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![Chuck Lever](/assets/img/avatar_default.png)
For xprtrdma, the RPC Call and Reply buffers are involved in real I/O operations. To start with, the DMA direction of the I/O for a Call is opposite that of a Reply. In the current arrangement, the Reply buffer address is on a four-byte alignment just past the call buffer. Would be friendlier on some platforms if that was at a DMA cache alignment instead. Because the current arrangement allocates a single memory region which contains both buffers, the RPC Reply buffer often contains a page boundary in it when the Call buffer is large enough (which is frequent). It would be a little nicer for setting up DMA operations (and possible registration of the Reply buffer) if the two buffers were separated, well-aligned, and contained as few page boundaries as possible. Now, I could just pad out the single memory region used for the pair of buffers. But frequently that would mean a lot of unused space to ensure the Reply buffer did not have a page boundary. Add a separate pointer to rpc_rqst that points right to the RPC Reply buffer. This makes no difference to xprtsock, but it will help xprtrdma in subsequent patches. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
1183 lines
30 KiB
C
1183 lines
30 KiB
C
/*
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* linux/net/sunrpc/sched.c
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*
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* Scheduling for synchronous and asynchronous RPC requests.
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*
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* Copyright (C) 1996 Olaf Kirch, <okir@monad.swb.de>
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*
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* TCP NFS related read + write fixes
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* (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/interrupt.h>
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#include <linux/slab.h>
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#include <linux/mempool.h>
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#include <linux/smp.h>
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#include <linux/spinlock.h>
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#include <linux/mutex.h>
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#include <linux/freezer.h>
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#include <linux/sunrpc/clnt.h>
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#include "sunrpc.h"
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#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
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#define RPCDBG_FACILITY RPCDBG_SCHED
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#endif
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#define CREATE_TRACE_POINTS
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#include <trace/events/sunrpc.h>
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/*
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* RPC slabs and memory pools
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*/
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#define RPC_BUFFER_MAXSIZE (2048)
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#define RPC_BUFFER_POOLSIZE (8)
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#define RPC_TASK_POOLSIZE (8)
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static struct kmem_cache *rpc_task_slabp __read_mostly;
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static struct kmem_cache *rpc_buffer_slabp __read_mostly;
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static mempool_t *rpc_task_mempool __read_mostly;
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static mempool_t *rpc_buffer_mempool __read_mostly;
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static void rpc_async_schedule(struct work_struct *);
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static void rpc_release_task(struct rpc_task *task);
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static void __rpc_queue_timer_fn(unsigned long ptr);
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/*
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* RPC tasks sit here while waiting for conditions to improve.
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*/
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static struct rpc_wait_queue delay_queue;
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/*
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* rpciod-related stuff
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*/
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struct workqueue_struct *rpciod_workqueue __read_mostly;
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struct workqueue_struct *xprtiod_workqueue __read_mostly;
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/*
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* Disable the timer for a given RPC task. Should be called with
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* queue->lock and bh_disabled in order to avoid races within
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* rpc_run_timer().
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*/
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static void
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__rpc_disable_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
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{
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if (task->tk_timeout == 0)
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return;
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dprintk("RPC: %5u disabling timer\n", task->tk_pid);
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task->tk_timeout = 0;
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list_del(&task->u.tk_wait.timer_list);
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if (list_empty(&queue->timer_list.list))
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del_timer(&queue->timer_list.timer);
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}
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static void
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rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires)
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{
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queue->timer_list.expires = expires;
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mod_timer(&queue->timer_list.timer, expires);
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}
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/*
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* Set up a timer for the current task.
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*/
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static void
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__rpc_add_timer(struct rpc_wait_queue *queue, struct rpc_task *task)
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{
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if (!task->tk_timeout)
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return;
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dprintk("RPC: %5u setting alarm for %u ms\n",
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task->tk_pid, jiffies_to_msecs(task->tk_timeout));
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task->u.tk_wait.expires = jiffies + task->tk_timeout;
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if (list_empty(&queue->timer_list.list) || time_before(task->u.tk_wait.expires, queue->timer_list.expires))
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rpc_set_queue_timer(queue, task->u.tk_wait.expires);
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list_add(&task->u.tk_wait.timer_list, &queue->timer_list.list);
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}
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static void rpc_rotate_queue_owner(struct rpc_wait_queue *queue)
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{
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struct list_head *q = &queue->tasks[queue->priority];
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struct rpc_task *task;
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if (!list_empty(q)) {
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task = list_first_entry(q, struct rpc_task, u.tk_wait.list);
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if (task->tk_owner == queue->owner)
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list_move_tail(&task->u.tk_wait.list, q);
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}
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}
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static void rpc_set_waitqueue_priority(struct rpc_wait_queue *queue, int priority)
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{
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if (queue->priority != priority) {
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/* Fairness: rotate the list when changing priority */
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rpc_rotate_queue_owner(queue);
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queue->priority = priority;
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}
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}
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static void rpc_set_waitqueue_owner(struct rpc_wait_queue *queue, pid_t pid)
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{
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queue->owner = pid;
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queue->nr = RPC_BATCH_COUNT;
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}
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static void rpc_reset_waitqueue_priority(struct rpc_wait_queue *queue)
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{
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rpc_set_waitqueue_priority(queue, queue->maxpriority);
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rpc_set_waitqueue_owner(queue, 0);
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}
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/*
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* Add new request to a priority queue.
