root/include/linux/psi_types.h

/* [<][>][^][v][top][bottom][index][help] */

INCLUDED FROM


   1 #ifndef _LINUX_PSI_TYPES_H
   2 #define _LINUX_PSI_TYPES_H
   3 
   4 #include <linux/kthread.h>
   5 #include <linux/seqlock.h>
   6 #include <linux/types.h>
   7 #include <linux/kref.h>
   8 #include <linux/wait.h>
   9 
  10 #ifdef CONFIG_PSI
  11 
  12 /* Tracked task states */
  13 enum psi_task_count {
  14         NR_IOWAIT,
  15         NR_MEMSTALL,
  16         NR_RUNNING,
  17         NR_PSI_TASK_COUNTS = 3,
  18 };
  19 
  20 /* Task state bitmasks */
  21 #define TSK_IOWAIT      (1 << NR_IOWAIT)
  22 #define TSK_MEMSTALL    (1 << NR_MEMSTALL)
  23 #define TSK_RUNNING     (1 << NR_RUNNING)
  24 
  25 /* Resources that workloads could be stalled on */
  26 enum psi_res {
  27         PSI_IO,
  28         PSI_MEM,
  29         PSI_CPU,
  30         NR_PSI_RESOURCES = 3,
  31 };
  32 
  33 /*
  34  * Pressure states for each resource:
  35  *
  36  * SOME: Stalled tasks & working tasks
  37  * FULL: Stalled tasks & no working tasks
  38  */
  39 enum psi_states {
  40         PSI_IO_SOME,
  41         PSI_IO_FULL,
  42         PSI_MEM_SOME,
  43         PSI_MEM_FULL,
  44         PSI_CPU_SOME,
  45         /* Only per-CPU, to weigh the CPU in the global average: */
  46         PSI_NONIDLE,
  47         NR_PSI_STATES = 6,
  48 };
  49 
  50 enum psi_aggregators {
  51         PSI_AVGS = 0,
  52         PSI_POLL,
  53         NR_PSI_AGGREGATORS,
  54 };
  55 
  56 struct psi_group_cpu {
  57         /* 1st cacheline updated by the scheduler */
  58 
  59         /* Aggregator needs to know of concurrent changes */
  60         seqcount_t seq ____cacheline_aligned_in_smp;
  61 
  62         /* States of the tasks belonging to this group */
  63         unsigned int tasks[NR_PSI_TASK_COUNTS];
  64 
  65         /* Aggregate pressure state derived from the tasks */
  66         u32 state_mask;
  67 
  68         /* Period time sampling buckets for each state of interest (ns) */
  69         u32 times[NR_PSI_STATES];
  70 
  71         /* Time of last task change in this group (rq_clock) */
  72         u64 state_start;
  73 
  74         /* 2nd cacheline updated by the aggregator */
  75 
  76         /* Delta detection against the sampling buckets */
  77         u32 times_prev[NR_PSI_AGGREGATORS][NR_PSI_STATES]
  78                         ____cacheline_aligned_in_smp;
  79 };
  80 
  81 /* PSI growth tracking window */
  82 struct psi_window {
  83         /* Window size in ns */
  84         u64 size;
  85 
  86         /* Start time of the current window in ns */
  87         u64 start_time;
  88 
  89         /* Value at the start of the window */
  90         u64 start_value;
  91 
  92         /* Value growth in the previous window */
  93         u64 prev_growth;
  94 };
  95 
  96 struct psi_trigger {
  97         /* PSI state being monitored by the trigger */
  98         enum psi_states state;
  99 
 100         /* User-spacified threshold in ns */
 101         u64 threshold;
 102 
 103         /* List node inside triggers list */
 104         struct list_head node;
 105 
 106         /* Backpointer needed during trigger destruction */
 107         struct psi_group *group;
 108 
 109         /* Wait queue for polling */
 110         wait_queue_head_t event_wait;
 111 
 112         /* Pending event flag */
 113         int event;
 114 
 115         /* Tracking window */
 116         struct psi_window win;
 117 
 118         /*
 119          * Time last event was generated. Used for rate-limiting
 120          * events to one per window
 121          */
 122         u64 last_event_time;
 123 
 124         /* Refcounting to prevent premature destruction */
 125         struct kref refcount;
 126 };
 127 
 128 struct psi_group {
 129         /* Protects data used by the aggregator */
 130         struct mutex avgs_lock;
 131 
 132         /* Per-cpu task state & time tracking */
 133         struct psi_group_cpu __percpu *pcpu;
 134 
 135         /* Running pressure averages */
 136         u64 avg_total[NR_PSI_STATES - 1];
 137         u64 avg_last_update;
 138         u64 avg_next_update;
 139 
 140         /* Aggregator work control */
 141         struct delayed_work avgs_work;
 142 
 143         /* Total stall times and sampled pressure averages */
 144         u64 total[NR_PSI_AGGREGATORS][NR_PSI_STATES - 1];
 145         unsigned long avg[NR_PSI_STATES - 1][3];
 146 
 147         /* Monitor work control */
 148         atomic_t poll_scheduled;
 149         struct kthread_worker __rcu *poll_kworker;
 150         struct kthread_delayed_work poll_work;
 151 
 152         /* Protects data used by the monitor */
 153         struct mutex trigger_lock;
 154 
 155         /* Configured polling triggers */
 156         struct list_head triggers;
 157         u32 nr_triggers[NR_PSI_STATES - 1];
 158         u32 poll_states;
 159         u64 poll_min_period;
 160 
 161         /* Total stall times at the start of monitor activation */
 162         u64 polling_total[NR_PSI_STATES - 1];
 163         u64 polling_next_update;
 164         u64 polling_until;
 165 };
 166 
 167 #else /* CONFIG_PSI */
 168 
 169 struct psi_group { };
 170 
 171 #endif /* CONFIG_PSI */
 172 
 173 #endif /* _LINUX_PSI_TYPES_H */

/* [<][>][^][v][top][bottom][index][help] */