[PATCH v2] memcg: refactor mem_cgroup_resize_limit()

Yu Zhao
2017-06-04T20:04:55Z

mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() have
identical logics. Refactor code so we don't need to keep two pieces
of code that does same thing.

Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
---
Changelog since v1:
* minor style change

mm/memcontrol.c | 73 ++++++++++-----------------------------------------------
1 file changed, 13 insertions(+), 60 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 94172089f52f..08a97a381b2a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2422,13 +2422,15 @@ static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
static DEFINE_MUTEX(memcg_limit_mutex);

static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
- unsigned long limit)
+ unsigned long limit, bool memsw)
{
unsigned long curusage;
unsigned long oldusage;
bool enlarge = false;
int retry_count;
int ret;
+ bool inverted;
+ struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;

/*
* For keeping hierarchical_reclaim simple, how long we should retry
@@ -2438,58 +2440,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
retry_count = MEM_CGROUP_RECLAIM_RETRIES *
mem_cgroup_count_children(memcg);

- oldusage = page_counter_read(&memcg->memory);
-
- do {
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
-
- mutex_lock(&memcg_limit_mutex);
- if (limit > memcg->memsw.limit) {
- mutex_unlock(&memcg_limit_mutex);
- ret = -EINVAL;
- break;
- }
- if (limit > memcg->memory.limit)
- enlarge = true;
- ret = page_counter_limit(&memcg->memory, limit);
- mutex_unlock(&memcg_limit_mutex);
-
- if (!ret)
- break;
-
- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
-
- curusage = page_counter_read(&memcg->memory);
- /* Usage is reduced ? */
- if (curusage >= oldusage)
- retry_count--;
- else
- oldusage = curusage;
- } while (retry_count);
-
- if (!ret && enlarge)
- memcg_oom_recover(memcg);
-
- return ret;
-}
-
-static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
- unsigned long limit)
-{
- unsigned long curusage;
- unsigned long oldusage;
- bool enlarge = false;
- int retry_count;
- int ret;
-
- /* see mem_cgroup_resize_res_limit */
- retry_count = MEM_CGROUP_RECLAIM_RETRIES *
- mem_cgroup_count_children(memcg);
-
- oldusage = page_counter_read(&memcg->memsw);
+ oldusage = page_counter_read(counter);

do {
if (signal_pending(current)) {
@@ -2498,22 +2449,24 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
}

mutex_lock(&memcg_limit_mutex);
- if (limit < memcg->memory.limit) {
+ inverted = memsw ? limit < memcg->memory.limit :
+ limit > memcg->memsw.limit;
+ if (inverted)
mutex_unlock(&memcg_limit_mutex);
ret = -EINVAL;
break;
}
- if (limit > memcg->memsw.limit)
+ if (limit > counter->limit)
enlarge = true;
- ret = page_counter_limit(&memcg->memsw, limit);
+ ret = page_counter_limit(counter, limit);
mutex_unlock(&memcg_limit_mutex);

if (!ret)
break;

- try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
+ try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, !memsw);

- curusage = page_counter_read(&memcg->memsw);
+ curusage = page_counter_read(counter);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
@@ -2975,10 +2928,10 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
}
switch (MEMFILE_TYPE(of_cft(of)->private)) {
case _MEM:
- ret = mem_cgroup_resize_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, false);
break;
case _MEMSWAP:
- ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, nr_pages, true);
break;
case _KMEM:
ret = memcg_update_kmem_limit(memcg, nr_pages);
--
2.13.0.506.g27d5fe0cd-goog