git: 120ca8d74b46 - main - Re-introduce kern.sched.topology_spec
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Date: Tue, 03 Feb 2026 02:43:25 UTC
The branch main has been updated by kib:
URL: https://cgit.FreeBSD.org/src/commit/?id=120ca8d74b46caa260702485e30fe5f9f9984682
commit 120ca8d74b46caa260702485e30fe5f9f9984682
Author: Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2026-02-02 20:22:46 +0000
Commit: Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2026-02-03 02:43:18 +0000
Re-introduce kern.sched.topology_spec
Move it back from kern.sched.ule.topology_spec.
Make it scheduler-agnostic.
Provide trivial report for UP kernels.
Apparently the MIB is used by some third-party software. Obviously it
did not worked on UP or 4BSD configs.
PR: 292574
Reviewed by: olce
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D55062
---
sys/kern/sched_shim.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++
sys/kern/sched_ule.c | 92 ---------------------------------------------------
sys/kern/subr_smp.c | 81 ++++++++++++++++++++++++++-------------------
sys/sys/smp.h | 9 +++--
4 files changed, 144 insertions(+), 129 deletions(-)
diff --git a/sys/kern/sched_shim.c b/sys/kern/sched_shim.c
index ec5c42c37aab..83e4412494d3 100644
--- a/sys/kern/sched_shim.c
+++ b/sys/kern/sched_shim.c
@@ -16,6 +16,7 @@
#include <sys/runq.h>
#include <sys/sbuf.h>
#include <sys/sched.h>
+#include <sys/smp.h>
#include <sys/sysctl.h>
#include <machine/ifunc.h>
@@ -171,9 +172,12 @@ schedinit(void)
active_sched->init();
}
+struct cpu_group __read_mostly *cpu_top; /* CPU topology */
+
static void
sched_setup(void *dummy)
{
+ cpu_top = smp_topo();
active_sched->setup();
}
SYSINIT(sched_setup, SI_SUB_RUN_QUEUE, SI_ORDER_FIRST, sched_setup, NULL);
@@ -232,3 +236,90 @@ SYSCTL_PROC(_kern_sched, OID_AUTO, available,
fixpt_t ccpu;
SYSCTL_UINT(_kern, OID_AUTO, ccpu, CTLFLAG_RD, &ccpu, 0,
"Decay factor used for updating %CPU");
+
+/*
+ * Build the CPU topology dump string. Is recursively called to collect
+ * the topology tree.
+ */
+static int
+sysctl_kern_sched_topology_spec_internal(struct sbuf *sb,
+ struct cpu_group *cg, int indent)
+{
+ char cpusetbuf[CPUSETBUFSIZ];
+ int i, first;
+
+ if (cpu_top == NULL) {
+ sbuf_printf(sb, "%*s<group level=\"1\" cache-level=\"1\">\n",
+ indent, "");
+ sbuf_printf(sb, "%*s</group>\n", indent, "");
+ return (0);
+ }
+
+ sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent,
+ "", 1 + indent / 2, cg->cg_level);
+ sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"%s\">", indent, "",
+ cg->cg_count, cpusetobj_strprint(cpusetbuf, &cg->cg_mask));
+ first = TRUE;
+ for (i = cg->cg_first; i <= cg->cg_last; i++) {
+ if (CPU_ISSET(i, &cg->cg_mask)) {
+ if (!first)
+ sbuf_cat(sb, ", ");
+ else
+ first = FALSE;
+ sbuf_printf(sb, "%d", i);
+ }
+ }
+ sbuf_cat(sb, "</cpu>\n");
+
+ if (cg->cg_flags != 0) {
+ sbuf_printf(sb, "%*s <flags>", indent, "");
+ if ((cg->cg_flags & CG_FLAG_HTT) != 0)
+ sbuf_cat(sb, "<flag name=\"HTT\">HTT group</flag>");
+ if ((cg->cg_flags & CG_FLAG_THREAD) != 0)
+ sbuf_cat(sb, "<flag name=\"THREAD\">THREAD group</flag>");
+ if ((cg->cg_flags & CG_FLAG_SMT) != 0)
+ sbuf_cat(sb, "<flag name=\"SMT\">SMT group</flag>");
+ if ((cg->cg_flags & CG_FLAG_NODE) != 0)
+ sbuf_cat(sb, "<flag name=\"NODE\">NUMA node</flag>");
+ sbuf_cat(sb, "</flags>\n");
+ }
+
+ if (cg->cg_children > 0) {
+ sbuf_printf(sb, "%*s <children>\n", indent, "");
+ for (i = 0; i < cg->cg_children; i++)
+ sysctl_kern_sched_topology_spec_internal(sb,
+ &cg->cg_child[i], indent + 2);
+ sbuf_printf(sb, "%*s </children>\n", indent, "");
+ }
+ sbuf_printf(sb, "%*s</group>\n", indent, "");
+ return (0);
+}
+
+/*
+ * Sysctl handler for retrieving topology dump. It's a wrapper for
+ * the recursive sysctl_kern_smp_topology_spec_internal().