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*/
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static void __rpc_add_wait_queue_priority(struct rpc_wait_queue *queue,
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struct rpc_task *task,
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unsigned char queue_priority)
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{
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struct list_head *q;
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struct rpc_task *t;
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INIT_LIST_HEAD(&task->u.tk_wait.links);
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if (unlikely(queue_priority > queue->maxpriority))
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queue_priority = queue->maxpriority;
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if (queue_priority > queue->priority)
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rpc_set_waitqueue_priority(queue, queue_priority);
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q = &queue->tasks[queue_priority];
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list_for_each_entry(t, q, u.tk_wait.list) {
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if (t->tk_owner == task->tk_owner) {
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list_add_tail(&task->u.tk_wait.list, &t->u.tk_wait.links);
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return;
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}
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}
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list_add_tail(&task->u.tk_wait.list, q);
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}
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/*
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* Add new request to wait queue.
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*
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* Swapper tasks always get inserted at the head of the queue.
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* This should avoid many nasty memory deadlocks and hopefully
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* improve overall performance.
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* Everyone else gets appended to the queue to ensure proper FIFO behavior.
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*/
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static void __rpc_add_wait_queue(struct rpc_wait_queue *queue,
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struct rpc_task *task,
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unsigned char queue_priority)
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{
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WARN_ON_ONCE(RPC_IS_QUEUED(task));
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if (RPC_IS_QUEUED(task))
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return;
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if (RPC_IS_PRIORITY(queue))
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__rpc_add_wait_queue_priority(queue, task, queue_priority);
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else if (RPC_IS_SWAPPER(task))
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list_add(&task->u.tk_wait.list, &queue->tasks[0]);
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else
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list_add_tail(&task->u.tk_wait.list, &queue->tasks[0]);
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task->tk_waitqueue = queue;
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queue->qlen++;
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/* barrier matches the read in rpc_wake_up_task_queue_locked() */
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smp_wmb();
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rpc_set_queued(task);
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dprintk("RPC: %5u added to queue %p \"%s\"\n",
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task->tk_pid, queue, rpc_qname(queue));
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}
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/*
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* Remove request from a priority queue.
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*/
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static void __rpc_remove_wait_queue_priority(struct rpc_task *task)
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{
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struct rpc_task *t;
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if (!list_empty(&task->u.tk_wait.links)) {
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t = list_entry(task->u.tk_wait.links.next, struct rpc_task, u.tk_wait.list);
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list_move(&t->u.tk_wait.list, &task->u.tk_wait.list);
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list_splice_init(&task->u.tk_wait.links, &t->u.tk_wait.links);
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}
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}
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/*
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* Remove request from queue.
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* Note: must be called with spin lock held.
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*/
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static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)
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{
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__rpc_disable_timer(queue, task);
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if (RPC_IS_PRIORITY(queue))
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__rpc_remove_wait_queue_priority(task);
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list_del(&task->u.tk_wait.list);
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queue->qlen--;
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dprintk("RPC: %5u removed from queue %p \"%s\"\n",
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task->tk_pid, queue, rpc_qname(queue));
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}
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static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname, unsigned char nr_queues)
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{
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int i;
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spin_lock_init(&queue->lock);
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for (i = 0; i < ARRAY_SIZE(queue->tasks); i++)
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INIT_LIST_HEAD(&queue->tasks[i]);
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queue->maxpriority = nr_queues - 1;
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rpc_reset_waitqueue_priority(queue);
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queue->qlen = 0;
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setup_timer(&queue->timer_list.timer, __rpc_queue_timer_fn, (unsigned long)queue);
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INIT_LIST_HEAD(&queue->timer_list.list);
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rpc_assign_waitqueue_name(queue, qname);
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}
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void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qname)
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{
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__rpc_init_priority_wait_queue(queue, qname, RPC_NR_PRIORITY);
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}
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EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue);
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void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
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{
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__rpc_init_priority_wait_queue(queue, qname, 1);
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}
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EXPORT_SYMBOL_GPL(rpc_init_wait_queue);
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void rpc_destroy_wait_queue(struct rpc_wait_queue *queue)
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{
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del_timer_sync(&queue->timer_list.timer);
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}
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EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue);
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static int rpc_wait_bit_killable(struct wait_bit_key *key, int mode)
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{
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freezable_schedule_unsafe();
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if (signal_pending_state(mode, current))
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return -ERESTARTSYS;
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return 0;
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}
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#if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS)
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static void rpc_task_set_debuginfo(struct rpc_task *task)
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{
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static atomic_t rpc_pid;
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task->tk_pid = atomic_inc_return(&rpc_pid);
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}
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#else
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static inline void rpc_task_set_debuginfo(struct rpc_task *task)
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{
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}
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#endif
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static void rpc_set_active(struct rpc_task *task)
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{
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trace_rpc_task_begin(task->tk_client, task, NULL);
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rpc_task_set_debuginfo(task);
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set_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
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}
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/*
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* Mark an RPC call as having completed by clearing the 'active' bit
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* and then waking up all tasks that were sleeping.
