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a433658c30
Currently, memcg reclaim can disable swap token even if the swap token mm doesn't belong in its memory cgroup. It's slightly risky. If an admin creates very small mem-cgroup and silly guy runs contentious heavy memory pressure workload, every tasks are going to lose swap token and then system may become unresponsive. That's bad. This patch adds 'memcg' parameter into disable_swap_token(). and if the parameter doesn't match swap token, VM doesn't disable it. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Rik van Riel<riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
127 lines
2.8 KiB
C
127 lines
2.8 KiB
C
/*
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* mm/thrash.c
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*
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* Copyright (C) 2004, Red Hat, Inc.
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* Copyright (C) 2004, Rik van Riel <riel@redhat.com>
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* Released under the GPL, see the file COPYING for details.
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*
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* Simple token based thrashing protection, using the algorithm
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* described in: http://www.cs.wm.edu/~sjiang/token.pdf
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*
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* Sep 2006, Ashwin Chaugule <ashwin.chaugule@celunite.com>
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* Improved algorithm to pass token:
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* Each task has a priority which is incremented if it contended
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* for the token in an interval less than its previous attempt.
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* If the token is acquired, that task's priority is boosted to prevent
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* the token from bouncing around too often and to let the task make
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* some progress in its execution.
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*/
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#include <linux/jiffies.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/swap.h>
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#include <linux/memcontrol.h>
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static DEFINE_SPINLOCK(swap_token_lock);
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struct mm_struct *swap_token_mm;
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struct mem_cgroup *swap_token_memcg;
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static unsigned int global_faults;
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#ifdef CONFIG_CGROUP_MEM_RES_CTLR
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static struct mem_cgroup *swap_token_memcg_from_mm(struct mm_struct *mm)
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{
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struct mem_cgroup *memcg;
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memcg = try_get_mem_cgroup_from_mm(mm);
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if (memcg)
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css_put(mem_cgroup_css(memcg));
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return memcg;
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}
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#else
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static struct mem_cgroup *swap_token_memcg_from_mm(struct mm_struct *mm)
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{
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return NULL;
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}
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#endif
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void grab_swap_token(struct mm_struct *mm)
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{
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int current_interval;
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global_faults++;
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current_interval = global_faults - mm->faultstamp;
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if (!spin_trylock(&swap_token_lock))
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return;
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/* First come first served */
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if (!swap_token_mm)
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goto replace_token;
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if (mm == swap_token_mm) {
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mm->token_priority += 2;
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goto out;
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}
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if (current_interval < mm->last_interval)
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mm->token_priority++;
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else {
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if (likely(mm->token_priority > 0))
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mm->token_priority--;
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}
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/* Check if we deserve the token */
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if (mm->token_priority > swap_token_mm->token_priority)
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goto replace_token;
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out:
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mm->faultstamp = global_faults;
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mm->last_interval = current_interval;
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spin_unlock(&swap_token_lock);
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return;
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replace_token:
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mm->token_priority += 2;
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swap_token_mm = mm;
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swap_token_memcg = swap_token_memcg_from_mm(mm);
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goto out;
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}
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/* Called on process exit. */
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void __put_swap_token(struct mm_struct *mm)
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{
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spin_lock(&swap_token_lock);
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if (likely(mm == swap_token_mm)) {
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swap_token_mm = NULL;
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swap_token_memcg = NULL;
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}
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spin_unlock(&swap_token_lock);
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}
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static bool match_memcg(struct mem_cgroup *a, struct mem_cgroup *b)
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{
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if (!a)
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return true;
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if (!b)
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return true;
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if (a == b)
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return true;
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return false;
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}
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void disable_swap_token(struct mem_cgroup *memcg)
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{
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/* memcg reclaim don't disable unrelated mm token. */
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if (match_memcg(memcg, swap_token_memcg)) {
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spin_lock(&swap_token_lock);
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if (match_memcg(memcg, swap_token_memcg)) {
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swap_token_mm = NULL;
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swap_token_memcg = NULL;
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}
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spin_unlock(&swap_token_lock);
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}
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}
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