From nobody Wed Dec 17 15:36:58 2025 Received: from smtp.smtpout.orange.fr (smtp-20.smtpout.orange.fr [80.12.242.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E9274158873; Mon, 6 May 2024 19:42:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.12.242.20 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715024576; cv=none; b=XfD1ZyQY7kJSErWiKSPxqRTjF3YdkH5qdxv5crSSi4n9nHoUnsV0uPH82OrIH+LNg4/cBBkn8L8b7TDj3fMlcQ5Rh7ojnmF+8RYHAf57WkKe8jjWAe+F9tD91vmA2ADJh4BM/8dnNffjH9ign7LShETaprPxwklObDyCtyiuCIU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715024576; c=relaxed/simple; bh=aSozFxS5LbgNSQ6h1GkeG3vjP/XR4gK6Qeg4TmIXR3s=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=s12PB6Ujcl9LZDHMGj5ENX/47tgUWSgUuPRf1rpaQmFA5dsUwZ1J/2LcxBC4DVS1SgwXJvkQZJBJciHerWvPIS2jZoxzzxFj/H0biPmYlJQKVCIswKMpN9+3RQUcptwkdSX8z+XMrzMAWBhGvdembzYh83hFLXX5srTb4esqilE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=wanadoo.fr; spf=pass smtp.mailfrom=wanadoo.fr; dkim=pass (2048-bit key) header.d=wanadoo.fr header.i=@wanadoo.fr header.b=mUSsGcAp; arc=none smtp.client-ip=80.12.242.20 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=wanadoo.fr Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=wanadoo.fr Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=wanadoo.fr header.i=@wanadoo.fr header.b="mUSsGcAp" Received: from localhost.localdomain ([86.243.17.157]) by smtp.orange.fr with ESMTPA id 445oszmYtR8o9445os7zWU; Mon, 06 May 2024 21:33:45 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=wanadoo.fr; s=t20230301; t=1715024025; bh=6Hx+nWx8Jayud7dD31s9JZH7LTHEVeGkErZx2PAlqvI=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=mUSsGcApRI0TG5SS3UlUyJbC8N+/yGrojRnDC718QSdW+Ibp33bFtxX4F9x9j6heZ tqG5HvFDs0wDMTobvvxFgIRr7pbUVOZQ80/fVfMC3NBpIzt5/lz7uCXbsf5E0UMubQ d3/xoAld68Q2L9N61zCg4AzC+PLMdCahbbSrCC0/QLHFzaYRCg9P+y8JnLKb+zOpxr sICvqdzxrGENOQOs8R/kwH3dINQA79rLgCznLN8BeHKFPyJz8mJkzf6obr1KEH0Zha /XRXsjG/eBxtpM3fHaBRlrBVSKghMAGPpW7BqZs64ynAUBIsB1+qMNnNXjT5ejHWqR vSLmtlluxWV3Q== X-ME-Helo: localhost.localdomain X-ME-Auth: Y2hyaXN0b3BoZS5qYWlsbGV0QHdhbmFkb28uZnI= X-ME-Date: Mon, 06 May 2024 21:33:45 +0200 X-ME-IP: 86.243.17.157 From: Christophe JAILLET To: Mark Brown Cc: linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Christophe JAILLET Subject: [PATCH v1] regmap: Reorder fields in 'struct regmap_config' to save some memory Date: Mon, 6 May 2024 21:33:33 +0200 Message-ID: <5e039cd8fe415dd7ab3169948c08a5311db9fb9a.1715024007.git.christophe.jaillet@wanadoo.fr> X-Mailer: git-send-email 2.45.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" On x86_64 and allmodconfig, this shrinks the size of 'struct regmap_config' from 328 to 312 bytes. This is usually a win, because this structure is used as a static global variable. When moving the kerneldoc fields, I've tried to keep the layout as consistent as possible, which is not really easy! Before: /* size: 328, cachelines: 6, members: 55 */ /* sum members: 296, holes: 6, sum holes: 25 */ /* padding: 7 */ /* last cacheline: 8 bytes */ After: /* size: 312, cachelines: 5, members: 55 */ /* sum members: 296, holes: 5, sum holes: 16 */ /* last cacheline: 56 bytes */ For the records, this is also widely used: $git grep static.*regmap_config | wc -l 1327 Signed-off-by: Christophe JAILLET --- Built-tested only on several dozens of modified files. Example of size reduction on drivers/clk/clk-si544.o (randomly chosen) Before: text data bss dec hex filename 9917 700 16 10633 2989 drivers/clk/clk-si544.o After: text data bss dec hex filename 9885 700 16 10601 2969 drivers/clk/clk-si544.o --- include/linux/regmap.h | 62 +++++++++++++++++++++--------------------- 1 file changed, 31 insertions(+), 31 deletions(-) diff --git a/include/linux/regmap.h b/include/linux/regmap.h index d470303b1bbb..a6bc2980a98b 100644 --- a/include/linux/regmap.h +++ b/include/linux/regmap.h @@ -297,15 +297,6 @@ typedef void (*regmap_unlock)(void *); * performed on such table (a register is no increment * readable if it belongs to one of the ranges specified * by rd_noinc_table). - * @disable_locking: This regmap is either protected by external means or - * is guaranteed not to be accessed from multiple thread= s. - * Don't use any locking mechanisms. - * @lock: Optional lock callback (overrides regmap's default lock - * function, based on spinlock or mutex). - * @unlock: As above for unlocking. - * @lock_arg: this field is passed as the only argument of lock/unlock - * functions (ignored in case regular