linux-stable/include/linux/padata.h
Herbert Xu 6fc4dbcf02 padata: Replace delayed timer with immediate workqueue in padata_reorder
The function padata_reorder will use a timer when it cannot progress
while completed jobs are outstanding (pd->reorder_objects > 0).  This
is suboptimal as if we do end up using the timer then it would have
introduced a gratuitous delay of one second.

In fact we can easily distinguish between whether completed jobs
are outstanding and whether we can make progress.  All we have to
do is look at the next pqueue list.

This patch does that by replacing pd->processed with pd->cpu so
that the next pqueue is more accessible.

A work queue is used instead of the original try_again to avoid
hogging the CPU.

Note that we don't bother removing the work queue in
padata_flush_queues because the whole premise is broken.  You
cannot flush async crypto requests so it makes no sense to even
try.  A subsequent patch will fix it by replacing it with a ref
counting scheme.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-07-27 21:08:36 +10:00

168 lines
5.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* padata.h - header for the padata parallelization interface
*
* Copyright (C) 2008, 2009 secunet Security Networks AG
* Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
*/
#ifndef PADATA_H
#define PADATA_H
#include <linux/workqueue.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/kobject.h>
#define PADATA_CPU_SERIAL 0x01
#define PADATA_CPU_PARALLEL 0x02
/**
* struct padata_priv - Embedded to the users data structure.
*
* @list: List entry, to attach to the padata lists.
* @pd: Pointer to the internal control structure.
* @cb_cpu: Callback cpu for serializatioon.
* @cpu: Cpu for parallelization.
* @seq_nr: Sequence number of the parallelized data object.
* @info: Used to pass information from the parallel to the serial function.
* @parallel: Parallel execution function.
* @serial: Serial complete function.
*/
struct padata_priv {
struct list_head list;
struct parallel_data *pd;
int cb_cpu;
int cpu;
int info;
void (*parallel)(struct padata_priv *padata);
void (*serial)(struct padata_priv *padata);
};
/**
* struct padata_list
*
* @list: List head.
* @lock: List lock.
*/
struct padata_list {
struct list_head list;
spinlock_t lock;
};
/**
* struct padata_serial_queue - The percpu padata serial queue
*
* @serial: List to wait for serialization after reordering.
* @work: work struct for serialization.
* @pd: Backpointer to the internal control structure.
*/
struct padata_serial_queue {
struct padata_list serial;
struct work_struct work;
struct parallel_data *pd;
};
/**
* struct padata_parallel_queue - The percpu padata parallel queue
*
* @parallel: List to wait for parallelization.
* @reorder: List to wait for reordering after parallel processing.
* @serial: List to wait for serialization after reordering.
* @pwork: work struct for parallelization.
* @swork: work struct for serialization.
* @work: work struct for parallelization.
* @num_obj: Number of objects that are processed by this cpu.
* @cpu_index: Index of the cpu.
*/
struct padata_parallel_queue {
struct padata_list parallel;
struct padata_list reorder;
struct work_struct work;
atomic_t num_obj;
int cpu_index;
};
/**
* struct padata_cpumask - The cpumasks for the parallel/serial workers
*
* @pcpu: cpumask for the parallel workers.
* @cbcpu: cpumask for the serial (callback) workers.
*/
struct padata_cpumask {
cpumask_var_t pcpu;
cpumask_var_t cbcpu;
};
/**
* struct parallel_data - Internal control structure, covers everything
* that depends on the cpumask in use.
*
* @pinst: padata instance.
* @pqueue: percpu padata queues used for parallelization.
* @squeue: percpu padata queues used for serialuzation.
* @reorder_objects: Number of objects waiting in the reorder queues.
* @refcnt: Number of objects holding a reference on this parallel_data.
* @max_seq_nr: Maximal used sequence number.
* @cpu: Next CPU to be processed.
* @cpumask: The cpumasks in use for parallel and serial workers.
* @reorder_work: work struct for reordering.
* @lock: Reorder lock.
*/
struct parallel_data {
struct padata_instance *pinst;
struct padata_parallel_queue __percpu *pqueue;
struct padata_serial_queue __percpu *squeue;
atomic_t reorder_objects;
atomic_t refcnt;
atomic_t seq_nr;
int cpu;
struct padata_cpumask cpumask;
struct work_struct reorder_work;
spinlock_t lock ____cacheline_aligned;
};
/**
* struct padata_instance - The overall control structure.
*
* @cpu_notifier: cpu hotplug notifier.
* @wq: The workqueue in use.
* @pd: The internal control structure.
* @cpumask: User supplied cpumasks for parallel and serial works.
* @cpumask_change_notifier: Notifiers chain for user-defined notify
* callbacks that will be called when either @pcpu or @cbcpu
* or both cpumasks change.
* @kobj: padata instance kernel object.
* @lock: padata instance lock.
* @flags: padata flags.
*/
struct padata_instance {
struct hlist_node node;
struct workqueue_struct *wq;
struct parallel_data *pd;
struct padata_cpumask cpumask;
struct blocking_notifier_head cpumask_change_notifier;
struct kobject kobj;
struct mutex lock;
u8 flags;
#define PADATA_INIT 1
#define PADATA_RESET 2
#define PADATA_INVALID 4
};
extern struct padata_instance *padata_alloc_possible(
struct workqueue_struct *wq);
extern void padata_free(struct padata_instance *pinst);
extern int padata_do_parallel(struct padata_instance *pinst,
struct padata_priv *padata, int cb_cpu);
extern void padata_do_serial(struct padata_priv *padata);
extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
cpumask_var_t cpumask);
extern int padata_start(struct padata_instance *pinst);
extern void padata_stop(struct padata_instance *pinst);
extern int padata_register_cpumask_notifier(struct padata_instance *pinst,
struct notifier_block *nblock);
extern int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
struct notifier_block *nblock);
#endif