+ */
+static int
+sysctl_kern_sched_topology_spec(SYSCTL_HANDLER_ARGS)
+{
+ struct sbuf *topo;
+ int err;
+
+ topo = sbuf_new_for_sysctl(NULL, NULL, 512, req);
+ if (topo == NULL)
+ return (ENOMEM);
+
+ sbuf_cat(topo, "<groups>\n");
+ err = sysctl_kern_sched_topology_spec_internal(topo, cpu_top, 1);
+ sbuf_cat(topo, "</groups>\n");
+
+ if (err == 0)
+ err = sbuf_finish(topo);
+ sbuf_delete(topo);
+ return (err);
+}
+
+SYSCTL_PROC(_kern_sched, OID_AUTO, topology_spec, CTLTYPE_STRING |
+ CTLFLAG_MPSAFE | CTLFLAG_RD, NULL, 0,
+ sysctl_kern_sched_topology_spec, "A",
+ "XML dump of detected CPU topology");
diff --git a/sys/kern/sched_ule.c b/sys/kern/sched_ule.c
index ccad7947c4f5..c6bfe15e768b 100644
--- a/sys/kern/sched_ule.c
+++ b/sys/kern/sched_ule.c
@@ -304,7 +304,6 @@ struct tdq {
atomic_load_short(&(tdq)->tdq_switchcnt) + 1))
#ifdef SMP
-struct cpu_group __read_mostly *cpu_top; /* CPU topology */
#define SCHED_AFFINITY_DEFAULT (max(1, hz / 1000))
/*
@@ -398,9 +397,6 @@ static void sched_balance(void);
static bool sched_balance_pair(struct tdq *, struct tdq *);
static inline struct tdq *sched_setcpu(struct thread *, int, int);
static inline void thread_unblock_switch(struct thread *, struct mtx *);
-static int sysctl_kern_sched_ule_topology_spec(SYSCTL_HANDLER_ARGS);
-static int sysctl_kern_sched_ule_topology_spec_internal(struct sbuf *sb,
- struct cpu_group *cg, int indent);
#endif
/*
@@ -1590,7 +1586,6 @@ sched_setup_smp(void)
struct tdq *tdq;
int i;
- cpu_top = smp_topo();
CPU_FOREACH(i) {
tdq = DPCPU_ID_PTR(i, tdq);
tdq_setup(tdq, i);
@@ -3452,89 +3447,6 @@ struct sched_instance sched_ule_instance = {
};
DECLARE_SCHEDULER(ule_sched_selector, "ULE", &sched_ule_instance);
-#ifdef SMP
-
-/*
- * Build the CPU topology dump string. Is recursively called to collect
- * the topology tree.
