From nobody Thu Dec 18 22:31:47 2025 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 70440C77B61 for ; Mon, 1 May 2023 12:41:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232609AbjEAMly (ORCPT ); Mon, 1 May 2023 08:41:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35002 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232600AbjEAMls (ORCPT ); Mon, 1 May 2023 08:41:48 -0400 Received: from smtp.smtpout.orange.fr (smtp-25.smtpout.orange.fr [80.12.242.25]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA6B01BD5 for ; Mon, 1 May 2023 05:41:13 -0700 (PDT) Received: from pop-os.home ([86.243.2.178]) by smtp.orange.fr with ESMTPA id tSpZpM6hwpwRItSpmpInbR; Mon, 01 May 2023 14:40:50 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=wanadoo.fr; s=t20230301; t=1682944850; bh=2WOGiov/m2pA1t59sXGUsmU4eYhd1snXKoF3h/t1OiE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=aNBie3PYKeQ+8ngqAp7gsv76YqsQqflNrSky9N0LmN8gnXehQ+LPWDHAKmWUZUb5L qsryuuTtFwuT+8QLeVPZK8Zx3uTwcqBcroYA4Svslx2AERgndJNOwav/rHzQmmr6Mt WNqcz6/9GRlSmXpRvtD2wGpLxh8XBgbtjjlHMaaYJFvW15zdeSgBcyUSRlqzHENnkr 6VJeeolJ/3v39moz7s+K3sWA9Vj20SGC4IDN+L38BMKjEQyMKBiSP0hYYFefHTIAeg MXlmJv5KKgsmvCmlX3f3iQr9pOzOI1JbmsjQdVqFz3sk2arnzQjmqdofkyNKX3kFQI mWurVPEaMkiPw== X-ME-Helo: pop-os.home X-ME-Auth: Y2hyaXN0b3BoZS5qYWlsbGV0QHdhbmFkb28uZnI= X-ME-Date: Mon, 01 May 2023 14:40:50 +0200 X-ME-IP: 86.243.2.178 From: Christophe JAILLET To: hch@lst.de, sagi@grimberg.me, kch@nvidia.com Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Christophe JAILLET Subject: [PATCH 5/5] nvmet: Reorder fields in 'struct nvmefc_fcp_req' Date: Mon, 1 May 2023 14:40:29 +0200 Message-Id: <9433a896eae368a65f430f4eb7310c56da81d954.1682941568.git.christophe.jaillet@wanadoo.fr> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Group some variables based on their sizes to reduce holes. On x86_64, this shrinks the size of 'struct nvmefc_fcp_req' from 112 to 104 bytes. This structure is embedded in some other structures (nvme_fc_fcp_op which itself is embedded in nvme_fcp_op_w_sgl), so it helps reducing the size of these structures too. Signed-off-by: Christophe JAILLET --- Using pahole Before: =3D=3D=3D=3D=3D=3D struct nvmefc_fcp_req { void * cmdaddr; /* 0 8 */ void * rspaddr; /* 8 8 */ dma_addr_t cmddma; /* 16 8 */ dma_addr_t rspdma; /* 24 8 */ u16 cmdlen; /* 32 2 */ u16 rsplen; /* 34 2 */ u32 payload_length; /* 36 4 */ struct sg_table sg_table; /* 40 16 */ struct scatterlist * first_sgl; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ int sg_cnt; /* 64 4 */ enum nvmefc_fcp_datadir io_dir; /* 68 4 */ __le16 sqid; /* 72 2 */ /* XXX 6 bytes hole, try to pack */ void (*done)(struct nvmefc_fcp_req *); /* 80 = 8 */ void * private; /* 88 8 */ u32 transferred_length; /* 96 4 */ u16 rcv_rsplen; /* 100 2 */ /* XXX 2 bytes hole, try to pack */ u32 status; /* 104 4 */ /* size: 112, cachelines: 2, members: 17 */ /* sum members: 100, holes: 2, sum holes: 8 */ /* padding: 4 */ /* last cacheline: 48 bytes */ } __attribute__((__aligned__(8))); After: =3D=3D=3D=3D=3D struct nvmefc_fcp_req { void * cmdaddr; /* 0 8 */ void * rspaddr; /* 8 8 */ dma_addr_t cmddma; /* 16 8 */ dma_addr_t rspdma; /* 24 8 */ u16 cmdlen; /* 32 2 */ u16 rsplen; /* 34 2 */ u32 payload_length; /* 36 4 */ struct sg_table sg_table; /* 40 16 */ struct scatterlist * first_sgl; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ int sg_cnt; /* 64 4 */ enum nvmefc_fcp_datadir io_dir; /* 68 4 */ void (*done)(struct nvmefc_fcp_req *); /* 72 = 8 */ void * private; /* 80 8 */ __le16 sqid; /* 88 2 */ u16 rcv_rsplen; /* 90 2 */ u32 transferred_length; /* 92 4 */ u32 status; /* 96 4 */ /* size: 104, cachelines: 2, members: 17 */ /* padding: 4 */ /* last cacheline: 40 bytes */ } __attribute__((__aligned__(8))); --- include/linux/nvme-fc-driver.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/include/linux/nvme-fc-driver.h b/include/linux/nvme-fc-driver.h index fa092b9be2fd..4109f1bd6128 100644 --- a/include/linux/nvme-fc-driver.h +++ b/include/linux/nvme-fc-driver.h @@ -185,7 +185,6 @@ enum nvmefc_fcp_datadir { * @first_sgl: memory for 1st scatter/gather list segment for payload data * @sg_cnt: number of elements in the scatter/gather list * @io_dir: direction of the FCP request (see NVMEFC_FCP_xxx) - * @sqid: The nvme SQID the command is being issued on * @done: The callback routine the LLDD is to invoke upon completion = of * the FCP operation. req argument is the pointer to the origi= nal * FCP IO operation. @@ -194,12 +193,13 @@ enum nvmefc_fcp_datadir { * while processing the operation. The length of the buffer * corresponds to the fcprqst_priv_sz value specified in the * nvme_fc_port_template supplied by the LLDD. + * @sqid: The nvme SQID the command is being issued on * * Values set by the LLDD indicating completion status of the FCP operatio= n. * Must be set prior to calling the done() callback. + * @rcv_rsplen: length, in bytes, of the FCP RSP IU received. * @transferred_length: amount of payload data, in bytes, that were * transferred. Should equal payload_length on success. - * @rcv_rsplen: length, in bytes, of the FCP RSP IU received. * @status: Completion status of the FCP operation. must be 0 upon succ= ess, * negative errno value upon failure (ex: -EIO). Note: this is * NOT a reflection of the NVME CQE completion status. Only the @@ -219,14 +219,14 @@ struct nvmefc_fcp_req { int sg_cnt; enum nvmefc_fcp_datadir io_dir; =20 - __le16 sqid; - void (*done)(struct nvmefc_fcp_req *req); =20 void *private; =20 - u32 transferred_length; + __le16 sqid; + u16 rcv_rsplen; + u32 transferred_length; u32 status; } __aligned(sizeof(u64)); /* alignment for other things alloc'd with */ =20 --=20 2.34.1