lock/unlock functions - * are not overridden). * @reg_read: Optional callback that if filled will be used to perform * all the reads from the registers. Should only be provided = for * devices whose read operation cannot be represented as a simple @@ -323,6 +314,7 @@ typedef void (*regmap_unlock)(void *); * @write: Same as above for writing. * @max_raw_read: Max raw read size that can be used on the device. * @max_raw_write: Max raw write size that can be used on the device. + * @can_sleep: Optional, specifies whether regmap operations can sleep. * @fast_io: Register IO is fast. Use a spinlock instead of a mutex * to perform locking. This field is ignored if custom lock/unlock * functions are used (see fields lock/unlock of struct regmap_con= fig). @@ -331,6 +323,15 @@ typedef void (*regmap_unlock)(void *); * Use it only for "no-bus" cases. * @io_port: Support IO port accessors. Makes sense only when MMIO vs. I= O port * access can be distinguished. + * @disable_locking: This regmap is either protected by external means or + * is guaranteed not to be accessed from multiple threads. + * Don't use any locking mechanisms. + * @lock: Optional lock callback (overrides regmap's default lock + * function, based on spinlock or mutex). + * @unlock: As above for unlocking. + * @lock_arg: This field is passed as the only argument of lock/unlock + * functions (ignored in case regular lock/unlock functions + * are not overridden). * @max_register: Optional, specifies the maximum valid register address. * @max_register_is_0: Optional, specifies that zero value in @max_register * should be taken into account. This is a workaround = to @@ -373,21 +374,20 @@ typedef void (*regmap_unlock)(void *); * @reg_defaults_raw: Power on reset values for registers (for use with * register cache support). * @num_reg_defaults_raw: Number of elements in reg_defaults_raw. - * @reg_format_endian: Endianness for formatted register addresses. If thi= s is - * DEFAULT, the @reg_format_endian_default value from = the - * regmap bus is used. - * @val_format_endian: Endianness for formatted register values. If this is - * DEFAULT, the @reg_format_endian_default value from = the - * regmap bus is used. - * - * @ranges: Array of configuration entries for virtual address ranges. - * @num_ranges: Number of range configuration entries. * @use_hwlock: Indicate if a hardware spinlock should be used. * @use_raw_spinlock: Indicate if a raw spinlock should be used. * @hwlock_id: Specify the hardware spinlock id. * @hwlock_mode: The hardware spinlock mode, should be HWLOCK_IRQSTATE, * HWLOCK_IRQ or 0. - * @can_sleep: Optional, specifies whether regmap operations can sleep. + * @reg_format_endian: Endianness for formatted register addresses. If thi= s is + * DEFAULT, the @reg_format_endian_default value from the + * regmap bus is used. + * @val_format_endian: Endianness for formatted register values. If this is + * DEFAULT, the @reg_format_endian_default value from the + * regmap bus is used. + * + * @ranges: Array of configuration entries for virtual address ranges. + * @num_ranges: Number of range configuration entries. */ struct regmap_config { const char *name; @@ -406,11 +406,6 @@ struct regmap_config { bool (*writeable_noinc_reg)(struct device *dev, unsigned int reg); bool (*readable_noinc_reg)(struct device *dev, unsigned int reg); =20 - bool disable_locking; - regmap_lock lock; - regmap_unlock unlock; - void *lock_arg; - int (*reg_read)(void *context, unsigned int reg, unsigned int *val); int (*reg_write)(void *context, unsigned int reg, unsigned int val); int (*reg_update_bits)(void *context, unsigned int reg, @@ -422,9 +417,16 @@ struct regmap_config { size_t max_raw_read; size_t max_raw_write; =20 + bool can_sleep; + bool fast_io; bool io_port; =20 + bool disable_locking; + regmap_lock lock; + regmap_unlock unlock; + void *lock_arg; + unsigned int max_register; bool max_register_is_0; const struct regmap_access_table *wr_table; @@ -448,18 +450,16 @@ struct regmap_config { bool use_relaxed_mmio; bool can_multi_write; =20 - enum regmap_endian reg_format_endian; - enum regmap_endian val_format_endian; - - const struct regmap_range_cfg *ranges; - unsigned int num_ranges; - bool use_hwlock; bool use_raw_spinlock; unsigned int hwlock_id; unsigned int hwlock_mode; =20 - bool can_sleep; + enum regmap_endian reg_format_endian; + enum regmap_endian val_format_endian; + + const struct regmap_range_cfg *ranges; + unsigned int num_ranges; }; =20 /** --=20 2.45.0