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

From: Andrey Ryabinin
Date: Wed Dec 20 2017 - 05:21:52 EST


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@xxxxxxxxxxxxx>
---
mm/memcontrol.c | 77 +++++++++++++--------------------------------------------
1 file changed, 17 insertions(+), 60 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 09ee052cf684..b263500626fe 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2459,9 +2459,17 @@ 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,
+static bool invalid_mem_limit(struct mem_cgroup *memcg, bool memsw,
+ unsigned long limit)
+{
+ return (!memsw && limit > memcg->memsw.limit) ||
+ (memsw && limit < memcg->memory.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 curusage;
unsigned long oldusage;
bool enlarge = false;
@@ -2476,7 +2484,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
retry_count = MEM_CGROUP_RECLAIM_RETRIES *
mem_cgroup_count_children(memcg);

- curusage = oldusage = page_counter_read(&memcg->memory);
+ curusage = oldusage = page_counter_read(counter);

do {
if (signal_pending(current)) {
@@ -2485,75 +2493,24 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
}

mutex_lock(&memcg_limit_mutex);
- if (limit > memcg->memsw.limit) {
+ if (invalid_mem_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, curusage - limit,
- 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);
-
- curusage = oldusage = page_counter_read(&memcg->memsw);
-
- do {
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
-
- mutex_lock(&memcg_limit_mutex);
- if (limit < memcg->memory.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;

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

- curusage = page_counter_read(&memcg->memsw);
+ curusage = page_counter_read(counter);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
@@ -3233,10 +3190,10 @@ 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