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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2F3F4F34C63 for ; Mon, 13 Apr 2026 15:38:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 68BE66B0093; Mon, 13 Apr 2026 11:38:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 663EB6B0095; Mon, 13 Apr 2026 11:38:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5A07F6B009B; Mon, 13 Apr 2026 11:38:30 -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 4D1086B0093 for ; Mon, 13 Apr 2026 11:38:30 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 19247E03DB for ; Mon, 13 Apr 2026 15:38:30 +0000 (UTC) X-FDA: 84653939580.05.0E7734C Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf10.hostedemail.com (Postfix) with ESMTP id 53952C0007 for ; Mon, 13 Apr 2026 15:38:28 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=nLWZvOC7; spf=pass (imf10.hostedemail.com: domain of vbabka@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=vbabka@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776094708; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=d389xsFpECFT5XvZW4LaomTpdNNCG/rYyqdyExKIQJw=; b=vcTMhFPWAJZDT0iErKVqv2xFbd0D+OAYy65o46aUbBIduakeglFg+jBeaTemSVQ+Aqg1jc 3LJZjvyiL7kACIRxI3wQFaw4fwQKEdOgWs2FapEeyC9xH+7GBtGKhM0QhQC3kmU2eTMiqd isbHgn70POoIIacCHgBSPBcLhgaZ6hE= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=nLWZvOC7; spf=pass (imf10.hostedemail.com: domain of vbabka@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=vbabka@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776094708; a=rsa-sha256; cv=none; b=XPECGqsnEw5djfODY9ReqJeXe/m4q9lwJND6gIFZdchW0K8WP/681uvKS7hk/5T0jSxZaI FTqpC21yV2fwhMkRAGEvEGdF+6NwJFWPLUxRUXmCqi3KIOJaJbsz5Gco9hGLi4WyNqNqsg axntIABmbmLDRPAbqSDGMku6000q8q8= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 9DEB660172; Mon, 13 Apr 2026 15:38:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54969C2BCAF; Mon, 13 Apr 2026 15:38:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776094707; bh=mZpRvz7G8OpmAEE71Wnk9PIg6d1HTndlpxTz7DDiNKg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=nLWZvOC7HXFamfr3d32XycFsgIQfHX370qoWehj9VS13JL9VHdZVOjADoNWax3WK1 8VsI0/KOM8L0oM3UiwNBqCRARPFU4i9VHi7RFiws0cf2/eHoAZHrlB30lLlKgTqDXe ecQ+rhI/BhzMxosHSIIAPdlPQxwjbDd6rOYskb1CDATWCybduvc0o1cN0Yc9gqch2F +Mrsg+VOiflf9XEoulGInr5BLopDQhBGe4miCALqYeO25d2EFKUzvf4MDq1wfAUx4x 1x8ZqAERHk3ArhlRo516dYON3z2FAtsLIzVDngdbY6TN3eGcyQP2aQ3lg6PgOVjJSt K7VvpIw7EcGLg== Message-ID: <6ca33173-145b-43aa-8a8a-34985d375246@kernel.org> Date: Mon, 13 Apr 2026 17:38:19 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: Require LRU reclaim progress before retrying direct reclaim Content-Language: en-US To: Matt Fleming , Andrew Morton Cc: Christoph Hellwig , Jens Axboe , Sergey Senozhatsky , Roman Gushchin , Minchan Kim , kernel-team@cloudflare.com, Matt Fleming , Johannes Weiner , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Zi Yan , Axel Rasmussen , Yuanchu Xie , Wei Xu , David Hildenbrand , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260410101550.2930139-1-matt@readmodwrite.com> From: "Vlastimil Babka (SUSE)" In-Reply-To: <20260410101550.2930139-1-matt@readmodwrite.