Certain people seem to have assumed tty->throttled was 'advisory'. In
the absence of tty->author->throttle(), it seems we should keep a simple
limit of our own to avoid problems when this occurs.
Signed-off-by: Alan Cox <[email protected]>
diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.18-rc2-mm1/drivers/char/tty_io.c linux-2.6.18-rc2-mm1/drivers/char/tty_io.c
--- linux.vanilla-2.6.18-rc2-mm1/drivers/char/tty_io.c 2006-07-27 16:19:51.000000000 +0100
+++ linux-2.6.18-rc2-mm1/drivers/char/tty_io.c 2006-07-27 16:44:17.000000000 +0100
@@ -247,6 +247,7 @@
kfree(thead);
}
tty->buf.tail = NULL;
+ tty->buf.memory_used = 0;
}
static void tty_buffer_init(struct tty_struct *tty)
@@ -255,11 +256,16 @@
tty->buf.head = NULL;
tty->buf.tail = NULL;
tty->buf.free = NULL;
+ tty->buf.memory_used = 0;
}
-static struct tty_buffer *tty_buffer_alloc(size_t size)
+static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size)
{
- struct tty_buffer *p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
+ struct tty_buffer *p;
+
+ if (tty->buf.memory_used + size > 65536)
+ return NULL;
+ p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
if(p == NULL)
return NULL;
p->used = 0;
@@ -269,7 +275,7 @@
p->read = 0;
p->char_buf_ptr = (char *)(p->data);
p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
-/* printk("Flip create %p\n", p); */
+ tty->buf.memory_used += size;
return p;
}
@@ -279,7 +285,9 @@
static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
{
/* Dumb strategy for now - should keep some stats */
-/* printk("Flip dispose %p\n", b); */
+ tty->buf.memory_used -= b->size;
+ WARN_ON(tty->buf.memory_used < 0);
+
if(b->size >= 512)
kfree(b);
else {
@@ -299,16 +307,14 @@
t->used = 0;
t->commit = 0;
t->read = 0;
- /* DEBUG ONLY */
- memset(t->data, '*', size);
-/* printk("Flip recycle %p\n", t); */
+ tty->buf.memory_used += t->size;
return t;
}
tbh = &((*tbh)->next);
}
/* Round the buffer size out */
size = (size + 0xFF) & ~ 0xFF;
- return tty_buffer_alloc(size);
+ return tty_buffer_alloc(tty, size);
/* Should possibly check if this fails for the largest buffer we
have queued and recycle that ? */
}
diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.18-rc2-mm1/include/linux/tty.h linux-2.6.18-rc2-mm1/include/linux/tty.h
--- linux.vanilla-2.6.18-rc2-mm1/include/linux/tty.h 2006-07-27 16:19:26.000000000 +0100
+++ linux-2.6.18-rc2-mm1/include/linux/tty.h 2006-07-27 16:45:37.000000000 +0100
@@ -59,6 +59,7 @@
struct tty_buffer *head; /* Queue head */
struct tty_buffer *tail; /* Active buffer */
struct tty_buffer *free; /* Free queue head */
+ int memory_used; /* Buffer space used excluding free queue */
};
/*
* The pty uses char_buf and flag_buf as a contiguous buffer
-
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