From d9661adfb8e53a7647360140af3b92284cbe52d4 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Thu, 18 Feb 2010 16:43:47 +0000 Subject: tty: Keep the default buffering to sub-page units We allocate during interrupts so while our buffering is normally diced up small anyway on some hardware at speed we can pressure the VM excessively for page pairs. We don't really need big buffers to be linear so don't try so hard. In order to make this work well we will tidy up excess callers to request_room, which cannot itself enforce this break up. Signed-off-by: Alan Cox Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 6abfcf5b5887..d96e5882f129 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -68,6 +68,16 @@ struct tty_buffer { unsigned long data[0]; }; +/* + * We default to dicing tty buffer allocations to this many characters + * in order to avoid multiple page allocations. We assume tty_buffer itself + * is under 256 bytes. See tty_buffer_find for the allocation logic this + * must match + */ + +#define TTY_BUFFER_PAGE ((PAGE_SIZE - 256) / 2) + + struct tty_bufhead { struct delayed_work work; spinlock_t lock; -- cgit v1.2.3 From 572b9adbd40b5565dc413db04af9cc234f72bf19 Mon Sep 17 00:00:00 2001 From: Rodolfo Giometti Date: Wed, 10 Mar 2010 15:23:46 -0800 Subject: ldisc n_tty: add new method n_tty_inherit_ops() This new method can be used to init a new struct tty_ldisc_ops as the default tty_ldisc_N_TTY struct. Signed-off-by: Rodolfo Giometti Cc: David Woodhouse Cc: Greg KH Cc: Alan Cox Cc: Alexander Gordeev Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/n_tty.c | 17 +++++++++++++++++ include/linux/tty.h | 1 + 2 files changed, 18 insertions(+) (limited to 'include/linux/tty.h') diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c index 2e50f4dfc79c..bdae8327143c 100644 --- a/drivers/char/n_tty.c +++ b/drivers/char/n_tty.c @@ -48,6 +48,7 @@ #include #include #include +#include #include @@ -2091,3 +2092,19 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = { .receive_buf = n_tty_receive_buf, .write_wakeup = n_tty_write_wakeup }; + +/** + * n_tty_inherit_ops - inherit N_TTY methods + * @ops: struct tty_ldisc_ops where to save N_TTY methods + * + * Used by a generic struct tty_ldisc_ops to easily inherit N_TTY + * methods. + */ + +void n_tty_inherit_ops(struct tty_ldisc_ops *ops) +{ + *ops = tty_ldisc_N_TTY; + ops->owner = NULL; + ops->refcount = ops->flags = 0; +} +EXPORT_SYMBOL_GPL(n_tty_inherit_ops); diff --git a/include/linux/tty.h b/include/linux/tty.h index d96e5882f129..568369a86306 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -514,6 +514,7 @@ extern void tty_ldisc_enable(struct tty_struct *tty); /* n_tty.c */ extern struct tty_ldisc_ops tty_ldisc_N_TTY; +extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops); /* tty_audit.c */ #ifdef CONFIG_AUDIT -- cgit v1.2.3 From 352fa6ad16b89f8ffd1a93b4419b1a8f2259feab Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 2 Mar 2010 22:24:19 +0000 Subject: tty: Take a 256 byte padding into account when buffering below sub-page units The TTY layer takes some care to ensure that only sub-page allocations are made with interrupts disabled. It does this by setting a goal of "TTY_BUFFER_PAGE" to allocate. Unfortunately, while TTY_BUFFER_PAGE takes the size of tty_buffer into account, it fails to account that tty_buffer_find() rounds the buffer size out to the next 256 byte boundary before adding on the size of the tty_buffer. This patch adjusts the TTY_BUFFER_PAGE calculation to take into account the size of the tty_buffer and the padding. Once applied, tty_buffer_alloc() should not require high-order allocations. Signed-off-by: Mel Gorman Cc: stable Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'include/linux/tty.h') diff --git a/include/linux/tty.h b/include/linux/tty.h index 568369a86306..593228a520e1 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -70,12 +70,13 @@ struct tty_buffer { /* * We default to dicing tty buffer allocations to this many characters - * in order to avoid multiple page allocations. We assume tty_buffer itself - * is under 256 bytes. See tty_buffer_find for the allocation logic this - * must match + * in order to avoid multiple page allocations. We know the size of + * tty_buffer itself but it must also be taken into account that the + * the buffer is 256 byte aligned. See tty_buffer_find for the allocation + * logic this must match */ -#define TTY_BUFFER_PAGE ((PAGE_SIZE - 256) / 2) +#define TTY_BUFFER_PAGE (((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF) struct tty_bufhead { -- cgit v1.2.3 From 336cee42dd52824e360ab419eab4e8888eb054ec Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Mon, 8 Mar 2010 21:50:11 -0600 Subject: tty_port,usb-console: Fix usb serial console open/close regression Commit e1108a63e10d344284011cccc06328b2cd3e5da3 ("usb_serial: Use the shutdown() operation") breaks the ability to use a usb console starting in 2.6.33. This was observed when using console=ttyUSB0,115200 as a boot argument with an FTDI device. The error is: ftdi_sio ttyUSB0: ftdi_submit_read_urb - failed submitting read urb, error -22 The handling of the ASYNCB_INITIALIZED changed in 2.6.32 such that in tty_port_shutdown() it always clears the flag if it is set. The fix is to add a variable to the tty_port struct to indicate when the tty port is a console. CC: Alan Cox CC: Alan Stern CC: Oliver Neukum CC: Andrew Morton Signed-off-by: Jason Wessel Signed-off-by: Greg Kroah-Hartman --- drivers/char/tty_port.c | 2 +- drivers/usb/serial/console.c | 1 + include/linux/tty.h | 1 + 3 files changed, 3 insertions(+), 1 deletion(-) (limited to 'include/linux/tty.h') diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c index be492dd66437..a3bd1d0b66cf 100644 --- a/drivers/char/tty_port.c +++ b/drivers/char/tty_port.c @@ -119,7 +119,7 @@ EXPORT_SYMBOL(tty_port_tty_set); static void tty_port_shutdown(struct tty_port *port) { mutex_lock(&port->mutex); - if (port->ops->shutdown && + if (port->ops->shutdown && !port->console && test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) port->ops->shutdown(port); mutex_unlock(&port->mutex); diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c index b22ac3258523..f347da2ef00a 100644 --- a/drivers/usb/serial/console.c +++ b/drivers/usb/serial/console.c @@ -181,6 +181,7 @@ static int usb_console_setup(struct console *co, char *options) /* The console is special in terms of closing the device so * indicate this port is now acting as a system console. */ port->console = 1; + port->port.console = 1; mutex_unlock(&serial->disc_mutex); return retval; diff --git a/include/linux/tty.h b/include/linux/tty.h index 593228a520e1..4409967db0c4 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -224,6 +224,7 @@ struct tty_port { wait_queue_head_t close_wait; /* Close waiters */ wait_queue_head_t delta_msr_wait; /* Modem status change */ unsigned long flags; /* TTY flags ASY_*/ + unsigned char console:1; /* port is a console */ struct mutex mutex; /* Locking */ struct mutex buf_mutex; /* Buffer alloc lock */ unsigned char *xmit_buf; /* Optional buffer */ -- cgit v1.2.3