[PATCH v5 2/2] sched/numa: add per-process numa_balancing
From: Gang Li
Date: Wed Oct 26 2022 - 22:54:28 EST
Add PR_NUMA_BALANCING in prctl.
A large number of page faults will cause performance loss when numa
balancing is performing. Thus those processes which care about worst-case
performance need numa balancing disabled. Others, on the contrary, allow a
temporary performance loss in exchange for higher average performance, so
enable numa balancing is better for them.
Numa balancing can only be controlled globally by
/proc/sys/kernel/numa_balancing. Due to the above case, we want to
disable/enable numa_balancing per-process instead.
Set per-process numa balancing:
prctl(PR_NUMA_BALANCING, PR_SET_NUMA_BALANCING_DISABLE); //disable
prctl(PR_NUMA_BALANCING, PR_SET_NUMA_BALANCING_ENABLE); //enable
prctl(PR_NUMA_BALANCING, PR_SET_NUMA_BALANCING_DEFAULT); //follow global
Get numa_balancing state:
prctl(PR_NUMA_BALANCING, PR_GET_NUMA_BALANCING, &ret);
cat /proc/<pid>/status | grep NumaB_mode
Cc: linux-api@xxxxxxxxxxxxxxx
Signed-off-by: Gang Li <ligang.bdlg@xxxxxxxxxxxxx>
---
Documentation/filesystems/proc.rst | 2 ++
fs/proc/task_mmu.c | 20 ++++++++++++
include/linux/mm_types.h | 3 ++
include/linux/sched/numa_balancing.h | 45 ++++++++++++++++++++++++++
include/uapi/linux/prctl.h | 7 +++++
kernel/fork.c | 4 +++
kernel/sched/fair.c | 9 +++---
kernel/sys.c | 47 ++++++++++++++++++++++++++++
mm/mprotect.c | 6 ++--
9 files changed, 137 insertions(+), 6 deletions(-)
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index ec6cfdf1796a..e7f058c4e906 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -193,6 +193,7 @@ read the file /proc/PID/status::
VmLib: 1412 kB
VmPTE: 20 kb
VmSwap: 0 kB
+ NumaB_mode: default
HugetlbPages: 0 kB
CoreDumping: 0
THP_enabled: 1
@@ -274,6 +275,7 @@ It's slow but very precise.
VmPTE size of page table entries
VmSwap amount of swap used by anonymous private data
(shmem swap usage is not included)
+ NumaB_mode numa balancing mode, set by prctl(PR_NUMA_BALANCING, ...)
HugetlbPages size of hugetlb memory portions
CoreDumping process's memory is currently being dumped
(killing the process may lead to a corrupted core)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 8a74cdcc9af0..835b68ec218b 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -19,6 +19,8 @@
#include <linux/shmem_fs.h>
#include <linux/uaccess.h>
#include <linux/pkeys.h>
+#include <linux/sched/numa_balancing.h>
+#include <linux/prctl.h>
#include <asm/elf.h>
#include <asm/tlb.h>
@@ -75,6 +77,24 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
" kB\nVmPTE:\t", mm_pgtables_bytes(mm) >> 10, 8);
SEQ_PUT_DEC(" kB\nVmSwap:\t", swap);
seq_puts(m, " kB\n");
+#ifdef CONFIG_NUMA_BALANCING
+ seq_puts(m, "NumaB_mode:\t");
+ switch (mm->numa_balancing_mode) {
+ case PR_SET_NUMA_BALANCING_DEFAULT:
+ seq_puts(m, "default");
+ break;
+ case PR_SET_NUMA_BALANCING_DISABLED:
+ seq_puts(m, "disabled");
+ break;
+ case PR_SET_NUMA_BALANCING_ENABLED:
+ seq_puts(m, "enabled");
+ break;
+ default:
+ seq_puts(m, "unknown");
+ break;
+ }
+ seq_putc(m, '\n');
+#endif
hugetlb_report_usage(m, mm);
}
#undef SEQ_PUT_DEC
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index a82f06ab18a1..b789acf1f69c 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -679,6 +679,9 @@ struct mm_struct {
/* numa_scan_seq prevents two threads remapping PTEs. */
int numa_scan_seq;
+
+ /* Controls whether NUMA balancing is active for this mm. */
+ int numa_balancing_mode;
#endif
/*
* An operation with batched TLB flushing is going on. Anything
diff --git a/include/linux/sched/numa_balancing.h b/include/linux/sched/numa_balancing.h
index 3988762efe15..aa8629dfde45 100644
