A trigger on one of the /proc/pressure files has a wait queue of its own for its poller, the cgroup pressure files use the queue of their kernfs node through kernfs_generic_poll() and kernfs_notify(). procfs owns the queue of its pressure files now, so use it the same way: the poll_wait() is procfs', and a trigger that fires wakes the pollers of its file with proc_poll_notify(). Like for the cgroup files every poller of the file is woken when any trigger on it fires, and each reports the state of its own trigger. psi_trigger_poll() doesn't need the file anymore.
Signed-off-by: Christian Brauner (Amutable) <[email protected]> --- include/linux/psi.h | 3 +-- include/linux/psi_types.h | 8 +++++--- kernel/cgroup/cgroup.c | 2 +- kernel/sched/psi.c | 30 +++++++++++++++++------------- 4 files changed, 24 insertions(+), 19 deletions(-) diff --git a/include/linux/psi.h b/include/linux/psi.h index 7966e3ac03b9..c6f536631411 100644 --- a/include/linux/psi.h +++ b/include/linux/psi.h @@ -30,8 +30,7 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf, int psi_trigger_create_rtpoll_worker(struct psi_group *group); void psi_trigger_destroy(struct psi_trigger *t); -__poll_t psi_trigger_poll(void **trigger_ptr, struct file *file, - poll_table *wait); +__poll_t psi_trigger_poll(void **trigger_ptr, poll_table *wait); #ifdef CONFIG_CGROUPS static inline struct psi_group *cgroup_psi(struct cgroup *cgrp) diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h index dd10c22299ab..ce772575c5da 100644 --- a/include/linux/psi_types.h +++ b/include/linux/psi_types.h @@ -8,6 +8,8 @@ #include <linux/kref.h> #include <linux/wait.h> +struct proc_dir_entry; + #ifdef CONFIG_PSI /* Tracked task states */ @@ -132,12 +134,12 @@ struct psi_trigger { /* Backpointer needed during trigger destruction */ struct psi_group *group; - /* Wait queue for polling */ - wait_queue_head_t event_wait; - /* Kernfs file for cgroup triggers */ struct kernfs_open_file *of; + /* /proc/pressure file for system triggers, see proc_poll_notify() */ + struct proc_dir_entry *pde; + /* Pending event flag */ int event; diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index a284225f8dc9..c5da33495ae3 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4232,7 +4232,7 @@ static __poll_t cgroup_pressure_poll(struct kernfs_open_file *of, { struct cgroup_file_ctx *ctx = of->priv; - return psi_trigger_poll(&ctx->psi.trigger, of->file, pt); + return psi_trigger_poll(&ctx->psi.trigger, pt); } static void cgroup_pressure_release(struct kernfs_open_file *of) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index cdb7a832333a..97b5e2488106 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -514,7 +514,7 @@ static void update_triggers(struct psi_group *group, u64 now, if (t->of) kernfs_notify(t->of->kn); else - wake_up_interruptible(&t->event_wait); + proc_poll_notify(t->pde); } t->last_event_time = now; /* Reset threshold breach flag once event got generated */ @@ -1327,6 +1327,9 @@ int psi_trigger_create_rtpoll_worker(struct psi_group *group) return 0; } +/* the /proc/pressure files, see psi_proc_init() */ +static struct proc_dir_entry *psi_proc_entry[NR_PSI_RESOURCES]; + struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf, enum psi_res res, struct file *file, struct kernfs_open_file *of, @@ -1392,8 +1395,7 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf, t->event = 0; t->last_event_time = 0; t->of = of; - if (!of) - init_waitqueue_head(&t->event_wait); + t->pde = of ? NULL : psi_proc_entry[res]; t->pending_event = false; t->aggregator = privileged ? PSI_POLL : PSI_AVGS; @@ -1441,7 +1443,7 @@ void psi_trigger_destroy(struct psi_trigger *t) if (t->of) kernfs_notify(t->of->kn); else - wake_up_interruptible(&t->event_wait); + proc_poll_notify(t->pde); if (t->aggregator == PSI_AVGS) { mutex_lock(&group->avgs_lock); @@ -1495,8 +1497,7 @@ void psi_trigger_destroy(struct psi_trigger *t) kfree(t); } -__poll_t psi_trigger_poll(void **trigger_ptr, - struct file *file, poll_table *wait) +__poll_t psi_trigger_poll(void **trigger_ptr, poll_table *wait) { __poll_t ret = DEFAULT_POLLMASK; struct psi_trigger *t; @@ -1508,10 +1509,9 @@ __poll_t psi_trigger_poll(void **trigger_ptr, if (!t) return DEFAULT_POLLMASK | EPOLLERR | EPOLLPRI; + /* a /proc/pressure file is polled on the queue procfs owns for it */ if (t->of) kernfs_generic_poll(t->of, wait); - else - poll_wait(file, &t->event_wait, wait); if (cmpxchg(&t->event, 1, 0) == 1) ret |= EPOLLPRI; @@ -1610,7 +1610,7 @@ static __poll_t psi_fop_poll(struct file *file, poll_table *wait) { struct seq_file *seq = file->private_data; - return psi_trigger_poll(&seq->private, file, wait); + return psi_trigger_poll(&seq->private, wait); } static int psi_fop_release(struct inode *inode, struct file *file) @@ -1670,11 +1670,15 @@ static int __init psi_proc_init(void) { if (psi_enable) { proc_mkdir("pressure", NULL); - proc_create("pressure/io", 0666, NULL, &psi_io_proc_ops); - proc_create("pressure/memory", 0666, NULL, &psi_memory_proc_ops); - proc_create("pressure/cpu", 0666, NULL, &psi_cpu_proc_ops); + psi_proc_entry[PSI_IO] = proc_create("pressure/io", 0666, NULL, + &psi_io_proc_ops); + psi_proc_entry[PSI_MEM] = proc_create("pressure/memory", 0666, + NULL, &psi_memory_proc_ops); + psi_proc_entry[PSI_CPU] = proc_create("pressure/cpu", 0666, NULL, + &psi_cpu_proc_ops); #ifdef CONFIG_IRQ_TIME_ACCOUNTING - proc_create("pressure/irq", 0666, NULL, &psi_irq_proc_ops); + psi_proc_entry[PSI_IRQ] = proc_create("pressure/irq", 0666, NULL, + &psi_irq_proc_ops); #endif } return 0; -- 2.53.0
