Re: [PATCH 2/2] memcg: clean up force_empty_list() return value check

[Kamezawa Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>]

(2012/06/22 5:13), Andrew Morton wrote:
> On Thu, 21 Jun 2012 17:17:01 +0900
> Kamezawa Hiroyuki<kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>  wrote:
>
>> Now, mem_cgroup_force_empty_list() just returns 0 or -EBUSY and
>> -EBUSY is just indicating 'you need to retry.'.
>> This patch makes mem_cgroup_force_empty_list() as boolean function and
>> make the logic simpler.
>>
>
> For some reason I'm having trouble applying these patches - many
> rejects, need to massage it in by hand.
>

Oh, sorry. Is it space breakage or some ? (I had mailer troubles in the last week..)
Or, maybe, my tree/patch queue was too old.
I'll rebased to new -mm tree when I post new patch.

>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -3797,7 +3797,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
>>     * This routine traverse page_cgroup in given list and drop them all.
>>     * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
>>     */
>> -static int mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
>> +static bool mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
>>    				int node, int zid, enum lru_list lru)
>
> Let's document the return value.  The mem_cgroup_force_empty_list()
> comment is a mess so I tried to help it a bit.  How does this look?
>
> --- a/mm/memcontrol.c~memcg-make-mem_cgroup_force_empty_list-return-bool-fix
> +++ a/mm/memcontrol.c
> @@ -3609,8 +3609,10 @@ unsigned long mem_cgroup_soft_limit_recl
>   }
>
>   /*
> - * This routine traverse page_cgroup in given list and drop them all.
> - * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
> + * Traverse a specified page_cgroup list and try to drop them all.  This doesn't
> + * reclaim the pages page themselves - it just removes the page_cgroups.
> + * Returns true if some page_cgroups were not freed, indicating that the caller
> + * must retry this operation.
>    */
>   static bool mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
>   				int node, int zid, enum lru_list lru)
> _

Seems nice! Thank you very much.

Regards,
-Kame