[Devel] [PATCH rh7] memcg/ub: fix limit > RESOURCE_MAX case

[Konstantin Khorenko]

Kirill, please review.

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 06/26/2015 02:59 PM, Vladimir Davydov wrote:
> A memcg limit can be greater than RESOURCE_MAX (LLONG_MAX), because it
> is rounded up to PAGE_SIZE. As a result, we will show huge numbers in
> meminfo for unlimited containers instead of the host's configuration.
> Fix this by making all limit-vs-RESOURCE_MAX comparisons use
> greater-or-equal sign.
> 
> Signed-off-by: Vladimir Davydov <vdavydov at parallels.com>
> ---
>  mm/memcontrol.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index cb153ac4567b..50eefe355d2c 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1648,7 +1648,7 @@ unsigned long mem_cgroup_total_pages(struct mem_cgroup *memcg, bool swap)
>  
>  	limit = swap ? res_counter_read_u64(&memcg->memsw, RES_LIMIT) :
>  			res_counter_read_u64(&memcg->res, RES_LIMIT);
> -	if (limit == RESOURCE_MAX)
> +	if (limit >= RESOURCE_MAX)
>  		return ULONG_MAX;
>  	return min_t(unsigned long long, ULONG_MAX, limit >> PAGE_SHIFT);
>  }
> @@ -5388,7 +5388,7 @@ void mem_cgroup_sync_beancounter(struct mem_cgroup *memcg,
>  	p->maxheld = res_counter_read_u64(&memcg->res, RES_MAX_USAGE) >> PAGE_SHIFT;
>  	p->failcnt = atomic_long_read(&memcg->mem_failcnt);
>  	lim = res_counter_read_u64(&memcg->res, RES_LIMIT);
> -	lim = lim == RESOURCE_MAX ? UB_MAXVALUE :
> +	lim = lim >= RESOURCE_MAX ? UB_MAXVALUE :
>  		min_t(unsigned long long, lim >> PAGE_SHIFT, UB_MAXVALUE);
>  	p->barrier = p->limit = lim;
>  
> @@ -5396,7 +5396,7 @@ void mem_cgroup_sync_beancounter(struct mem_cgroup *memcg,
>  	k->maxheld = res_counter_read_u64(&memcg->kmem, RES_MAX_USAGE);
>  	k->failcnt = res_counter_read_u64(&memcg->kmem, RES_FAILCNT);
>  	lim = res_counter_read_u64(&memcg->kmem, RES_LIMIT);
> -	lim = lim == RESOURCE_MAX ? UB_MAXVALUE :
> +	lim = lim >= RESOURCE_MAX ? UB_MAXVALUE :
>  		min_t(unsigned long long, lim, UB_MAXVALUE);
>  	k->barrier = k->limit = lim;
>  
> @@ -5410,7 +5410,7 @@ void mem_cgroup_sync_beancounter(struct mem_cgroup *memcg,
>  	maxheld = memcg->swap_max >> PAGE_SHIFT;
>  	s->failcnt = atomic_long_read(&memcg->swap_failcnt);
>  	lim = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
> -	lim = lim == RESOURCE_MAX ? UB_MAXVALUE :
> +	lim = lim >= RESOURCE_MAX ? UB_MAXVALUE :
>  		min_t(unsigned long long, lim >> PAGE_SHIFT, UB_MAXVALUE);
>  	if (lim != UB_MAXVALUE)
>  		lim -= p->limit;
> @@ -5425,7 +5425,7 @@ void mem_cgroup_sync_beancounter(struct mem_cgroup *memcg,
>  	o->maxheld = res_counter_read_u64(&memcg->memsw, RES_MAX_USAGE) >> PAGE_SHIFT;
>  	o->failcnt = atomic_long_read(&memcg->oom_kill_cnt);
>  	lim = memcg->oom_guarantee;
> -	lim = lim == RESOURCE_MAX ? UB_MAXVALUE :
> +	lim = lim >= RESOURCE_MAX ? UB_MAXVALUE :
>  		min_t(unsigned long long, lim >> PAGE_SHIFT, UB_MAXVALUE);
>  	o->barrier = o->limit = lim;
>  }
> @@ -5486,7 +5486,7 @@ int mem_cgroup_apply_beancounter(struct mem_cgroup *memcg,
>  
>  	if (mem != mem_old) {
>  		/* first, reset memsw limit since it cannot be < mem limit */
> -		if (memsw_old != RESOURCE_MAX) {
> +		if (memsw_old < RESOURCE_MAX) {
>  			memsw_old = RESOURCE_MAX;
>  			ret = mem_cgroup_resize_memsw_limit(memcg, memsw_old);
>  			if (ret)
>