From patchwork Tue Apr 28 17:19:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?VmlsbGUgU3lyasOkbMOk?= X-Patchwork-Id: 11515205 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9654315E6 for ; Tue, 28 Apr 2020 17:20:52 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7E76B208E0 for ; Tue, 28 Apr 2020 17:20:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E76B208E0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 490DB6E887; Tue, 28 Apr 2020 17:20:51 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4ED636E887; Tue, 28 Apr 2020 17:20:49 +0000 (UTC) IronPort-SDR: pl1x8XCM4SbX3TMR6mufkBDJmUT55uTUAPg39riBwS6vTuD8i4jlD3kLKMnTFMHbzQPznwtrPM dWQdJheMbV7A== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Apr 2020 10:20:48 -0700 IronPort-SDR: HK/UTZ8dPToClZi55Qqe3vPaIetJ+SPs4kANYYHFhXTJOAjySQoQsXWa/a5IhtO+DmJJp6BdBm heiwXWrOT83g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,328,1583222400"; d="scan'208";a="293926097" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.174]) by orsmga008.jf.intel.com with SMTP; 28 Apr 2020 10:20:45 -0700 Received: by stinkbox (sSMTP sendmail emulation); Tue, 28 Apr 2020 20:20:44 +0300 From: Ville Syrjala To: dri-devel@lists.freedesktop.org Subject: [PATCH v3 16/16] drm: Replace mode->export_head with a boolean Date: Tue, 28 Apr 2020 20:19:40 +0300 Message-Id: <20200428171940.19552-17-ville.syrjala@linux.intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200428171940.19552-1-ville.syrjala@linux.intel.com> References: <20200428171940.19552-1-ville.syrjala@linux.intel.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Vetter , intel-gfx@lists.freedesktop.org, Sam Ravnborg , Emil Velikov Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Ville Syrjälä In order to shrink drm_display_mode below the magic two cacheline mark in 64bit we need to shrink it by another 8 bytes. The easiest thing to eliminate is the 'export_head' list head which is only used during the getconnector ioctl to temporarly track which modes on the connector's mode list are to be exposed and which are to remain hidden. We can simply replace the list head with a boolean which we use to tag the modes that are to be exposed. If we make sure to clear the tags after we're done with them we don't even need an extra loop over the modes to reset the tags at the start of the getconnector ioctl. Conveniently we already have a hole for the boolean left behind by the removal of mode->private_flags. The final size of the struct is now 112 bytes on 32bit and 120 bytes on 64bit. The downside is that drm_mode_expose_to_userspace() gets to iterate a few more modes. It already was O(n^2), now it's a slightly worse O(n^2). Another alternative would be a temp bitmask so we wouldn't have to have anything in the mode struct itself. The main issue is how large of a bitmask do we need? I guess we could allocate it dynamically but that means an extra kcalloc() and an extra loop through the modes to count them first (or grow the bitmask with krealloc() as needed). CC: Sam Ravnborg Cc: Daniel Vetter Cc: Emil Velikov Signed-off-by: Ville Syrjälä Reviewed-by: Emil Velikov --- drivers/gpu/drm/drm_connector.c | 45 +++++++++++++++++++++++---------- include/drm/drm_modes.h | 24 ++++++++---------- 2 files changed, 43 insertions(+), 26 deletions(-) diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index b1099e1251a2..7e719b08564d 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -2198,7 +2198,7 @@ static struct drm_encoder *drm_connector_get_encoder(struct drm_connector *conne static bool drm_mode_expose_to_userspace(const struct drm_display_mode *mode, - const struct list_head *export_list, + const struct list_head *modes, const struct drm_file *file_priv) { /* @@ -2214,15 +2214,17 @@ drm_mode_expose_to_userspace(const struct drm_display_mode *mode, * while preparing the list of user-modes. */ if (!file_priv->aspect_ratio_allowed) { - struct drm_display_mode *mode_itr; + const