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 EEDCF1099B3A for ; Fri, 20 Mar 2026 19:27:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0D8EC6B0155; Fri, 20 Mar 2026 15:27:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0B10A6B0158; Fri, 20 Mar 2026 15:27:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CBD6B6B0159; Fri, 20 Mar 2026 15:27:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id AC4546B0155 for ; Fri, 20 Mar 2026 15:27:49 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 6EEB2C132D for ; Fri, 20 Mar 2026 19:27:49 +0000 (UTC) X-FDA: 84567426258.24.E7F5683 Received: from mail-oi1-f182.google.com (mail-oi1-f182.google.com [209.85.167.182]) by imf21.hostedemail.com (Postfix) with ESMTP id A22E61C0004 for ; Fri, 20 Mar 2026 19:27:47 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=hRzWcnGm; spf=pass (imf21.hostedemail.com: domain of nphamcs@gmail.com designates 209.85.167.182 as permitted sender) smtp.mailfrom=nphamcs@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774034867; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=augNyOBtiYJ0dgm3cOulQaqdWfbdzgL3KEY1IT/V5Xs=; b=yVq4NT67yvAM5QDCK/eIYPBA2LyC+pIlfid1ppq7G3HD6O+YFOx1fAf1nri0rP8yPm/NHU CmdNHMZydjOO5AgghWUZLMpeMHR3wGDsHhf/RKpr2fCE5V/x2ffGl3zfE1trBUx1r0pkLG U3LOjNb0nB7lffM3rP0f5TRP18B6r9I= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=hRzWcnGm; spf=pass (imf21.hostedemail.com: domain of nphamcs@gmail.com designates 209.85.167.182 as permitted sender) smtp.mailfrom=nphamcs@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774034867; a=rsa-sha256; cv=none; b=kUiOuVt1V5MHPUgS+Y160B+4DJyhrGiQJM7ECibPKYlwWKSbUmgE/WOmumV29vJ1rTDS+s QDgrtcZaiOL21sauAbvy3E0lW75+eZVkz11aRX/19TlAvW8872bnJnuqQjIVsdqMF2quQO L6nuC9/CdFro+VBlMDghy8edWD0xCRk= Received: by mail-oi1-f182.google.com with SMTP id 5614622812f47-467e044082dso352316b6e.1 for ; Fri, 20 Mar 2026 12:27:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1774034867; x=1774639667; darn=kvack.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=augNyOBtiYJ0dgm3cOulQaqdWfbdzgL3KEY1IT/V5Xs=; b=hRzWcnGmespPHXcpUP7rrrJMebrE3O3TYVZVJjhpD13NASby+F+cQD4iqmdu+OLXOj t0eY2pdEJvr/+eybdplOzhBMGmlMdsgqGHYTpSJ2lmkA88/ZP7qT1VkP+OGc65eyV6QW quYuxyKeM30cO+hfjD9KmVEqAJlKlDcSAheOxz4MZEZyO7dSTeaOH72CTcxWSIfLKyjv XnZD8h4Iy0Pe+M9EG78XBS1ATYPoPgEQW7VOwurNYUm5M2U0w4R+F7m1Evsb1iVaUV0p cHwKxpHcqYFuGr9/dUoGFvmKPYsbRQdN4WBJxXD/bYp+samA1lZM7w26KwhdIVjoNzSL xf0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774034867; x=1774639667; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=augNyOBtiYJ0dgm3cOulQaqdWfbdzgL3KEY1IT/V5Xs=; b=YvWGBwVt9c8dKZVFNUzyh5XEi3LgDPT9LVR++qTegjYYzDlgHKRk8bisfspTpcAVES Mp6GZCG8IgaRY64YJFwQ1Gs+SJ4n1dfK0DYsCIgkrp9mcWacFiJANl/lMfNL7Df4a+DL K0DTdp5lbFr2d0vIbpv9HND4gEFe6knUC56NHP8w7kJnv3/t6ruqNgwCRSryux+nYvCH U8SIAxyjhDpNYWu6V1tnCeWzlVrbEZk47MW3jfHbjGJtT6nJenI6rPdEgerspxRK6ldm YtbN1w2jel+H2mqLi+N2kekFIoyqwV9qB7LfOjFFpxrM7p3Y7/1g5xtn9MmjR/zBORSI jpRQ== X-Forwarded-Encrypted: i=1; AJvYcCXW88PtjogipNFF4tCd96E49++DJSpSbgXO58ZPFkdaVqaqM4u070qPZgQC1UIRHDW0nNo7QbAG+Q==@kvack.org