KAMEZAWA Hiroyuki wrote:
> Now, when we remove memcg, we call force_empty().
> This call drops all page_cgroup accounting in this mem_cgroup but doesn't
> drop pages. So, some page caches can be remaind as "not accounted" memory
> while they are alive. (because it's accounted only when add_to_page_cache())
> If they are not used by other memcg, global LRU will drop them.
>
> This patch tries to drop pages at removing memcg. Other memcg will
> reload and re-account page caches. (but this will increase page-in
> after rmdir().)
>
The approach seems fair, but I am not sure about the overhead of flushing out
cached pages. Might well be worth it.
> Consideration: should we recharge all pages to the parent at last ?
> But it's not precise logic.
>
We should look into this - I should send out the multi-hierarchy patches soon.
We should discuss this after that.
> Changelog v1->v2
> - renamed res_counter_empty().
>
> Signed-off-by: KAMEZAWA Hiroyuki <[EMAIL PROTECTED]>
>
> ---
> include/linux/res_counter.h | 11 +++++++++++
> mm/memcontrol.c | 19 +++++++++++++++++++
> 2 files changed, 30 insertions(+)
>
> Index: mm-2.6.26-rc2-mm1/mm/memcontrol.c
> ===================================================================
> --- mm-2.6.26-rc2-mm1.orig/mm/memcontrol.c
> +++ mm-2.6.26-rc2-mm1/mm/memcontrol.c
> @@ -791,6 +791,20 @@ int mem_cgroup_shrink_usage(struct mm_st
> return 0;
> }
>
> +
> +static void mem_cgroup_drop_all_pages(struct mem_cgroup *mem)
> +{
> + int progress;
> + while (!res_counter_empty(&mem->res)) {
> + progress = try_to_free_mem_cgroup_pages(mem,
> + GFP_HIGHUSER_MOVABLE);
> + if (!progress) /* we did as much as possible */
> + break;
> + cond_resched();
> + }
> + return;
> +}
> +
> /*
> * This routine traverse page_cgroup in given list and drop them all.
> * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
> @@ -848,7 +862,12 @@ static int mem_cgroup_force_empty(struct
> if (mem_cgroup_subsys.disabled)
> return 0;
>
> + if (atomic_read(&mem->css.cgroup->count) > 0)
> + goto out;
> +
> css_get(&mem->css);
> + /* drop pages as much as possible */
> + mem_cgroup_drop_all_pages(mem);
> /*
> * page reclaim code (kswapd etc..) will move pages between
> * active_list <-> inactive_list while we don't take a lock.
> Index: mm-2.6.26-rc2-mm1/include/linux/res_counter.h
> ===================================================================
> --- mm-2.6.26-rc2-mm1.orig/include/linux/res_counter.h
> +++ mm-2.6.26-rc2-mm1/include/linux/res_counter.h
> @@ -153,4 +153,15 @@ static inline void res_counter_reset_fai
> cnt->failcnt = 0;
> spin_unlock_irqrestore(&cnt->lock, flags);
> }
> +/* returns 0 if usage is 0. */
> +static inline int res_counter_empty(struct res_counter *cnt)
> +{
> + unsigned long flags;
> + int ret;
> +
> + spin_lock_irqsave(&cnt->lock, flags);
> + ret = (cnt->usage == 0) ? 0 : 1;
> + spin_unlock_irqrestore(&cnt->lock, flags);
> + return ret;
> +}
> #endif
>
--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
_______________________________________________
Containers mailing list
[EMAIL PROTECTED]
https://lists.linux-foundation.org/mailman/listinfo/containers
_______________________________________________
Devel mailing list
[email protected]
https://openvz.org/mailman/listinfo/devel
