The patch titled
Subject: memcontrol: allows mem_cgroup_iter() to check for onlineness
has been added to the -mm mm-unstable branch. Its filename is
memcontrol-allows-mem_cgroup_iter-to-check-for-onlineness.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/memcontrol-allows-mem_cgroup_iter-to-check-for-onlineness.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Nhat Pham <nphamcs@xxxxxxxxx>
Subject: memcontrol: allows mem_cgroup_iter() to check for onlineness
Date: Mon, 27 Nov 2023 11:36:59 -0800
The new zswap writeback scheme requires an online-only memcg hierarchy
traversal. Add a new parameter to mem_cgroup_iter() to check for
onlineness before returning.
Link: https://lkml.kernel.org/r/20231127193703.1980089-3-nphamcs@xxxxxxxxx
Signed-off-by: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Chris Li <chrisl@xxxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 4 ++--
mm/memcontrol.c | 17 ++++++++++-------
mm/shrinker.c | 4 ++--
mm/vmscan.c | 26 +++++++++++++-------------
4 files changed, 27 insertions(+), 24 deletions(-)
--- a/include/linux/memcontrol.h~memcontrol-allows-mem_cgroup_iter-to-check-for-onlineness
+++ a/include/linux/memcontrol.h
@@ -832,7 +832,7 @@ static inline void mem_cgroup_put(struct
struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
struct mem_cgroup *,
- struct mem_cgroup_reclaim_cookie *);
+ struct mem_cgroup_reclaim_cookie *, bool online);
void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
void mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
int (*)(struct task_struct *, void *), void *arg);
@@ -1381,7 +1381,7 @@ static inline struct lruvec *folio_lruve
static inline struct mem_cgroup *
mem_cgroup_iter(struct mem_cgroup *root,
struct mem_cgroup *prev,
- struct mem_cgroup_reclaim_cookie *reclaim)
+ struct mem_cgroup_reclaim_cookie *reclaim, bool online)
{
return NULL;
}
--- a/mm/memcontrol.c~memcontrol-allows-mem_cgroup_iter-to-check-for-onlineness
+++ a/mm/memcontrol.c
@@ -221,14 +221,14 @@ enum res_type {
* be used for reference counting.
*/
#define for_each_mem_cgroup_tree(iter, root) \
- for (iter = mem_cgroup_iter(root, NULL, NULL); \
+ for (iter = mem_cgroup_iter(root, NULL, NULL, false); \
iter != NULL; \
- iter = mem_cgroup_iter(root, iter, NULL))
+ iter = mem_cgroup_iter(root, iter, NULL, false))
#define for_each_mem_cgroup(iter) \
- for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
+ for (iter = mem_cgroup_iter(NULL, NULL, NULL, false); \
iter != NULL; \
- iter = mem_cgroup_iter(NULL, iter, NULL))
+ iter = mem_cgroup_iter(NULL, iter, NULL, false))
static inline bool task_is_dying(void)
{
@@ -1115,6 +1115,7 @@ again:
* @root: hierarchy root
* @prev: previously returned memcg, NULL on first invocation
* @reclaim: cookie for shared reclaim walks, NULL for full walks
+ * @online: skip offline memcgs
*
* Returns references to children of the hierarchy below @root, or
* @root itself, or %NULL after a full round-trip.
@@ -1129,7 +1130,8 @@ again:
*/
struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
struct mem_cgroup *prev,
- struct mem_cgroup_reclaim_cookie *reclaim)
+ struct mem_cgroup_reclaim_cookie *reclaim,
+ bool online)
{
struct mem_cgroup_reclaim_iter *iter;
struct cgroup_subsys_state *css = NULL;
@@ -1199,7 +1201,8 @@ struct mem_cgroup *mem_cgroup_iter(struc
* is provided by the caller, so we know it's alive
* and kicking, and don't take an extra reference.
