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 B4157CA0EC4 for ; Mon, 11 Aug 2025 20:43:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 691F38E00A0; Mon, 11 Aug 2025 16:43:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 669BF8E0091; Mon, 11 Aug 2025 16:43:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5A6E28E00A0; Mon, 11 Aug 2025 16:43:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 49F958E0091 for ; Mon, 11 Aug 2025 16:43:05 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id C97E7811FC for ; Mon, 11 Aug 2025 20:43:04 +0000 (UTC) X-FDA: 83765651088.17.D15E508 Received: from prime.voidband.net (prime.voidband.net [199.247.17.104]) by imf14.hostedemail.com (Postfix) with ESMTP id D4CFA100007 for ; Mon, 11 Aug 2025 20:43:02 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=natalenko.name header.s=dkim-20170712 header.b=sicsFSqE; spf=pass (imf14.hostedemail.com: domain of oleksandr@natalenko.name designates 199.247.17.104 as permitted sender) smtp.mailfrom=oleksandr@natalenko.name; dmarc=pass (policy=reject) header.from=natalenko.name ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1754944983; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=epr51fyacq8S8wo/Irurh0cQPovilFvLcdw3EwV5RAo=; b=Uv24WCxETKd0m/FpmrXhRuPpO4+ypW/Cqk/SupI1TnGmfnZYViuhA6btabJUziVKw2g6gp gqMV0ro1v3AJqcxOplvxeWpt6XcZ7KgVoQr1LT9vXUYs2v9m5mIcG6dHFDBBEyCcszl6ox yHKlOzpevT7skLMguAqDPtfkTNjQ+Mo= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=natalenko.name header.s=dkim-20170712 header.b=sicsFSqE; spf=pass (imf14.hostedemail.com: domain of oleksandr@natalenko.name designates 199.247.17.104 as permitted sender) smtp.mailfrom=oleksandr@natalenko.name; dmarc=pass (policy=reject) header.from=natalenko.name ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1754944983; a=rsa-sha256; cv=none; b=g19lht3zUocKW7ovjLMxxZJX7fBj0x+XQ1pRTA63YzikL3w3N9jHBAd73h1wK7YFy1H0OO 2WRIaolQkiVPiSBoma/F9z5KC+xHK0Zj0Vi5+ngrVpW4wT55EYE9Ta6sa6A33umuXtoPDQ q34h4EJqMgPa/i7DKd3ljBV9jinoPRA= Received: from spock.localnet (unknown [212.20.115.26]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by prime.voidband.net (Postfix) with ESMTPSA id 1258B635B040; Mon, 11 Aug 2025 22:43:00 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=natalenko.name; s=dkim-20170712; t=1754944980; 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=epr51fyacq8S8wo/Irurh0cQPovilFvLcdw3EwV5RAo=; b=sicsFSqEBfPjKKKc8vl3Ha5STHfVdeVdOjrq7qOnr3T1QQmkNB3n1e8eBsbt1c1WlO1ytq oyyJ2Z8WtrTwW3um9OuESyXSx9ja8YqKgXsCsCUTdi5kljoOXE/Lh/o9pYAq1dylWPpQ7y G9Lt76MLVXpCJ0r5qPDI1J7gS/dx0pA= From: Oleksandr Natalenko To: David Rientjes Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, Jens Axboe , Damien Le Moal , John Garry , Christoph Hellwig , "Martin