Revision e02f5f52cafbea013817d81f1acc4baf50d6324b authored by Bjorn Helgaas on 15 November 2007, 00:59:59 UTC, committed by Linus Torvalds on 15 November 2007, 02:45:41 UTC
"Luming Yu" <luming.yu@gmail.com> says: There is a "ttyS1 irq is -1" problem observed on tiger4 which cause the serial port broken. It is because that there is __no__ ACPI IRQ resource assigned for the serial port. So the value of the IRQ for the port is never changed since it got initialized to -1. If PNP supplies a valid IRQ, use it. Otherwise, leave port.irq == 0, which means "no IRQ" to the serial core. Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Yu Luming <luming.yu@intel.com> Acked-by: Matthew Wilcox <matthew@wil.cx> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 57510c2
thrash.c
/*
* mm/thrash.c
*
* Copyright (C) 2004, Red Hat, Inc.
* Copyright (C) 2004, Rik van Riel <riel@redhat.com>
* Released under the GPL, see the file COPYING for details.
*
* Simple token based thrashing protection, using the algorithm
* described in: http://www.cs.wm.edu/~sjiang/token.pdf
*
* Sep 2006, Ashwin Chaugule <ashwin.chaugule@celunite.com>
* Improved algorithm to pass token:
* Each task has a priority which is incremented if it contended
* for the token in an interval less than its previous attempt.
* If the token is acquired, that task's priority is boosted to prevent
* the token from bouncing around too often and to let the task make
* some progress in its execution.
*/
#include <linux/jiffies.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/swap.h>
static DEFINE_SPINLOCK(swap_token_lock);
struct mm_struct *swap_token_mm;
static unsigned int global_faults;
void grab_swap_token(void)
{
int current_interval;
global_faults++;
current_interval = global_faults - current->mm->faultstamp;
if (!spin_trylock(&swap_token_lock))
return;
/* First come first served */
if (swap_token_mm == NULL) {
current->mm->token_priority = current->mm->token_priority + 2;
swap_token_mm = current->mm;
goto out;
}
if (current->mm != swap_token_mm) {
if (current_interval < current->mm->last_interval)
current->mm->token_priority++;
else {
if (likely(current->mm->token_priority > 0))
current->mm->token_priority--;
}
/* Check if we deserve the token */
if (current->mm->token_priority >
swap_token_mm->token_priority) {
current->mm->token_priority += 2;
swap_token_mm = current->mm;
}
} else {
/* Token holder came in again! */
current->mm->token_priority += 2;
}
out:
current->mm->faultstamp = global_faults;
current->mm->last_interval = current_interval;
spin_unlock(&swap_token_lock);
return;
}
/* Called on process exit. */
void __put_swap_token(struct mm_struct *mm)
{
spin_lock(&swap_token_lock);
if (likely(mm == swap_token_mm))
swap_token_mm = NULL;
spin_unlock(&swap_token_lock);
}
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