From 72a9e0c3d4f8daca9f7dc389edbc1013d7c0d808 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nikola=20Forr=C3=B3?= <nforro@redhat.com>
Date: Fri, 8 Apr 2016 17:00:19 +0200
Subject: [PATCH] api.c: fix order of memory subsystem parameters generated by
 cgsnapshot
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Order of parameters usually doesn't matter, but that's not the case with
memory.limit_in_bytes and memory.memsw.limit_in_bytes. When the latter
is first in the list of parameters, the resulting configuration is not
loadable with cgconfigparser.

This happens because when a cgroup is created, both memory.limit_in_bytes
and memory.memsw.limit_in_bytes parameters are initialized to highest
value possible (RESOURCE_MAX). And because memory.memsw.limit_in_bytes
must be always higher or equal to memory.limit_in_bytes, it's impossible
to change its value first.

Make sure that after constructing parameter list of memory subsystem,
the mentioned parameters are in correct order.

Signed-off-by: Nikola Forró <nforro@redhat.com>
---
 src/api.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/src/api.c b/src/api.c
index 0bf0615..f5da553 100644
--- a/src/api.c
+++ b/src/api.c
@@ -2651,6 +2651,30 @@ int cgroup_get_cgroup(struct cgroup *cgroup)
 			}
 		}
 		closedir(dir);
+
+		if (! strcmp(cgc->name, "memory")) {
+			/*
+			 * Make sure that memory.limit_in_bytes is placed before
+			 * memory.memsw.limit_in_bytes in the list of values
+			 */
+			int memsw_limit = -1;
+			int mem_limit = -1;
+
+			for (j = 0; j < cgc->index; j++) {
+				if (! strcmp(cgc->values[j]->name,
+								"memory.memsw.limit_in_bytes"))
+					memsw_limit = j;
+				else if (! strcmp(cgc->values[j]->name,
+									"memory.limit_in_bytes"))
+					mem_limit = j;
+			}
+
+			if (memsw_limit >= 0 && memsw_limit < mem_limit) {
+				struct control_value *val = cgc->values[memsw_limit];
+				cgc->values[memsw_limit] = cgc->values[mem_limit];
+				cgc->values[mem_limit] = val;
+			}
+		}
 	}
 
 	/* Check if the group really exists or not */
-- 
2.4.11

