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 EEF43EDF16E for ; Fri, 13 Feb 2026 14:33:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1FE456B0005; Fri, 13 Feb 2026 09:33:43 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1E00A6B008A; Fri, 13 Feb 2026 09:33:43 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 11FF06B0088; Fri, 13 Feb 2026 09:33:43 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id EB87E6B0005 for ; Fri, 13 Feb 2026 09:33:42 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 2C31213B2AF for ; Fri, 13 Feb 2026 14:33:42 +0000 (UTC) X-FDA: 84439677084.05.BBAEA06 Received: from lgeamrelo07.lge.com (lgeamrelo07.lge.com [156.147.51.103]) by imf06.hostedemail.com (Postfix) with ESMTP id 3207A180009 for ; Fri, 13 Feb 2026 14:33:38 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=lge.com; spf=pass (imf06.hostedemail.com: domain of youngjun.park@lge.com designates 156.147.51.103 as permitted sender) smtp.mailfrom=youngjun.park@lge.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1770993220; 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; bh=7zlauq2NXmYcYr161AptaUs9JIe11MydsXKwgR9OyVs=; b=3phJ0287sucfDW/AZPTxEcBM/wPjM7xlWKHBGKZyw1vr40Nw/b86uc3GYEfJaovduntofy 5bBKuURUtZ7w2qPdARjxMbbC7gMUzUpjIpJcCIvdOXXIy0CHaePzs9QrXQXpSNQvHOsN1t Tb+iMZWVj9vlR8jSVOcsOKg9lYasSmI= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1770993220; a=rsa-sha256; cv=none; b=Hposb4gx0hHsDsetlgdammywAMRBgY4qqAGZWCMHQZuUscNUAj/+61YtvzvibzX/xu+xg1 baq7f2dwwb1i7Ezhi4kfUJK8rezAO9iujJAt9J7EJ5YefSxQa1es+aeuxwamnbeNHDXgAq tngBKN0r6eaL8ECcaa+SA5wrp3IEl2w= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=lge.com; spf=pass (imf06.hostedemail.com: domain of youngjun.park@lge.com designates 156.147.51.103 as permitted sender) smtp.mailfrom=youngjun.park@lge.com Received: from unknown (HELO yjaykim-PowerEdge-T330) (10.177.112.156) by 156.147.51.103 with ESMTP; 13 Feb 2026 23:33:35 +0900 X-Original-SENDERIP: 10.177.112.156 X-Original-MAILFROM: youngjun.park@lge.com Date: Fri, 13 Feb 2026 23:33:35 +0900 From: YoungJun Park To: Chris Li Cc: Andrew Morton , linux-mm@kvack.org, Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , gunho.lee@lge.com, taejoon.song@lge.com, austin.kim@lge.com Subject: Re: [RFC PATCH v2 v2 1/5] mm: swap: introduce swap tier infrastructure Message-ID: References: <20260126065242.1221862-1-youngjun.park@lge.com> <20260126065242.1221862-2-youngjun.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 3207A180009 X-Stat-Signature: 36o4ro3q5i1hb9eqw39hbjzmb96agzjj X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1770993218-865451 X-HE-Meta: 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 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: On Thu, Feb 12, 2026 at 01:07:45AM -0800, Chris Li wrote: > > +} > > + > > +int swap_tiers_add(const char *name, int prio) > > When we add, modify, remove a tier. The simple case is there is no > swap file under any tiers. > But if the modification causes some swap files to jump to different > tiers. That might be problematic. I missed one comment. The tier of existing swapfiles is immutable once assigned at swapon. I removed tier reference. Instead of reference counting, each operation validates the tier range at operation time to guarantee this invariant. - add: Does not change existing swapfiles' tier. New tier may split priority range, but existing assignments stay. - remove: Rejected with -EBUSY if any swapfile is attached. - modify: Rejected if the change would cause any swapfile to move to a different tier. So swapfiles never jump between tiers at runtime. Youngjun Park