cgroup, psi: Init root cgroup psi to psi_system

laoar · Kernel Patches Daemon · commit 8bfd3b506588 · 2023-08-01T07:41:36.000-07:00
By initializing the root cgroup's psi field to psi_system, we can
consistently obtain the psi information for all cgroups from the struct
cgroup.

Signed-off-by: Yafang Shao &lt;laoar.shao@gmail.com&gt;
diff --git a/include/linux/psi.h b/include/linux/psi.h
@@ -34,7 +34,7 @@ __poll_t psi_trigger_poll(void **trigger_ptr, struct file *file,
 #ifdef CONFIG_CGROUPS
 static inline struct psi_group *cgroup_psi(struct cgroup *cgrp)
 {
-	return cgroup_ino(cgrp) == 1 ? &psi_system : cgrp->psi;
+	return cgrp->psi;
 }
 
 int psi_cgroup_alloc(struct cgroup *cgrp);
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
@@ -164,7 +164,10 @@ static struct static_key_true *cgroup_subsys_on_dfl_key[] = {
 static DEFINE_PER_CPU(struct cgroup_rstat_cpu, cgrp_dfl_root_rstat_cpu);
 
 /* the default hierarchy */
-struct cgroup_root cgrp_dfl_root = { .cgrp.rstat_cpu = &cgrp_dfl_root_rstat_cpu };
+struct cgroup_root cgrp_dfl_root = {
+	.cgrp.rstat_cpu = &cgrp_dfl_root_rstat_cpu,
+	.cgrp.psi = &psi_system,
+};
 EXPORT_SYMBOL_GPL(cgrp_dfl_root);
 
 /*

Original file line number	Diff line number	Diff line change
`@@ -34,7 +34,7 @@ __poll_t psi_trigger_poll(void *trigger_ptr, struct file file,`
`34`	`34`	`#ifdef CONFIG_CGROUPS`
`35`	`35`	`static inline struct psi_group cgroup_psi(struct cgroup cgrp)`
`36`	`36`	`{`
`37`		`- return cgroup_ino(cgrp) == 1 ? &psi_system : cgrp->psi;`
	`37`	`+ return cgrp->psi;`
`38`	`38`	`}`
`39`	`39`
`40`	`40`	`int psi_cgroup_alloc(struct cgroup *cgrp);`