Commit cbee9f88 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Mel Gorman
Browse files

mm: numa: Add fault driven placement and migration 



NOTE: This patch is based on "sched, numa, mm: Add fault driven
	placement and migration policy" but as it throws away all the policy
	to just leave a basic foundation I had to drop the signed-offs-by.

This patch creates a bare-bones method for setting PTEs pte_numa in the
context of the scheduler that when faulted later will be faulted onto the
node the CPU is running on.  In itself this does nothing useful but any
placement policy will fundamentally depend on receiving hints on placement
from fault context and doing something intelligent about it.

Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
Acked-by: default avatarRik van Riel <riel@redhat.com>
parent a720094d

arch/sh/mm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ config VSYSCALL 
config NUMA

	bool "Non Uniform Memory Access (NUMA) Support"

	depends on MMU && SYS_SUPPORTS_NUMA && EXPERIMENTAL

	select ARCH_WANT_NUMA_VARIABLE_LOCALITY

	default n

	help

	  Some SH systems have many various memories scattered around

arch/x86/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ config X86 
	def_bool y

	select HAVE_AOUT if X86_32

	select HAVE_UNSTABLE_SCHED_CLOCK

	select ARCH_SUPPORTS_NUMA_BALANCING

	select ARCH_WANTS_PROT_NUMA_PROT_NONE

	select HAVE_IDE

	select HAVE_OPROFILE

	select HAVE_PCSPKR_PLATFORM

include/linux/mm_types.h

+11 −0
Original line number Diff line number Diff line
@@ -397,6 +397,17 @@ struct mm_struct { 
#endif

#ifdef CONFIG_CPUMASK_OFFSTACK

	struct cpumask cpumask_allocation;

#endif

#ifdef CONFIG_NUMA_BALANCING

	/*

	 * numa_next_scan is the next time when the PTEs will me marked

	 * pte_numa to gather statistics and migrate pages to new nodes

	 * if necessary

	 */

	unsigned long numa_next_scan;



	/* numa_scan_seq prevents two threads setting pte_numa */

	int numa_scan_seq;

#endif

	struct uprobes_state uprobes_state;

};

include/linux/sched.h

+20 −0
Original line number Diff line number Diff line
@@ -1479,6 +1479,14 @@ struct task_struct { 
	short il_next;

	short pref_node_fork;

#endif

#ifdef CONFIG_NUMA_BALANCING

	int numa_scan_seq;

	int numa_migrate_seq;

	unsigned int numa_scan_period;

	u64 node_stamp;			/* migration stamp  */

	struct callback_head numa_work;

#endif /* CONFIG_NUMA_BALANCING */



	struct rcu_head rcu;



	/*
@@ -1553,6 +1561,14 @@ struct task_struct { 
/* Future-safe accessor for struct task_struct's cpus_allowed. */

#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)



#ifdef CONFIG_NUMA_BALANCING

extern void task_numa_fault(int node, int pages);

#else

static inline void task_numa_fault(int node, int pages)

{

}

#endif



/*

 * Priority of a process goes from 0..MAX_PRIO-1, valid RT

 * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
@@ -1990,6 +2006,10 @@ enum sched_tunable_scaling { 
};

extern enum sched_tunable_scaling sysctl_sched_tunable_scaling;



extern unsigned int sysctl_numa_balancing_scan_period_min;

extern unsigned int sysctl_numa_balancing_scan_period_max;

extern unsigned int sysctl_numa_balancing_settle_count;



#ifdef CONFIG_SCHED_DEBUG

extern unsigned int sysctl_sched_migration_cost;

extern unsigned int sysctl_sched_nr_migrate;

kernel/sched/core.c

+13 −0
Original line number Diff line number Diff line
@@ -1533,6 +1533,19 @@ static void __sched_fork(struct task_struct *p) 
#ifdef CONFIG_PREEMPT_NOTIFIERS

	INIT_HLIST_HEAD(&p->preempt_notifiers);

#endif



#ifdef CONFIG_NUMA_BALANCING

	if (p->mm && atomic_read(&p->mm->mm_users) == 1) {

		p->mm->numa_next_scan = jiffies;

		p->mm->numa_scan_seq = 0;

	}



	p->node_stamp = 0ULL;

	p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0;

	p->numa_migrate_seq = p->mm ? p->mm->numa_scan_seq - 1 : 0;

	p->numa_scan_period = sysctl_numa_balancing_scan_period_min;

	p->numa_work.next = &p->numa_work;

#endif /* CONFIG_NUMA_BALANCING */

}



/*

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