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X-CSE-ConnectionGUID: XJMslmJBTlambWSRPRTdAg== X-CSE-MsgGUID: P0j5HeVsQKanWU0LLnkCDw== X-IronPort-AV: E=McAfee;i="6800,10657,11768"; a="100826034" X-IronPort-AV: E=Sophos;i="6.23,201,1770624000"; d="scan'208";a="100826034" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Apr 2026 03:35:55 -0700 X-CSE-ConnectionGUID: x0J3iKZQS0Kd9ijvLEpTBg== X-CSE-MsgGUID: haAKQJ1ZSueUDO0iE/PuBA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,201,1770624000"; d="scan'208";a="264017003" Received: from egrumbac-mobl6.ger.corp.intel.com (HELO fedora) ([10.245.244.36]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Apr 2026 03:35:52 -0700 From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= To: intel-xe@lists.freedesktop.org Cc: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Andrew Morton , David Hildenbrand , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Axel Rasmussen , Yuanchu Xie , Wei Xu , Brian Geffon , Steven Barrett , Oleksandr Natalenko , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH 0/1] Fix halted scanning of swap-cache folios Date: Mon, 27 Apr 2026 12:35:31 +0200 Message-ID: <20260427103532.5623-1-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.53.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Stat-Signature: hp3tiooqg5wpmakpmy6ghyuam1n5nsru X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 95F211C0007 X-Rspam-User: X-HE-Tag: 1777286156-713859 X-HE-Meta: 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 meUiYEKc NoKAEdv34stNiJ93+TbTSgYqujjJDbElLE6CTGueBJeIp7ifS1QIidg1cL8lm4fdnxR4w/IpLtqhla5E4LVOQU+Upe3DzLa2R0MMulNDNFdK0DUE1L7dUAF2sKuNEjzuZ2aga1Qg0c5nw9CgIMkhfxpvorM+TW7IDG+NM/VoUNoAPDhvgoBgBjbrpt+Jn2RWbWZLoVg8grs8+hn7hYaJ0y3APYDACbd/fGTvXEXht+sAybJVaXCKi1tBGWbmiq+Ptc5qXxe3qKSG8igTDqZd8UsfleOUu2sK1NpUSoJ+ef/r5azjoIqkVPuCrAQ/Plhj+/oBD6m6dTvC01S3A+kJ1Uwnlei0OxPQUGeDH/OWHCak+KeI6ncziwQNudZXiXj5O4QH/mruVYbAK0Xv8zTnZsoxKgLCvhzOz/Ep1fB3yJeIk2H4+0HoVyVY3wjjB2uLpXCF2vABbkPFZwepVR3nDNbjcgvA8YbXXvDt5PcXpHXTxiuE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: While experimenting with an interface for inserting isolated dirty GPU folios directly into the swap-cache for backup, I noticed that when the number of swap entries were almost exhausted, scanning and freeing of these pages already inserted into the swapc-cache stopped. Apparently there are guards that stop LRU scanning of anonymous pages when the number of free swap entries are low. However that also blocks pages already present in the swap cache from being scanned and freed. Not sure whether that is intentional, but anyway I'm sending a patch that implements one (crude) way of fixing the problem. Cc: Andrew Morton Cc: David Hildenbrand Cc: Michal Hocko Cc: Qi Zheng Cc: Shakeel Butt Cc: Lorenzo Stoakes Cc: Axel Rasmussen Cc: Yuanchu Xie Cc: Wei Xu Cc: Brian Geffon Cc: Steven Barrett Cc: Oleksandr Natalenko Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org Thomas Hellström (1): mm: vmscan: keep anon scanning enabled when swapcache folios are present mm/vmscan.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) -- 2.53.0