From nobody Fri Apr 3 01:29:33 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC72129ACC0; Mon, 16 Feb 2026 14:58:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771253887; cv=none; b=gjxNZpXz15dXBFjjhNZqKMkXiaNWJ6NIEIPvlSXilGv7HiW8pk+9/bLZIuPIdgWUvQM3e1w8aBo5CQrfmnT6EnYy+VOYZDC2w06jSBIQt6YxaJCLAEa2iYju5RFo2DwXfHjiXTIe/4p2d3pzQR27ChbHmtl0R6YzMwqZk7SlaHE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771253887; c=relaxed/simple; bh=ijCT+Mg7d3790XUMIRWeaMLVEKai5+A/PxJRt61VFl4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=F64yzK/M/xHL+OlVg1YzKaOEeCbj+MU5+5j/0etYxMI0O4puNdfiCcm8RASeyo1batB0DxS50wNIwi0CKjazl55O4SDOGSwUkpKVjurZdyXUtFjkwTvaSxTu2H4UyFD5XMbc7aCU+ko2GNm2BSEVT08+hlWoTTkO5IW3OT1G0vU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bscfflmo; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bscfflmo" Received: by smtp.kernel.org (Postfix) with ESMTPS id 94F5AC19423; Mon, 16 Feb 2026 14:58:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771253887; bh=ijCT+Mg7d3790XUMIRWeaMLVEKai5+A/PxJRt61VFl4=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=bscfflmoBukdJNZyPNYP0zJ95O8NpJxdXS5KVMOFS1tSazf4yN9d8BgInRxT1k7vj 0GU0hgjestKOZ7Xyx2RDNObFGJRZ3ZoUYhrdu9w1qZnkSLjGSYP2twTYsmWnDpmVtS /+l9UrhxdXye2SNCyGrfJSmNDjyNzDUYZpMTMjwRADlr5+QkrmSN8J5ABJHvW3mmfD d7d3kd/FHIadjDIITNDvIGmwnk17ZQ/jTQyLH4+jFvzsQbKCQMX46CkdechMzwS4nw EWUwIpqBcfpWIHdDYLNll9Orj7AkyD+EqQfpQzT4tMOXmDs1klktA+ykYQKBZYex2y 00UGdyR9cLu6g== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 832D6E81A2F; Mon, 16 Feb 2026 14:58:07 +0000 (UTC) From: Kairui Song via B4 Relay Date: Mon, 16 Feb 2026 22:58:02 +0800 Subject: [PATCH v4 1/3] mm, swap: speed up hibernation allocation and writeout Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20260216-hibernate-perf-v4-1-1ba9f0bf1ec9@tencent.com> References: <20260216-hibernate-perf-v4-0-1ba9f0bf1ec9@tencent.com> In-Reply-To: <20260216-hibernate-perf-v4-0-1ba9f0bf1ec9@tencent.com> To: linux-mm@kvack.org Cc: Andrew Morton , Chris Li , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Carsten Grohmann , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, "open list:SUSPEND TO RAM" , Carsten Grohmann , Kairui Song , stable@vger.kernel.org X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1771253885; l=2673; i=kasong@tencent.com; s=kasong-sign-tencent; h=from:subject:message-id; bh=AP2Agry4RlYj89KzjPUleAMF+xnfApgEpjtkm4VqQJg=; b=bYE9CeOOUGzRx+yNxVfIU5aCtzWSmeScGretFXZJqot6KApMpREnHU1VqdZoQCKDTf2OtmG22 hfw1sagCcsYBeIpg3RySdPKCrxkRVZmWNBmjGE/dx7rS7MzapMvhc7C X-Developer-Key: i=kasong@tencent.com; a=ed25519; pk=kCdoBuwrYph+KrkJnrr7Sm1pwwhGDdZKcKrqiK8Y1mI= X-Endpoint-Received: by B4 Relay for kasong@tencent.com/kasong-sign-tencent with auth_id=562 X-Original-From: Kairui Song Reply-To: kasong@tencent.com From: Kairui Song Since commit 0ff67f990bd4 ("mm, swap: remove swap slot cache"), hibernation has been using the swap slot slow allocation path for simplification, which turns out might cause regression for some devices because the allocator now rotates clusters too often, leading to slower allocation and more random distribution of data. Fast allocation is not complex, so implement hibernation support as well. Test result with Samsung SSD 830 Series (SATA II, 3.0 Gbps) shows the performance is several times better [1]: 6.19: 324 seconds After this series: 35 seconds Fixes: 0ff67f990bd4 ("mm, swap: remove swap slot cache") Reported-by: Carsten Grohmann Closes: https://lore.kernel.org/linux-mm/20260206121151.dea3633d1f0ded7bbf4= 9c22e@linux-foundation.org/ Link: https://lore.kernel.org/linux-mm/8b4bdcfa-ce3f-4e23-839f-31367df7c18f= @gmx.de/ [1] Cc: stable@vger.kernel.org Signed-off-by: Kairui Song --- mm/swapfile.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index c6863ff7152c..32e0e7545ab8 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1926,8 +1926,9 @@ void swap_put_entries_direct(swp_entry_t entry, int n= r) /* Allocate a slot for hibernation */ swp_entry_t swap_alloc_hibernation_slot(int type) { - struct swap_info_struct *si =3D swap_type_to_info(type); - unsigned long offset; + struct swap_info_struct *pcp_si, *si =3D swap_type_to_info(type); + unsigned long pcp_offset, offset =3D SWAP_ENTRY_INVALID; + struct swap_cluster_info *ci; swp_entry_t entry =3D {0}; =20 if (!si) @@ -1937,11 +1938,21 @@ swp_entry_t swap_alloc_hibernation_slot(int type) if (get_swap_device_info(si)) { if (si->flags & SWP_WRITEOK) { /* - * Grab the local lock to be compliant - * with swap table allocation. + * Try the local cluster first if it matches the device. If + * not, try grab a new cluster and override local cluster. */ local_lock(&percpu_swap_cluster.lock); - offset =3D cluster_alloc_swap_entry(si, NULL); + pcp_si =3D this_cpu_read(percpu_swap_cluster.si[0]); + pcp_offset =3D this_cpu_read(percpu_swap_cluster.offset[0]); + if (pcp_si =3D=3D si && pcp_offset) { + ci =3D swap_cluster_lock(si, pcp_offset); + if (cluster_is_usable(ci, 0)) + offset =3D alloc_swap_scan_cluster(si, ci, NULL, pcp_offset); + else + swap_cluster_unlock(ci); + } + if (!offset) + offset =3D cluster_alloc_swap_entry(si, NULL); local_unlock(&percpu_swap_cluster.lock); if (offset) entry =3D swp_entry(si->type, offset); --=20 2.52.0