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 */
 36struct 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 */
 52struct 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*/
 64struct 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 */
 76struct 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 */
 94struct parallel_data {
 95	struct padata_shell		*ps;
 96	struct padata_list		__percpu *reorder_list;
 97	struct padata_serial_queue	__percpu *squeue;
 98	refcount_t			refcnt;
 99	unsigned int			seq_nr;
100	unsigned int			processed;
101	int				cpu;
102	struct padata_cpumask		cpumask;
103};
104
105/**
106 * struct padata_shell - Wrapper around struct parallel_data, its
107 * purpose is to allow the underlying control structure to be replaced
108 * on the fly using RCU.
109 *
110 * @pinst: padat instance.
111 * @pd: Actual parallel_data structure which may be substituted on the fly.
112 * @opd: Pointer to old pd to be freed by padata_replace.
113 * @list: List entry in padata_instance list.
114 */
115struct padata_shell {
116	struct padata_instance		*pinst;
117	struct parallel_data __rcu	*pd;
118	struct parallel_data		*opd;
119	struct list_head		list;
120};
121
122/**
123 * struct padata_mt_job - represents one multithreaded job
124 *
125 * @thread_fn: Called for each chunk of work that a padata thread does.
126 * @fn_arg: The thread function argument.
127 * @start: The start of the job (units are job-specific).
128 * @size: size of this node's work (units are job-specific).
129 * @align: Ranges passed to the thread function fall on this boundary, with the
130 *         possible exceptions of the beginning and end of the job.
131 * @min_chunk: The minimum chunk size in job-specific units.  This allows
132 *             the client to communicate the minimum amount of work that's
133 *             appropriate for one worker thread to do at once.
134 * @max_threads: Max threads to use for the job, actual number may be less
135 *               depending on task size and minimum chunk size.
136 * @numa_aware: Distribute jobs to different nodes with CPU in a round robin fashion.
137 */
138struct padata_mt_job {
139	void (*thread_fn)(unsigned long start, unsigned long end, void *arg);
140	void			*fn_arg;
141	unsigned long		start;
142	unsigned long		size;
143	unsigned long		align;
144	unsigned long		min_chunk;
145	int			max_threads;
146	bool			numa_aware;
147};
148
149/**
150 * struct padata_instance - The overall control structure.
151 *
152 * @cpu_online_node: Linkage for CPU online callback.
153 * @cpu_dead_node: Linkage for CPU offline callback.
154 * @parallel_wq: The workqueue used for parallel work.
155 * @serial_wq: The workqueue used for serial work.
156 * @pslist: List of padata_shell objects attached to this instance.
157 * @cpumask: User supplied cpumasks for parallel and serial works.
158 * @kobj: padata instance kernel object.
159 * @lock: padata instance lock.
160 * @flags: padata flags.
161 */
162struct padata_instance {
163	struct hlist_node		cpu_online_node;
164	struct hlist_node		cpu_dead_node;
165	struct workqueue_struct		*parallel_wq;
166	struct workqueue_struct		*serial_wq;
167	struct list_head		pslist;
168	struct padata_cpumask		cpumask;
169	struct kobject                   kobj;
170	struct mutex			 lock;
171	u8				 flags;
172#define	PADATA_INIT	1
173#define	PADATA_RESET	2
174#define	PADATA_INVALID	4
175};
176
177#ifdef CONFIG_PADATA
178extern void __init padata_init(void);
179extern struct padata_instance *padata_alloc(const char *name);
180extern void padata_free(struct padata_instance *pinst);
181extern struct padata_shell *padata_alloc_shell(struct padata_instance *pinst);
182extern void padata_free_shell(struct padata_shell *ps);
183extern int padata_do_parallel(struct padata_shell *ps,
184			      struct padata_priv *padata, int *cb_cpu);
185extern void padata_do_serial(struct padata_priv *padata);
186extern void __init padata_do_multithreaded(struct padata_mt_job *job);
187extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
188			      cpumask_var_t cpumask);
189#else
190static inline void __init padata_init(void) {}
191static inline void __init padata_do_multithreaded(struct padata_mt_job *job)
192{
193	job->thread_fn(job->start, job->start + job->size, job->fn_arg);
194}
195#endif
196
197#endif