K. Petersen" , linux-mm@kvack.org, Lorenzo Stoakes , Shakeel Butt , Qi Zheng , Michal Hocko , David Hildenbrand , Johannes Weiner , Andrew Morton Subject: Re: [REGRESSION][BISECTED] Unexpected OOM instead of reclaiming inactive file pages Date: Mon, 11 Aug 2025 22:42:46 +0200 Message-ID: <15056829.uLZWGnKmhe@natalenko.name> In-Reply-To: <199fb020-19ee-89d1-6373-7cc7f5babab8@google.com> References: <5905724.LvFx2qVVIh@natalenko.name> <199fb020-19ee-89d1-6373-7cc7f5babab8@google.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart4238270.e9J7NaK4W3"; micalg="pgp-sha512"; protocol="application/pgp-signature" X-Stat-Signature: rsbi5cnbscpm6sot5xyxjhi9s78pysgd X-Rspam-User: X-Rspamd-Queue-Id: D4CFA100007 X-Rspamd-Server: rspam05 X-HE-Tag: 1754944982-558571 X-HE-Meta: U2FsdGVkX18pbXilVn50MOCq8RenwwSr1ep5bH1O+rXxDkGe4raQ8e+2umc5Cp9CtbMrYHI3GpYijhRzAezoWi/y4g5zB5oW+wedVuWXkWpitYKcW25lABxB0GCrIYPHZeBnS05e41FT31uU4b6/2BN5iyXbgpiWgp06TT/yUq3TTgzTetZjP2Y8TOHnuCBs2I4wZAMfOQNWoAKEpwlXB8H9ApcuB1fTU53bA/u15Dt/0fTKvR5Kewc8CBa/gJKFElh4f2GhPNkksJ2ZKH2txDzFiNA9/E0clFtZLqTy+rtxgQYQ1pSwz1+s0RbgAim4FTEqu9yV1lVflfwQgTX1iXTcRtZl9LT/b3Kvf2HzgVPgE7jqcHocQ/QB8oJU2n9PZsGHUG3AimdvfOedcMemNvi5yu6rizf3M/l8/2IBhMH1ebiCuuKekuXsG2kC6foRLKvWWfhDJ/8YNMM1Mc94Ny/pmWdKY+Uz/bPSkzLUDYX/V2StBI8NB/Y5O+juIA6ovRYd3PRHfiva8roI8m00borpw5JMZHW8rZVZ93gbBGkCqUuJIIdnPZZsgy1VB+Zqp2kItXUjR/DuHW7tgbalxGJdj37vM5hHX/Y4FBbzLedUMvFTxpAcU0BevVuNAcELO2F3v548AE2WJakXKMpOZQjgdC5C7j1/mw/lThdK46O6MSLE3djNWvPJYeces0tSjek2GsaDMhJpWNiDiCa7d+hZ7+03WG9MwLnnN44daoF1LmF5VcRuxqilIPOgNTUVd3TvD5CxvSok8ZnvIU8mRQTJH8Gh74yycZL8wo1qiZZTzIH7xxr0/GqHGPezq0wEeevzGGTT+9zxMLgJ7XbhhO1xZ9LKmNy2rUqNXe/MYyDyVOtHqXD2+Mc9+q7BKRVZRBfm0I8xmF9wylJnGljQEij0K6u+Tg2cn9XLjFeFN2aoWC9rxneHyVTysLMEmMBWEZCAhRhkO1GGJZ7hxqp reaxHga2 zoHsxdI1SYc+3VZkNmONObWAbLDKGa8aMstcbSABlhJvANG2d4bC0LdHxHbppBhKMqp0UlTn4MhtjEtpcwsvA8FdMyNVFF16vWjFvYOHz5ElJy0nwuhRGivfP39sa8AmNXQcwkHU2PLUFxewPQGhQ8hEZePJqmYrz5Fm0pYpeN+2qJpkah5AQMsSfeoXDhx5Ys3veQEdl7RTr3GjvxfguN/AIg7fpBU3IwAZZ20EkHtgYfV7LdLuTT6zKajLPbyl/ywVA9gy8poKNFU+7gALE3L61Jb0WTgHKqINE7t/OvdxEiMZ0bCH1ZX+jAzBMg9baMGDbXuQnZKypoegT0bUO1QdJjqWLmaY+FSsTmsPPKX5wYZ0Zw5rsxQEba3oi0enGgZMvJ2h/jqvPUsvNlUHQPMVCwyiLsp5IoJ37PeV1Go55grlfGp3MKfiMrY751/psmqcSOdDIbP6RCX7245+UirXV/A== 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: List-Subscribe: List-Unsubscribe: --nextPart4238270.e9J7NaK4W3 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8"; protected-headers="v1" From: Oleksandr Natalenko To: David Rientjes Date: Mon, 11 Aug 2025 22:42:46 +0200 Message-ID: <15056829.uLZWGnKmhe@natalenko.name> In-Reply-To: <199fb020-19ee-89d1-6373-7cc7f5babab8@google.com> MIME-Version: 1.0 Hello. On pond=C4=9Bl=C3=AD 11. srpna 2025 18:06:16, st=C5=99edoevropsk=C3=BD letn= =C3=AD =C4=8Das