| Message ID | 20220623090852.29622-2-roger.pau@citrix.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | console/serial: adjust default TX buffer size | expand |
On 23.06.2022 11:08, Roger Pau Monne wrote: > --- a/xen/drivers/char/Kconfig > +++ b/xen/drivers/char/Kconfig > @@ -74,3 +74,13 @@ config HAS_EHCI > help > This selects the USB based EHCI debug port to be used as a UART. If > you have an x86 based system with USB, say Y. > + > +config SERIAL_TX_BUFSIZE > + int "Size of the transmit serial buffer" > + default 16384 > + help > + Controls the default size of the transmit buffer (in bytes) used by > + the serial driver. Note the value provided will be rounder up to > + PAGE_SIZE. I first wanted to point out the spelling mistake (rounded), but I wonder what good that rounding does and whether this description isn't really misleading: serial_async_transmit() rounds down to a power of two. So likely the value here would better be a log-2 one. > + Default value is 16384 (16KB). Perhaps (16kiB) (albeit the default value would change anyway if the above is followed)? Jan
diff --git a/xen/drivers/char/Kconfig b/xen/drivers/char/Kconfig index e5f7b1d8eb..a349d55f18 100644 --- a/xen/drivers/char/Kconfig +++ b/xen/drivers/char/Kconfig @@ -74,3 +74,13 @@ config HAS_EHCI help This selects the USB based EHCI debug port to be used as a UART. If you have an x86 based system with USB, say Y. + +config SERIAL_TX_BUFSIZE + int "Size of the transmit serial buffer" + default 16384 + help + Controls the default size of the transmit buffer (in bytes) used by + the serial driver. Note the value provided will be rounder up to + PAGE_SIZE. + + Default value is 16384 (16KB). diff --git a/xen/drivers/char/serial.c b/xen/drivers/char/serial.c index 5ecba0af33..8d375a41e3 100644 --- a/xen/drivers/char/serial.c +++ b/xen/drivers/char/serial.c @@ -16,7 +16,8 @@ /* Never drop characters, even if the async transmit buffer fills. */ /* #define SERIAL_NEVER_DROP_CHARS 1 */ -unsigned int __read_mostly serial_txbufsz = 16384; +unsigned int __ro_after_init serial_txbufsz = ROUNDUP(CONFIG_SERIAL_TX_BUFSIZE, + PAGE_SIZE); size_param("serial_tx_buffer", serial_txbufsz); #define mask_serial_rxbuf_idx(_i) ((_i)&(serial_rxbufsz-1))
Take the opportunity to convert the variable to read-only after init. No functional change intended. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> --- xen/drivers/char/Kconfig | 10 ++++++++++ xen/drivers/char/serial.c | 3 ++- 2 files changed, 12 insertions(+), 1 deletion(-)