[PATCH mm v5 RESEND 3/4] mm: move cgroup high memory limit setting into struct page_counter

Jakub Kicinski
2020-05-21T00:24:20Z

High memory limit is currently recorded directly in
struct mem_cgroup. We are about to add a high limit
for swap, move the field to struct page_counter and
add some helpers.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
--
v5: make page_counter_set_high() a static inline in the header
v4: new patch
---
include/linux/memcontrol.h | 3 ---
include/linux/page_counter.h | 13 +++++++++++++
mm/memcontrol.c | 17 +++++++++--------
3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e0bcef180672..d726867d8af9 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -206,9 +206,6 @@ struct mem_cgroup {
struct page_counter kmem;
struct page_counter tcpmem;

- /* Upper bound of normal memory consumption range */
- unsigned long high;
-
/* Range enforcement for interrupt charges */
struct work_struct high_work;

diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h
index bab7e57f659b..6a89ff948412 100644
--- a/include/linux/page_counter.h
+++ b/include/linux/page_counter.h
@@ -10,6 +10,7 @@ struct page_counter {
atomic_long_t usage;
unsigned long min;
unsigned long low;
+ unsigned long high;
unsigned long max;
struct page_counter *parent;

@@ -55,6 +56,13 @@ bool page_counter_try_charge(struct page_counter *counter,
void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages);
void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages);
+
+static inline void page_counter_set_high(struct page_counter *counter,
+ unsigned long nr_pages)
+{
+ WRITE_ONCE(counter->high, nr_pages);
+}
+
int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages);
int page_counter_memparse(const char *buf, const char *max,
unsigned long *nr_pages);
@@ -64,4 +72,9 @@ static inline void page_counter_reset_watermark(struct page_counter *counter)
counter->watermark = page_counter_read(counter);
}

+static inline bool page_counter_is_above_high(struct page_counter *counter)
+{
+ return page_counter_read(counter) > READ_ONCE(counter->high);
+}
+
#endif /* _LINUX_PAGE_COUNTER_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index dd8605a9137a..d4b7bc80aa38 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2233,7 +2233,7 @@ static void reclaim_high(struct mem_cgroup *memcg,
gfp_t gfp_mask)
{
do {
- if (page_counter_read(&memcg->memory) <= READ_ONCE(memcg->high))
+ if (!page_counter_is_above_high(&memcg->memory))
continue;
memcg_memory_event(memcg, MEMCG_HIGH);
try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true);
@@ -2326,7 +2326,7 @@ static u64 mem_find_max_overage(struct mem_cgroup *memcg)

do {
overage = calculate_overage(page_counter_read(&memcg->memory),
- READ_ONCE(memcg->high));
+ READ_ONCE(memcg->memory.high));
max_overage = max(overage, max_overage);
} while ((memcg = parent_mem_cgroup(memcg)) &&
!mem_cgroup_is_root(memcg));
@@ -2585,7 +2585,7 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
* reclaim, the cost of mismatch is negligible.
*/
do {
- if (page_counter_read(&memcg->memory) > READ_ONCE(memcg->high)) {
+ if (page_counter_is_above_high(&memcg->memory)) {
/* Don't bother a random interrupted task */
if (in_interrupt()) {
schedule_work(&memcg->high_work);
@@ -4286,7 +4286,7 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,

while ((parent = parent_mem_cgroup(memcg))) {
unsigned long ceiling = min(READ_ONCE(memcg->memory.max),
- READ_ONCE(memcg->high));
+ READ_ONCE(memcg->memory.high));
unsigned long used = page_counter_read(&memcg->memory);

*pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
@@ -5011,7 +5011,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
if (IS_ERR(memcg))
return ERR_CAST(memcg);

- WRITE_ONCE(memcg->high, PAGE_COUNTER_MAX);
+ page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
memcg->soft_limit = PAGE_COUNTER_MAX;
if (parent) {
memcg->swappiness = mem_cgroup_swappiness(parent);
@@ -5164,7 +5164,7 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX);
page_counter_set_min(&memcg->memory, 0);
page_counter_set_low(&memcg->memory, 0);
- WRITE_ONCE(memcg->high, PAGE_COUNTER_MAX);
+ page_counter_set_high(&memcg->memory, PAGE_COUNTER_MAX);
memcg->soft_limit = PAGE_COUNTER_MAX;
memcg_wb_domain_size_changed(memcg);
}
@@ -5984,7 +5984,8 @@ static ssize_t memory_low_write(struct kernfs_open_file *of,

static int memory_high_show(struct seq_file *m, void *v)
{
- return seq_puts_memcg_tunable(m, READ_ONCE(mem_cgroup_from_seq(m)->high));
+ return seq_puts_memcg_tunable(m,
+ READ_ONCE(mem_cgroup_from_seq(m)->memory.high));
}

static ssize_t memory_high_write(struct kernfs_open_file *of,
@@ -6001,7 +6002,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
if (err)
return err;

- WRITE_ONCE(memcg->high, high);
+ page_counter_set_high(&memcg->memory, high);

for (;;) {
unsigned long nr_pages = page_counter_read(&memcg->memory);
--
2.25.4