- */
-static int
-sysctl_kern_sched_ule_topology_spec_internal(struct sbuf *sb,
- struct cpu_group *cg, int indent)
-{
- char cpusetbuf[CPUSETBUFSIZ];
- int i, first;
-
- sbuf_printf(sb, "%*s<group level=\"%d\" cache-level=\"%d\">\n", indent,
- "", 1 + indent / 2, cg->cg_level);
- sbuf_printf(sb, "%*s <cpu count=\"%d\" mask=\"%s\">", indent, "",
- cg->cg_count, cpusetobj_strprint(cpusetbuf, &cg->cg_mask));
- first = TRUE;
- for (i = cg->cg_first; i <= cg->cg_last; i++) {
- if (CPU_ISSET(i, &cg->cg_mask)) {
- if (!first)
- sbuf_cat(sb, ", ");
- else
- first = FALSE;
- sbuf_printf(sb, "%d", i);
- }
- }
- sbuf_cat(sb, "</cpu>\n");
-
- if (cg->cg_flags != 0) {
- sbuf_printf(sb, "%*s <flags>", indent, "");
- if ((cg->cg_flags & CG_FLAG_HTT) != 0)
- sbuf_cat(sb, "<flag name=\"HTT\">HTT group</flag>");
- if ((cg->cg_flags & CG_FLAG_THREAD) != 0)
- sbuf_cat(sb, "<flag name=\"THREAD\">THREAD group</flag>");
- if ((cg->cg_flags & CG_FLAG_SMT) != 0)
- sbuf_cat(sb, "<flag name=\"SMT\">SMT group</flag>");
- if ((cg->cg_flags & CG_FLAG_NODE) != 0)
- sbuf_cat(sb, "<flag name=\"NODE\">NUMA node</flag>");
- sbuf_cat(sb, "</flags>\n");
- }
-
- if (cg->cg_children > 0) {
- sbuf_printf(sb, "%*s <children>\n", indent, "");
- for (i = 0; i < cg->cg_children; i++)
- sysctl_kern_sched_ule_topology_spec_internal(sb,
- &cg->cg_child[i], indent+2);
- sbuf_printf(sb, "%*s </children>\n", indent, "");
- }
- sbuf_printf(sb, "%*s</group>\n", indent, "");
- return (0);
-}
-
-/*
- * Sysctl handler for retrieving topology dump. It's a wrapper for
- * the recursive sysctl_kern_smp_topology_spec_internal().
- */
-static int
-sysctl_kern_sched_ule_topology_spec(SYSCTL_HANDLER_ARGS)
-{
- struct sbuf *topo;
- int err;
-
- if (cpu_top == NULL)
- return (ENOTTY);
-
- topo = sbuf_new_for_sysctl(NULL, NULL, 512, req);
- if (topo == NULL)
- return (ENOMEM);
-
- sbuf_cat(topo, "<groups>\n");
- err = sysctl_kern_sched_ule_topology_spec_internal(topo, cpu_top, 1);
- sbuf_cat(topo, "</groups>\n");
-
- if (err == 0) {
- err = sbuf_finish(topo);
- }
- sbuf_delete(topo);
- return (err);
-}
-
-#endif
-
static int
sysctl_kern_quantum(SYSCTL_HANDLER_ARGS)
{
@@ -3597,8 +3509,4 @@ SYSCTL_INT(_kern_sched_ule, OID_AUTO, trysteal_limit, CTLFLAG_RWTUN,
SYSCTL_INT(_kern_sched_ule, OID_AUTO, always_steal, CTLFLAG_RWTUN,
&always_steal, 0,
"Always run the stealer from the idle thread");
-SYSCTL_PROC(_kern_sched_ule, OID_AUTO, topology_spec, CTLTYPE_STRING |
- CTLFLAG_MPSAFE | CTLFLAG_RD, NULL, 0,
- sysctl_kern_sched_ule_topology_spec, "A",
- "XML dump of detected CPU topology");
#endif
diff --git a/sys/kern/subr_smp.c b/sys/kern/subr_smp.c
index 353a69435971..2256ba648e4d 100644
--- a/sys/kern/subr_smp.c
+++ b/sys/kern/subr_smp.c
@@ -50,9 +50,43 @@
#include "opt_sched.h"
-#ifdef SMP
MALLOC_DEFINE(M_TOPO, "toponodes", "SMP topology data");
+struct cpu_group *
+smp_topo_alloc(u_int count)
+{
+ static struct cpu_group *group = NULL;
+ static u_int index;