--- a/include/linux/sched/numa_balancing.h
+++ b/include/linux/sched/numa_balancing.h
@@ -8,6 +8,8 @@
*/
#include <linux/sched.h>
+#include <linux/sched/sysctl.h>
+#include <linux/prctl.h>
#define TNF_MIGRATED 0x01
#define TNF_NO_GROUP 0x02
@@ -16,12 +18,47 @@
#define TNF_MIGRATE_FAIL 0x10
#ifdef CONFIG_NUMA_BALANCING
+DECLARE_STATIC_KEY_FALSE(sched_numa_balancing);
extern void task_numa_fault(int last_node, int node, int pages, int flags);
extern pid_t task_numa_group_id(struct task_struct *p);
extern void set_numabalancing_state(bool enabled);
extern void task_numa_free(struct task_struct *p, bool final);
extern bool should_numa_migrate_memory(struct task_struct *p, struct page *page,
int src_nid, int dst_cpu);
+static inline bool numa_balancing_enabled(struct task_struct *p)
+{
+ if (!static_branch_unlikely(&sched_numa_balancing))
+ return false;
+
+ if (p->mm) switch (p->mm->numa_balancing_mode) {
+ case PR_SET_NUMA_BALANCING_ENABLED:
+ return true;
+ case PR_SET_NUMA_BALANCING_DISABLED:
+ return false;
+ default:
+ break;
+ }
+
+ return sysctl_numa_balancing_mode;
+}
+static inline int numa_balancing_mode(struct mm_struct *mm)
+{
+ if (!static_branch_unlikely(&sched_numa_balancing))
+ return PR_SET_NUMA_BALANCING_DISABLED;
+
+ if (mm) switch (mm->numa_balancing_mode) {
+ case PR_SET_NUMA_BALANCING_ENABLED:
+ return sysctl_numa_balancing_mode == NUMA_BALANCING_DISABLED ?
+ NUMA_BALANCING_NORMAL : sysctl_numa_balancing_mode;
+ case PR_SET_NUMA_BALANCING_DISABLED:
+ return NUMA_BALANCING_DISABLED;
+ case PR_SET_NUMA_BALANCING_DEFAULT:
+ default:
+ break;
+ }
+
+ return sysctl_numa_balancing_mode;
+}
#else
static inline void task_numa_fault(int last_node, int node, int pages,
int flags)
@@ -42,6 +79,14 @@ static inline bool should_numa_migrate_memory(struct task_struct *p,
{
return true;
}
+static inline int numa_balancing_mode(struct mm_struct *mm)
+{
+ return 0;
+}
+static inline bool numa_balancing_enabled(struct task_struct *p)
+{
+ return 0;
+}
#endif
#endif /* _LINUX_SCHED_NUMA_BALANCING_H */
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index a5e06dcbba13..25477fe0b4ef 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -284,4 +284,11 @@ struct prctl_mm_map {
#define PR_SET_VMA 0x53564d41
# define PR_SET_VMA_ANON_NAME 0
+/* Set/get enabled per-process numa_balancing */
+#define PR_NUMA_BALANCING 65
+# define PR_SET_NUMA_BALANCING_DISABLED 0
+# define PR_SET_NUMA_BALANCING_ENABLED 1
+# define PR_SET_NUMA_BALANCING_DEFAULT 2
+# define PR_GET_NUMA_BALANCING 3
+
#endif /* _LINUX_PRCTL_H */
diff --git a/kernel/fork.c b/kernel/fork.c
index cfb09ca1b1bc..7811fa5e098d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -97,6 +97,7 @@
#include <linux/scs.h>
#include <linux/io_uring.h>
#include <linux/bpf.h>
+#include <linux/prctl.h>
#include <asm/pgalloc.h>
#include <linux/uaccess.h>
@@ -1133,6 +1134,9 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
init_tlb_flush_pending(mm);
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
mm->pmd_huge_pte = NULL;
+#endif
+#ifdef CONFIG_NUMA_BALANCING
+ mm->numa_balancing_mode = PR_SET_NUMA_BALANCING_DEFAULT;
#endif
mm_init_uprobes_state(mm);
hugetlb_count_init(mm);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e4a0b8bd941c..94fd6f48fd45 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -47,6 +47,7 @@
#include <linux/psi.h>
#include <linux/ratelimit.h>
#include <linux/task_work.h>
+#include <linux/prctl.h>
#include <asm/switch_to.h>
@@ -2830,7 +2831,7 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
struct numa_group *ng;
int priv;
- if (!static_branch_likely(&sched_numa_balancing))
+ if (!numa_balancing_enabled(p))
return;
/* for example, ksmd faulting in a user's mm */
