[Devel] Re: [PATCH 08/10] memcg: add cgroupfs interface to memcg dirty limits

[Greg Thelen]

Balbir Singh <balbir at linux.vnet.ibm.com> writes:

> * Balbir Singh <balbir at linux.vnet.ibm.com> [2010-10-06 19:00:24]:
>
>> * Greg Thelen <gthelen at google.com> [2010-10-03 23:58:03]:
>> 
>> > Add cgroupfs interface to memcg dirty page limits:
>> >   Direct write-out is controlled with:
>> >   - memory.dirty_ratio
>> >   - memory.dirty_bytes
>> > 
>> >   Background write-out is controlled with:
>> >   - memory.dirty_background_ratio
>> >   - memory.dirty_background_bytes
>> > 
>> > Signed-off-by: Andrea Righi <arighi at develer.com>
>> > Signed-off-by: Greg Thelen <gthelen at google.com>
>> > ---
>> 
>> The added interface is not uniform with the rest of our write
>> operations. Does the patch below help? I did a quick compile and run
>> test.
> here is a version with my signed-off-by
>
>
> Make writes to memcg dirty tunables more uniform
>
> From: Balbir Singh <balbir at linux.vnet.ibm.com>
>
> We today support 'M', 'm', 'k', 'K', 'g' and 'G' suffixes for
> general memcg writes. This patch provides the same functionality
> for dirty tunables.
>
> Signed-off-by: Balbir Singh <balbir at linux.vnet.ibm.com>
> ---
>
>  mm/memcontrol.c |   47 +++++++++++++++++++++++++++++++++++++----------
>  1 files changed, 37 insertions(+), 10 deletions(-)
>
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 2d45a0a..116fecd 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -4323,6 +4323,41 @@ static u64 mem_cgroup_dirty_read(struct cgroup *cgrp, struct cftype *cft)
>  }
>  
>  static int
> +mem_cgroup_dirty_write_string(struct cgroup *cgrp, struct cftype *cft,
> +				const char *buffer)
> +{
> +	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> +	int type = cft->private;
> +	int ret = -EINVAL;
> +	unsigned long long val;
> +
> +	if (cgrp->parent == NULL)
> +		return ret;
> +
> +	switch (type) {
> +	case MEM_CGROUP_DIRTY_BYTES:
> +		/* This function does all necessary parse...reuse it */
> +		ret = res_counter_memparse_write_strategy(buffer, &val);
> +		if (ret)
> +			break;
> +		memcg->dirty_param.dirty_bytes = val;
> +		memcg->dirty_param.dirty_ratio  = 0;
> +		break;
> +	case MEM_CGROUP_DIRTY_BACKGROUND_BYTES:
> +		ret = res_counter_memparse_write_strategy(buffer, &val);
> +		if (ret)
> +			break;
> +		memcg->dirty_param.dirty_background_bytes = val;
> +		memcg->dirty_param.dirty_background_ratio = 0;
> +		break;
> +	default:
> +		BUG();
> +		break;
> +	}
> +	return ret;
> +}
> +
> +static int
>  mem_cgroup_dirty_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
>  {
>  	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> @@ -4338,18 +4373,10 @@ mem_cgroup_dirty_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
>  		memcg->dirty_param.dirty_ratio = val;
>  		memcg->dirty_param.dirty_bytes = 0;
>  		break;
> -	case MEM_CGROUP_DIRTY_BYTES:
> -		memcg->dirty_param.dirty_bytes = val;
> -		memcg->dirty_param.dirty_ratio  = 0;
> -		break;
>  	case MEM_CGROUP_DIRTY_BACKGROUND_RATIO:
>  		memcg->dirty_param.dirty_background_ratio = val;
>  		memcg->dirty_param.dirty_background_bytes = 0;
>  		break;
> -	case MEM_CGROUP_DIRTY_BACKGROUND_BYTES:
> -		memcg->dirty_param.dirty_background_bytes = val;
> -		memcg->dirty_param.dirty_background_ratio = 0;
> -		break;
>  	default:
>  		BUG();
>  		break;
> @@ -4429,7 +4456,7 @@ static struct cftype mem_cgroup_files[] = {
>  	{
>  		.name = "dirty_bytes",
>  		.read_u64 = mem_cgroup_dirty_read,
> -		.write_u64 = mem_cgroup_dirty_write,
> +		.write_string = mem_cgroup_dirty_write_string,
>  		.private = MEM_CGROUP_DIRTY_BYTES,
>  	},
>  	{
> @@ -4441,7 +4468,7 @@ static struct cftype mem_cgroup_files[] = {
>  	{
>  		.name = "dirty_background_bytes",
>  		.read_u64 = mem_cgroup_dirty_read,
> -		.write_u64 = mem_cgroup_dirty_write,
> +		.write_string = mem_cgroup_dirty_write_string,
>  		.private = MEM_CGROUP_DIRTY_BACKGROUND_BYTES,
>  	},
>  };

Looks good to me.  I am currently gather performance data on the memcg
series.  It should be done in an hour or so.  I'll then repost V2 of the
memcg dirty limits series.  I'll integrate this patch into the series,
unless there's objection.
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