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*/
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static int rpc_complete_task(struct rpc_task *task)
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{
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void *m = &task->tk_runstate;
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wait_queue_head_t *wq = bit_waitqueue(m, RPC_TASK_ACTIVE);
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struct wait_bit_key k = __WAIT_BIT_KEY_INITIALIZER(m, RPC_TASK_ACTIVE);
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unsigned long flags;
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int ret;
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trace_rpc_task_complete(task->tk_client, task, NULL);
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spin_lock_irqsave(&wq->lock, flags);
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clear_bit(RPC_TASK_ACTIVE, &task->tk_runstate);
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ret = atomic_dec_and_test(&task->tk_count);
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if (waitqueue_active(wq))
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__wake_up_locked_key(wq, TASK_NORMAL, &k);
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spin_unlock_irqrestore(&wq->lock, flags);
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return ret;
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}
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/*
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* Allow callers to wait for completion of an RPC call
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*
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* Note the use of out_of_line_wait_on_bit() rather than wait_on_bit()
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* to enforce taking of the wq->lock and hence avoid races with
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* rpc_complete_task().
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*/
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int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *action)
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{
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if (action == NULL)
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action = rpc_wait_bit_killable;
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return out_of_line_wait_on_bit(&task->tk_runstate, RPC_TASK_ACTIVE,
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action, TASK_KILLABLE);
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}
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EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
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/*
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* Make an RPC task runnable.
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*
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* Note: If the task is ASYNC, and is being made runnable after sitting on an
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* rpc_wait_queue, this must be called with the queue spinlock held to protect
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* the wait queue operation.
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* Note the ordering of rpc_test_and_set_running() and rpc_clear_queued(),
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* which is needed to ensure that __rpc_execute() doesn't loop (due to the
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* lockless RPC_IS_QUEUED() test) before we've had a chance to test
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* the RPC_TASK_RUNNING flag.
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*/
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static void rpc_make_runnable(struct workqueue_struct *wq,
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struct rpc_task *task)
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{
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bool need_wakeup = !rpc_test_and_set_running(task);
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rpc_clear_queued(task);
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if (!need_wakeup)
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return;
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if (RPC_IS_ASYNC(task)) {
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INIT_WORK(&task->u.tk_work, rpc_async_schedule);
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queue_work(wq, &task->u.tk_work);
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} else
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wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
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}
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/*
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* Prepare for sleeping on a wait queue.
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* By always appending tasks to the list we ensure FIFO behavior.
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* NB: An RPC task will only receive interrupt-driven events as long
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* as it's on a wait queue.
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*/
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static void __rpc_sleep_on_priority(struct rpc_wait_queue *q,
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struct rpc_task *task,
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rpc_action action,
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unsigned char queue_priority)
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{
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dprintk("RPC: %5u sleep_on(queue \"%s\" time %lu)\n",
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task->tk_pid, rpc_qname(q), jiffies);
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trace_rpc_task_sleep(task->tk_client, task, q);
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__rpc_add_wait_queue(q, task, queue_priority);
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WARN_ON_ONCE(task->tk_callback != NULL);
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task->tk_callback = action;
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__rpc_add_timer(q, task);
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}
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void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
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rpc_action action)
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{
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/* We shouldn't ever put an inactive task to sleep */
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WARN_ON_ONCE(!RPC_IS_ACTIVATED(task));
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if (!RPC_IS_ACTIVATED(task)) {
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task->tk_status = -EIO;
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rpc_put_task_async(task);
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return;
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}
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/*
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* Protect the queue operations.
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*/
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spin_lock_bh(&q->lock);
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__rpc_sleep_on_priority(q, task, action, task->tk_priority);
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spin_unlock_bh(&q->lock);
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}
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EXPORT_SYMBOL_GPL(rpc_sleep_on);
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void rpc_sleep_on_priority(struct rpc_wait_queue *q, struct rpc_task *task,
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rpc_action action, int priority)
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{
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/* We shouldn't ever put an inactive task to sleep */
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WARN_ON_ONCE(!RPC_IS_ACTIVATED(task));
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if (!RPC_IS_ACTIVATED(task)) {
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task->tk_status = -EIO;
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rpc_put_task_async(task);
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return;
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}
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/*
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* Protect the queue operations.
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*/
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spin_lock_bh(&q->lock);
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__rpc_sleep_on_priority(q, task, action, priority - RPC_PRIORITY_LOW);
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spin_unlock_bh(&q->lock);
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}
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EXPORT_SYMBOL_GPL(rpc_sleep_on_priority);
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|
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/**
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* __rpc_do_wake_up_task_on_wq - wake up a single rpc_task
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* @wq: workqueue on which to run task
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* @queue: wait queue
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* @task: task to be woken up
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*
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* Caller must hold queue->lock, and have cleared the task queued flag.
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*/
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static void __rpc_do_wake_up_task_on_wq(struct workqueue_struct *wq,
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struct rpc_wait_queue *queue,
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struct rpc_task *task)
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{
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dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
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task->tk_pid, jiffies);
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|
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/* Has the task been executed yet? If not, we cannot wake it up! */
|
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if (!RPC_IS_ACTIVATED(task)) {
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printk(KERN_ERR "RPC: Inactive task (%p) being woken up!\n", task);
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return;
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}
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trace_rpc_task_wakeup(task->tk_client, task, queue);
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__rpc_remove_wait_queue(queue, task);
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rpc_make_runnable(wq, task);
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|
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dprintk("RPC: __rpc_wake_up_task done\n");
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}
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|
|
/*
|
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* Wake up a queued task while the queue lock is being held
|
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*/
|
|
static void rpc_wake_up_task_on_wq_queue_locked(struct workqueue_struct *wq,
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struct rpc_wait_queue *queue, struct rpc_task *task)
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{
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if (RPC_IS_QUEUED(task)) {
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smp_rmb();
|
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if (task->tk_waitqueue == queue)
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__rpc_do_wake_up_task_on_wq(wq, queue, task);
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}
|
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}
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|
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/*
|
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* Wake up a queued task while the queue lock is being held
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*/
|
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static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
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{
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rpc_wake_up_task_on_wq_queue_locked(rpciod_workqueue, queue, task);
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}
|
|
|
|
/*
|
|
* Wake up a task on a specific queue
|
|
*/
|
|
void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
|
|
{
|
|
spin_lock_bh(&queue->lock);
|
|
rpc_wake_up_task_queue_locked(queue, task);
|
|
spin_unlock_bh(&queue->lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
|
|
|
|
/*
|
|
* Wake up the next task on a priority queue.