X-Gm-Message-State: AOJu0YxNVbBeJdaYD/Q+thiiEQ+MN3FIgnvm3bJ108GbyaaEhuYeYAtl zPt/nLmCLdmzQa3WG4Lqvaoc8cnBBwQczXQQcxmfV30ma4cP9ac+JTKi X-Gm-Gg: ATEYQzxuDqsL3CsuhkCQt150+eBDclGb+XQURCB0d86NOrtW0TQK4UZ4KVQjbLd3GWC iHOBbJgpsScjAsEEoCcPOZTqYx5JG8U7DwUaSV+TTo70LcbjYq2PzU4LTStBeqErvm0DQH60u8O 1hHb68ZdJuaa5zuDaIqWTVbVp2QFZDRoqVAuDHi9B/gGv945EZGwi7hQNpaM8es7+k2g//td55+ BjYF7Ku0SuwPXdnhU0gZm1b7wlcJH0DWtGS5Cswvmbrz/+nEvQFFqgnOGN+djfBIjKGjxVOuo3W w/nkD8UAHwnJLLF150MRmlkF44nLhVhwiCCAMFP2hL9+8XPgCOOdw0M59Y9+N0/OVQ85+bkRzQR M2npHk+Kr7TPIMzdHvDUxtrL5avwduUoJJ/sqLO6jZ9bQY2GDGOFAkpBlOUYOmh1K7yhl6FVT8e cKPo1HVl6i9TK3aKathmR/jXO/q/8o7Y75uzr8DVGRnG+OeA== X-Received: by 2002:a05:6808:190d:b0:466:f054:c3b6 with SMTP id 5614622812f47-467e5fe7105mr2485514b6e.59.1774034866661; Fri, 20 Mar 2026 12:27:46 -0700 (PDT) Received: from localhost ([2a03:2880:10ff:48::]) by smtp.gmail.com with ESMTPSA id 5614622812f47-467e7d19abfsm1824746b6e.2.2026.03.20.12.27.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Mar 2026 12:27:46 -0700 (PDT) From: Nhat Pham To: kasong@tencent.com Cc: Liam.Howlett@oracle.com, akpm@linux-foundation.org, apopple@nvidia.com, axelrasmussen@google.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, bhe@redhat.com, byungchul@sk.com, cgroups@vger.kernel.org, chengming.zhou@linux.dev, chrisl@kernel.org, corbet@lwn.net, david@kernel.org, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jannh@google.com, joshua.hahnjy@gmail.com, lance.yang@linux.dev, lenb@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, lorenzo.stoakes@oracle.com, matthew.brost@intel.com, mhocko@suse.com, muchun.song@linux.dev, npache@redhat.com, nphamcs@gmail.com, pavel@kernel.org, peterx@redhat.com, peterz@infradead.org, pfalcato@suse.de, rafael@kernel.org, rakie.kim@sk.com, roman.gushchin@linux.dev, rppt@kernel.org, ryan.roberts@arm.com, shakeel.butt@linux.dev, shikemeng@huaweicloud.com, surenb@google.com, tglx@kernel.org, vbabka@suse.cz, weixugc@google.com, ying.huang@linux.alibaba.com, yosry.ahmed@linux.dev, yuanchu@google.com, zhengqi.arch@bytedance.com, ziy@nvidia.com, kernel-team@meta.com, riel@surriel.com Subject: [PATCH v5 07/21] mm: create scaffolds for the new virtual swap implementation Date: Fri, 20 Mar 2026 12:27:21 -0700 Message-ID: <20260320192735.748051-8-nphamcs@gmail.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260320192735.748051-1-nphamcs@gmail.com> References: <20260320192735.748051-1-nphamcs@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: A22E61C0004 X-Stat-Signature: rpxxs9cpqo3qridye53srbpoxbi5j678 X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1774034867-723695 X-HE-Meta: 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 lbsNcWcu 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: In prepration for the implementation of swap virtualization, add new scaffolds for the new code: a new mm/vswap.c source file, which currently only holds the logic to set up the (for now, empty) vswap debugfs directory. Hook this up in the swap