Thanks Greg & Peter for your direction. While we pursue the idea of having debugfs based on kernfs, we thought about having a boot time parameter which would disable creating and updating of the sched_domain debugfs files and this would also be useful even when the kernfs solution kicks in, as users who may not care about these debugfs files would benefit from a faster CPU hotplug operation.
However, these sched_domain debugfs files are created by default. -- vishal.c ------>8-----------------------------------------------------8<-------------- From f66f66ee05a9f719b58822d13e501d65391dd9d3 Mon Sep 17 00:00:00 2001 From: Vishal Chourasia <vish...@linux.vnet.ibm.com> Date: Tue, 8 Nov 2022 14:21:15 +0530 Subject: [PATCH] Add kernel parameter to disable creation of sched_domain files For large systems, creation of sched_domain debug files takes unusually long time. In which case, sched_sd_export can be passed as kernel command line parameter during boot time to prevent kernel from creating sched_domain files. This commit adds a kernel command line parameter, sched_sd_export, which can be used to, optionally, disable the creation of sched_domain debug files. --- kernel/sched/debug.c | 9 ++++++--- kernel/sched/sched.h | 1 + kernel/sched/topology.c | 11 ++++++++++- 3 files changed, 17 insertions(+), 4 deletions(-) diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index bb3d63bdf4ae..bd307847b76a 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -279,6 +279,7 @@ static const struct file_operations sched_dynamic_fops = { #endif /* CONFIG_PREEMPT_DYNAMIC */ __read_mostly bool sched_debug_verbose; +__read_mostly int sched_debug_export = 1; static const struct seq_operations sched_debug_sops; @@ -321,9 +322,11 @@ static __init int sched_init_debug(void) debugfs_create_u32("migration_cost_ns", 0644, debugfs_sched, &sysctl_sched_migration_cost); debugfs_create_u32("nr_migrate", 0644, debugfs_sched, &sysctl_sched_nr_migrate); - mutex_lock(&sched_domains_mutex); - update_sched_domain_debugfs(); - mutex_unlock(&sched_domains_mutex); + if (likely(sched_debug_export)) { + mutex_lock(&sched_domains_mutex); + update_sched_domain_debugfs(); + mutex_unlock(&sched_domains_mutex); + } #endif #ifdef CONFIG_NUMA_BALANCING diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index e26688d387ae..a4d06588d876 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2738,6 +2738,7 @@ extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq); #ifdef CONFIG_SCHED_DEBUG extern bool sched_debug_verbose; +extern int sched_debug_export; extern void print_cfs_stats(struct seq_file *m, int cpu); extern void print_rt_stats(struct seq_file *m, int cpu); diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 8739c2a5a54e..7bcdbc2f856d 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -19,6 +19,13 @@ static int __init sched_debug_setup(char *str) } early_param("sched_verbose", sched_debug_setup); +static int __init sched_debug_disable_export(char *str) +{ + sched_debug_export = 0; + return 0; +} +early_param("sched_sd_export", sched_debug_disable_export); + static inline bool sched_debug(void) { return sched_debug_verbose; @@ -152,6 +159,7 @@ static void sched_domain_debug(struct sched_domain *sd, int cpu) #else /* !CONFIG_SCHED_DEBUG */ # define sched_debug_verbose 0 +# define sched_debug_export 1 # define sched_domain_debug(sd, cpu) do { } while (0) static inline bool sched_debug(void) { @@ -2632,7 +2640,8 @@ void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[], dattr_cur = dattr_new; ndoms_cur = ndoms_new; - update_sched_domain_debugfs(); + if (likely(sched_debug_export)) + update_sched_domain_debugfs(); } /* base-commit: 7e18e42e4b280c85b76967a9106a13ca61c16179 -- 2.31.1
signature.asc
Description: PGP signature