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-rw-r--r--drivers/char/tty_buffer.c6
-rw-r--r--include/linux/tty.h10
2 files changed, 14 insertions, 2 deletions
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))
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 6abfcf5b588..d96e5882f12 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;