The patch titled
Subject: mm: memcontrol: switch to rstat fix
has been added to the -mm tree. Its filename is
mm-memcontrol-switch-to-rstat-fix-2.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-switch-to-rstat-fix-2.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-switch-to-rstat-fix-2.patch
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------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm: memcontrol: switch to rstat fix
Fix a sleep in atomic section problem: wb_writeback() takes a spinlock and
calls wb_over_bg_thresh() -> mem_cgroup_wb_stats, but the regular rstat
flushing function called from in there does lockbreaking and may sleep.
Switch to the atomic variant, cgroup_rstat_irqsafe().
To be consistent with other memcg flush calls, but without adding another
memcg wrapper, inline and drop memcg_flush_vmstats() instead.
Link: https://lkml.kernel.org/r/20210315234100.64307-1-hannes@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Acked-by: Balbir Singh <bsingharora@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Michal Koutny <mkoutny@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)
--- a/mm/memcontrol.c~mm-memcontrol-switch-to-rstat-fix-2
+++ a/mm/memcontrol.c
@@ -757,11 +757,6 @@ mem_cgroup_largest_soft_limit_node(struc
return mz;
}
-static void memcg_flush_vmstats(struct mem_cgroup *memcg)
-{
- cgroup_rstat_flush(memcg->css.cgroup);
-}
-
/**
* __mod_memcg_state - update cgroup memory statistics
* @memcg: the memory cgroup
@@ -1572,7 +1567,7 @@ static char *memory_stat_format(struct m
*
* Current memory state:
*/
- memcg_flush_vmstats(memcg);
+ cgroup_rstat_flush(memcg->css.cgroup);
for (i = 0; i < ARRAY_SIZE(memory_stats); i++) {
u64 size;
@@ -3523,7 +3518,7 @@ static unsigned long mem_cgroup_usage(st
unsigned long val;
if (mem_cgroup_is_root(memcg)) {
- memcg_flush_vmstats(memcg);
+ cgroup_rstat_flush(memcg->css.cgroup);
val = memcg_page_state(memcg, NR_FILE_PAGES) +
memcg_page_state(memcg, NR_ANON_MAPPED);
if (swap)
@@ -3925,7 +3920,7 @@ static int memcg_numa_stat_show(struct s
int nid;
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
- memcg_flush_vmstats(memcg);
+ cgroup_rstat_flush(memcg->css.cgroup);
for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
seq_printf(m, "%s=%lu", stat->name,
@@ -3997,7 +3992,7 @@ static int memcg_stat_show(struct seq_fi
BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
- memcg_flush_vmstats(memcg);
+ cgroup_rstat_flush(memcg->css.cgroup);
for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
unsigned long nr;
@@ -4500,7 +4495,7 @@ void mem_cgroup_wb_stats(struct bdi_writ
struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
struct mem_cgroup *parent;
- memcg_flush_vmstats(memcg);
+ cgroup_rstat_flush_irqsafe(memcg->css.cgroup);
*pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
*pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
mm-page-writeback-simplify-memcg-handling-in-test_clear_page_writeback.patch
mm-memcontrol-fix-cpuhotplug-statistics-flushing.patch
mm-memcontrol-kill-mem_cgroup_nodeinfo.patch
mm-memcontrol-privatize-memcg_page_state-query-functions.patch
cgroup-rstat-support-cgroup1.patch
cgroup-rstat-punt-root-level-optimization-to-individual-controllers.patch
mm-memcontrol-switch-to-rstat.patch
mm-memcontrol-switch-to-rstat-fix-2.patch
mm-memcontrol-consolidate-lruvec-stat-flushing.patch
kselftests-cgroup-update-kmem-test-for-new-vmstat-implementation.patch
