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 --- drivers/char/tty_buffer.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/char') diff --git a/drivers/char/tty_buffer.c b/drivers/char/tty_buffer.c index 66fa4e10d76..f27c4d6d956 100644 --- a/drivers/char/tty_buffer.c +++ b/drivers/char/tty_buffer.c @@ -247,7 +247,8 @@ int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars, { int copied = 0; do { - int space = tty_buffer_request_room(tty, size - copied); + int goal = min(size - copied, TTY_BUFFER_PAGE); + int space = tty_buffer_request_room(tty, goal); struct tty_buffer *tb = tty->buf.tail; /* If there is no space then tb may be NULL */ if (unlikely(space == 0)) @@ -283,7 +284,8 @@ int tty_insert_flip_string_flags(struct tty_struct *tty, { int copied = 0; do { - int space = tty_buffer_request_room(tty, size - copied); + int goal = min(size - copied, TTY_BUFFER_PAGE); + int space = tty_buffer_request_room(tty, goal); struct tty_buffer *tb = tty->buf.tail; /* If there is no space then tb may be NULL */ if (unlikely(space == 0)) -- cgit v1.2.3