From nobody Thu Oct 2 17:01:17 2025 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 92BFF2F532F; Mon, 15 Sep 2025 09:24:12 +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=1757928253; cv=none; b=VgSJquI+Z9bug79t3kIgG25mxVE7+cSq1ow7+ReAahkxQsBNir5vc0RoHdZOJrR2yLNvf4gbWWOfTBDdOpWge4PcQ7IinCwskSgg2+jukx7Z1VXC04kytpikejUXfCIFatlRAnj7TM6jIMHeBkcOientNDH83aBZCMLBXyxRuts= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757928253; c=relaxed/simple; bh=gm+woyX1D71Rz/dX+IbC3aBt0rZz/g3wLYE4eykaqrI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=r1DmiplcP3lKqSH+mwlT3Qenq9tOH8veHyvH+e2CeKFAFVHSrDQYeCrUub/Kx+HzU/wi1qDhtp6+CthVP2FzdWMpTxZ5CoWW9fSR18fnUn/BASkTvrqT6sMdEFAuTtHQAapP5gcqT0RK2dEJPjdpRFPO93JcQHGkaSaJMurM2t8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ghI5+AMT; 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="ghI5+AMT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E735C4CEF5; Mon, 15 Sep 2025 09:24:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757928252; bh=gm+woyX1D71Rz/dX+IbC3aBt0rZz/g3wLYE4eykaqrI=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=ghI5+AMT63tI+DNjURhsoN9xbturA4qb9aH7BS7/KF6aRAGzCMNdFgaheAKgK4W0c LlTF+0N4y3KCZLyFLL8UJkAa0APo8IgPjdKzU1vf4cFAnK6A+RYoQQYoSiVSMeo+P1 fWOskuzh6adYPpF37iN25dEV0F51d14Y4LhdmxBgOZ3pQbYYD1xHpb8W9r68Zz9w61 fpYb4VLMSfaQcB9FQml43BzoK7CuVU3mD9+xFimat/qQIZ9bJ1MY3LXddAK3hBuCPQ cIr7xPjP0/lVs1U6bg76HLj6Bzl6gweiIXvDtotUg0oq1vJ4sRc8FB86ZYLklYQeB0 eV/rGRnpkPNBA== From: Vincent Mailhol Date: Mon, 15 Sep 2025 18:23:13 +0900 Subject: [PATCH 1/3] can: raw: reorder struct uniqframe's members to optimise packing 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: <20250915-can-raw-repack-v1-1-5ea293bc6d33@kernel.org> References: <20250915-can-raw-repack-v1-0-5ea293bc6d33@kernel.org> In-Reply-To: <20250915-can-raw-repack-v1-0-5ea293bc6d33@kernel.org> To: Oliver Hartkopp , Marc Kleine-Budde Cc: linux-can@vger.kernel.org, linux-kernel@vger.kernel.org, Vincent Mailhol X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=1480; i=mailhol@kernel.org; h=from:subject:message-id; bh=gm+woyX1D71Rz/dX+IbC3aBt0rZz/g3wLYE4eykaqrI=; b=owGbwMvMwCV2McXO4Xp97WbG02pJDBnHbxukqhSwZXX+91z25/mRHdFHuxaWlweZHF1jnbYml 7nj382VHaUsDGJcDLJiiizLyjm5FToKvcMO/bWEmcPKBDKEgYtTACai18/wv2LF2YlT2I6fNdmy 89dFAYWXWxr5/0hcmLBXXkWyrXvarw6G/7XF3x0mdcw5oJV230rhqclUnijl1aE+128w1GpJ8Ew 4yQoA X-Developer-Key: i=mailhol@kernel.org; a=openpgp; fpr=ED8F700574E67F20E574E8E2AB5FEB886DBB99C2 struct uniqframe has one hole. Reorder the fields to save 8 bytes. Statistics before: $ pahole --class_name=3Duniqframe net/can/raw.o struct uniqframe { int skbcnt; /* 0 4 */ /* XXX 4 bytes hole, try to pack */ const struct sk_buff * skb; /* 8 8 */ unsigned int join_rx_count; /* 16 4 */ /* size: 24, cachelines: 1, members: 3 */ /* sum members: 16, holes: 1, sum holes: 4 */ /* padding: 4 */ /* last cacheline: 24 bytes */ }; ...and after: $ pahole --class_name=3Duniqframe net/can/raw.o struct uniqframe { const struct sk_buff * skb; /* 0 8 */ int skbcnt; /* 8 4 */ unsigned int join_rx_count; /* 12 4 */ /* size: 16, cachelines: 1, members: 3 */ /* last cacheline: 16 bytes */ }; Signed-off-by: Vincent Mailhol Acked-by: Oliver Hartkopp --- net/can/raw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/can/raw.c b/net/can/raw.c index 76b867d21def209f5c6d236604c0e434a1c55a4d..db21d8a8c54d1b6a25a72c7a9d1= 1d5c94f3187b5 100644 --- a/net/can/raw.c +++ b/net/can/raw.c @@ -75,8 +75,8 @@ MODULE_ALIAS("can-proto-1"); */ =20 struct uniqframe { - int skbcnt; const struct sk_buff *skb; + int skbcnt; unsigned int join_rx_count; }; =20 --=20 2.49.1