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 E504CC531D0 for ; Mon, 27 Jul 2026 14:05:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BF75B6B0088; Mon, 27 Jul 2026 10:05:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BCF5C6B0093; Mon, 27 Jul 2026 10:05:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AE5936B0098; Mon, 27 Jul 2026 10:05:25 -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 7EE0E6B0088 for ; Mon, 27 Jul 2026 10:05:25 -0400 (EDT) Received: from smtpin24.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id EBF5F8074A for ; Mon, 27 Jul 2026 14:05:24 +0000 (UTC) X-FDA: 85034728968.24.69F5ACF Received: from out-180.mta1.migadu.com (out-180.mta1.migadu.com [95.215.58.180]) by imf03.hostedemail.com (Postfix) with ESMTP id 0CCAA20014 for ; Mon, 27 Jul 2026 14:05:22 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=pjU+OTh7; spf=pass (imf03.hostedemail.com: domain of baoquan.he@linux.dev designates 95.215.58.180 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=1785161123; b=o32+5QmwPFOOONDnE7m/a3BIRkoBEJICpK+EsMDoGl/ardTI+MceEB9YlYX3FjCwsUPVtp i6nczxgETtHS/z3rMhAhWA/4wHLfGyplaPpEtaiNCHm+uJrIHTdVjP6pbUwLQZMA4vobjj l6bXElwUR1LoMsVeYsUiHCDNjA2K1D4= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=pjU+OTh7; spf=pass (imf03.hostedemail.com: domain of baoquan.he@linux.dev designates 95.215.58.180 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=1785161123; 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=1guC9stZtNs1FbSf+QBPICcmcWlpa8QQY12wosAxqEI=; b=ua+STIOm5EuCUWnmk9fKOQfTm7YBHCfMy0Qmf2qI37RS1qIZ2f/ZaZXIUY68mSDCnxFvAC C/uBYHIsna6WeSnsY5cTpJXeVHfVeGM5U9YqMZdXjmKmTb6pOCa+q9ocsoLmWrMQb8fxhu Ft3rLO+L80IvIh8A6/VfH2tLjDZlRZ8= 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=1785161121; 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=1guC9stZtNs1FbSf+QBPICcmcWlpa8QQY12wosAxqEI=; b=pjU+OTh7mmGoTwPzPdTGP707faCv5tCNRm/O9qfRfkuCjRxF9lYbV33L3P83XqxH1DIhCe wBBaZM2o0Avc9uOQa3Rv7/sy4bPX9iZzZP4QDLqASXVkOI7BYCWIzHM/KEAVITvLDV1AeA 74pLAP7R7MCP39JSb765Q660BAwDx5U= From: Baoquan He To: linux-mm@kvack.org Cc: akpm@linux-foundation.org, 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 02/11] mm, swap: add CONFIG_XSWAP and xswap fields to swap_info_struct Date: Mon, 27 Jul 2026 22:04:53 +0800 Message-ID: <20260727140503.1060918-1-baoquan.he@linux.dev> In-Reply-To: <20260727135029.1059441-1-baoquan.he@linux.dev> References: <20260727135029.1059441-1-baoquan.he@linux.dev> MIME-Version: 1.0 Content-type: text/plain Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Stat-Signature: t1bowimc9u7qgu9pzicbixfb379cp3et X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 0CCAA20014 X-Rspam-User: X-HE-Tag: 1785161122-790979 X-HE-Meta: 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 o0p38jXm ZN6l5BixhQ7Syb5eqZ+hvqCK1g3gw1WhtVu3/VN+RLPeBz+y6IDPFgIGqT+jWDJfTBy8d9qTTokILYBpt3g33H8zTZomkJU6xoV7Eauj9jLh5q3R9fMOFMy+TgBIAZo3LpMi84rskC7UOKIONbyDy8JuhNVqjEdb2RKw1phGowpJUVLYDezhpxfdIDRSi7XQvF50TGoD9CCAhoUP+ffgDHACuQfk0DAIYkjXTELymXg6JyF48uwkvci9+cw== 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 80c83dd8804f..5f6b14d30758 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 c52ab6afcb15..889d5ce20a55 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