[PATCH mmotm 2/2] memcg: allow mem.limit bigger than memsw.limit iff unlimited

[Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>]

Now users cannot set mem.limit bigger than memsw.limit.
This patch allows mem.limit bigger than memsw.limit iff mem.limit==unlimited.

By this, users can set memsw.limit without setting mem.limit.
I think it's usefull if users want to limit memsw only.
They must set mem.limit first and memsw.limit to the same value now for this purpose.
They can save the first step by this patch.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
---
 mm/memcontrol.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6629ed2..2b63cb1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1742,11 +1742,12 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
 		/*
 		 * Rather than hide all in some function, I do this in
 		 * open coded manner. You see what this really does.
-		 * We have to guarantee mem->res.limit < mem->memsw.limit.
+		 * We have to guarantee mem->res.limit < mem->memsw.limit,
+		 * except for mem->res.limit == RESOURCE_MAX(unlimited) case.
 		 */
 		mutex_lock(&set_limit_mutex);
 		memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
-		if (memswlimit < val) {
+		if (val != RESOURCE_MAX && memswlimit < val) {
 			ret = -EINVAL;
 			mutex_unlock(&set_limit_mutex);
 			break;
@@ -1789,11 +1790,12 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
 		/*
 		 * Rather than hide all in some function, I do this in
 		 * open coded manner. You see what this really does.
-		 * We have to guarantee mem->res.limit < mem->memsw.limit.
+		 * We have to guarantee mem->res.limit < mem->memsw.limit,
+		 * except for mem->res.limit == RESOURCE_MAX(unlimited) case.
 		 */
 		mutex_lock(&set_limit_mutex);
 		memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
-		if (memlimit > val) {
+		if (memlimit != RESOURCE_MAX && memlimit > val) {
 			ret = -EINVAL;
 			mutex_unlock(&set_limit_mutex);
 			break;

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