Move the locking inside __list_lru_walk_one() to its caller. This is a preparation step in order to introduce list_lru_walk_one_irq() which does spin_lock_irq() instead of spin_lock() for the locking. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- mm/list_lru.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/mm/list_lru.c b/mm/list_lru.c index ddbffbdd3d72..819e0595303e 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -204,7 +204,6 @@ __list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx, struct list_head *item, *n; unsigned long isolated = 0; - spin_lock(&nlru->lock); l = list_lru_from_memcg_idx(nlru, memcg_idx); restart: list_for_each_safe(item, n, &l->list) { @@ -250,8 +249,6 @@ __list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx, BUG(); } } - - spin_unlock(&nlru->lock); return isolated; } @@ -260,8 +257,14 @@ 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) { - return __list_lru_walk_one(lru, nid, memcg_cache_id(memcg), - isolate, cb_arg, nr_to_walk); + struct list_lru_node *nlru = &lru->node[nid]; + unsigned long ret; + + spin_lock(&nlru->lock); + ret = __list_lru_walk_one(lru, nid, memcg_cache_id(memcg), + isolate, cb_arg, nr_to_walk); + spin_unlock(&nlru->lock); + return ret; } EXPORT_SYMBOL_GPL(list_lru_walk_one); @@ -276,8 +279,13 @@ unsigned long list_lru_walk_node(struct list_lru *lru, int nid, nr_to_walk); if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) { for_each_memcg_cache_index(memcg_idx) { + struct list_lru_node *nlru = &lru->node[nid]; + + spin_lock(&nlru->lock); isolated += __list_lru_walk_one(lru, nid, memcg_idx, isolate, cb_arg, nr_to_walk); + spin_unlock(&nlru->lock); + if (*nr_to_walk <= 0) break; } -- 2.18.0
This series removes the local_irq_disable() around list_lru_shrink_walk() (as used by mm/workingset) by adding list_lru_shrink_walk_irq(). Vladimir Davydov preferred this over an `irq' argument which I added to struct list_lru. The initial post (of this series) received a Reviewed-by tag by Vladimir Davydov which I added to each patch of the series. The series applies on top of akpm's tree which has Kirill's shrink_slab series and does not clash with it (akpm asked me to wait a week or so and repost it then). I tested the code paths by triggering the OOM-killer via memory over commit and lockdep did not complain (nor did I see any warnings). Sebastian Sebastian
list_lru_walk_node() invokes __list_lru_walk_one() with -1 as the memcg_idx parameter. The same can be achieved by list_lru_walk_one() and passing NULL as memcg argument which then gets converted into -1. This is a preparation step when the spin_lock() function is lifted to the caller of __list_lru_walk_one(). Invoke list_lru_walk_one() instead __list_lru_walk_one() when possible. Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- mm/list_lru.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/list_lru.c b/mm/list_lru.c index ca6dbcfe4256..344306714636 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -294,8 +294,8 @@ unsigned long list_lru_walk_node(struct list_lru *lru, int nid, long isolated = 0; int memcg_idx; - isolated += __list_lru_walk_one(lru, nid, -1, isolate, cb_arg, - nr_to_walk); + isolated += list_lru_walk_one(lru, nid, NULL, isolate, cb_arg, + nr_to_walk); if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) { for_each_memcg_cache_index(memcg_idx) { isolated += __list_lru_walk_one(lru, nid, memcg_idx, -- 2.18.0
