KAMEZAWA Hiroyuki wrote:
> This patch adds an interface "memory.force_reclaim".
> Any write to this file will drop all charges in this cgroup if
> there is no task under.
>
> %echo 1 > /....../memory.force_reclaim
>
Looks like a good name, do you think system administrators would
find force_empty more useful?
> will drop all charges of memory cgroup if cgroup's tasks is empty.
>
> This is useful to invoke rmdir() against memory cgroup successfully.
>
> Tested and worked well on x86_64/fake-NUMA system.
>
> Changelog:
> - added a new interface force_relcaim.
> - changes spin_lock to spin_lock_irqsave().
>
>
> Signed-off-by: KAMEZAWA Hiroyuki <[EMAIL PROTECTED]>
>
>
> mm/memcontrol.c | 79
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 79 insertions(+)
>
> Index: devel-2.6.23-rc8-mm2/mm/memcontrol.c
> ===================================================================
> --- devel-2.6.23-rc8-mm2.orig/mm/memcontrol.c
> +++ devel-2.6.23-rc8-mm2/mm/memcontrol.c
> @@ -507,6 +507,55 @@ retry:
> return;
> }
>
> +static void
> +mem_cgroup_force_reclaim_list(struct mem_cgroup *mem, struct list_head *list)
> +{
> + struct page_cgroup *pc;
> + struct page *page;
> + int count = SWAP_CLUSTER_MAX;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&mem->lru_lock, flags);
> +
Can we add a comment here stating that this routine reclaims just
from the per cgroup LRU and not from the zone LRU to which the
page belongs.
> + while (!list_empty(list)) {
> + pc = list_entry(list->prev, struct page_cgroup, lru);
> + page = pc->page;
> + if (clear_page_cgroup(page, pc) == pc) {
> + css_put(&mem->css);
> + res_counter_uncharge(&mem->res, PAGE_SIZE);
> + list_del_init(&pc->lru);
> + kfree(pc);
> + } else
> + count = 1; /* race? ...do relax */
> +
> + if (--count == 0) {
> + spin_unlock_irqrestore(&mem->lru_lock, flags);
> + cond_resched();
> + spin_lock_irqsave(&mem->lru_lock, flags);
> + count = SWAP_CLUSTER_MAX;
> + }
> + }
> + spin_unlock_irqrestore(&mem->lru_lock, flags);
> +}
> +
> +int mem_cgroup_force_reclaim(struct mem_cgroup *mem)
> +{
> + int ret = -EBUSY;
> + while (!list_empty(&mem->active_list) ||
> + !list_empty(&mem->inactive_list)) {
> + if (atomic_read(&mem->css.cgroup->count) > 0)
> + goto out;
> + mem_cgroup_force_reclaim_list(mem, &mem->active_list);
> + mem_cgroup_force_reclaim_list(mem, &mem->inactive_list);
> + }
> + ret = 0;
> +out:
> + css_put(&mem->css);
We do a css_put() here, did we do a css_get() anywhere?
> + return ret;
> +}
> +
> +
> +
> int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
> {
> *tmp = memparse(buf, &buf);
> @@ -592,6 +641,31 @@ static ssize_t mem_control_type_read(str
> ppos, buf, s - buf);
> }
>
> +
> +static ssize_t mem_force_reclaim_write(struct cgroup *cont,
> + struct cftype *cft, struct file *file,
> + const char __user *userbuf,
> + size_t nbytes, loff_t *ppos)
> +{
> + struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
> + int ret;
> + ret = mem_cgroup_force_reclaim(mem);
> + if (!ret)
> + ret = nbytes;
> + return ret;
> +}
> +
> +static ssize_t mem_force_reclaim_read(struct cgroup *cont,
> + struct cftype *cft,
> + struct file *file, char __user *userbuf,
> + size_t nbytes, loff_t *ppos)
> +{
> + char buf[2] = "0";
> + return simple_read_from_buffer((void __user *)userbuf, nbytes,
> + ppos, buf, strlen(buf));
> +}
> +
> +
> static struct cftype mem_cgroup_files[] = {
> {
> .name = "usage_in_bytes",
> @@ -614,6 +688,11 @@ static struct cftype mem_cgroup_files[]
> .write = mem_control_type_write,
> .read = mem_control_type_read,
> },
> + {
> + .name = "force_reclaim",
> + .write = mem_force_reclaim_write,
> + .read = mem_force_reclaim_read,
> + },
> };
>
> static struct mem_cgroup init_mem_cgroup;
>
>
--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
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