This patch add a new api 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. Add numa_balancing under mm_struct. Then use it in task_tick_fair. Set per-process numa balancing: prctl(PR_NUMA_BALANCING, PR_SET_NUMAB_DISABLE); //disable prctl(PR_NUMA_BALANCING, PR_SET_NUMAB_ENABLE); //enable prctl(PR_NUMA_BALANCING, PR_SET_NUMAB_DEFAULT); //follow global Get numa_balancing state: prctl(PR_NUMA_BALANCING, PR_GET_NUMAB, &ret); cat /proc/<pid>/status | grep NumaB_enabled Cc: linux-api@xxxxxxxxxxxxxxx Signed-off-by: Gang Li <ligang.bdlg@xxxxxxxxxxxxx> --- Changes in v4: - code clean: add wrapper function `numa_balancing_enabled` Changes in v3: - Fix compile error. Changes in v2: - Now PR_NUMA_BALANCING support three states: enabled, disabled, default. enabled and disabled will ignore global setting, and default will follow global setting. --- Documentation/filesystems/proc.rst | 2 ++ fs/proc/task_mmu.c | 19 +++++++++++++++ include/linux/mm_types.h | 3 +++ include/linux/sched/numa_balancing.h | 8 +++++++ include/uapi/linux/prctl.h | 7 ++++++ kernel/fork.c | 3 +++ kernel/sched/core.c | 15 ++++++++++++ kernel/sched/fair.c | 32 ++++++++++++++++++++----- kernel/sys.c | 35 ++++++++++++++++++++++++++++ 9 files changed, 118 insertions(+), 6 deletions(-) diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index e7aafc82be99..b2ddffad015f 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -192,6 +192,7 @@ read the file /proc/PID/status:: VmLib: 1412 kB VmPTE: 20 kb VmSwap: 0 kB + NumaB_enabled: default HugetlbPages: 0 kB CoreDumping: 0 THP_enabled: 1 @@ -273,6 +274,7 @@ 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_enabled numa balancing state, 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 8b4f3073f8f5..7358a5932e5a 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -19,6 +19,7 @@ #include <linux/shmem_fs.h> #include <linux/uaccess.h> #include <linux/pkeys.h> +#include <linux/sched/numa_balancing.h> #include <asm/elf.h> #include <asm/tlb.h> @@ -75,6 +76,24 @@ 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_enabled:\t"); + switch (mm->numab_enabled) { + case NUMAB_DEFAULT: + seq_puts(m, "default"); + break; + case NUMAB_DISABLED: + seq_puts(m, "disabled"); + break; + case NUMAB_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 500e536796ca..d9bfa740d905 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -665,6 +665,9 @@ 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 numab_enabled; #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..f4a4cdf264bc 100644 --- a/include/linux/sched/numa_balancing.h +++ b/include/linux/sched/numa_balancing.h @@ -16,12 +16,20 @@ #define TNF_MIGRATE_FAIL 0x10 #ifdef CONFIG_NUMA_BALANCING +enum { + NUMAB_DISABLED, + NUMAB_ENABLED, + NUMAB_DEFAULT +}; +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); +extern bool numa_balancing_enabled(struct task_struct *p); +extern int numa_balancing_mode(struct mm_struct *mm); #else static inline void task_numa_fault(int last_node, int node, int pages, int flags) diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index a5e06dcbba13..4c57724b04c3 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_NUMAB_DISABLED NUMAB_DISABLED +# define PR_SET_NUMAB_ENABLED NUMAB_ENABLED +# define PR_SET_NUMAB_DEFAULT NUMAB_DEFAULT +# define PR_GET_NUMAB 3 + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/fork.c b/kernel/fork.c index 844dfdc8c639..1b9254315770 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1133,6 +1133,9 @@ 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->numab_enabled = NUMAB_DEFAULT; #endif mm_init_uprobes_state(mm); hugetlb_count_init(mm); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a77e8bfbfb5b..12d171978538 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4396,6 +4396,21 @@ void set_numabalancing_state(bool enabled) __set_numabalancing_state(enabled); } +inline int numa_balancing_mode(struct mm_struct *mm) +{ + int numab = mm->numab_enabled; + + switch (numab) { + case NUMAB_ENABLED: + return NUMA_BALANCING_NORMAL; + case NUMAB_DISABLED: + return NUMA_BALANCING_DISABLED; + case NUMAB_DEFAULT: + default: + return sysctl_numa_balancing_mode; + } +} + #ifdef CONFIG_PROC_SYSCTL static void reset_memory_tiering(void) { diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ef0e6b3e08ff..87215b3776c9 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2818,6 +2818,24 @@ void task_numa_free(struct task_struct *p, bool final) } } +inline bool numa_balancing_enabled(struct task_struct *p) +{ + if (p->mm) { + int numab = p->mm->numab_enabled; + + switch (numab) { + case NUMAB_ENABLED: + return true; + case NUMAB_DISABLED: + return false; + case NUMAB_DEFAULT: + break; + } + } + + return static_branch_unlikely(&sched_numa_balancing); +} + /* * Got a PROT_NONE fault for a page on @node. */ @@ -2830,13 +2848,13 @@ 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)) - return; - /* for example, ksmd faulting in a user's mm */ if (!p->mm) return; + if (!numa_balancing_enabled(p)) + return; + /* * NUMA faults statistics are unnecessary for the slow memory * node for memory tiering mode. @@ -3151,7 +3169,7 @@ 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 +8014,7 @@ 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)) @@ -11581,8 +11599,10 @@ 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)) +#ifdef CONFIG_NUMA_BALANCING + if (numa_balancing_enabled(curr)) task_tick_numa(rq, curr); +#endif update_misfit_status(curr, rq); update_overutilized_status(task_rq(curr)); diff --git a/kernel/sys.c b/kernel/sys.c index 8a6432465dc5..11720a35455a 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -59,6 +59,7 @@ #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> @@ -2101,6 +2102,23 @@ 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) +{ + if (numa_balancing != PR_SET_NUMAB_DEFAULT + && numa_balancing != PR_SET_NUMAB_DISABLED + && numa_balancing != PR_SET_NUMAB_ENABLED) + return -EINVAL; + current->mm->numab_enabled = numa_balancing; + return 0; +} + +static int prctl_pid_numa_balancing_read(void) +{ + return current->mm->numab_enabled; +} +#endif + static int prctl_set_mm(int opt, unsigned long addr, unsigned long arg4, unsigned long arg5) { @@ -2615,6 +2633,23 @@ 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_NUMAB_DEFAULT: + case PR_SET_NUMAB_DISABLED: + case PR_SET_NUMAB_ENABLED: + error = prctl_pid_numa_balancing_write((int)arg2); + break; + case PR_GET_NUMAB: + 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); -- 2.20.1