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mm/list_lru: introduce list_lru_shrink_walk_irq()

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Provide list_lru_shrink_walk_irq() and let it behave like
list_lru_walk_one() except that it locks the spinlock with
spin_lock_irq().  This is used by scan_shadow_nodes() because its lock
nests within the i_pages lock which is acquired with IRQ.  This change
allows to use proper locking promitives instead hand crafted
lock_irq_disable() plus spin_lock().

There is no EXPORT_SYMBOL provided because the current user is in-kernel
only.

Add list_lru_shrink_walk_irq() which acquires the spinlock with the
proper locking primitives.

Link: http://lkml.kernel.org/r/20180716111921.5365-5-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Sebastian Andrzej Siewior 2018-08-17 15:49:55 -07:00 committed by Linus Torvalds
parent 6e018968f8
commit 6b51e88199
3 changed files with 42 additions and 6 deletions
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25
include/linux/list_lru.h
View file

@ -166,6 +166,23 @@ unsigned long list_lru_walk_one(struct list_lru *lru,
int nid, struct mem_cgroup *memcg,
list_lru_walk_cb isolate, void *cb_arg,
unsigned long *nr_to_walk);
/**
* list_lru_walk_one_irq: walk a list_lru, isolating and disposing freeable items.
* @lru: the lru pointer.
* @nid: the node id to scan from.
* @memcg: the cgroup to scan from.
* @isolate: callback function that is resposible for deciding what to do with
* the item currently being scanned
* @cb_arg: opaque type that will be passed to @isolate
* @nr_to_walk: how many items to scan.
*
* Same as @list_lru_walk_one except that the spinlock is acquired with
* spin_lock_irq().
*/
unsigned long list_lru_walk_one_irq(struct list_lru *lru,
int nid, struct mem_cgroup *memcg,
list_lru_walk_cb isolate, void *cb_arg,
unsigned long *nr_to_walk);
unsigned long list_lru_walk_node(struct list_lru *lru, int nid,
list_lru_walk_cb isolate, void *cb_arg,
unsigned long *nr_to_walk);
@ -178,6 +195,14 @@ list_lru_shrink_walk(struct list_lru *lru, struct shrink_control *sc,
&sc->nr_to_scan);
}
static inline unsigned long
list_lru_shrink_walk_irq(struct list_lru *lru, struct shrink_control *sc,
list_lru_walk_cb isolate, void *cb_arg)
{
return list_lru_walk_one_irq(lru, sc->nid, sc->memcg, isolate, cb_arg,
&sc->nr_to_scan);
}
static inline unsigned long
list_lru_walk(struct list_lru *lru, list_lru_walk_cb isolate,
void *cb_arg, unsigned long nr_to_walk)

15
mm/list_lru.c
View file

@ -282,6 +282,21 @@ list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
}
EXPORT_SYMBOL_GPL(list_lru_walk_one);
unsigned long
list_lru_walk_one_irq(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
list_lru_walk_cb isolate, void *cb_arg,
unsigned long *nr_to_walk)
{
struct list_lru_node *nlru = &lru->node[nid];
unsigned long ret;
spin_lock_irq(&nlru->lock);
ret = __list_lru_walk_one(nlru, memcg_cache_id(memcg), isolate, cb_arg,
nr_to_walk);
spin_unlock_irq(&nlru->lock);
return ret;
}
unsigned long list_lru_walk_node(struct list_lru *lru, int nid,
list_lru_walk_cb isolate, void *cb_arg,
unsigned long *nr_to_walk)

8
mm/workingset.c
View file

@ -483,13 +483,9 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
static unsigned long scan_shadow_nodes(struct shrinker *shrinker,
struct shrink_control *sc)
{
unsigned long ret;
/* list_lru lock nests inside the IRQ-safe i_pages lock */
local_irq_disable();
ret = list_lru_shrink_walk(&shadow_nodes, sc, shadow_lru_isolate, NULL);
local_irq_enable();
return ret;
return list_lru_shrink_walk_irq(&shadow_nodes, sc, shadow_lru_isolate,
NULL);
}
static struct shrinker workingset_shadow_shrinker = {