struct drm_display_mode *mode_itr; - list_for_each_entry(mode_itr, export_list, export_head) - if (drm_mode_match(mode_itr, mode, + list_for_each_entry(mode_itr, modes, head) { + if (mode_itr->expose_to_userspace && + drm_mode_match(mode_itr, mode, DRM_MODE_MATCH_TIMINGS | DRM_MODE_MATCH_CLOCK | DRM_MODE_MATCH_FLAGS | DRM_MODE_MATCH_3D_FLAGS)) return false; + } } return true; @@ -2242,7 +2244,6 @@ int drm_mode_getconnector(struct drm_device *dev, void *data, struct drm_mode_modeinfo u_mode; struct drm_mode_modeinfo __user *mode_ptr; uint32_t __user *encoder_ptr; - LIST_HEAD(export_list); if (!drm_core_check_feature(dev, DRIVER_MODESET)) return -EOPNOTSUPP; @@ -2286,25 +2287,30 @@ int drm_mode_getconnector(struct drm_device *dev, void *data, out_resp->connection = connector->status; /* delayed so we get modes regardless of pre-fill_modes state */ - list_for_each_entry(mode, &connector->modes, head) - if (drm_mode_expose_to_userspace(mode, &export_list, + list_for_each_entry(mode, &connector->modes, head) { + WARN_ON(mode->expose_to_userspace); + + if (drm_mode_expose_to_userspace(mode, &connector->modes, file_priv)) { - list_add_tail(&mode->export_head, &export_list); + mode->expose_to_userspace = true; mode_count++; } + } /* * This ioctl is called twice, once to determine how much space is * needed, and the 2nd time to fill it. - * The modes that need to be exposed to the user are maintained in the - * 'export_list'. When the ioctl is called first time to determine the, - * space, the export_list gets filled, to find the no.of modes. In the - * 2nd time, the user modes are filled, one by one from the export_list. */ if ((out_resp->count_modes >= mode_count) && mode_count) { copied = 0; mode_ptr = (struct drm_mode_modeinfo __user *)(unsigned long)out_resp->modes_ptr; - list_for_each_entry(mode, &export_list, export_head) { + list_for_each_entry(mode, &connector->modes, head) { + if (!mode->expose_to_userspace) + continue; + + /* Clear the tag for the next time around */ + mode->expose_to_userspace = false; + drm_mode_convert_to_umode(&u_mode, mode); /* * Reset aspect ratio flags of user-mode, if modes with @@ -2315,13 +2321,26 @@ int drm_mode_getconnector(struct drm_device *dev, void *data, if (copy_to_user(mode_ptr + copied, &u_mode, sizeof(u_mode))) { ret = -EFAULT; + + /* + * Clear the tag for the rest of + * the modes for the next time around. + */ + list_for_each_entry_continue(mode, &connector->modes, head) + mode->expose_to_userspace = false; + mutex_unlock(&dev->mode_config.mutex); goto out; } copied++; } + } else { + /* Clear the tag for the next time around */ + list_for_each_entry(mode, &connector->modes, head) + mode->expose_to_userspace = false; } + out_resp->count_modes = mode_count; mutex_unlock(&dev->mode_config.mutex); diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h index 1e97138a9b8c..ac0589aab23e 100644 --- a/include/drm/drm_modes.h +++ b/include/drm/drm_modes.h @@ -348,6 +348,17 @@ struct drm_display_mode { */ u8 type; + /** + * @expose_to_userspace: + * + * Indicates whether the mode is to be exposed to the userspace. + * This is to maintain a set of exposed modes while preparing + * user-mode's list in drm_mode_getconnector ioctl. The purpose of + * this only lies in the ioctl function, and is not to be used + * outside the function. + */ + bool expose_to_userspace; + /** * @head: * @@ -355,19 +366,6 @@ struct drm_display_mode { */ struct list_head head; - /** - * @export_head: - * - * struct list_head for modes to be exposed to the userspace. - * This is to maintain a list of exposed modes while preparing - * user-mode's list in drm_mode_getconnector ioctl. The purpose of this - * list_head only lies in the ioctl function, and is not expected to be - * used outside the function. - * Once used, the stale pointers are not reset, but left as it is, to - * avoid overhead of protecting it by mode_config.mutex. - */ - struct list_head export_head; - /** * @name: *