On Wed 27-11-13 18:42:32, Tejun Heo wrote:
> In preparation of conversion to kernfs, cgroup file handling is being
> consolidated so that it can be easily mapped to the seq_file based
> interface of kernfs.
>
> All users of cftype->read() can be easily served, usually better, by
> seq_file and other methods. Update hugetlb_cgroup_read() to return
> u64 instead of printing itself and rename it to
> hugetlb_cgroup_read_u64().
>
> This patch doesn't make any visible behavior changes.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxx>
Reviewed-by: Michal Hocko <mhocko@xxxxxxx>
Thanks!
> ---
> mm/hugetlb_cgroup.c | 22 ++++++++--------------
> 1 file changed, 8 insertions(+), 14 deletions(-)
>
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> index bda8e44..d747a84 100644
> --- a/mm/hugetlb_cgroup.c
> +++ b/mm/hugetlb_cgroup.c
> @@ -242,22 +242,16 @@ void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
> return;
> }
>
> -static ssize_t hugetlb_cgroup_read(struct cgroup_subsys_state *css,
> - struct cftype *cft, struct file *file,
> - char __user *buf, size_t nbytes,
> - loff_t *ppos)
> +static u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css,
> + struct cftype *cft)
> {
> - u64 val;
> - char str[64];
> - int idx, name, len;
> + int idx, name;
> struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
>
> idx = MEMFILE_IDX(cft->private);
> name = MEMFILE_ATTR(cft->private);
>
> - val = res_counter_read_u64(&h_cg->hugepage[idx], name);
> - len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
> - return simple_read_from_buffer(buf, nbytes, ppos, str, len);
> + return res_counter_read_u64(&h_cg->hugepage[idx], name);
> }
>
> static int hugetlb_cgroup_write(struct cgroup_subsys_state *css,
> @@ -337,28 +331,28 @@ static void __init __hugetlb_cgroup_file_init(int idx)
> cft = &h->cgroup_files[0];
> snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
> cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
> - cft->read = hugetlb_cgroup_read;
> + cft->read_u64 = hugetlb_cgroup_read_u64;
> cft->write_string = hugetlb_cgroup_write;
>
> /* Add the usage file */
> cft = &h->cgroup_files[1];
> snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
> cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
> - cft->read = hugetlb_cgroup_read;
> + cft->read_u64 = hugetlb_cgroup_read_u64;
>
> /* Add the MAX usage file */
> cft = &h->cgroup_files[2];
> snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
> cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
> cft->trigger = hugetlb_cgroup_reset;
> - cft->read = hugetlb_cgroup_read;
> + cft->read_u64 = hugetlb_cgroup_read_u64;
>
> /* Add the failcntfile */
> cft = &h->cgroup_files[3];
> snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
> cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT);
> cft->trigger = hugetlb_cgroup_reset;
> - cft->read = hugetlb_cgroup_read;
> + cft->read_u64 = hugetlb_cgroup_read_u64;
>
> /* NULL terminate the last cft */
> cft = &h->cgroup_files[4];
> --
> 1.8.4.2
>
--
Michal Hocko
SUSE Labs
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