include/linux/padata.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * padata.h - header for the padata parallelization interface
   4  *
   5  * Copyright (C) 2008, 2009 secunet Security Networks AG
   6  * Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
   7  *
   8  * Copyright (c) 2020 Oracle and/or its affiliates.
   9  * Author: Daniel Jordan <daniel.m.jordan@oracle.com>
  10  */
  11
  12 #ifndef PADATA_H
  13 #define PADATA_H
  14
  15 #include <linux/refcount.h>
  16 #include <linux/compiler_types.h>
  17 #include <linux/workqueue.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/list.h>
  20 #include <linux/kobject.h>
  21
  22 #define PADATA_CPU_SERIAL   0x01
  23 #define PADATA_CPU_PARALLEL 0x02
  24
  25 /**
  26  * struct padata_priv - Represents one job
  27  *
  28  * @list: List entry, to attach to the padata lists.
  29  * @pd: Pointer to the internal control structure.
  30  * @cb_cpu: Callback cpu for serializatioon.
  31  * @seq_nr: Sequence number of the parallelized data object.
  32  * @info: Used to pass information from the parallel to the serial function.
  33  * @parallel: Parallel execution function.
  34  * @serial: Serial complete function.
  35  */
  36 struct padata_priv {
  37         struct list_head        list;
  38         struct parallel_data    *pd;
  39         int                     cb_cpu;
  40         unsigned int            seq_nr;
  41         int                     info;
  42         void                    (*parallel)(struct padata_priv *padata);
  43         void                    (*serial)(struct padata_priv *padata);
  44 };
  45
  46 /**
  47  * struct padata_list - one per work type per CPU
  48  *
  49  * @list: List head.
  50  * @lock: List lock.
  51  */
  52 struct padata_list {
  53         struct list_head        list;
  54         spinlock_t              lock;
  55 };
  56
  57 /**
  58 * struct padata_serial_queue - The percpu padata serial queue
  59 *
  60 * @serial: List to wait for serialization after reordering.
  61 * @work: work struct for serialization.
  62 * @pd: Backpointer to the internal control structure.
  63 */
  64 struct padata_serial_queue {
  65        struct padata_list    serial;
  66        struct work_struct    work;
  67        struct parallel_data *pd;
  68 };
  69
  70 /**
  71  * struct padata_cpumask - The cpumasks for the parallel/serial workers
  72  *
  73  * @pcpu: cpumask for the parallel workers.
  74  * @cbcpu: cpumask for the serial (callback) workers.
  75  */
  76 struct padata_cpumask {
  77         cpumask_var_t   pcpu;
  78         cpumask_var_t   cbcpu;
  79 };
  80
  81 /**
  82  * struct parallel_data - Internal control structure, covers everything
  83  * that depends on the cpumask in use.
  84  *
  85  * @ps: padata_shell object.
  86  * @reorder_list: percpu reorder lists
  87  * @squeue: percpu padata queues used for serialuzation.
  88  * @refcnt: Number of objects holding a reference on this parallel_data.
  89  * @seq_nr: Sequence number of the parallelized data object.
  90  * @processed: Number of already processed objects.
  91  * @cpu: Next CPU to be processed.
  92  * @cpumask: The cpumasks in use for parallel and serial workers.
  93  * @reorder_work: work struct for reordering.
  94  * @lock: Reorder lock.
  95  */
  96 struct parallel_data {
  97         struct padata_shell             *ps;
  98         struct padata_list              __percpu *reorder_list;
  99         struct padata_serial_queue      __percpu *squeue;
 100         refcount_t                      refcnt;
 101         unsigned int                    seq_nr;
 102         unsigned int                    processed;
 103         int                             cpu;
 104         struct padata_cpumask           cpumask;
 105         struct work_struct              reorder_work;
 106         spinlock_t                      ____cacheline_aligned lock;
 107 };
 108
 109 /**
 110  * struct padata_shell - Wrapper around struct parallel_data, its
 111  * purpose is to allow the underlying control structure to be replaced
 112  * on the fly using RCU.