|
|
*/
|
|
static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *queue)
|
|
{
|
|
struct list_head *q;
|
|
struct rpc_task *task;
|
|
|
|
/*
|
|
* Service a batch of tasks from a single owner.
|
|
*/
|
|
q = &queue->tasks[queue->priority];
|
|
if (!list_empty(q)) {
|
|
task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
|
|
if (queue->owner == task->tk_owner) {
|
|
if (--queue->nr)
|
|
goto out;
|
|
list_move_tail(&task->u.tk_wait.list, q);
|
|
}
|
|
/*
|
|
* Check if we need to switch queues.
|
|
*/
|
|
goto new_owner;
|
|
}
|
|
|
|
/*
|
|
* Service the next queue.
|
|
*/
|
|
do {
|
|
if (q == &queue->tasks[0])
|
|
q = &queue->tasks[queue->maxpriority];
|
|
else
|
|
q = q - 1;
|
|
if (!list_empty(q)) {
|
|
task = list_entry(q->next, struct rpc_task, u.tk_wait.list);
|
|
goto new_queue;
|
|
}
|
|
} while (q != &queue->tasks[queue->priority]);
|
|
|
|
rpc_reset_waitqueue_priority(queue);
|
|
return NULL;
|
|
|
|
new_queue:
|
|
rpc_set_waitqueue_priority(queue, (unsigned int)(q - &queue->tasks[0]));
|
|
new_owner:
|
|
rpc_set_waitqueue_owner(queue, task->tk_owner);
|
|
out:
|
|
return task;
|
|
}
|
|
|
|
static struct rpc_task *__rpc_find_next_queued(struct rpc_wait_queue *queue)
|
|
{
|
|
if (RPC_IS_PRIORITY(queue))
|
|
return __rpc_find_next_queued_priority(queue);
|
|
if (!list_empty(&queue->tasks[0]))
|
|
return list_first_entry(&queue->tasks[0], struct rpc_task, u.tk_wait.list);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Wake up the first task on the wait queue.
|
|
*/
|
|
struct rpc_task *rpc_wake_up_first_on_wq(struct workqueue_struct *wq,
|
|
struct rpc_wait_queue *queue,
|
|
bool (*func)(struct rpc_task *, void *), void *data)
|
|
{
|
|
struct rpc_task *task = NULL;
|
|
|
|
dprintk("RPC: wake_up_first(%p \"%s\")\n",
|
|
queue, rpc_qname(queue));
|
|
spin_lock_bh(&queue->lock);
|
|
task = __rpc_find_next_queued(queue);
|
|
if (task != NULL) {
|
|
if (func(task, data))
|
|
rpc_wake_up_task_on_wq_queue_locked(wq, queue, task);
|
|
else
|
|
task = NULL;
|
|
}
|
|
spin_unlock_bh(&queue->lock);
|
|
|
|
return task;
|
|
}
|
|
|
|
/*
|
|
* Wake up the first task on the wait queue.
|
|
*/
|
|
struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *queue,
|
|
bool (*func)(struct rpc_task *, void *), void *data)
|
|
{
|
|
return rpc_wake_up_first_on_wq(rpciod_workqueue, queue, func, data);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_wake_up_first);
|
|
|
|
static bool rpc_wake_up_next_func(struct rpc_task *task, void *data)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Wake up the next task on the wait queue.
|
|
*/
|
|
struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *queue)
|
|
{
|
|
return rpc_wake_up_first(queue, rpc_wake_up_next_func, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_wake_up_next);
|
|
|
|
/**
|
|
* rpc_wake_up - wake up all rpc_tasks
|
|
* @queue: rpc_wait_queue on which the tasks are sleeping
|
|
*
|
|
* Grabs queue->lock
|
|
*/
|
|
void rpc_wake_up(struct rpc_wait_queue *queue)
|
|
{
|
|
struct list_head *head;
|
|
|
|
spin_lock_bh(&queue->lock);
|
|
head = &queue->tasks[queue->maxpriority];
|
|
for (;;) {
|
|
while (!list_empty(head)) {
|
|
struct rpc_task *task;
|
|
task = list_first_entry(head,
|
|
struct rpc_task,
|
|
u.tk_wait.list);
|
|
rpc_wake_up_task_queue_locked(queue, task);
|
|
}
|
|
if (head == &queue->tasks[0])
|
|
break;
|
|
head--;
|
|
}
|
|
spin_unlock_bh(&queue->lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_wake_up);
|
|
|
|
/**
|
|
* rpc_wake_up_status - wake up all rpc_tasks and set their status value.
