Revision b097f494cc3def2ec39ded3b80a62b9d257e4b01 authored by David Brownell on 07 December 2006, 01:14:04 UTC, committed by Tony Lindgren on 02 March 2007, 09:47:10 UTC
Teach OMAP2 gp timer that HZ isn't always 100. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Tony Lindgren <tony@atomide.com>
1 parent 2f5c4b6
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 {
current->mm->token_priority--;
if (unlikely(current->mm->token_priority < 0))
current->mm->token_priority = 0;
}
/* 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);
}
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...