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 53952C0007 X-Stat-Signature: 5crqq1nnq9caxf6es141ankggf91cjdc X-Rspam-User: X-HE-Tag: 1776094708-819398 X-HE-Meta: U2FsdGVkX1+0bAJsXg0ijk/6DvylgtfK1bibiZdhsQKJxvZQ+CJm8AdqNT+oBhcapnERWGwcT0aOYSzlaetSF6CfZSXL3Z13twxdW8TMr8/PGZAiUu3GzqAO/BAhLCzCY1uoUbJk9GfkWIWDDQk8Ok0qW2DpPeFh60AgYkZHsn85a0RtEWJYpEFf66lbdGzR60II54bD2nMFfAlRtbPLWjzA1LkHwfCu1K08cyOlPvt7UI/MxhDtlpKIdf5SI5oJyfw+FfVg/lwiZOHZBdvFuDdphGKyG12j4XG0xyl0APq3oP4caSa0aGyMamqMt7tyDp23OTp2fDhpftOmODmrG2hcUw9jbzbI5pFjU1TjxA4kgbMPLdhpZxD4viXiVNh7ttLyayPySzlSQk9V8BqkSLifIevh3XSXy9eRbKCrbtmj0j7XmSMrUPrNMY0rJcqHSgS2ElTLqITAGVuVGNlHOB38z+v2/ZmH5zZh/1QsDPGpbwJTLtDdiCu9iwVIGoSqsZZ+IsyTwtx2jWPPtaP7P3MLmN7Gw5op03SQFQU4DNfYu/eqIDZ+0g3SdwOPa6B17BBnp5IpTMO6dkWbxcgqpRuHv6DIUXwcF+MbnrJJYEoUYck/awf2NNy/SHTKNC47DcYo/qQ0B1uwDOmq+juJ52HQHl69hTchWPaklPIJMc2U6ITwWLl1ztmnSSubwd7BXyAluf3KQg8J408TDEWL8qxL668Uj2kgGC4PXKprm6KDC5YyHzbUU2QabZNU4V8lv8iEk8lw+R50STz6f1bICakW9LgVHZgeaeUvVjnQVHBPK2r2Tevu/zYBB5Aputh3lUlx73883IvWn44Klk6zXCifFqHwSuCr4FOOa0gELWdJkE2zIBCXcxoBWJu5/iB0iAFVRVX3Gxiufvh+x93IHnby74YfIzxZ397JomoXypcj55YajNgVz5vxom+DDw5xNzWpDjYeoGPxoi1U1gX oKDy0BJJ +wRLFVNKRVOHknEXLA7E+tPDj4fsaalvaPe4DyfT0D6FdTfBuuHJMXjk2rOJmlR6+4WSNFY0xAMA2G1CPagdLyusxCS4X3wuTyUAo3yKDEvoWp9xeePMjyIHG18W1dHVyU34EF4EH4z3xnxKtYcX+QhTLRMg9t7wfK02I1rJgkyaQTXWvKPRcaZH0mZq0dh7YXuxWG8NB1Eznicqa119CHgClfzdV4m2YwHfa8cV9MwGcsL+fyrIOsQRFCxmQ5A1euKKluWEsDZZNBce3+lsi0RGiipmv3xhKpX1IIt4jHkO4J/0jhjrPeMb3jJL2lg3w529RIdAtjX5FaF1cSzh5cHSsWw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/10/26 12:15, Matt Fleming wrote: > From: Matt Fleming > > should_reclaim_retry() uses zone_reclaimable_pages() to estimate whether > retrying reclaim could eventually satisfy an allocation. It's possible > for reclaim to make minimal or no progress on an LRU type despite having > ample reclaimable pages, e.g. anonymous pages when the only swap is > RAM-backed (zram). This can cause the reclaim path to loop indefinitely. > > Track LRU reclaim progress (anon vs file) through a new struct > reclaim_progress passed out of try_to_free_pages(), and only count a > type's reclaimable pages if at least reclaim_progress_pct% was actually > reclaimed in the last cycle. > > The threshold is exposed as /proc/sys/vm/reclaim_progress_pct (default > 1, range 0-100). Setting 0 disables the gate and restores the previous > behaviour. Environments with only RAM-backed swap (zram) and small > memory may need a higher value to prevent futile anon LRU churn from > keeping the allocator spinning. > > Suggested-by: Johannes Weiner > Signed-off-by: Matt Fleming Hi Matt, so have you tested it for your usecase with zram and have any observations how it helped, what values did you set etc? Vlastimil