Ciju Rajan K <ciju@xxxxxxxxxxxxxxxxxx> writes:
> Greg Thelen wrote:
>> 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@xxxxxxxxxxx>
>> Signed-off-by: Greg Thelen <gthelen@xxxxxxxxxx>
>> ---
>> mm/memcontrol.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 files changed, 89 insertions(+), 0 deletions(-)
>>
>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>> index 6ec2625..2d45a0a 100644
>> --- a/mm/memcontrol.c
>> +++ b/mm/memcontrol.c
>> @@ -100,6 +100,13 @@ enum mem_cgroup_stat_index {
>> MEM_CGROUP_STAT_NSTATS,
>> };
>>
>> +enum {
>> + MEM_CGROUP_DIRTY_RATIO,
>> + MEM_CGROUP_DIRTY_BYTES,
>> + MEM_CGROUP_DIRTY_BACKGROUND_RATIO,
>> + MEM_CGROUP_DIRTY_BACKGROUND_BYTES,
>> +};
>> +
>> struct mem_cgroup_stat_cpu {
>> s64 count[MEM_CGROUP_STAT_NSTATS];
>> };
>> @@ -4292,6 +4299,64 @@ static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
>> return 0;
>> }
>>
>> +static u64 mem_cgroup_dirty_read(struct cgroup *cgrp, struct cftype *cft)
>> +{
>> + struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
>> + bool root;
>> +
>> + root = mem_cgroup_is_root(mem);
>> +
>> + switch (cft->private) {
>> + case MEM_CGROUP_DIRTY_RATIO:
>> + return root ? vm_dirty_ratio : mem->dirty_param.dirty_ratio;
>> + case MEM_CGROUP_DIRTY_BYTES:
>> + return root ? vm_dirty_bytes : mem->dirty_param.dirty_bytes;
>> + case MEM_CGROUP_DIRTY_BACKGROUND_RATIO:
>> + return root ? dirty_background_ratio :
>> + mem->dirty_param.dirty_background_ratio;
>> + case MEM_CGROUP_DIRTY_BACKGROUND_BYTES:
>> + return root ? dirty_background_bytes :
>> + mem->dirty_param.dirty_background_bytes;
>> + default:
>> + BUG();
>> + }
>> +}
>> +
>> +static int
>> +mem_cgroup_dirty_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
>> +{
>> + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
>> + int type = cft->private;
>> +
>> + if (cgrp->parent == NULL)
>> + return -EINVAL;
>> + if ((type == MEM_CGROUP_DIRTY_RATIO ||
>> + type == MEM_CGROUP_DIRTY_BACKGROUND_RATIO) && val > 100)
>> + return -EINVAL;
>> + switch (type) {
>> + case MEM_CGROUP_DIRTY_RATIO:
>> + 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;
>> + }
>> + return 0;
>> +}
>> +
>> static struct cftype mem_cgroup_files[] = {
>> {
>> .name = "usage_in_bytes",
>> @@ -4355,6 +4420,30 @@ static struct cftype mem_cgroup_files[] = {
>> .unregister_event = mem_cgroup_oom_unregister_event,
>> .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
>> },
>> + {
>> + .name = "dirty_ratio",
>> + .read_u64 = mem_cgroup_dirty_read,
>> + .write_u64 = mem_cgroup_dirty_write,
>> + .private = MEM_CGROUP_DIRTY_RATIO,
>> + },
>> + {
>> + .name = "dirty_bytes",
>> + .read_u64 = mem_cgroup_dirty_read,
>> + .write_u64 = mem_cgroup_dirty_write,
>> + .private = MEM_CGROUP_DIRTY_BYTES,
>> + },
>> + {
>>
> Is it a good idea to rename "dirty_bytes" to "dirty_limit_in_bytes" ?
> So that it can match with other memcg tunable naming convention.
> We already have memory.memsw.limit_in_bytes, memory.limit_in_bytes,
> memory.soft_limit_in_bytes, etc.
I see your point in trying to be more internally consistent with other
memcg counter.
It's a trade-off, either use names consistent with /proc/sys/vm, or use
names similar to other memory.* control files. I prefer your suggestion
and will rename as you suggested, unless I hear strong objection.
>> + .name = "dirty_background_ratio",
>> + .read_u64 = mem_cgroup_dirty_read,
>> + .write_u64 = mem_cgroup_dirty_write,
>> + .private = MEM_CGROUP_DIRTY_BACKGROUND_RATIO,
>> + },
>> + {
>> + .name = "dirty_background_bytes",
>> + .read_u64 = mem_cgroup_dirty_read,
>> + .write_u64 = mem_cgroup_dirty_write,
>> + .private = MEM_CGROUP_DIRTY_BACKGROUND_BYTES,
>>
> Similarly "dirty_background_bytes" to dirty_background_limit_in_bytes ?
>> + },
>> };
>>
>> #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
>>
PS: I am collecting performance data on patch series (including Kame's
lockless writeback stats). I should have some useful data today.
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