From patchwork Mon May 8 07:42:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe JAILLET X-Patchwork-Id: 680454 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 8FABBC77B73 for ; Mon, 8 May 2023 07:42:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233535AbjEHHmo (ORCPT ); Mon, 8 May 2023 03:42:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233466AbjEHHmg (ORCPT ); Mon, 8 May 2023 03:42:36 -0400 Received: from smtp.smtpout.orange.fr (smtp-19.smtpout.orange.fr [80.12.242.19]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75FA11A4A5 for ; Mon, 8 May 2023 00:42:29 -0700 (PDT) Received: from pop-os.home ([86.243.2.178]) by smtp.orange.fr with ESMTPA id vvVppzG33MVk3vvVppHiv1; Mon, 08 May 2023 09:42:27 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=wanadoo.fr; s=t20230301; t=1683531747; bh=40maiApoVL/VucoidkRFV2whGpUtUx6B9fd6pg++S/k=; h=From:To:Cc:Subject:Date; b=D2QwQF0t8cox0Q93u6udOg/olj4OPRQGaaAENj0UmMDsvgDLzBWCH3cE6bmbAyuKQ bvLaFuAkqOKH/UwLzQFofyuseYHHIh+TA+MUVCaSVTLx3TuPKXWqOKJxZC0ATO2BT2 vKTMCE0F86h72lgVM7tUmYr/WN8a5SEcOBm0uRCqRXO4M2AoejHdP3KuiwPRxS1LSX KYzGSXcJDCZdTAc1gETCk/6dLjZMtrDBzat/2hCe9ugYjAYQbwk9URoZkw+oFwSFE/ i7zzY14k74ruBB3uDB9LpJ1EGsrC5cMGm3VsQnqTkymlqiIpnnZTC8xLjPOM+VDF7B iWBgEmEjapEZg== X-ME-Helo: pop-os.home X-ME-Auth: Y2hyaXN0b3BoZS5qYWlsbGV0QHdhbmFkb28uZnI= X-ME-Date: Mon, 08 May 2023 09:42:27 +0200 X-ME-IP: 86.243.2.178 From: Christophe JAILLET To: MyungJoo Ham , Kyungmin Park , Chanwoo Choi Cc: linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Christophe JAILLET , linux-pm@vger.kernel.org Subject: [PATCH] PM / devfreq: Reorder fields in 'struct devfreq_dev_status' Date: Mon, 8 May 2023 09:42:15 +0200 Message-Id: <6b1611f1440c8b73feb475723ad25f390cad3480.1683531691.git.christophe.jaillet@wanadoo.fr> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Group some variables based on their sizes to reduce holes. On x86_64, this shrinks the size of 'struct devfreq_dev_status' from 72 to 64 bytes. This structure is used both to allocate static variables or is embedded in some other structures. In both cases, reducing its size is nice to have. Moreover, the whole structure now fits in a single cache line on x86_64. Finally, it makes the order of code match the order of the above kernel doc. Signed-off-by: Christophe JAILLET --- Using pahole Before: ====== struct devfreq_dev_profile { long unsigned int initial_freq; /* 0 8 */ unsigned int polling_ms; /* 8 4 */ enum devfreq_timer timer; /* 12 4 */ bool is_cooling_device; /* 16 1 */ /* XXX 7 bytes hole, try to pack */ int (*target)(struct device *, long unsigned int *, u32); /* 24 8 */ int (*get_dev_status)(struct device *, struct devfreq_dev_status *); /* 32 8 */ int (*get_cur_freq)(struct device *, long unsigned int *); /* 40 8 */ void (*exit)(struct device *); /* 48 8 */ long unsigned int * freq_table; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ unsigned int max_state; /* 64 4 */ /* size: 72, cachelines: 2, members: 10 */ /* sum members: 61, holes: 1, sum holes: 7 */ /* padding: 4 */ /* last cacheline: 8 bytes */ }; After: ===== struct devfreq_dev_profile { long unsigned int initial_freq; /* 0 8 */ unsigned int polling_ms; /* 8 4 */ enum devfreq_timer timer; /* 12 4 */ int (*target)(struct device *, long unsigned int *, u32); /* 16 8 */ int (*get_dev_status)(struct device *, struct devfreq_dev_status *); /* 24 8 */ int (*get_cur_freq)(struct device *, long unsigned int *); /* 32 8 */ void (*exit)(struct device *); /* 40 8 */ long unsigned int * freq_table; /* 48 8 */ unsigned int max_state; /* 56 4 */ bool is_cooling_device; /* 60 1 */ /* size: 64, cachelines: 1, members: 10 */ /* padding: 3 */ }; --- include/linux/devfreq.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index 7fd704bb8f3d..d312ffbac4dd 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -108,7 +108,6 @@ struct devfreq_dev_profile { unsigned long initial_freq; unsigned int polling_ms; enum devfreq_timer timer; - bool is_cooling_device; int (*target)(struct device *dev, unsigned long *freq, u32 flags); int (*get_dev_status)(struct device *dev, @@ -118,6 +117,8 @@ struct devfreq_dev_profile { unsigned long *freq_table; unsigned int max_state; + + bool is_cooling_device; }; /**