From: Peter Zijlstra peterz@infradead.org
mainline inclusion from mainline-v5.14-rc1 commit 6e33cad0af49336952e5541464bd02f5b5fd433e category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5OOWG CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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In order to not have to use pid_struct, create a new, smaller, structure to manage task cookies for core scheduling.
Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Tested-by: Don Hiatt dhiatt@digitalocean.com Tested-by: Hongyu Ning hongyu.ning@linux.intel.com Tested-by: Vincent Guittot vincent.guittot@linaro.org Link: https://lkml.kernel.org/r/20210422123308.919768100@infradead.org Signed-off-by: Lin Shengwang linshengwang1@huawei.com Reviewed-by: lihua hucool.lihua@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- include/linux/sched.h | 6 +++ kernel/fork.c | 1 + kernel/sched/Makefile | 1 + kernel/sched/core.c | 7 +-- kernel/sched/core_sched.c | 109 ++++++++++++++++++++++++++++++++++++++ kernel/sched/sched.h | 16 ++++++ 6 files changed, 137 insertions(+), 3 deletions(-) create mode 100644 kernel/sched/core_sched.c
diff --git a/include/linux/sched.h b/include/linux/sched.h index dd1feff73c7d..6f8e0cb8b55b 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2173,6 +2173,12 @@ int sched_trace_rq_nr_running(struct rq *rq);
const struct cpumask *sched_trace_rd_span(struct root_domain *rd);
+#ifdef CONFIG_SCHED_CORE +extern void sched_core_free(struct task_struct *tsk); +#else +static inline void sched_core_free(struct task_struct *tsk) { } +#endif + #ifdef CONFIG_QOS_SCHED void sched_move_offline_task(struct task_struct *p); void sched_qos_offline_wait(void); diff --git a/kernel/fork.c b/kernel/fork.c index 0fb86b65ae60..628c2b3fafed 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -739,6 +739,7 @@ void __put_task_struct(struct task_struct *tsk) exit_creds(tsk); delayacct_tsk_free(tsk); put_signal_struct(tsk->signal); + sched_core_free(tsk);
if (!profile_handoff_task(tsk)) free_task(tsk); diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile index 5fc9c9b70862..978fcfca5871 100644 --- a/kernel/sched/Makefile +++ b/kernel/sched/Makefile @@ -36,3 +36,4 @@ obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o obj-$(CONFIG_MEMBARRIER) += membarrier.o obj-$(CONFIG_CPU_ISOLATION) += isolation.o obj-$(CONFIG_PSI) += psi.o +obj-$(CONFIG_SCHED_CORE) += core_sched.o diff --git a/kernel/sched/core.c b/kernel/sched/core.c index d4598582240b..a485c8729f7c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -158,7 +158,7 @@ static inline int rb_sched_core_cmp(const void *key, const struct rb_node *node) return 0; }
-static void sched_core_enqueue(struct rq *rq, struct task_struct *p) +void sched_core_enqueue(struct rq *rq, struct task_struct *p) { rq->core->core_task_seq++;
@@ -168,14 +168,15 @@ static void sched_core_enqueue(struct rq *rq, struct task_struct *p) rb_add(&p->core_node, &rq->core_tree, rb_sched_core_less); }
-static void sched_core_dequeue(struct rq *rq, struct task_struct *p) +void sched_core_dequeue(struct rq *rq, struct task_struct *p) { rq->core->core_task_seq++;
- if (!p->core_cookie) + if (!sched_core_enqueued(p)) return;
rb_erase(&p->core_node, &rq->core_tree); + RB_CLEAR_NODE(&p->core_node); }
/* diff --git a/kernel/sched/core_sched.c b/kernel/sched/core_sched.c new file mode 100644 index 000000000000..8d0869a9eb8c --- /dev/null +++ b/kernel/sched/core_sched.c @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include "sched.h" + +/* + * A simple wrapper around refcount. An allocated sched_core_cookie's + * address is used to compute the cookie of the task. + */ +struct sched_core_cookie { + refcount_t refcnt; +}; + +unsigned long sched_core_alloc_cookie(void) +{ + struct sched_core_cookie *ck = kmalloc(sizeof(*ck), GFP_KERNEL); + if (!ck) + return 0; + + refcount_set(&ck->refcnt, 1); + sched_core_get(); + + return (unsigned long)ck; +} + +void sched_core_put_cookie(unsigned long cookie) +{ + struct sched_core_cookie *ptr = (void *)cookie; + + if (ptr && refcount_dec_and_test(&ptr->refcnt)) { + kfree(ptr); + sched_core_put(); + } +} + +unsigned long sched_core_get_cookie(unsigned long cookie) +{ + struct sched_core_cookie *ptr = (void *)cookie; + + if (ptr) + refcount_inc(&ptr->refcnt); + + return cookie; +} + +/* + * sched_core_update_cookie - replace the cookie on a task + * @p: the task to update + * @cookie: the new cookie + * + * Effectively exchange the task cookie; caller is responsible for lifetimes on + * both ends. + * + * Returns: the old cookie + */ +unsigned long sched_core_update_cookie(struct task_struct *p, unsigned long cookie) +{ + unsigned long old_cookie; + struct rq_flags rf; + struct rq *rq; + bool enqueued; + + rq = task_rq_lock(p, &rf); + + /* + * Since creating a cookie implies sched_core_get(), and we cannot set + * a cookie until after we've created it, similarly, we cannot destroy + * a cookie until after we've removed it, we must have core scheduling + * enabled here. + */ + SCHED_WARN_ON((p->core_cookie || cookie) && !sched_core_enabled(rq)); + + enqueued = sched_core_enqueued(p); + if (enqueued) + sched_core_dequeue(rq, p); + + old_cookie = p->core_cookie; + p->core_cookie = cookie; + + if (enqueued) + sched_core_enqueue(rq, p); + + /* + * If task is currently running, it may not be compatible anymore after + * the cookie change, so enter the scheduler on its CPU to schedule it + * away. + */ + if (task_running(rq, p)) + resched_curr(rq); + + task_rq_unlock(rq, p, &rf); + + return old_cookie; +} + +static unsigned long sched_core_clone_cookie(struct task_struct *p) +{ + unsigned long cookie, flags; + + raw_spin_lock_irqsave(&p->pi_lock, flags); + cookie = sched_core_get_cookie(p->core_cookie); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); + + return cookie; +} + +void sched_core_free(struct task_struct *p) +{ + sched_core_put_cookie(p->core_cookie); +} diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 05bcd51b25da..91f8795f0693 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1267,6 +1267,22 @@ static inline bool sched_group_cookie_match(struct rq *rq,
extern void queue_core_balance(struct rq *rq);
+static inline bool sched_core_enqueued(struct task_struct *p) +{ + return !RB_EMPTY_NODE(&p->core_node); +} + +extern void sched_core_enqueue(struct rq *rq, struct task_struct *p); +extern void sched_core_dequeue(struct rq *rq, struct task_struct *p); + +extern void sched_core_get(void); +extern void sched_core_put(void); + +extern unsigned long sched_core_alloc_cookie(void); +extern void sched_core_put_cookie(unsigned long cookie); +extern unsigned long sched_core_get_cookie(unsigned long cookie); +extern unsigned long sched_core_update_cookie(struct task_struct *p, unsigned long cookie); + #else /* !CONFIG_SCHED_CORE */
static inline bool sched_core_enabled(struct rq *rq)