From bb5b553c33cb3393f604483b103158bf7d01ca1c Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Thu, 8 Nov 2018 10:08:44 -0500 Subject: cpuset: Use descriptive text when reading/writing cpuset.sched.partition Currently, cpuset.sched.partition returns the values, 0, 1 or -1 on read. A person who is not familiar with the partition code may not understand what they mean. In order to make cpuset.sched.partition more user-friendly, it will now display the following descriptive text on read: "root" - A partition root (top cpuset of a partition) "member" - A non-root member of a partition "root invalid" - An invalid partition root Note that there is at least one partition in the whole cgroup hierarchy. The top cpuset is the root of that partition. The rests are either a root if it starts a new partition or a member of a partition. The cpuset.sched.partition file will now also accept "root" and "member" besides 1 and 0 as valid input values. The "root invalid" value is internal only and cannot be written to the file. Suggested-by: Tejun Heo Signed-off-by: Waiman Long Acked-by: Peter Zijlstra (Intel) Signed-off-by: Tejun Heo --- kernel/cgroup/cpuset.c | 58 ++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 51 insertions(+), 7 deletions(-) (limited to 'kernel/cgroup') diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index fc1a809cd5bb..c739fda805e0 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2278,9 +2278,6 @@ static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft, case FILE_SCHED_RELAX_DOMAIN_LEVEL: retval = update_relax_domain_level(cs, val); break; - case FILE_PARTITION_ROOT: - retval = update_prstate(cs, val); - break; default: retval = -EINVAL; break; @@ -2431,8 +2428,6 @@ static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft) switch (type) { case FILE_SCHED_RELAX_DOMAIN_LEVEL: return cs->relax_domain_level; - case FILE_PARTITION_ROOT: - return cs->partition_root_state; default: BUG(); } @@ -2441,6 +2436,55 @@ static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft) return 0; } +static int sched_partition_show(struct seq_file *seq, void *v) +{ + struct cpuset *cs = css_cs(seq_css(seq)); + + switch (cs->partition_root_state) { + case PRS_ENABLED: + seq_puts(seq, "root\n"); + break; + case PRS_DISABLED: + seq_puts(seq, "member\n"); + break; + case PRS_ERROR: + seq_puts(seq, "root invalid\n"); + break; + } + return 0; +} + +static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) +{ + struct cpuset *cs = css_cs(of_css(of)); + int val; + int retval = -ENODEV; + + buf = strstrip(buf); + + /* + * Convert "root"/"1" to 1, and convert "member"/"0" to 0. + */ + if (!strcmp(buf, "root") || !strcmp(buf, "1")) + val = PRS_ENABLED; + else if (!strcmp(buf, "member") || !strcmp(buf, "0")) + val = PRS_DISABLED; + else + return -EINVAL; + + css_get(&cs->css); + mutex_lock(&cpuset_mutex); + if (!is_cpuset_online(cs)) + goto out_unlock; + + retval = update_prstate(cs, val); +out_unlock: + mutex_unlock(&cpuset_mutex); + css_put(&cs->css); + return retval ?: nbytes; +} + /* * for the common functions, 'private' gives the type of file */ @@ -2584,8 +2628,8 @@ static struct cftype dfl_files[] = { { .name = "sched.partition", - .read_s64 = cpuset_read_s64, - .write_s64 = cpuset_write_s64, + .seq_show = sched_partition_show, + .write = sched_partition_write, .private = FILE_PARTITION_ROOT, .flags = CFTYPE_NOT_ON_ROOT, }, -- cgit