mirror of
https://github.com/torvalds/linux.git
synced 2024-11-26 22:21:42 +00:00
f7b7fd8f3e
Some users (hi Zwane) have seen a problem when running a workload that eats nearly all of physical memory - th system does an OOM kill, even when there is still a lot of swap free. The problem appears to be a very big task that is holding the swap token, and the VM has a very hard time finding any other page in the system that is swappable. Instead of ignoring the swap token when sc->priority reaches 0, we could simply take the swap token away from the memory hog and make sure we don't give it back to the memory hog for a few seconds. This patch resolves the problem Zwane ran into. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
107 lines
2.7 KiB
C
107 lines
2.7 KiB
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
|
|
*/
|
|
#include <linux/jiffies.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/swap.h>
|
|
|
|
static DEFINE_SPINLOCK(swap_token_lock);
|
|
static unsigned long swap_token_timeout;
|
|
static unsigned long swap_token_check;
|
|
struct mm_struct * swap_token_mm = &init_mm;
|
|
|
|
#define SWAP_TOKEN_CHECK_INTERVAL (HZ * 2)
|
|
#define SWAP_TOKEN_TIMEOUT (300 * HZ)
|
|
/*
|
|
* Currently disabled; Needs further code to work at HZ * 300.
|
|
*/
|
|
unsigned long swap_token_default_timeout = SWAP_TOKEN_TIMEOUT;
|
|
|
|
/*
|
|
* Take the token away if the process had no page faults
|
|
* in the last interval, or if it has held the token for
|
|
* too long.
|
|
*/
|
|
#define SWAP_TOKEN_ENOUGH_RSS 1
|
|
#define SWAP_TOKEN_TIMED_OUT 2
|
|
static int should_release_swap_token(struct mm_struct *mm)
|
|
{
|
|
int ret = 0;
|
|
if (!mm->recent_pagein)
|
|
ret = SWAP_TOKEN_ENOUGH_RSS;
|
|
else if (time_after(jiffies, swap_token_timeout))
|
|
ret = SWAP_TOKEN_TIMED_OUT;
|
|
mm->recent_pagein = 0;
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Try to grab the swapout protection token. We only try to
|
|
* grab it once every TOKEN_CHECK_INTERVAL, both to prevent
|
|
* SMP lock contention and to check that the process that held
|
|
* the token before is no longer thrashing.
|
|
*/
|
|
void grab_swap_token(void)
|
|
{
|
|
struct mm_struct *mm;
|
|
int reason;
|
|
|
|
/* We have the token. Let others know we still need it. */
|
|
if (has_swap_token(current->mm)) {
|
|
current->mm->recent_pagein = 1;
|
|
if (unlikely(!swap_token_default_timeout))
|
|
disable_swap_token();
|
|
return;
|
|
}
|
|
|
|
if (time_after(jiffies, swap_token_check)) {
|
|
|
|
if (!swap_token_default_timeout) {
|
|
swap_token_check = jiffies + SWAP_TOKEN_CHECK_INTERVAL;
|
|
return;
|
|
}
|
|
|
|
/* ... or if we recently held the token. */
|
|
if (time_before(jiffies, current->mm->swap_token_time))
|
|
return;
|
|
|
|
if (!spin_trylock(&swap_token_lock))
|
|
return;
|
|
|
|
swap_token_check = jiffies + SWAP_TOKEN_CHECK_INTERVAL;
|
|
|
|
mm = swap_token_mm;
|
|
if ((reason = should_release_swap_token(mm))) {
|
|
unsigned long eligible = jiffies;
|
|
if (reason == SWAP_TOKEN_TIMED_OUT) {
|
|
eligible += swap_token_default_timeout;
|
|
}
|
|
mm->swap_token_time = eligible;
|
|
swap_token_timeout = jiffies + swap_token_default_timeout;
|
|
swap_token_mm = current->mm;
|
|
}
|
|
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)) {
|
|
mm->swap_token_time = jiffies + SWAP_TOKEN_CHECK_INTERVAL;
|
|
swap_token_mm = &init_mm;
|
|
swap_token_check = jiffies;
|
|
}
|
|
spin_unlock(&swap_token_lock);
|
|
}
|