The patch titled
Subject: mm/list_lru: introduce list_lru_shrink_walk_irq()
has been added to the -mm tree. Its filename is
mm-list_lru-introduce-list_lru_shrink_walk_irq.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-list_lru-introduce-list_lru_shrink_walk_irq.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-list_lru-introduce-list_lru_shrink_walk_irq.patch
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------------------------------------------------------
From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Subject: mm/list_lru: introduce list_lru_shrink_walk_irq()
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@xxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Reviewed-by: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/list_lru.h | 25 +++++++++++++++++++++++++
mm/list_lru.c | 15 +++++++++++++++
mm/workingset.c | 8 ++------
3 files changed, 42 insertions(+), 6 deletions(-)
diff -puN include/linux/list_lru.h~mm-list_lru-introduce-list_lru_shrink_walk_irq include/linux/list_lru.h
--- a/include/linux/list_lru.h~mm-list_lru-introduce-list_lru_shrink_walk_irq
+++ a/include/linux/list_lru.h
@@ -166,6 +166,23 @@ unsigned long list_lru_walk_one(struct l
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);
@@ -179,6 +196,14 @@ list_lru_shrink_walk(struct list_lru *lr
}
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)
{
diff -puN mm/list_lru.c~mm-list_lru-introduce-list_lru_shrink_walk_irq mm/list_lru.c
--- a/mm/list_lru.c~mm-list_lru-introduce-list_lru_shrink_walk_irq
+++ a/mm/list_lru.c
@@ -282,6 +282,21 @@ list_lru_walk_one(struct list_lru *lru,
}
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)
diff -puN mm/workingset.c~mm-list_lru-introduce-list_lru_shrink_walk_irq mm/workingset.c
--- a/mm/workingset.c~mm-list_lru-introduce-list_lru_shrink_walk_irq
+++ a/mm/workingset.c
@@ -510,13 +510,9 @@ out:
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 = {
_
Patches currently in -mm which might be from bigeasy@xxxxxxxxxxxxx are
ntfs-dont-disable-interrupts-during-kmap_atomic.patch
mm-workingset-remove-local_irq_disable-from-count_shadow_nodes.patch
mm-workingset-make-shadow_lru_isolate-use-locking-suffix.patch
mm-list_lru-use-list_lru_walk_one-in-list_lru_walk_node.patch
mm-list_lru-move-locking-from-__list_lru_walk_one-to-its-caller.patch
mm-list_lru-pass-struct-list_lru_node-as-an-argument-__list_lru_walk_one.patch
mm-list_lru-introduce-list_lru_shrink_walk_irq.patch
bdi-use-refcount_t-for-reference-counting-instead-atomic_t.patch
userns-use-refcount_t-for-reference-counting-instead-atomic_t.patch
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