 113  *
 114  * @pinst: padat instance.
 115  * @pd: Actual parallel_data structure which may be substituted on the fly.
 116  * @opd: Pointer to old pd to be freed by padata_replace.
 117  * @list: List entry in padata_instance list.
 118  */
 119 struct padata_shell {
 120         struct padata_instance          *pinst;
 121         struct parallel_data __rcu      *pd;
 122         struct parallel_data            *opd;
 123         struct list_head                list;
 124 };
 125
 126 /**
 127  * struct padata_mt_job - represents one multithreaded job
 128  *
 129  * @thread_fn: Called for each chunk of work that a padata thread does.
 130  * @fn_arg: The thread function argument.
 131  * @start: The start of the job (units are job-specific).
 132  * @size: size of this node's work (units are job-specific).
 133  * @align: Ranges passed to the thread function fall on this boundary, with the
 134  *         possible exceptions of the beginning and end of the job.
 135  * @min_chunk: The minimum chunk size in job-specific units.  This allows
 136  *             the client to communicate the minimum amount of work that's
 137  *             appropriate for one worker thread to do at once.
 138  * @max_threads: Max threads to use for the job, actual number may be less
 139  *               depending on task size and minimum chunk size.
 140  * @numa_aware: Distribute jobs to different nodes with CPU in a round robin fashion.
 141  */
 142 struct padata_mt_job {
 143         void (*thread_fn)(unsigned long start, unsigned long end, void *arg);
 144         void                    *fn_arg;
 145         unsigned long           start;
 146         unsigned long           size;
 147         unsigned long           align;
 148         unsigned long           min_chunk;
 149         int                     max_threads;
 150         bool                    numa_aware;
 151 };
 152
 153 /**
 154  * struct padata_instance - The overall control structure.
 155  *
 156  * @cpu_online_node: Linkage for CPU online callback.
 157  * @cpu_dead_node: Linkage for CPU offline callback.
 158  * @parallel_wq: The workqueue used for parallel work.
 159  * @serial_wq: The workqueue used for serial work.
 160  * @pslist: List of padata_shell objects attached to this instance.
 161  * @cpumask: User supplied cpumasks for parallel and serial works.
 162  * @kobj: padata instance kernel object.
 163  * @lock: padata instance lock.
 164  * @flags: padata flags.
 165  */
 166 struct padata_instance {
 167         struct hlist_node               cpu_online_node;
 168         struct hlist_node               cpu_dead_node;
 169         struct workqueue_struct         *parallel_wq;
 170         struct workqueue_struct         *serial_wq;
 171         struct list_head                pslist;
 172         struct padata_cpumask           cpumask;
 173         struct kobject                   kobj;
 174         struct mutex                     lock;
 175         u8                               flags;
 176 #define PADATA_INIT     1
 177 #define PADATA_RESET    2
 178 #define PADATA_INVALID  4
 179 };
 180
 181 #ifdef CONFIG_PADATA
 182 extern void __init padata_init(void);
 183 extern struct padata_instance *padata_alloc(const char *name);
 184 extern void padata_free(struct padata_instance *pinst);
 185 extern struct padata_shell *padata_alloc_shell(struct padata_instance *pinst);
 186 extern void padata_free_shell(struct padata_shell *ps);
 187 extern int padata_do_parallel(struct padata_shell *ps,
 188                               struct padata_priv *padata, int *cb_cpu);
 189 extern void padata_do_serial(struct padata_priv *padata);
 190 extern void __init padata_do_multithreaded(struct padata_mt_job *job);
 191 extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
 192                               cpumask_var_t cpumask);
 193 #else
 194 static inline void __init padata_init(void) {}
 195 static inline void __init padata_do_multithreaded(struct padata_mt_job *job)
 196 {
 197         job->thread_fn(job->start, job->start + job->size, job->fn_arg);
 198 }
 199 #endif
 200
 201 #endif