@@ -3151,7 +3152,7 @@ static void update_scan_period(struct task_struct *p, int new_cpu)
int src_nid = cpu_to_node(task_cpu(p));
int dst_nid = cpu_to_node(new_cpu);
- if (!static_branch_likely(&sched_numa_balancing))
+ if (!numa_balancing_enabled(p))
return;
if (!p->mm || !p->numa_faults || (p->flags & PF_EXITING))
@@ -7996,7 +7997,7 @@ static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
unsigned long src_weight, dst_weight;
int src_nid, dst_nid, dist;
- if (!static_branch_likely(&sched_numa_balancing))
+ if (!numa_balancing_enabled(p))
return -1;
if (!p->numa_faults || !(env->sd->flags & SD_NUMA))
@@ -11584,7 +11585,7 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
entity_tick(cfs_rq, se, queued);
}
- if (static_branch_unlikely(&sched_numa_balancing))
+ if (numa_balancing_enabled(curr))
task_tick_numa(rq, curr);
update_misfit_status(curr, rq);
diff --git a/kernel/sys.c b/kernel/sys.c
index 5fd54bf0e886..f683fb065bc7 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -60,6 +60,7 @@
#include <linux/sched/coredump.h>
#include <linux/sched/task.h>
#include <linux/sched/cputime.h>
+#include <linux/sched/numa_balancing.h>
#include <linux/rcupdate.h>
#include <linux/uidgid.h>
#include <linux/cred.h>
@@ -2104,6 +2105,35 @@ static int prctl_set_auxv(struct mm_struct *mm, unsigned long addr,
return 0;
}
+#ifdef CONFIG_NUMA_BALANCING
+static int prctl_pid_numa_balancing_write(int numa_balancing)
+{
+ int old_numa_balancing;
+
+ if (numa_balancing != PR_SET_NUMA_BALANCING_DEFAULT &&
+ numa_balancing != PR_SET_NUMA_BALANCING_DISABLED &&
+ numa_balancing != PR_SET_NUMA_BALANCING_ENABLED)
+ return -EINVAL;
+
+ old_numa_balancing = xchg(¤t->mm->numa_balancing_mode, numa_balancing);
+
+ if (numa_balancing == old_numa_balancing)
+ return 0;
+
+ if (numa_balancing == 1)
+ static_branch_inc(&sched_numa_balancing);
+ else if (old_numa_balancing == 1)
+ static_branch_dec(&sched_numa_balancing);
+
+ return 0;
+}
+
+static int prctl_pid_numa_balancing_read(void)
+{
+ return current->mm->numa_balancing_mode;
+}
+#endif
+
static int prctl_set_mm(int opt, unsigned long addr,
unsigned long arg4, unsigned long arg5)
{
@@ -2618,6 +2648,23 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
error = set_syscall_user_dispatch(arg2, arg3, arg4,
(char __user *) arg5);
break;
+#ifdef CONFIG_NUMA_BALANCING
+ case PR_NUMA_BALANCING:
+ switch (arg2) {
+ case PR_SET_NUMA_BALANCING_DEFAULT:
+ case PR_SET_NUMA_BALANCING_DISABLED:
+ case PR_SET_NUMA_BALANCING_ENABLED:
+ error = prctl_pid_numa_balancing_write((int)arg2);
+ break;
+ case PR_GET_NUMA_BALANCING:
+ error = put_user(prctl_pid_numa_balancing_read(), (int __user *)arg3);
+ break;
+ default:
+ error = -EINVAL;
+ break;
+ }
+ break;
+#endif
#ifdef CONFIG_SCHED_CORE
case PR_SCHED_CORE:
error = sched_core_share_pid(arg2, arg3, arg4, arg5);
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 99762403cc8f..968a389467d5 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -30,6 +30,7 @@
#include <linux/mm_inline.h>
#include <linux/pgtable.h>
#include <linux/sched/sysctl.h>
+#include <linux/sched/numa_balancing.h>
#include <linux/userfaultfd_k.h>
#include <linux/memory-tiers.h>
#include <asm/cacheflush.h>
@@ -158,10 +159,11 @@ static unsigned long change_pte_range(struct mmu_gather *tlb,
* Skip scanning top tier node if normal numa
* balancing is disabled
*/
- if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) &&
+ if (!(numa_balancing_mode(vma->vm_mm) & NUMA_BALANCING_NORMAL) &&
toptier)
continue;
- if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
+ if (numa_balancing_mode(vma->vm_mm) &
+ NUMA_BALANCING_MEMORY_TIERING &&
!toptier)
xchg_page_access_time(page,
jiffies_to_msecs(jiffies));
--
2.20.1