|
|
* @queue: rpc_wait_queue on which the tasks are sleeping
|
|
* @status: status value to set
|
|
*
|
|
* Grabs queue->lock
|
|
*/
|
|
void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
|
|
{
|
|
struct list_head *head;
|
|
|
|
spin_lock_bh(&queue->lock);
|
|
head = &queue->tasks[queue->maxpriority];
|
|
for (;;) {
|
|
while (!list_empty(head)) {
|
|
struct rpc_task *task;
|
|
task = list_first_entry(head,
|
|
struct rpc_task,
|
|
u.tk_wait.list);
|
|
task->tk_status = status;
|
|
rpc_wake_up_task_queue_locked(queue, task);
|
|
}
|
|
if (head == &queue->tasks[0])
|
|
break;
|
|
head--;
|
|
}
|
|
spin_unlock_bh(&queue->lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_wake_up_status);
|
|
|
|
static void __rpc_queue_timer_fn(unsigned long ptr)
|
|
{
|
|
struct rpc_wait_queue *queue = (struct rpc_wait_queue *)ptr;
|
|
struct rpc_task *task, *n;
|
|
unsigned long expires, now, timeo;
|
|
|
|
spin_lock(&queue->lock);
|
|
expires = now = jiffies;
|
|
list_for_each_entry_safe(task, n, &queue->timer_list.list, u.tk_wait.timer_list) {
|
|
timeo = task->u.tk_wait.expires;
|
|
if (time_after_eq(now, timeo)) {
|
|
dprintk("RPC: %5u timeout\n", task->tk_pid);
|
|
task->tk_status = -ETIMEDOUT;
|
|
rpc_wake_up_task_queue_locked(queue, task);
|
|
continue;
|
|
}
|
|
if (expires == now || time_after(expires, timeo))
|
|
expires = timeo;
|
|
}
|
|
if (!list_empty(&queue->timer_list.list))
|
|
rpc_set_queue_timer(queue, expires);
|
|
spin_unlock(&queue->lock);
|
|
}
|
|
|
|
static void __rpc_atrun(struct rpc_task *task)
|
|
{
|
|
if (task->tk_status == -ETIMEDOUT)
|
|
task->tk_status = 0;
|
|
}
|
|
|
|
/*
|
|
* Run a task at a later time
|
|
*/
|
|
void rpc_delay(struct rpc_task *task, unsigned long delay)
|
|
{
|
|
task->tk_timeout = delay;
|
|
rpc_sleep_on(&delay_queue, task, __rpc_atrun);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_delay);
|
|
|
|
/*
|
|
* Helper to call task->tk_ops->rpc_call_prepare
|
|
*/
|
|
void rpc_prepare_task(struct rpc_task *task)
|
|
{
|
|
task->tk_ops->rpc_call_prepare(task, task->tk_calldata);
|
|
}
|
|
|
|
static void
|
|
rpc_init_task_statistics(struct rpc_task *task)
|
|
{
|
|
/* Initialize retry counters */
|
|
task->tk_garb_retry = 2;
|
|
task->tk_cred_retry = 2;
|
|
task->tk_rebind_retry = 2;
|
|
|
|
/* starting timestamp */
|
|
task->tk_start = ktime_get();
|
|
}
|
|
|
|
static void
|
|
rpc_reset_task_statistics(struct rpc_task *task)
|
|
{
|
|
task->tk_timeouts = 0;
|
|
task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_KILLED|RPC_TASK_SENT);
|
|
|
|
rpc_init_task_statistics(task);
|
|
}
|
|
|
|
/*
|
|
* Helper that calls task->tk_ops->rpc_call_done if it exists
|
|
*/
|
|
void rpc_exit_task(struct rpc_task *task)
|
|
{
|
|
task->tk_action = NULL;
|
|
if (task->tk_ops->rpc_call_done != NULL) {
|
|
task->tk_ops->rpc_call_done(task, task->tk_calldata);
|
|
if (task->tk_action != NULL) {
|
|
WARN_ON(RPC_ASSASSINATED(task));
|
|
/* Always release the RPC slot and buffer memory */
|
|
xprt_release(task);
|
|
rpc_reset_task_statistics(task);
|
|
}
|
|
}
|
|
}
|
|
|
|
void rpc_exit(struct rpc_task *task, int status)
|
|
{
|
|
task->tk_status = status;
|
|
task->tk_action = rpc_exit_task;
|
|
if (RPC_IS_QUEUED(task))
|
|
rpc_wake_up_queued_task(task->tk_waitqueue, task);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_exit);
|
|
|
|
void rpc_release_calldata(const struct rpc_call_ops *ops, void *calldata)
|
|
{
|
|
if (ops->rpc_release != NULL)
|
|
ops->rpc_release(calldata);
|
|
}
|
|
|
|
/*
|
|
* This is the RPC `scheduler' (or rather, the finite state machine).
|
|
*/
|
|
static void __rpc_execute(struct rpc_task *task)
|
|
{
|
|
struct rpc_wait_queue *queue;
|
|
int task_is_async = RPC_IS_ASYNC(task);
|
|
int status = 0;
|
|
|
|
dprintk("RPC: %5u __rpc_execute flags=0x%x\n",
|
|
task->tk_pid, task->tk_flags);
|
|
|
|
WARN_ON_ONCE(RPC_IS_QUEUED(task));
|
|
if (RPC_IS_QUEUED(task))
|
|
return;
|
|
|
|
for (;;) {
|
|
void (*do_action)(struct rpc_task *);
|
|
|
|
/*
|
|
* Execute any pending callback first.
|
|
*/
|
|
do_action = task->tk_callback;
|
|
task->tk_callback = NULL;
|
|
if (do_action == NULL) {
|
|
/*
|
|
* Perform the next FSM step.
