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Commit c054a78c authored by Yu Zhao's avatar Yu Zhao Committed by Linus Torvalds
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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.

Link: http://lkml.kernel.org/r/20180108224238.14583-1-yuzhao@google.com


Signed-off-by: default avatarYu Zhao <yuzhao@google.com>
Acked-by: default avatarVladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9c3760eb

mm/memcontrol.c

+17 −60
Original line number Diff line number Diff line
@@ -2461,13 +2461,15 @@ 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
@@ -2477,58 +2479,7 @@ 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)) {
@@ -2537,22 +2488,28 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, 
		}



		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--;
@@ -3014,10 +2971,10 @@ 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);