*/
- if (css == &root->css || css_tryget(css)) {
+ if (css == &root->css || (!online && css_tryget(css)) ||
+ css_tryget_online(css)) {
memcg = mem_cgroup_from_css(css);
break;
}
@@ -1812,7 +1815,7 @@ static int mem_cgroup_soft_reclaim(struc
excess = soft_limit_excess(root_memcg);
while (1) {
- victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
+ victim = mem_cgroup_iter(root_memcg, victim, &reclaim, false);
if (!victim) {
loop++;
if (loop >= 2) {
--- a/mm/shrinker.c~memcontrol-allows-mem_cgroup_iter-to-check-for-onlineness
+++ a/mm/shrinker.c
@@ -160,7 +160,7 @@ static int expand_shrinker_info(int new_
new_size = shrinker_unit_size(new_nr_max);
old_size = shrinker_unit_size(shrinker_nr_max);
- memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ memcg = mem_cgroup_iter(NULL, NULL, NULL, false);
do {
ret = expand_one_shrinker_info(memcg, new_size, old_size,
new_nr_max);
@@ -168,7 +168,7 @@ static int expand_shrinker_info(int new_
mem_cgroup_iter_break(NULL, memcg);
goto out;
}
- } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
+ } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL, false)) != NULL);
out:
if (!ret)
shrinker_nr_max = new_nr_max;
--- a/mm/vmscan.c~memcontrol-allows-mem_cgroup_iter-to-check-for-onlineness
+++ a/mm/vmscan.c
@@ -382,10 +382,10 @@ static unsigned long drop_slab_node(int
unsigned long freed = 0;
struct mem_cgroup *memcg = NULL;
- memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ memcg = mem_cgroup_iter(NULL, NULL, NULL, false);
do {
freed += shrink_slab(GFP_KERNEL, nid, memcg, 0);
- } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
+ } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL, false)) != NULL);
return freed;
}
@@ -3911,7 +3911,7 @@ static void lru_gen_age_node(struct pgli
if (!min_ttl || sc->order || sc->priority == DEF_PRIORITY)
return;
- memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ memcg = mem_cgroup_iter(NULL, NULL, NULL, false);
do {
struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
@@ -3921,7 +3921,7 @@ static void lru_gen_age_node(struct pgli
}
cond_resched();
- } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)));
+ } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL, false)));
/*
* The main goal is to OOM kill if every generation from all memcgs is
@@ -5013,7 +5013,7 @@ static void lru_gen_change_state(bool en
else
static_branch_disable_cpuslocked(&lru_gen_caps[LRU_GEN_CORE]);
- memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ memcg = mem_cgroup_iter(NULL, NULL, NULL, false);
do {
int nid;
@@ -5037,7 +5037,7 @@ static void lru_gen_change_state(bool en
}
cond_resched();
- } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)));
+ } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL, false)));
unlock:
mutex_unlock(&state_mutex);
put_online_mems();
@@ -5140,7 +5140,7 @@ static void *lru_gen_seq_start(struct se
if (!m->private)
return ERR_PTR(-ENOMEM);
- memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ memcg = mem_cgroup_iter(NULL, NULL, NULL, false);
do {
int nid;
@@ -5148,7 +5148,7 @@ static void *lru_gen_seq_start(struct se
if (!nr_to_skip--)
return get_lruvec(memcg, nid);
}
- } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)));
+ } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL, false)));
return NULL;
}
@@ -5171,7 +5171,7 @@ static void *lru_gen_seq_next(struct seq
nid = next_memory_node(nid);
if (nid == MAX_NUMNODES) {
- memcg = mem_cgroup_iter(NULL, memcg, NULL);
+ memcg = mem_cgroup_iter(NULL, memcg, NULL, false);
if (!memcg)
return NULL;
@@ -5774,7 +5774,7 @@ static void shrink_node_memcgs(pg_data_t
struct mem_cgroup *target_memcg = sc->target_mem_cgroup;
struct mem_cgroup *memcg;
- memcg = mem_cgroup_iter(target_memcg, NULL, NULL);
+ memcg = mem_cgroup_iter(target_memcg, NULL, NULL, false);
do {
struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
unsigned long reclaimed;
@@ -5831,7 +5831,7 @@ static void shrink_node_memcgs(pg_data_t
sc->nr_scanned - scanned,
sc->nr_reclaimed - reclaimed);
- } while ((memcg = mem_cgroup_iter(target_memcg, memcg, NULL)));
+ } while ((memcg = mem_cgroup_iter(target_memcg, memcg, NULL, false)));
}
static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
@@ -6498,12 +6498,12 @@ static void kswapd_age_node(struct pglis
if (!inactive_is_low(lruvec, LRU_INACTIVE_ANON))
return;
- memcg = mem_cgroup_iter(NULL, NULL, NULL);
+ memcg = mem_cgroup_iter(NULL, NULL, NULL, false);
do {
lruvec = mem_cgroup_lruvec(memcg, pgdat);
shrink_active_list(SWAP_CLUSTER_MAX, lruvec,
sc, LRU_ACTIVE_ANON);
- memcg = mem_cgroup_iter(NULL, memcg, NULL);
+ memcg = mem_cgroup_iter(NULL, memcg, NULL, false);
} while (memcg);
}
_
Patches currently in -mm which might be from nphamcs@xxxxxxxxx are
list_lru-allows-explicit-memcg-and-numa-node-selection.patch
memcontrol-allows-mem_cgroup_iter-to-check-for-onlineness.patch
zswap-shrinks-zswap-pool-based-on-memory-pressure.patch