+ u_int curr;
+
+ if (group == NULL) {
+ group = mallocarray((mp_maxid + 1) * MAX_CACHE_LEVELS + 1,
+ sizeof(*group), M_DEVBUF, M_WAITOK | M_ZERO);
+ }
+ curr = index;
+ index += count;
+ return (&group[curr]);
+}
+
+struct cpu_group *
+smp_topo_none(void)
+{
+ struct cpu_group *top;
+
+ top = smp_topo_alloc(1);
+ top->cg_parent = NULL;
+ top->cg_child = NULL;
+ top->cg_mask = all_cpus;
+ top->cg_count = mp_ncpus;
+ top->cg_children = 0;
+ top->cg_level = CG_SHARE_NONE;
+ top->cg_flags = 0;
+
+ return (top);
+}
+
+#ifdef SMP
+
volatile cpuset_t stopped_cpus;
volatile cpuset_t started_cpus;
volatile cpuset_t suspended_cpus;
@@ -731,39 +765,6 @@ smp_topo(void)
return (top);
}
-struct cpu_group *
-smp_topo_alloc(u_int count)
-{
- static struct cpu_group *group = NULL;
- static u_int index;
- u_int curr;
-
- if (group == NULL) {
- group = mallocarray((mp_maxid + 1) * MAX_CACHE_LEVELS + 1,
- sizeof(*group), M_DEVBUF, M_WAITOK | M_ZERO);
- }
- curr = index;
- index += count;
- return (&group[curr]);
-}
-
-struct cpu_group *
-smp_topo_none(void)
-{
- struct cpu_group *top;
-
- top = smp_topo_alloc(1);
- top->cg_parent = NULL;
- top->cg_child = NULL;
- top->cg_mask = all_cpus;
- top->cg_count = mp_ncpus;
- top->cg_children = 0;
- top->cg_level = CG_SHARE_NONE;
- top->cg_flags = 0;
-
- return (top);
-}
-
static int
smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share,
int count, int flags, int start)
@@ -901,6 +902,18 @@ smp_rendezvous(void (*setup_func)(void *),
arg);
}
+struct cpu_group *
+smp_topo(void)
+{
+ static struct cpu_group *top = NULL;
+
+ if (top != NULL)
+ return (top);
+
+ top = smp_topo_none();
+ return (top);
+}
+
/*
* Provide dummy SMP support for UP kernels. Modules that need to use SMP
* APIs will still work using this dummy support.
diff --git a/sys/sys/smp.h b/sys/sys/smp.h
index fdb69b13c0d4..493dc91043bd 100644
--- a/sys/sys/smp.h
+++ b/sys/sys/smp.h
@@ -89,6 +89,8 @@ struct cpu_group {
typedef struct cpu_group *cpu_group_t;
+extern cpu_group_t cpu_top;
+
/*
* Defines common resources for CPUs in the group. The highest level
* resource should be used when multiple are shared.
@@ -147,9 +149,6 @@ int topo_analyze(struct topo_node *topo_root, int all,
#define TOPO_FOREACH(i, root) \
for (i = root; i != NULL; i = topo_next_node(root, i))
-struct cpu_group *smp_topo(void);
-struct cpu_group *smp_topo_alloc(u_int count);
-struct cpu_group *smp_topo_none(void);
struct cpu_group *smp_topo_1level(int l1share, int l1count, int l1flags);
struct cpu_group *smp_topo_2level(int l2share, int l2count, int l1share,
int l1count, int l1flags);
@@ -166,6 +165,10 @@ extern cpuset_t hlt_cpus_mask; /* XXX 'mask' is detail in old impl */
extern cpuset_t logical_cpus_mask;
#endif /* SMP */
+struct cpu_group *smp_topo(void);
+struct cpu_group *smp_topo_alloc(u_int count);
+struct cpu_group *smp_topo_none(void);
+
extern u_int mp_maxid;
extern int mp_maxcpus;
extern int mp_ncores;