|
|
* tk_action may be NULL if the task has been killed.
|
|
* In particular, note that rpc_killall_tasks may
|
|
* do this at any time, so beware when dereferencing.
|
|
*/
|
|
do_action = task->tk_action;
|
|
if (do_action == NULL)
|
|
break;
|
|
}
|
|
trace_rpc_task_run_action(task->tk_client, task, task->tk_action);
|
|
do_action(task);
|
|
|
|
/*
|
|
* Lockless check for whether task is sleeping or not.
|
|
*/
|
|
if (!RPC_IS_QUEUED(task))
|
|
continue;
|
|
/*
|
|
* The queue->lock protects against races with
|
|
* rpc_make_runnable().
|
|
*
|
|
* Note that once we clear RPC_TASK_RUNNING on an asynchronous
|
|
* rpc_task, rpc_make_runnable() can assign it to a
|
|
* different workqueue. We therefore cannot assume that the
|
|
* rpc_task pointer may still be dereferenced.
|
|
*/
|
|
queue = task->tk_waitqueue;
|
|
spin_lock_bh(&queue->lock);
|
|
if (!RPC_IS_QUEUED(task)) {
|
|
spin_unlock_bh(&queue->lock);
|
|
continue;
|
|
}
|
|
rpc_clear_running(task);
|
|
spin_unlock_bh(&queue->lock);
|
|
if (task_is_async)
|
|
return;
|
|
|
|
/* sync task: sleep here */
|
|
dprintk("RPC: %5u sync task going to sleep\n", task->tk_pid);
|
|
status = out_of_line_wait_on_bit(&task->tk_runstate,
|
|
RPC_TASK_QUEUED, rpc_wait_bit_killable,
|
|
TASK_KILLABLE);
|
|
if (status == -ERESTARTSYS) {
|
|
/*
|
|
* When a sync task receives a signal, it exits with
|
|
* -ERESTARTSYS. In order to catch any callbacks that
|
|
* clean up after sleeping on some queue, we don't
|
|
* break the loop here, but go around once more.
|
|
*/
|
|
dprintk("RPC: %5u got signal\n", task->tk_pid);
|
|
task->tk_flags |= RPC_TASK_KILLED;
|
|
rpc_exit(task, -ERESTARTSYS);
|
|
}
|
|
dprintk("RPC: %5u sync task resuming\n", task->tk_pid);
|
|
}
|
|
|
|
dprintk("RPC: %5u return %d, status %d\n", task->tk_pid, status,
|
|
task->tk_status);
|
|
/* Release all resources associated with the task */
|
|
rpc_release_task(task);
|
|
}
|
|
|
|
/*
|
|
* User-visible entry point to the scheduler.
|
|
*
|
|
* This may be called recursively if e.g. an async NFS task updates
|
|
* the attributes and finds that dirty pages must be flushed.
|
|
* NOTE: Upon exit of this function the task is guaranteed to be
|
|
* released. In particular note that tk_release() will have
|
|
* been called, so your task memory may have been freed.
|
|
*/
|
|
void rpc_execute(struct rpc_task *task)
|
|
{
|
|
bool is_async = RPC_IS_ASYNC(task);
|
|
|
|
rpc_set_active(task);
|
|
rpc_make_runnable(rpciod_workqueue, task);
|
|
if (!is_async)
|
|
__rpc_execute(task);
|
|
}
|
|
|
|
static void rpc_async_schedule(struct work_struct *work)
|
|
{
|
|
__rpc_execute(container_of(work, struct rpc_task, u.tk_work));
|
|
}
|
|
|
|
/**
|
|
* rpc_malloc - allocate RPC buffer resources
|
|
* @task: RPC task
|
|
*
|
|
* A single memory region is allocated, which is split between the
|
|
* RPC call and RPC reply that this task is being used for. When
|
|
* this RPC is retired, the memory is released by calling rpc_free.
|
|
*
|
|
* To prevent rpciod from hanging, this allocator never sleeps,
|
|
* returning -ENOMEM and suppressing warning if the request cannot
|
|
* be serviced immediately. The caller can arrange to sleep in a
|
|
* way that is safe for rpciod.
|
|
*
|
|
* Most requests are 'small' (under 2KiB) and can be serviced from a
|
|
* mempool, ensuring that NFS reads and writes can always proceed,
|
|
* and that there is good locality of reference for these buffers.
|
|
*
|
|
* In order to avoid memory starvation triggering more writebacks of
|
|
* NFS requests, we avoid using GFP_KERNEL.
