.linux-foundation.org" List-Id: virtualization@lists.linuxfoundation.org T24gMDMuMDIuMjAgMjE6MzIsIFR5bGVyIFNhbmRlcnNvbiB3cm90ZToKPiBUaGVyZSB3ZXJlIGFw cGFyZW50bHkgZ29vZCByZWFzb25zIGZvciBtb3ZpbmcgYXdheSBmcm9tIE9PTSBub3RpZmllcgo+ IGNhbGxiYWNrOgo+IGh0dHBzOi8vbGttbC5vcmcvbGttbC8yMDE4LzcvMTIvMzE0Cj4gaHR0cHM6 Ly9sa21sLm9yZy9sa21sLzIwMTgvOC8yLzMyMgo+IAo+IEluIHBhcnRpY3VsYXIgdGhlIE9PTSBu b3RpZmllciBpcyB3b3JzZSB0aGFuIHRoZSBzaHJpbmtlciBiZWNhdXNlOgoKVGhlIGlzc3VlIGlz IHRoYXQgREVGTEFURV9PTl9PT00gaXMgdW5kZXItc3BlY2lmaWVkLgoKPiAKPiAgMS4gSXQgaXMg bGFzdC1yZXNvcnQsIHdoaWNoIG1lYW5zIHRoZSBzeXN0ZW0gaGFzIGFscmVhZHkgZ29uZSB0aHJv dWdoCj4gICAgIGhlcm9pY3MgdG8gcHJldmVudCBPT00uIFRob3NlIGhlcm9pYyByZWNsYWltIGVm Zm9ydHMgYXJlIGV4cGVuc2l2ZQo+ICAgICBhbmQgaW1wYWN0IGFwcGxpY2F0aW9uIHBlcmZvcm1h bmNlLgoKVGhhdCdzICpleGFjdGx5KiB3aGF0ICJkZWZsYXRlIG9uIE9PTSIgc3VnZ2VzdHMuCgpB c3N1bWUgeW91IGFyZSB1c2luZyB2aXJ0aW8tYmFsbG9vbiBmb3Igc29tZSB3ZWlyZCB3YXkgb2Yg bWVtb3J5CmhvdHVucGx1ZyAod2hpY2ggaXMgd2hhdCBzb21lIHBlb3BsZSBkbykgYW5kIHlvdSB3 YW50IHRvIG1pbmltaXplIHRoZQpmb290cHJpbnQgb2YgeW91ciBndWVzdC4gVGhlbiB5b3UgcmVh bGx5IG9ubHkgd2FudCB0byBnaXZlIHRoZSBndWVzdAptb3JlIG1lbW9yeSAob3IgcmF0aGVyLCBs ZXQgaXQgdGFrZSBiYWNrIG1lbW9yeSBhdXRvbWF0aWNhbGx5IGluIHRoaXMKY2FzZSkgaW4gY2Fz ZSBpdCByZWFsbHkgbmVlZHMgbW9yZSBtZW1vcnkuIEl0IHNob3VsZCB0cnkgdG8gcmVjbGFpbSBm aXJzdC4KClVuZGVyLXNwZWNpZmllZC4KCgo+ICAyLiBJdCBsYWNrcyB1bmRlcnN0YW5kaW5nIG9m IE5VTUEgb3Igb3RoZXIgT09NIGNvbnN0cmFpbnRzLgoKQmFsbG9vbmluZyBpbiBnZW5lcmFsIGxh Y2tzIHRoZSB1bmRlcnN0YW5kaW5nIG9mIE5VTUEuCgo+ICAzLiBJdCBoYXMgYSBoaWdoZXIgcG90 ZW50aWFsIGZvciBidWdzIGR1ZSB0byB0aGUgc3VidGxldHnCoG9mIHRoZQo+ICAgICBjYWxsYmFj ayBjb250ZXh0LgoKV2hpbGUgdGhhdCBpcyBhIHZhbGlkIHBvaW50LCBpdCBkb2Vzbid0IGV4cGxh aW4gd2h5IGV4aXN0aW5nCmZ1bmN0aW9uYWxpdHkgaXMgY2hhbmdlZC4KClBlcnNvbmFsbHksIEkg dGhpbmsgREVGTEFURV9PTl9PT00gc2hvdWxkIG5ldmVyIGhhdmUgYmVlbiBpbnRyb2R1Y2VkIChh dApsZWFzdCBub3QgaW4gdGhpcyBmb3JtKS4KCgotLSAKVGhhbmtzLAoKRGF2aWQgLyBkaGlsZGVu YgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KVmlydHVh bGl6YXRpb24gbWFpbGluZyBsaXN0ClZpcnR1YWxpemF0aW9uQGxpc3RzLmxpbnV4LWZvdW5kYXRp b24ub3JnCmh0dHBzOi8vbGlzdHMubGludXhmb3VuZGF0aW9uLm9yZy9tYWlsbWFuL2xpc3RpbmZv L3ZpcnR1YWxpemF0aW9u