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 6248DC55ABA for ; Wed, 5 Aug 2026 07:54:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7C77A6B00A4; Wed, 5 Aug 2026 03:54:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 778696B00A6; Wed, 5 Aug 2026 03:54:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 68E0B6B00A7; Wed, 5 Aug 2026 03:54:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 461646B00A4 for ; Wed, 5 Aug 2026 03:54:18 -0400 (EDT) Received: from smtpin29.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id BD7DFA0E72 for ; Wed, 5 Aug 2026 07:54:17 +0000 (UTC) X-FDA: 85066452954.29.ED16EB5 Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) by imf07.hostedemail.com (Postfix) with ESMTP id E2E7C40004 for ; Wed, 5 Aug 2026 07:54:15 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=MSUvCXlN; spf=pass (imf07.hostedemail.com: domain of baoquan.he@linux.dev designates 91.218.175.177 as permitted sender) smtp.mailfrom=baoquan.he@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1785916456; b=77uOT/96N1L2IEwJTPd4PDlLo9Q75W8HilRAnCRhXWG5R2O9+XK+IMj2Tw3bIH6RchfM7Q S+KfOkHjIGpNs944Tc3OzXb14Tm6yGjVPc3SupbMEcucbzN1YodtAKaxJSt40JDCJQEbz2 9bnF4PepEbgES9D1TXUMkCYi0Ew+S34= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=MSUvCXlN; spf=pass (imf07.hostedemail.com: domain of baoquan.he@linux.dev designates 91.218.175.177 as permitted sender) smtp.mailfrom=baoquan.he@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1785916456; 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=Vyg1JuKKGQsuDU1bKZ0uj2oDV98R+6DJe0buLRSbuTU=; b=0YW306sBncqCGzsiUqw+Kk/rnUcUzAEKymmy+cyondipwXbXSgsue6T98jneR/8WrBjEW+ XIbyw15FtXgtjhhJeqK94XLhej0WAxZ4R+KkdSn4/xIqAGFlNBp1ETnao7Y3JqwSKvypX2 I1gHmubitRFVYF29YSsdMGQ5bGXTcQs= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1785916453; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Vyg1JuKKGQsuDU1bKZ0uj2oDV98R+6DJe0buLRSbuTU=; b=MSUvCXlNL2jJBQKWRW6MwT/fPVE0vP3PeCSPlPH7WhqywWqLqS1Xh114SiWC01cikNT09/ vfXD2m/xesXSYNU3Uzfu6TaN8oGfy6pMdMom1JUDyeE9I7rEKk2LCr72CVqA+BGcdQoSY6 xBeD/z12DtBqmFC/8ZqDvGdWQfznWFU= From: Baoquan He To: linux-mm@kvack.org Cc: chrisl@kernel.org, nphamcs@gmail.com, kasong@tencent.com, baohua@kernel.org, youngjun.park@lge.com, hannes@cmpxchg.org, yosry@kernel.org, david@kernel.org, shikemeng@huaweicloud.com, chengming.zhou@linux.dev, linux-kernel@vger.kernel.org, Baoquan He Subject: [RFC PATCH v2 02/10] mm, swap: add CONFIG_XSWAP and xswap fields to swap_info_struct Date: Wed, 5 Aug 2026 15:53:25 +0800 Message-ID: <20260805075336.3579395-3-baoquan.he@linux.dev> In-Reply-To: <20260805075336.3579395-1-baoquan.he@linux.dev> References: <20260805075336.3579395-1-baoquan.he@linux.dev> MIME-Version: 1.0 Content-type: text/plain Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: E2E7C40004 X-Stat-Signature: zodo7bywfny1szqz3ceh4e1xitrbojrx X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1785916455-9086 X-HE-Meta: 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 uBm9yaXA BYZSfWchbVJa45JaoVaFOFhO5sGWPx4t0umySSQ8hiXCITKac/RSZVp5AqmM8DUQ9XOBsloFQa/T0/ABhIYRoUlT5n/Nc24jmx1NKet/HR9j1aEEyxKO+vfyE+4a2b/V3VdFgg2q9efmFvA+Oj46b/farDU+NKKqEbYNPVSYQNpEiPg7oY/ZCaAYvy2ZMO4QGYr9fzMIfQs1VwbPqR1ck7uTnsgBBPllRpMUa/DUrmDM3LYQr7dh13o4kFA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add CONFIG_XSWAP Kconfig option (depends on SWAP && 64BIT) for extendable (virtual) swap device support. Add three fields to struct swap_info_struct under CONFIG_XSWAP: - cluster_vm: the VM_SPARSE vm_struct backing the cluster_info array - nr_clusters: total number of clusters in the xswap address space - nr_clusters_mapped: number of clusters currently mapped (lazy grow) These fields enable lazy vmalloc-based dynamic cluster management where the cluster_info array is backed by a sparse vmalloc area that grows on demand and shrinks when clusters are freed. Signed-off-by: Baoquan He --- include/linux/swap.h | 5 +++++ mm/Kconfig | 9 +++++++++ 2 files changed, 14 insertions(+) diff --git a/include/linux/swap.h b/include/linux/swap.h index 78f4302b92e1..970232f6359d 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -248,6 +248,11 @@ struct swap_info_struct { signed char type; /* strange name for an index */ unsigned int max; /* size of this swap device */ struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */ +#ifdef CONFIG_XSWAP + struct vm_struct *cluster_vm; /* VM_SPARSE area for xswap dynamic cluster_info */ + unsigned long nr_clusters; /* total cluster count for xswap */ + unsigned long nr_clusters_mapped; /* currently mapped cluster count */ +#endif struct list_head free_clusters; /* free clusters list */ struct list_head full_clusters; /* full clusters list */ struct list_head nonfull_clusters[SWAP_NR_ORDERS]; diff --git a/mm/Kconfig b/mm/Kconfig index 060190e12bce..82f62f4c5b23 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -122,6 +122,15 @@ config ZSWAP_COMPRESSOR_DEFAULT default "zstd" if ZSWAP_COMPRESSOR_DEFAULT_ZSTD default "" +config XSWAP + bool "Extendable (virtual) swap device" + depends on SWAP && 64BIT + help + Adds support for extendable swap devices (xswap) that decouple + PTE swap entries from physical backing storage. The cluster_info + array is backed by a sparse vmalloc area that grows and shrinks + on demand, avoiding static pre-allocation overhead. + config ZSMALLOC tristate -- 2.54.0