Commit-ID: 56c12cdbeaaaf38fbbfd4de355ea146ce52d8194 Gitweb: http://git.kernel.org/tip/56c12cdbeaaaf38fbbfd4de355ea146ce52d8194 Author: Peter Zijlstra <a.p.zijls...@chello.nl> AuthorDate: Sat, 3 Mar 2012 17:05:16 +0100 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 27 Sep 2012 14:46:02 +0200
sched, mm: Introduce tsk_home_node() Introduce the home-node concept for tasks. In order to keep memory locality we need to have a something to stay local to, we define the home-node of a task as the node we prefer to allocate memory from and prefer to execute on. These are no hard guarantees, merely soft preferences. This allows for optimal resource usage, we can run a task away from the home-node, the remote memory hit -- while expensive -- is less expensive than not running at all, or very little, due to severe cpu overload. Similarly, we can allocate memory from another node if our home-node is depleted, again, some memory is better than no memory. This patch merely introduces the basic infrastructure, all policy comes later. Signed-off-by: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: Lee Schermerhorn <lee.schermerh...@hp.com> Cc: Rik van Riel <r...@redhat.com> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-ii8j8cp87cgctecfqp2ib...@git.kernel.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/sh/mm/Kconfig | 1 + include/linux/init_task.h | 8 ++++++++ include/linux/sched.h | 12 ++++++++++++ init/Kconfig | 11 +++++++++++ kernel/sched/core.c | 36 ++++++++++++++++++++++++++++++++++++ 5 files changed, 68 insertions(+), 0 deletions(-) diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig index cb8f992..1210cc7 100644 --- a/arch/sh/mm/Kconfig +++ b/arch/sh/mm/Kconfig @@ -111,6 +111,7 @@ config VSYSCALL config NUMA bool "Non Uniform Memory Access (NUMA) Support" depends on MMU && SYS_SUPPORTS_NUMA && EXPERIMENTAL + select EMBEDDED_NUMA default n help Some SH systems have many various memories scattered around diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 89f1cb1..18906c1 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -143,6 +143,13 @@ extern struct task_group root_task_group; #define INIT_TASK_COMM "swapper" +#ifdef CONFIG_SCHED_NUMA +# define INIT_TASK_NUMA(tsk) \ + .node = -1, +#else +# define INIT_TASK_NUMA(tsk) +#endif + /* * INIT_TASK is used to set up the first task table, touch at * your own risk!. Base=0, limit=0x1fffff (=2MB) @@ -210,6 +217,7 @@ extern struct task_group root_task_group; INIT_TRACE_RECURSION \ INIT_TASK_RCU_PREEMPT(tsk) \ INIT_CPUSET_SEQ \ + INIT_TASK_NUMA(tsk) \ } diff --git a/include/linux/sched.h b/include/linux/sched.h index 8c38df0..d28ff49 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1518,6 +1518,9 @@ struct task_struct { short il_next; short pref_node_fork; #endif +#ifdef CONFIG_SCHED_NUMA + int node; +#endif struct rcu_head rcu; /* @@ -1589,6 +1592,15 @@ struct task_struct { /* Future-safe accessor for struct task_struct's cpus_allowed. */ #define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed) +static inline int tsk_home_node(struct task_struct *p) +{ +#ifdef CONFIG_SCHED_NUMA + return p->node; +#else + return -1; +#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 diff --git a/init/Kconfig b/init/Kconfig index c40d0fb..beee6d5 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -634,6 +634,17 @@ config LOG_BUF_SHIFT config HAVE_UNSTABLE_SCHED_CLOCK bool +# +# For architectures that (ab)use NUMA to represent different memory regions +# all cpu-local but of different latencies, such as SuperH. +# +config EMBEDDED_NUMA + bool + +config SCHED_NUMA + def_bool y + depends on SMP && NUMA && MIGRATION && !EMBEDDED_NUMA + menuconfig CGROUPS boolean "Control Group support" depends on EVENTFD diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ba144b1..a64c43b 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5979,6 +5979,42 @@ static struct sched_domain_topology_level default_topology[] = { static struct sched_domain_topology_level *sched_domain_topology = default_topology; +#ifdef CONFIG_SCHED_NUMA + +/* + * Requeues a task ensuring its on the right load-balance list so + * that it might get migrated to its new home. + * + * Note that we cannot actively migrate ourselves since our callers + * can be from atomic context. We rely on the regular load-balance + * mechanisms to move us around -- its all preference anyway. + */ +void sched_setnode(struct task_struct *p, int node) +{ + unsigned long flags; + int on_rq, running; + struct rq *rq; + + rq = task_rq_lock(p, &flags); + on_rq = p->on_rq; + running = task_current(rq, p); + + if (on_rq) + dequeue_task(rq, p, 0); + if (running) + p->sched_class->put_prev_task(rq, p); + + p->node = node; + + if (running) + p->sched_class->set_curr_task(rq); + if (on_rq) + enqueue_task(rq, p, 0); + task_rq_unlock(rq, p, &flags); +} + +#endif /* CONFIG_SCHED_NUMA */ + #ifdef CONFIG_NUMA static int sched_domains_numa_levels; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