David Rientjes wrote: > On Mon, 11 Aug 2025, Oleksandr Natalenko wrote: >=20 > > Hello Damien. > >=20 > > I'm fairly confident that the following commit > >=20 > > 459779d04ae8d block: Improve read ahead size for rotational devices > >=20 > > caused a regression in my test bench. > >=20 > > I'm running v6.17-rc1 in a small QEMU VM with virtio-scsi disk. It has = got 1 GiB of RAM, so I can saturate it easily causing reclaiming mechanism = to kick in. > >=20 > > If MGLRU is enabled: > >=20 > > $ echo 1000 | sudo tee /sys/kernel/mm/lru_gen/min_ttl_ms > >=20 > > then, once page cache builds up, an OOM happens without reclaiming inac= tive file pages: [1]. Note that inactive_file:506952kB, I'd expect these to= be reclaimed instead, like how it happens with v6.16. > >=20 > > If MGLRU is disabled: > >=20 > > $ echo 0 | sudo tee /sys/kernel/mm/lru_gen/min_ttl_ms > >=20 > > then OOM doesn't occur, and things seem to work as usual. > >=20 > > If MGLRU is enabled, and 459779d04ae8d is reverted on top of v6.17-rc1,= the OOM doesn't happen either. > >=20 > > Could you please check this? > >=20 >=20 > This looks to be an MGLRU policy decision rather than a readahead=20 > regression, correct? >=20 > Mem-Info: > active_anon:388 inactive_anon:5382 isolated_anon:0 > active_file:9638 inactive_file:126738 isolated_file:0 >=20 > Setting min_ttl_ms to 1000 is preserving the working set and triggering=20 > the oom kill is the only alternative to free memory in that configuration= =2E =20 > The oom kill is being triggered by kswapd for this purpose. >=20 > So additional readahead would certainly increase that working set. This= =20 > looks working as intended. OK, this makes sense indeed, thanks for the explanation. But is inactive_fi= le explosion expected and justified? Without revert: $ echo 3 | sudo tee /proc/sys/vm/drop_caches; free -m; sudo journalctl -kb = >/dev/null; free -m 3 total used free shared buff/cache avai= lable Mem: 690 179 536 3 57 = 510 Swap: 1379 12 1367 /* OOM happens here */ total used free shared buff/cache avai= lable Mem: 690 177 52 3 561 = 513 Swap: 1379 17 1362=20 With revert: $ echo 3 | sudo tee /proc/sys/vm/drop_caches; free -m; sudo journalctl -kb = >/dev/null; free -m 3 total used free shared buff/cache avai= lable Mem: 690 214 498 4 64 = 476 Swap: 1379 0 1379 /* no OOM */ total used free shared buff/cache avai= lable Mem: 690 209 462 4 119 = 481 Swap: 1379 0 1379 The journal folder size is: $ sudo du -hs /var/log/journal 575M /var/log/journal It looks like this readahead change causes far more data to be read than ac= tually needed? =2D-=20 Oleksandr Natalenko, MSE --nextPart4238270.e9J7NaK4W3 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. 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