Re: [PATCH] tty: Take a 256 byte padding into account whenbuffering below sub-page units

From: Greg KH
Date: Tue Mar 02 2010 - 18:43:52 EST

On Tue, Mar 02, 2010 at 10:24:19PM +0000, Mel Gorman wrote:
> (applies on top of linux-next, depends on "tty: Keep the default buffering to 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 <mel@xxxxxxxxx>
> ---
> include/linux/tty.h | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)

Thanks, I'll queue this up after the current round of patches make it
into Linus's tree.

greg k-h
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