|
|
*/
|
|
int rpc_malloc(struct rpc_task *task)
|
|
{
|
|
struct rpc_rqst *rqst = task->tk_rqstp;
|
|
size_t size = rqst->rq_callsize + rqst->rq_rcvsize;
|
|
struct rpc_buffer *buf;
|
|
gfp_t gfp = GFP_NOIO | __GFP_NOWARN;
|
|
|
|
if (RPC_IS_SWAPPER(task))
|
|
gfp = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
|
|
|
|
size += sizeof(struct rpc_buffer);
|
|
if (size <= RPC_BUFFER_MAXSIZE)
|
|
buf = mempool_alloc(rpc_buffer_mempool, gfp);
|
|
else
|
|
buf = kmalloc(size, gfp);
|
|
|
|
if (!buf)
|
|
return -ENOMEM;
|
|
|
|
buf->len = size;
|
|
dprintk("RPC: %5u allocated buffer of size %zu at %p\n",
|
|
task->tk_pid, size, buf);
|
|
rqst->rq_buffer = buf->data;
|
|
rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_malloc);
|
|
|
|
/**
|
|
* rpc_free - free RPC buffer resources allocated via rpc_malloc
|
|
* @task: RPC task
|
|
*
|
|
*/
|
|
void rpc_free(struct rpc_task *task)
|
|
{
|
|
void *buffer = task->tk_rqstp->rq_buffer;
|
|
size_t size;
|
|
struct rpc_buffer *buf;
|
|
|
|
buf = container_of(buffer, struct rpc_buffer, data);
|
|
size = buf->len;
|
|
|
|
dprintk("RPC: freeing buffer of size %zu at %p\n",
|
|
size, buf);
|
|
|
|
if (size <= RPC_BUFFER_MAXSIZE)
|
|
mempool_free(buf, rpc_buffer_mempool);
|
|
else
|
|
kfree(buf);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_free);
|
|
|
|
/*
|
|
* Creation and deletion of RPC task structures
|
|
*/
|
|
static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *task_setup_data)
|
|
{
|
|
memset(task, 0, sizeof(*task));
|
|
atomic_set(&task->tk_count, 1);
|
|
task->tk_flags = task_setup_data->flags;
|
|
task->tk_ops = task_setup_data->callback_ops;
|
|
task->tk_calldata = task_setup_data->callback_data;
|
|
INIT_LIST_HEAD(&task->tk_task);
|
|
|
|
task->tk_priority = task_setup_data->priority - RPC_PRIORITY_LOW;
|
|
task->tk_owner = current->tgid;
|
|
|
|
/* Initialize workqueue for async tasks */
|
|
task->tk_workqueue = task_setup_data->workqueue;
|
|
|
|
task->tk_xprt = xprt_get(task_setup_data->rpc_xprt);
|
|
|
|
if (task->tk_ops->rpc_call_prepare != NULL)
|
|
task->tk_action = rpc_prepare_task;
|
|
|
|
rpc_init_task_statistics(task);
|
|
|
|
dprintk("RPC: new task initialized, procpid %u\n",
|
|
task_pid_nr(current));
|
|
}
|
|
|
|
static struct rpc_task *
|
|
rpc_alloc_task(void)
|
|
{
|
|
return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOIO);
|
|
}
|
|
|
|
/*
|
|
* Create a new task for the specified client.
|
|
*/
|
|
struct rpc_task *rpc_new_task(const struct rpc_task_setup *setup_data)
|
|
{
|
|
struct rpc_task *task = setup_data->task;
|
|
unsigned short flags = 0;
|
|
|
|
if (task == NULL) {
|
|
task = rpc_alloc_task();
|
|
if (task == NULL) {
|
|
rpc_release_calldata(setup_data->callback_ops,
|
|
setup_data->callback_data);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
flags = RPC_TASK_DYNAMIC;
|
|
}
|
|
|
|
rpc_init_task(task, setup_data);
|
|
task->tk_flags |= flags;
|
|
dprintk("RPC: allocated task %p\n", task);
|
|
return task;
|
|
}
|
|
|
|
/*
|
|
* rpc_free_task - release rpc task and perform cleanups
|
|
*
|
|
* Note that we free up the rpc_task _after_ rpc_release_calldata()
|
|
* in order to work around a workqueue dependency issue.
|
|
*
|
|
* Tejun Heo states:
|
|
* "Workqueue currently considers two work items to be the same if they're
|
|
* on the same address and won't execute them concurrently - ie. it
|
|
* makes a work item which is queued again while being executed wait
|
|
* for the previous execution to complete.
|
|
*
|
|
* If a work function frees the work item, and then waits for an event
|
|
* which should be performed by another work item and *that* work item
|
|
* recycles the freed work item, it can create a false dependency loop.
|
|
* There really is no reliable way to detect this short of verifying
|
|
* every memory free."
|
|
*
|
|
*/
|
|
static void rpc_free_task(struct rpc_task *task)
|
|
{
|
|
unsigned short tk_flags = task->tk_flags;
|
|
|
|
rpc_release_calldata(task->tk_ops, task->tk_calldata);
|
|
|
|
if (tk_flags & RPC_TASK_DYNAMIC) {
|
|
dprintk("RPC: %5u freeing task\n", task->tk_pid);
|
|
mempool_free(task, rpc_task_mempool);
|
|
}
|
|
}
|
|
|
|
static void rpc_async_release(struct work_struct *work)
|
|
{
|
|
rpc_free_task(container_of(work, struct rpc_task, u.tk_work));
|
|
}
|
|
|
|
static void rpc_release_resources_task(struct rpc_task *task)
|
|
{
|
|
xprt_release(task);
|
|
if (task->tk_msg.rpc_cred) {
|
|
put_rpccred(task->tk_msg.rpc_cred);
|
|
task->tk_msg.rpc_cred = NULL;
|
|
}
|
|
rpc_task_release_client(task);
|
|
}
|
|
|
|
static void rpc_final_put_task(struct rpc_task *task,
|
|
struct workqueue_struct *q)
|
|
{
|
|
if (q != NULL) {
|
|
INIT_WORK(&task->u.tk_work, rpc_async_release);
|
|
queue_work(q, &task->u.tk_work);
|
|
} else
|
|
rpc_free_task(task);
|
|
}
|
|
|
|
static void rpc_do_put_task(struct rpc_task *task, struct workqueue_struct *q)
|
|
{
|
|
if (atomic_dec_and_test(&task->tk_count)) {
|
|
rpc_release_resources_task(task);
|
|
rpc_final_put_task(task, q);
|
|
}
|
|
}
|
|
|
|
void rpc_put_task(struct rpc_task *task)
|
|
{
|
|
rpc_do_put_task(task, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_put_task);
|
|
|
|
void rpc_put_task_async(struct rpc_task *task)
|
|
{
|
|
rpc_do_put_task(task, task->tk_workqueue);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rpc_put_task_async);
|
|
|
|
static void rpc_release_task(struct rpc_task *task)
|
|
{
|
|
dprintk("RPC: %5u release task\n", task->tk_pid);
|
|
|
|
WARN_ON_ONCE(RPC_IS_QUEUED(task));
|
|
|
|
rpc_release_resources_task(task);
|
|
|
|
/*
|
|
* Note: at this point we have been removed from rpc_clnt->cl_tasks,
|
|
* so it should be safe to use task->tk_count as a test for whether
|
|
* or not any other processes still hold references to our rpc_task.
