Add as_usage_in_bytes and as_limit_in_bytes interfaces. These provide
control over the total address space that the processes combined together
in the cgroup can grow upto. This functionality is analogous to
the RLIMIT_AS function of the getrlimit(2) and setrlimit(2) calls.
A as_res resource counter is added to the mem_cgroup structure. The
as_res counter handles all the accounting associated with the virtual
address space accounting and control of cgroups.

Signed-off-by: Balbir Singh
---

init/Kconfig | 10 ++++++++++
mm/memcontrol.c | 39 +++++++++++++++++++++++++++++++++++++++
2 files changed, 49 insertions(+)

diff -puN mm/memcontrol.c~memory-controller-virtual-address-space-control-user-interface mm/memcontrol.c
--- linux-2.6.25-rc5/mm/memcontrol.c~memory-controller-virtual-address-space-control-user-interface 2008-03-26 16:00:42.000000000 +0530
+++ linux-2.6.25-rc5-balbir/mm/memcontrol.c 2008-03-26 16:07:56.000000000 +0530
@@ -127,6 +127,12 @@ struct mem_cgroup {
* the counter to account for memory usage
*/
struct res_counter res;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_AS
+ /*
+ * Address space limits
+ */
+ struct res_counter as_res;
+#endif
/*
* Per cgroup active and inactive list, similar to the
* per zone LRU lists.
@@ -870,6 +876,23 @@ static ssize_t mem_cgroup_write(struct c
mem_cgroup_write_strategy);
}

+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_AS
+static u64 mem_cgroup_as_read(struct cgroup *cont, struct cftype *cft)
+{
+ return res_counter_read_u64(&mem_cgroup_from_cont(cont)->as_res,
+ cft->private);
+}
+
+static ssize_t mem_cgroup_as_write(struct cgroup *cont, struct cftype *cft,
+ struct file *file, const char __user *userbuf,
+ size_t nbytes, loff_t *ppos)
+{
+ return res_counter_write(&mem_cgroup_from_cont(cont)->as_res,
+ cft->private, userbuf, nbytes, ppos,
+ mem_cgroup_write_strategy);
+}
+#endif
+
static ssize_t mem_force_empty_write(struct cgroup *cont,
struct cftype *cft, struct file *file,
const char __user *userbuf,
@@ -943,6 +966,19 @@ static struct cftype mem_cgroup_files[]
.name = "stat",
.read_map = mem_control_stat_show,
},
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_AS
+ {
+ .name = "as_usage_in_bytes",
+ .private = RES_USAGE,
+ .read_u64 = mem_cgroup_as_read,
+ },
+ {
+ .name = "as_limit_in_bytes",
+ .private = RES_LIMIT,
+ .write = mem_cgroup_as_write,
+ .read_u64 = mem_cgroup_as_read,
+ },
+#endif
};

static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
@@ -999,6 +1035,9 @@ mem_cgroup_create(struct cgroup_subsys *
return ERR_PTR(-ENOMEM);

res_counter_init(&mem->res);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_AS
+ res_counter_init(&mem->as_res);
+#endif

memset(&mem->info, 0, sizeof(mem->info));

diff -puN include/linux/memcontrol.h~memory-controller-virtual-address-space-control-user-interface include/linux/memcontrol.h
diff -puN init/Kconfig~memory-controller-virtual-address-space-control-user-interface init/Kconfig
--- linux-2.6.25-rc5/init/Kconfig~memory-controller-virtual-address-space-control-user-interface 2008-03-26 16:06:34.000000000 +0530
+++ linux-2.6.25-rc5-balbir/init/Kconfig 2008-03-26 16:13:06.000000000 +0530
@@ -379,6 +379,16 @@ config CGROUP_MEM_RES_CTLR
Only enable when you're ok with these trade offs and really
sure you need the memory resource controller.

+confg CGROUP_MEM_RES_CTLR_AS
+ bool "Virtual Address Space Controller for Control Groups"
+ depends on CGROUP_MEM_RES_CTLR
+ help
+ Provides control over the maximum amount of virtual address space
+ that can be consumed by the tasks in the cgroup. Setting a reasonable
+ address limit will allow applications to fail more gracefully and
+ avoid forceful reclaim or OOM when a cgroup exceeds it's memory
+ limit.
+
config SYSFS_DEPRECATED
bool

_

--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
--
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