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From: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-renesas-soc@vger.kernel.org
Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v2 02/11] media: vsp1: Remove packed attributes from aligned structures
Date: Tue, 13 Mar 2018 19:05:18 +0100	[thread overview]
Message-ID: <30abb41033b9670c06a54ff484d61d25d3c6e5cd.1520963956.git-series.kieran.bingham+renesas@ideasonboard.com> (raw)
In-Reply-To: <cover.89a4a5175efbf31441ba717a99b0e3c31088179f.1520963956.git-series.kieran.bingham+renesas@ideasonboard.com>
In-Reply-To: <cover.89a4a5175efbf31441ba717a99b0e3c31088179f.1520963956.git-series.kieran.bingham+renesas@ideasonboard.com>

The use of the packed attribute can cause a performance penalty for
all accesses to the struct members, as the compiler will assume that the
structure has the potential to have an unaligned base.

These structures are all correctly aligned and contain no holes, thus
the attribute is redundant and negatively impacts performance, so we
remove the attributes entirely.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
---
v2
 - Remove attributes entirely

 drivers/media/platform/vsp1/vsp1_dl.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/vsp1/vsp1_dl.c b/drivers/media/platform/vsp1/vsp1_dl.c
index 37e2c984fbf3..85795b55a357 100644
--- a/drivers/media/platform/vsp1/vsp1_dl.c
+++ b/drivers/media/platform/vsp1/vsp1_dl.c
@@ -29,19 +29,19 @@
 struct vsp1_dl_header_list {
 	u32 num_bytes;
 	u32 addr;
-} __attribute__((__packed__));
+};
 
 struct vsp1_dl_header {
 	u32 num_lists;
 	struct vsp1_dl_header_list lists[8];
 	u32 next_header;
 	u32 flags;
-} __attribute__((__packed__));
+};
 
 struct vsp1_dl_entry {
 	u32 addr;
 	u32 data;
-} __attribute__((__packed__));
+};
 
 /**
  * struct vsp1_dl_body - Display list body
-- 
git-series 0.9.1

  parent reply	other threads:[~2018-03-13 18:05 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.89a4a5175efbf31441ba717a99b0e3c31088179f.1520963956.git-series.kieran.bingham+renesas@ideasonboard.com>
2018-03-13 18:05 ` [PATCH v2 01/11] media: vsp1: drm: Fix minor grammar error Kieran Bingham
2018-03-13 18:05 ` Kieran Bingham [this message]
2018-03-14  8:21   ` [PATCH v2 02/11] media: vsp1: Remove packed attributes from aligned structures Geert Uytterhoeven
2018-03-13 18:05 ` [PATCH v2 03/11] media: vsp1: Rename dl_child to dl_next Kieran Bingham
2018-03-13 18:05 ` [PATCH v2 04/11] media: vsp1: Remove unused display list structure field Kieran Bingham
2018-03-13 18:05 ` [PATCH v2 05/11] media: vsp1: Clean up DLM objects on error Kieran Bingham
2018-03-13 18:05 ` [PATCH v2 06/11] media: vsp1: Provide VSP1 feature helper macro Kieran Bingham
2018-03-13 18:05 ` [PATCH v2 07/11] media: vsp1: Use header display lists for all WPF outputs linked to the DU Kieran Bingham
2018-03-13 18:05 ` [PATCH v2 08/11] media: vsp1: Add support for extended display list headers Kieran Bingham
2018-03-13 18:05 ` [PATCH v2 09/11] media: vsp1: Provide support for extended command pools Kieran Bingham
2018-03-13 18:05 ` [PATCH v2 10/11] media: vsp1: Support Interlaced display pipelines Kieran Bingham
2018-03-13 18:05 ` [PATCH v2 11/11] drm: rcar-du: Support interlaced video output through vsp1 Kieran Bingham

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