[PATCH v2 2/2] mm/memcg: Consolidate mem_cgroup_resize_[memsw]_limit() functions.

Andrey Ryabinin
2017-12-20T13:21:14Z

mem_cgroup_resize_limit() and mem_cgroup_resize_memsw_limit() are almost
identical functions. Instead of having two of them, we could pass an
additional argument to mem_cgroup_resize_limit() and by using it,
consolidate all the code in a single function.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
---
mm/memcontrol.c | 61 +++++++++++++--------------------------------------------
1 file changed, 14 insertions(+), 47 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0d26db9a665d..f6253c80a5c8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2445,50 +2445,17 @@ 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)
+static bool invalid_mem_limit(struct mem_cgroup *memcg, bool memsw,
+ unsigned long limit)
{
- unsigned long usage;
- bool enlarge = false;
- int ret;
-
- 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;
-
- usage = page_counter_read(&memcg->memory);
- if (!try_to_free_mem_cgroup_pages(memcg, usage - limit,
- GFP_KERNEL, true)) {
- ret = -EBUSY;
- break;
- }
- } while (true);
-
- if (!ret && enlarge)
- memcg_oom_recover(memcg);
-
- return ret;
+ return (!memsw && limit > memcg->memsw.limit) ||
+ (memsw && limit < memcg->memory.limit);
}

-static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
- unsigned long limit)
+static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, bool memsw,
+ unsigned long limit)
{
+ struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
unsigned long usage;
bool enlarge = false;
int ret;
@@ -2500,22 +2467,22 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
}

mutex_lock(&memcg_limit_mutex);
- if (limit < memcg->memory.limit) {
+ if (invalid_mem_limit(memcg, memsw, limit)) {
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;

- usage = page_counter_read(&memcg->memsw);
+ usage = page_counter_read(counter);
if (!try_to_free_mem_cgroup_pages(memcg, usage - limit,
- GFP_KERNEL, false)) {
+ GFP_KERNEL, !memsw)) {
ret = -EBUSY;
break;
}
@@ -3193,10 +3160,10 @@ 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, false, nr_pages);
break;
case _MEMSWAP:
- ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
+ ret = mem_cgroup_resize_limit(memcg, true, nr_pages);
break;
case _KMEM:
ret = memcg_update_kmem_limit(memcg, nr_pages);
--
2.13.6