setup step in mm/swap_state.c, and set up vswap compilation in the Makefile. Other than the debugfs directory, no behavioral change intended. Finally, make Johannes a swap reviewer, given that he has contributed majorly to the developments of virtual swap. Signed-off-by: Nhat Pham --- MAINTAINERS | 2 ++ include/linux/swap.h | 3 +++ mm/Makefile | 2 +- mm/swap_state.c | 6 ++++++ mm/vswap.c | 35 +++++++++++++++++++++++++++++++++++ 5 files changed, 47 insertions(+), 1 deletion(-) create mode 100644 mm/vswap.c diff --git a/MAINTAINERS b/MAINTAINERS index d3780bb330378..042dbc06c3d3c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -16728,6 +16728,7 @@ R: Kemeng Shi R: Nhat Pham R: Baoquan He R: Barry Song +R: Johannes Weiner L: linux-mm@kvack.org S: Maintained F: include/linux/swap.h @@ -16739,6 +16740,7 @@ F: mm/swap.h F: mm/swap_table.h F: mm/swap_state.c F: mm/swapfile.c +F: mm/vswap.c MEMORY MANAGEMENT - THP (TRANSPARENT HUGE PAGE) M: Andrew Morton diff --git a/include/linux/swap.h b/include/linux/swap.h index 918b47da55f44..df0771903a952 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -423,6 +423,9 @@ extern void __meminit kswapd_stop(int nid); #ifdef CONFIG_SWAP +/* Virtual swap space API (mm/vswap.c) */ +int vswap_init(void); + /* Lifecycle swap API (mm/swapfile.c) */ int folio_alloc_swap(struct folio *folio); bool folio_free_swap(struct folio *folio); diff --git a/mm/Makefile b/mm/Makefile index 2d0570a16e5be..67fa4586e7e18 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -75,7 +75,7 @@ ifdef CONFIG_MMU obj-$(CONFIG_ADVISE_SYSCALLS) += madvise.o endif -obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o +obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o vswap.o obj-$(CONFIG_ZSWAP) += zswap.o obj-$(CONFIG_HAS_DMA) += dmapool.o obj-$(CONFIG_HUGETLBFS) += hugetlb.o hugetlb_sysfs.o hugetlb_sysctl.o diff --git a/mm/swap_state.c b/mm/swap_state.c index e2e9f55bea3bb..29ec666be4204 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -882,6 +882,12 @@ static int __init swap_init(void) int err; struct kobject *swap_kobj; + err = vswap_init(); + if (err) { + pr_err("failed to initialize virtual swap space\n"); + return err; + } + swap_kobj = kobject_create_and_add("swap", mm_kobj); if (!swap_kobj) { pr_err("failed to create swap kobject\n"); diff --git a/mm/vswap.c b/mm/vswap.c new file mode 100644 index 0000000000000..e68234f053fc9 --- /dev/null +++ b/mm/vswap.c @@ -0,0 +1,35 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Virtual swap space + * + * Copyright (C) 2024 Meta Platforms, Inc., Nhat Pham + */ +#include + +#ifdef CONFIG_DEBUG_FS +#include + +static struct dentry *vswap_debugfs_root; + +static int vswap_debug_fs_init(void) +{ + if (!debugfs_initialized()) + return -ENODEV; + + vswap_debugfs_root = debugfs_create_dir("vswap", NULL); + return 0; +} +#else +static int vswap_debug_fs_init(void) +{ + return 0; +} +#endif + +int vswap_init(void) +{ + if (vswap_debug_fs_init()) + pr_warn("Failed to initialize vswap debugfs\n"); + + return 0; +} -- 2.52.0