Messages in this thread Patch in this message | | | From | Waiman Long <> | Subject | [PATCH 2/2] sched/debug: Use sched_debug_lock to serialize use of cgroup_path[] only | Date | Sat, 27 Mar 2021 19:25:29 -0400 |
| |
The purpose of sched_debug_lock is to serialize the use of the global cgroup_path[] buffer in print_cpu(). The rests of the printf calls don't need serialization from sched_debug_lock. The printing of sched debug data to console can take quite a while, taking sched_debug_lock at the print_cpu() level will unnecessarily block the progress of other print_cpu() users. Fix that by holding sched_debug_lock only when using cgroup_path[] via task_group_path().
Signed-off-by: Waiman Long <longman@redhat.com> --- kernel/sched/debug.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index c4ae8a0853a1..87168d13714f 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -8,8 +8,6 @@ */ #include "sched.h" -static DEFINE_SPINLOCK(sched_debug_lock); - /* * This allows printing both to /proc/sched_debug and * to the console @@ -470,6 +468,7 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group #endif #ifdef CONFIG_CGROUP_SCHED +static DEFINE_SPINLOCK(sched_debug_lock); static char group_path[PATH_MAX]; static char *task_group_path(struct task_group *tg) @@ -506,7 +505,9 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p)); #endif #ifdef CONFIG_CGROUP_SCHED + spin_lock(&sched_debug_lock); SEQ_printf(m, " %s", task_group_path(task_group(p))); + spin_unlock(&sched_debug_lock); #endif SEQ_printf(m, "\n"); @@ -543,7 +544,9 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) #ifdef CONFIG_FAIR_GROUP_SCHED SEQ_printf(m, "\n"); + spin_lock(&sched_debug_lock); SEQ_printf(m, "cfs_rq[%d]:%s\n", cpu, task_group_path(cfs_rq->tg)); + spin_unlock(&sched_debug_lock); #else SEQ_printf(m, "\n"); SEQ_printf(m, "cfs_rq[%d]:\n", cpu); @@ -614,7 +617,9 @@ void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq) { #ifdef CONFIG_RT_GROUP_SCHED SEQ_printf(m, "\n"); + spin_lock(&sched_debug_lock); SEQ_printf(m, "rt_rq[%d]:%s\n", cpu, task_group_path(rt_rq->tg)); + spin_unlock(&sched_debug_lock); #else SEQ_printf(m, "\n"); SEQ_printf(m, "rt_rq[%d]:\n", cpu); @@ -716,13 +721,11 @@ do { \ } #undef P - spin_lock(&sched_debug_lock); print_cfs_stats(m, cpu); print_rt_stats(m, cpu); print_dl_stats(m, cpu); print_rq(m, rq, cpu); - spin_unlock(&sched_debug_lock); SEQ_printf(m, "\n"); } -- 2.18.1
| |