|
|
*/
|
|
if (atomic_read(&task->tk_count) != 1 + !RPC_IS_ASYNC(task)) {
|
|
/* Wake up anyone who may be waiting for task completion */
|
|
if (!rpc_complete_task(task))
|
|
return;
|
|
} else {
|
|
if (!atomic_dec_and_test(&task->tk_count))
|
|
return;
|
|
}
|
|
rpc_final_put_task(task, task->tk_workqueue);
|
|
}
|
|
|
|
int rpciod_up(void)
|
|
{
|
|
return try_module_get(THIS_MODULE) ? 0 : -EINVAL;
|
|
}
|
|
|
|
void rpciod_down(void)
|
|
{
|
|
module_put(THIS_MODULE);
|
|
}
|
|
|
|
/*
|
|
* Start up the rpciod workqueue.
|
|
*/
|
|
static int rpciod_start(void)
|
|
{
|
|
struct workqueue_struct *wq;
|
|
|
|
/*
|
|
* Create the rpciod thread and wait for it to start.
|
|
*/
|
|
dprintk("RPC: creating workqueue rpciod\n");
|
|
wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM, 0);
|
|
if (!wq)
|
|
goto out_failed;
|
|
rpciod_workqueue = wq;
|
|
/* Note: highpri because network receive is latency sensitive */
|
|
wq = alloc_workqueue("xprtiod", WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
|
|
if (!wq)
|
|
goto free_rpciod;
|
|
xprtiod_workqueue = wq;
|
|
return 1;
|
|
free_rpciod:
|
|
wq = rpciod_workqueue;
|
|
rpciod_workqueue = NULL;
|
|
destroy_workqueue(wq);
|
|
out_failed:
|
|
return 0;
|
|
}
|
|
|
|
static void rpciod_stop(void)
|
|
{
|
|
struct workqueue_struct *wq = NULL;
|
|
|
|
if (rpciod_workqueue == NULL)
|
|
return;
|
|
dprintk("RPC: destroying workqueue rpciod\n");
|
|
|
|
wq = rpciod_workqueue;
|
|
rpciod_workqueue = NULL;
|
|
destroy_workqueue(wq);
|
|
wq = xprtiod_workqueue;
|
|
xprtiod_workqueue = NULL;
|
|
destroy_workqueue(wq);
|
|
}
|
|
|
|
void
|
|
rpc_destroy_mempool(void)
|
|
{
|
|
rpciod_stop();
|
|
mempool_destroy(rpc_buffer_mempool);
|
|
mempool_destroy(rpc_task_mempool);
|
|
kmem_cache_destroy(rpc_task_slabp);
|
|
kmem_cache_destroy(rpc_buffer_slabp);
|
|
rpc_destroy_wait_queue(&delay_queue);
|
|
}
|
|
|
|
int
|
|
rpc_init_mempool(void)
|
|
{
|
|
/*
|
|
* The following is not strictly a mempool initialisation,
|
|
* but there is no harm in doing it here
|
|
*/
|
|
rpc_init_wait_queue(&delay_queue, "delayq");
|
|
if (!rpciod_start())
|
|
goto err_nomem;
|
|
|
|
rpc_task_slabp = kmem_cache_create("rpc_tasks",
|
|
sizeof(struct rpc_task),
|
|
0, SLAB_HWCACHE_ALIGN,
|
|
NULL);
|
|
if (!rpc_task_slabp)
|
|
goto err_nomem;
|
|
rpc_buffer_slabp = kmem_cache_create("rpc_buffers",
|
|
RPC_BUFFER_MAXSIZE,
|
|
0, SLAB_HWCACHE_ALIGN,
|
|
NULL);
|
|
if (!rpc_buffer_slabp)
|
|
goto err_nomem;
|
|
rpc_task_mempool = mempool_create_slab_pool(RPC_TASK_POOLSIZE,
|
|
rpc_task_slabp);
|
|
if (!rpc_task_mempool)
|
|
goto err_nomem;
|
|
rpc_buffer_mempool = mempool_create_slab_pool(RPC_BUFFER_POOLSIZE,
|
|
rpc_buffer_slabp);
|
|
if (!rpc_buffer_mempool)
|
|
goto err_nomem;
|
|
return 0;
|
|
err_nomem:
|
|
rpc_destroy_mempool();
|
|
return -ENOMEM;
|
|
}
|