[patch 1/2] mm: page_counter: pull "-1" handling out of page_counter_memparse()

Johannes Weiner
2015-01-20T15:31:54Z

The unified hierarchy interface for memory cgroups will no longer use
"-1" to mean maximum possible resource value. In preparation for
this, make the string an argument and let the caller supply it.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
---
include/linux/page_counter.h | 3 ++-
mm/hugetlb_cgroup.c | 2 +-
mm/memcontrol.c | 4 ++--
mm/page_counter.c | 7 ++++---
net/ipv4/tcp_memcontrol.c | 2 +-
5 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h
index 955421575d16..17fa4f8de3a6 100644
--- a/include/linux/page_counter.h
+++ b/include/linux/page_counter.h
@@ -41,7 +41,8 @@ int page_counter_try_charge(struct page_counter *counter,
struct page_counter **fail);
void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
int page_counter_limit(struct page_counter *counter, unsigned long limit);
-int page_counter_memparse(const char *buf, unsigned long *nr_pages);
+int page_counter_memparse(const char *buf, const char *max,
+ unsigned long *nr_pages);

static inline void page_counter_reset_watermark(struct page_counter *counter)
{
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 037e1c00a5b7..6e0057439a46 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -279,7 +279,7 @@ static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
return -EINVAL;

buf = strstrip(buf);
- ret = page_counter_memparse(buf, &nr_pages);
+ ret = page_counter_memparse(buf, "-1", &nr_pages);
if (ret)
return ret;

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 05ad91cda22c..a3592a756ad9 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3442,7 +3442,7 @@ static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
int ret;

buf = strstrip(buf);
- ret = page_counter_memparse(buf, &nr_pages);
+ ret = page_counter_memparse(buf, "-1", &nr_pages);
if (ret)
return ret;

@@ -3814,7 +3814,7 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
unsigned long usage;
int i, size, ret;

- ret = page_counter_memparse(args, &threshold);
+ ret = page_counter_memparse(args, "-1", &threshold);
if (ret)
return ret;

diff --git a/mm/page_counter.c b/mm/page_counter.c
index a009574fbba9..11b4beda14ba 100644
--- a/mm/page_counter.c
+++ b/mm/page_counter.c
@@ -166,18 +166,19 @@ int page_counter_limit(struct page_counter *counter, unsigned long limit)
/**
* page_counter_memparse - memparse() for page counter limits
* @buf: string to parse
+ * @max: string meaning maximum possible value
* @nr_pages: returns the result in number of pages
*
* Returns -EINVAL, or 0 and @nr_pages on success. @nr_pages will be
* limited to %PAGE_COUNTER_MAX.
*/
-int page_counter_memparse(const char *buf, unsigned long *nr_pages)
+int page_counter_memparse(const char *buf, const char *max,
+ unsigned long *nr_pages)
{
- char unlimited[] = "-1";
char *end;
u64 bytes;

- if (!strncmp(buf, unlimited, sizeof(unlimited))) {
+ if (!strcmp(buf, max)) {
*nr_pages = PAGE_COUNTER_MAX;
return 0;
}
diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c
index 272327134a1b..c2a75c6957a1 100644
--- a/net/ipv4/tcp_memcontrol.c
+++ b/net/ipv4/tcp_memcontrol.c
@@ -120,7 +120,7 @@ static ssize_t tcp_cgroup_write(struct kernfs_open_file *of,
switch (of_cft(of)->private) {
case RES_LIMIT:
/* see memcontrol.c */
- ret = page_counter_memparse(buf, &nr_pages);
+ ret = page_counter_memparse(buf, "-1", &nr_pages);
if (ret)
break;
mutex_lock(&tcp_limit_mutex);
--
2.2.0