From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Dmitry Safonov <dima@arista.com>
Cc: linux-kernel@vger.kernel.org,
Dmitry Safonov <0x7f454c46@gmail.com>,
Jiri Slaby <jslaby@suse.com>,
Vasiliy Khoruzhick <vasilykh@arista.com>,
linux-serial@vger.kernel.org
Subject: Re: [PATCH 02/58] serial: Move sysrq members above
Date: Fri, 13 Dec 2019 08:17:49 +0100 [thread overview]
Message-ID: <20191213071749.GA1750354@kroah.com> (raw)
In-Reply-To: <20191213000657.931618-3-dima@arista.com>
On Fri, Dec 13, 2019 at 12:06:01AM +0000, Dmitry Safonov wrote:
> At the current place members those follow are:
> : upf_t flags;
> : upstat_t status;
> : int hw_stopped;
> : unsigned int mctrl;
> : unsigned int timeout;
> : unsigned int type;
> : const struct uart_ops *ops;
>
> Together, they give (*ops) 8-byte align on 64-bit platforms.
> And `sysrq_ch` introduces 4-byte padding.
>
> On the other side, above:
> : struct device *dev;
> : unsigned char hub6;
> : unsigned char suspended;
> : unsigned char unused[2];
> : const char *name;
>
> Adds another 4-byte padding.
>
> Moving sysrq members just before `hub6` allows to save 8 bytes
> per-uart_port on 64-bit platforms:
> On my gcc, x86_64 sizeof(struct uart_port) goes from 528 to 520.
>
> Signed-off-by: Dmitry Safonov <dima@arista.com>
> ---
> include/linux/serial_core.h | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index 2b78cc734719..bbbe57bf5163 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -161,11 +161,6 @@ struct uart_port {
> struct uart_icount icount; /* statistics */
>
> struct console *cons; /* struct console, if any */
> -#if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ)
> - unsigned long sysrq; /* sysrq timeout */
> - unsigned int sysrq_ch; /* char for sysrq */
> -#endif
> -
> /* flags must be updated while holding port mutex */
> upf_t flags;
>
> @@ -244,6 +239,12 @@ struct uart_port {
> resource_size_t mapbase; /* for ioremap */
> resource_size_t mapsize;
> struct device *dev; /* parent device */
> +
> +#if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ)
> + unsigned long sysrq; /* sysrq timeout */
> + unsigned int sysrq_ch; /* char for sysrq */
> +#endif
Let's just always have these 2 fields in the structure, no need for a
#ifdef at all, right? There is no real "savings" from removing them (8
bytes for a structure that is maybe created 2-4 times per machine?)
That way it would keep any of this mess of if the SUPPORT_SYSRQ is
enabled or not to keep everything in sync.
thanks,
greg k-h
next prev parent reply other threads:[~2019-12-13 7:17 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20191213000657.931618-1-dima@arista.com>
2019-12-13 0:06 ` [PATCH 01/58] sysrq: Remove sysrq_handler_registered Dmitry Safonov
2019-12-13 0:06 ` [PATCH 02/58] serial: Move sysrq members above Dmitry Safonov
2019-12-13 7:17 ` Greg Kroah-Hartman [this message]
2019-12-13 0:06 ` [PATCH 03/58] serial_core: Un-ifdef sysrq SUPPORT_SYSRQ Dmitry Safonov
2019-12-13 7:18 ` Greg Kroah-Hartman
2019-12-17 13:48 ` Greg Kroah-Hartman
2019-12-17 13:51 ` Greg Kroah-Hartman
2019-12-13 0:06 ` [PATCH 04/58] tty/serial: Migrate aspeed_vuart to use has_sysrq Dmitry Safonov
2019-12-13 1:32 ` Andrew Jeffery
2019-12-13 0:06 ` [PATCH 05/58] tty/serial: Migrate 8250_fsl " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 06/58] tty/serial: Migrate bcm63xx_uart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 07/58] tty/serial: Migrate 8250_omap " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 08/58] tty/serial: Migrate 8250_port " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 09/58] tty/serial: Migrate amba-pl01* " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 10/58] tty/serial: Migrate apbuart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 11/58] tty/serial: Migrate arc_uart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 12/58] tty/serial: Migrate atmel_serial " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 13/58] tty/serial: Migrate clps711x " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 14/58] tty/serial: Migrate cpm_uart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 15/58] tty/serial: Migrate dz " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 16/58] tty/serial: Migrate efm32-uart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 17/58] tty/serial: Migrate fsl_linflexuart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 18/58] tty/serial: Migrate fsl_lpuart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 19/58] tty/serial: Migrate imx " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 20/58] tty/serial: Migrate ip22zilog " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 21/58] tty/serial: Migrate meson_uart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 22/58] tty/serial: Migrate milbeaut_usio " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 23/58] tty/serial: Migrate mpc52xx_uart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 24/58] tty/serial: Don't zero port->sysrq Dmitry Safonov
2019-12-13 0:06 ` [PATCH 25/58] tty/serial: Migrate msm_serial to use has_sysrq Dmitry Safonov
2019-12-13 0:06 ` [PATCH 26/58] tty/serial: Migrate mux " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 27/58] tty/serial: Migrate mxs-auart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 28/58] tty/serial: Migrate omap-serial " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 29/58] tty/serial: Migrate pch_uart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 30/58] tty/serial: Don't check port->sysrq Dmitry Safonov
2019-12-13 0:06 ` [PATCH 31/58] tty/serial: Migrate pmac_zilog to use has_sysrq Dmitry Safonov
2019-12-13 0:06 ` [PATCH 32/58] tty/serial: Migrate pnx8xxx_uart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 33/58] serial/f81534: Don't check port->sysrq Dmitry Safonov
2019-12-16 12:10 ` Johan Hovold
2019-12-16 16:36 ` Dmitry Safonov
2019-12-13 0:06 ` [PATCH 34/58] tty/serial: Migrate pxa to use has_sysrq Dmitry Safonov
2019-12-13 0:06 ` [PATCH 35/58] tty/serial: Migrate qcom_geni_serial " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 36/58] tty/serial: Migrate sa1100 " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 37/58] tty/serial: Migrate samsung_tty " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 38/58] tty/serial: Migrate sb1250-duart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 39/58] tty/serial: Migrate sccnxp " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 40/58] tty/serial: Migrate serial_txx9 " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 41/58] tty/serial: Migrate sh-sci " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 42/58] tty/serial: Migrate sprd_serial " Dmitry Safonov
2019-12-16 2:30 ` Chunyan Zhang
2019-12-13 0:06 ` [PATCH 43/58] tty/serial: Migrate st-asc " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 44/58] tty/serial: Migrate stm32-usart " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 45/58] tty/serial: Migrate sunhv " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 46/58] tty/serial: Migrate sunsab " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 47/58] tty/serial: Migrate sunsu " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 48/58] tty/serial: Migrate sunzilog " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 49/58] serial/ucc_uart: Remove ifdef SUPPORT_SYSRQ Dmitry Safonov
2019-12-13 0:06 ` [PATCH 50/58] tty/serial: Migrate vr41xx_siu to use has_sysrq Dmitry Safonov
2019-12-13 0:06 ` [PATCH 51/58] tty/serial: Migrate vt8500_serial " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 52/58] tty/serial: Migrate xilinx_uartps " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 53/58] tty/serial: Migrate zs " Dmitry Safonov
2019-12-13 0:06 ` [PATCH 54/58] serial_core: Remove SUPPORT_SYSRQ ifdeffery Dmitry Safonov
2019-12-17 14:27 ` Greg Kroah-Hartman
2019-12-17 15:50 ` Dmitry Safonov
2019-12-13 0:06 ` [PATCH 55/58] usb/serial: Don't handle break when CONFIG_MAGIC_SYSRQ is disabled Dmitry Safonov
2019-12-13 0:06 ` [PATCH 56/58] serial_core: Move sysrq functions from header file Dmitry Safonov
2019-12-13 0:06 ` [PATCH 57/58] sysctl/sysrq: Remove __sysrq_enabled copy Dmitry Safonov
2019-12-13 0:06 ` [PATCH 58/58] serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE Dmitry Safonov
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