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Message-Id: <20180108224238.14583-1-yuzhao@google.com>
Date: Mon, 8 Jan 2018 14:42:38 -0800
From: Yu Zhao <yuzhao@...gle.com>
To: Johannes Weiner <hannes@...xchg.org>,
Michal Hocko <mhocko@...nel.org>,
Vladimir Davydov <vdavydov.dev@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>, cgroups@...r.kernel.org,
linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Yu Zhao <yuzhao@...gle.com>
Subject: [PATCH v4] memcg: refactor mem_cgroup_resize_limit()
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@...gle.com>
Acked-by: Vladimir Davydov <vdavydov.dev@...il.com>
Acked-by: Michal Hocko <mhocko@...e.com>
---
mm/memcontrol.c | 77 +++++++++++++--------------------------------------------
1 file changed, 17 insertions(+), 60 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ac2ffd5e02b9..9af733fa9381 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2467,13 +2467,15 @@ 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 limits_invariant;
+ struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
/*
* For keeping hierarchical_reclaim simple, how long we should retry
@@ -2483,7 +2485,7 @@ 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);
+ oldusage = page_counter_read(counter);
do {
if (signal_pending(current)) {
@@ -2492,73 +2494,28 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
}
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);
-
- do {
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
-
- mutex_lock(&memcg_limit_mutex);
- if (limit < memcg->memory.limit) {
+ /*
+ * Make sure that the new limit (memsw or memory limit) doesn't
+ * break our basic invariant rule memory.limit <= memsw.limit.
+ */
+ limits_invariant = memsw ? limit >= memcg->memory.limit :
+ limit <= memcg->memsw.limit;
+ if (!limits_invariant) {
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--;
@@ -3020,10 +2977,10 @@ 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);
--
2.16.0.rc0.223.g4a4ac83678-goog
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