Move the locking inside __list_lru_walk_one() to its caller. This is a preparation step in order to introduce list_lru_walk_one_irq() which does spin_lock_irq() instead of spin_lock() for the locking. Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- mm/list_lru.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/mm/list_lru.c b/mm/list_lru.c index 344306714636..3e36e7a239e5 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -226,7 +226,6 @@ __list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx, struct list_head *item, *n; unsigned long isolated = 0; - spin_lock(&nlru->lock); l = list_lru_from_memcg_idx(nlru, memcg_idx); restart: list_for_each_safe(item, n, &l->list) { @@ -272,8 +271,6 @@ __list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx, BUG(); } } - - spin_unlock(&nlru->lock); return isolated; } @@ -282,8 +279,14 @@ 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) { - return __list_lru_walk_one(lru, nid, memcg_cache_id(memcg), - isolate, cb_arg, nr_to_walk); + struct list_lru_node *nlru = &lru->node[nid]; + unsigned long ret; + + spin_lock(&nlru->lock); + ret = __list_lru_walk_one(lru, nid, memcg_cache_id(memcg), + isolate, cb_arg, nr_to_walk); + spin_unlock(&nlru->lock); + return ret; } EXPORT_SYMBOL_GPL(list_lru_walk_one); @@ -298,8 +301,13 @@ unsigned long list_lru_walk_node(struct list_lru *lru, int nid, nr_to_walk); if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) { for_each_memcg_cache_index(memcg_idx) { + struct list_lru_node *nlru = &lru->node[nid]; + + spin_lock(&nlru->lock); isolated += __list_lru_walk_one(lru, nid, memcg_idx, isolate, cb_arg, nr_to_walk); + spin_unlock(&nlru->lock); + if (*nr_to_walk <= 0) break; } -- 2.18.0
__list_lru_walk_one() is invoked with struct list_lru *lru, int nid as the first two argument. Those two are only used to retrieve struct list_lru_node. Since this is already done by the caller of the function for the locking, we can pass struct list_lru_node directly and avoid the dance around it. Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- mm/list_lru.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/mm/list_lru.c b/mm/list_lru.c index 3e36e7a239e5..7b7a737f0963 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -216,12 +216,11 @@ unsigned long list_lru_count_node(struct list_lru *lru, int nid) EXPORT_SYMBOL_GPL(list_lru_count_node); static unsigned long -__list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx, +__list_lru_walk_one(struct list_lru_node *nlru, int memcg_idx, list_lru_walk_cb isolate, void *cb_arg, unsigned long *nr_to_walk) { - struct list_lru_node *nlru = &lru->node[nid]; struct list_lru_one *l; struct list_head *item, *n; unsigned long isolated = 0; @@ -283,8 +282,8 @@ list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg, unsigned long ret; spin_lock(&nlru->lock); - ret = __list_lru_walk_one(lru, nid, memcg_cache_id(memcg), - isolate, cb_arg, nr_to_walk); + ret = __list_lru_walk_one(nlru, memcg_cache_id(memcg), isolate, cb_arg, + nr_to_walk); spin_unlock(&nlru->lock); return ret; } @@ -304,8 +303,9 @@ unsigned long list_lru_walk_node(struct list_lru *lru, int nid, struct list_lru_node *nlru = &lru->node[nid]; spin_lock(&nlru->lock); - isolated += __list_lru_walk_one(lru, nid, memcg_idx, - isolate, cb_arg, nr_to_walk); + isolated += __list_lru_walk_one(nlru, memcg_idx, + isolate, cb_arg, + nr_to_walk); spin_unlock(&nlru->lock); if (*nr_to_walk <= 0) -- 2.18.0
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. Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- include/linux/list_lru.h | 25 +++++++++++++++++++++++++ mm/list_lru.c | 15 +++++++++++++++ mm/workingset.c | 8 ++------ 3 files changed, 42 insertions(+), 6 deletions(-) diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h index d9c16f2f2f00..aa5efd9351eb 100644 --- a/include/linux/list_lru.h +++ b/include/linux/list_lru.h @@ -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) diff --git a/mm/list_lru.c b/mm/list_lru.c index 7b7a737f0963..89349a0276de 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -289,6 +289,21 @@ 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) diff --git a/mm/workingset.c b/mm/workingset.c index 06b45147e892..0b4f471d07ba 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -501,13 +501,9 @@ 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 = { -- 2.18.0