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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10E91C6379F for ; Tue, 14 Feb 2023 12:54:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232223AbjBNMyL (ORCPT ); Tue, 14 Feb 2023 07:54:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230162AbjBNMyJ (ORCPT ); Tue, 14 Feb 2023 07:54:09 -0500 Received: from smtp.smtpout.orange.fr (smtp-17.smtpout.orange.fr [80.12.242.17]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 823DE21280 for ; Tue, 14 Feb 2023 04:53:57 -0800 (PST) Received: from pop-os.home ([86.243.2.178]) by smtp.orange.fr with ESMTPA id Ruokph5lwOJaFRuolpOzce; Tue, 14 Feb 2023 13:53:55 +0100 X-ME-Helo: pop-os.home X-ME-Auth: Y2hyaXN0b3BoZS5qYWlsbGV0QHdhbmFkb28uZnI= X-ME-Date: Tue, 14 Feb 2023 13:53:55 +0100 X-ME-IP: 86.243.2.178 From: Christophe JAILLET To: Jason Gunthorpe , Leon Romanovsky Cc: linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Christophe JAILLET , linux-rdma@vger.kernel.org Subject: [PATCH] RDMA/restrack: Reorder fields in 'struct rdma_restrack_entry' Date: Tue, 14 Feb 2023 13:53:52 +0100 Message-Id: X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Group some variables based on their sizes to reduce hole and avoid padding. On x86_64, this shrinks the size from 136 to 128 bytes. Signed-off-by: Christophe JAILLET --- Using pahole Before: ====== struct rdma_restrack_entry { bool valid; /* 0 1 */ u8 no_track:1; /* 1: 0 1 */ /* XXX 7 bits hole, try to pack */ /* XXX 2 bytes hole, try to pack */ struct kref kref; /* 4 4 */ struct completion comp; /* 8 96 */ /* --- cacheline 1 boundary (64 bytes) was 40 bytes ago --- */ struct task_struct * task; /* 104 8 */ const char * kern_name; /* 112 8 */ enum rdma_restrack_type type; /* 120 4 */ bool user; /* 124 1 */ /* XXX 3 bytes hole, try to pack */ /* --- cacheline 2 boundary (128 bytes) --- */ u32 id; /* 128 4 */ /* size: 136, cachelines: 3, members: 9 */ /* sum members: 126, holes: 2, sum holes: 5 */ /* sum bitfield members: 1 bits, bit holes: 1, sum bit holes: 7 bits */ /* padding: 4 */ /* last cacheline: 8 bytes */ }; After: ===== struct rdma_restrack_entry { bool valid; /* 0 1 */ u8 no_track:1; /* 1: 0 1 */ /* XXX 7 bits hole, try to pack */ bool user; /* 2 1 */ /* XXX 1 byte hole, try to pack */ struct kref kref; /* 4 4 */ struct completion comp; /* 8 96 */ /* --- cacheline 1 boundary (64 bytes) was 40 bytes ago --- */ struct task_struct * task; /* 104 8 */ const char * kern_name; /* 112 8 */ enum rdma_restrack_type type; /* 120 4 */ u32 id; /* 124 4 */ /* size: 128, cachelines: 2, members: 9 */ /* sum members: 126, holes: 1, sum holes: 1 */ /* sum bitfield members: 1 bits, bit holes: 1, sum bit holes: 7 bits */ }; --- include/rdma/restrack.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/include/rdma/restrack.h b/include/rdma/restrack.h index 8b7c46daeb07..da53fefe6f9e 100644 --- a/include/rdma/restrack.h +++ b/include/rdma/restrack.h @@ -80,6 +80,10 @@ struct rdma_restrack_entry { * query stage. */ u8 no_track : 1; + /** + * @user: user resource + */ + bool user; /* * @kref: Protect destroy of the resource */ @@ -106,10 +110,6 @@ struct rdma_restrack_entry { * @type: various objects in restrack database */ enum rdma_restrack_type type; - /** - * @user: user resource - */ - bool user; /** * @id: ID to expose to users */ -- 2.34.1