numam-spdk/include/spdk/thread.h
Niu Yawei 0901744bb1 thread: Export spdk_set_thread()
Export the spdk_set_thread(), so that apps may use it to associate
a thread with SPDK thread when necessary.

Change-Id: I488bea639729d68d7261a497085bbec274357224
Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/461509
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
2019-07-15 01:34:41 +00:00

558 lines
18 KiB
C

/*-
* BSD LICENSE
*
* Copyright (c) Intel Corporation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** \file
* Thread
*/
#ifndef SPDK_THREAD_H_
#define SPDK_THREAD_H_
#include "spdk/stdinc.h"
#include "spdk/cpuset.h"
#include "spdk/queue.h"
#ifdef __cplusplus
extern "C" {
#endif
struct spdk_thread;
struct spdk_io_channel_iter;
struct spdk_poller;
/**
* A function that is called each time a new thread is created.
* The implementor of this function should frequently call
* spdk_thread_poll() on the thread provided.
*
* \param thread The new spdk_thread.
*/
typedef int (*spdk_new_thread_fn)(struct spdk_thread *thread);
/**
* A function that will be called on the target thread.
*
* \param ctx Context passed as arg to spdk_thread_pass_msg().
*/
typedef void (*spdk_msg_fn)(void *ctx);
/**
* Function to be called to pass a message to a thread.
*
* \param fn Callback function for a thread.
* \param ctx Context passed to fn.
* \param thread_ctx Context for the thread.
*/
typedef void (*spdk_thread_pass_msg)(spdk_msg_fn fn, void *ctx,
void *thread_ctx);
/**
* Callback function for a poller.
*
* \param ctx Context passed as arg to spdk_poller_register().
* \return 0 to indicate that polling took place but no events were found;
* positive to indicate that polling took place and some events were processed;
* negative if the poller does not provide spin-wait information.
*/
typedef int (*spdk_poller_fn)(void *ctx);
/**
* Function to be called to start a poller for the thread.
*
* \param thread_ctx Context for the thread.
* \param fn Callback function for a poller.
* \param arg Argument passed to callback.
* \param period Polling period in microseconds.
*
* \return a pointer to the poller on success, or NULL on failure.
*/
typedef struct spdk_poller *(*spdk_start_poller)(void *thread_ctx,
spdk_poller_fn fn,
void *arg,
uint64_t period_microseconds);
/**
* Function to be called to stop a poller.
*
* \param poller Poller to stop.
* \param thread_ctx Context for the thread.
*/
typedef void (*spdk_stop_poller)(struct spdk_poller *poller, void *thread_ctx);
/**
* I/O channel creation callback.
*
* \param io_device I/O device associated with this channel.
* \param ctx_buf Context for the I/O device.
*/
typedef int (*spdk_io_channel_create_cb)(void *io_device, void *ctx_buf);
/**
* I/O channel destruction callback.
*
* \param io_device I/O device associated with this channel.
* \param ctx_buf Context for the I/O device.
*/
typedef void (*spdk_io_channel_destroy_cb)(void *io_device, void *ctx_buf);
/**
* I/O device unregister callback.
*
* \param io_device Unregistered I/O device.
*/
typedef void (*spdk_io_device_unregister_cb)(void *io_device);
/**
* Called on the appropriate thread for each channel associated with io_device.
*
* \param i I/O channel iterator.
*/
typedef void (*spdk_channel_msg)(struct spdk_io_channel_iter *i);
/**
* spdk_for_each_channel() callback.
*
* \param i I/O channel iterator.
* \param status 0 if it completed successfully, or negative errno if it failed.
*/
typedef void (*spdk_channel_for_each_cpl)(struct spdk_io_channel_iter *i, int status);
/**
* \brief Represents a per-thread channel for accessing an I/O device.
*
* An I/O device may be a physical entity (i.e. NVMe controller) or a software
* entity (i.e. a blobstore).
*
* This structure is not part of the API - all accesses should be done through
* spdk_io_channel function calls.
*/
struct spdk_io_channel {
struct spdk_thread *thread;
struct io_device *dev;
uint32_t ref;
uint32_t destroy_ref;
TAILQ_ENTRY(spdk_io_channel) tailq;
spdk_io_channel_destroy_cb destroy_cb;
/*
* Modules will allocate extra memory off the end of this structure
* to store references to hardware-specific references (i.e. NVMe queue
* pairs, or references to child device spdk_io_channels (i.e.
* virtual bdevs).
*/
};
/**
* Initialize the threading library. Must be called once prior to allocating any threads.
*
* \param new_thread_fn Called each time a new SPDK thread is created. The implementor
* is expected to frequently call spdk_thread_poll() on the provided thread.
* \param ctx_sz For each thread allocated, an additional region of memory of
* size ctx_size will also be allocated, for use by the thread scheduler. A pointer
* to this region may be obtained by calling spdk_thread_get_ctx().
*
* \return 0 on success. Negated errno on failure.
*/
int spdk_thread_lib_init(spdk_new_thread_fn new_thread_fn, size_t ctx_sz);
/**
* Release all resources associated with this library.
*/
void spdk_thread_lib_fini(void);
/**
* Creates a new SPDK thread object.
*
* \param name Human-readable name for the thread; can be retrieved with spdk_thread_get_name().
* The string is copied, so the pointed-to data only needs to be valid during the
* spdk_thread_create() call. May be NULL to specify no name.
* \param cpumask Optional mask of CPU cores on which to schedule this thread. This is only
* a suggestion to the scheduler. The value is copied, so cpumask may be released when
* this function returns. May be NULL if no mask is required.
*
* \return a pointer to the allocated thread on success or NULL on failure..
*/
struct spdk_thread *spdk_thread_create(const char *name, struct spdk_cpuset *cpumask);
/**
* Force the current system thread to act as if executing the given SPDK thread.
*
* \param thread The thread to set.
*/
void spdk_set_thread(struct spdk_thread *thread);
/**
* Mark the thread as exited, failing all future spdk_thread_poll() calls. May
* only be called within an spdk poller or message.
*
*
* \param thread The thread to destroy.
*
* All I/O channel references associated with the thread must be released using
* spdk_put_io_channel() prior to calling this function.
*/
void spdk_thread_exit(struct spdk_thread *thread);
/**
* Destroy a thread, releasing all of its resources. May only be called
* on a thread previously marked as exited.
*
* \param thread The thread to destroy.
*
*/
void spdk_thread_destroy(struct spdk_thread *thread);
/**
* Return a pointer to this thread's context.
*
* \param thread The thread on which to get the context.
*
* \return a pointer to the per-thread context, or NULL if there is
* no per-thread context.
*/
void *spdk_thread_get_ctx(struct spdk_thread *thread);
/**
* Get the thread's cpumask.
*
* \param thread The thread to get the cpumask for.
*
* \return cpuset pointer
*/
struct spdk_cpuset *spdk_thread_get_cpumask(struct spdk_thread *thread);
/**
* Return the thread object associated with the context handle previously
* obtained by calling spdk_thread_get_ctx().
*
* \param ctx A context previously obtained by calling spdk_thread_get_ctx()
*
* \return The associated thread.
*/
struct spdk_thread *spdk_thread_get_from_ctx(void *ctx);
/**
* Perform one iteration worth of processing on the thread. This includes
* both expired and continuous pollers as well as messages.
*
* \param thread The thread to process
* \param max_msgs The maximum number of messages that will be processed.
* Use 0 to process the default number of messages (8).
* \param now The current time, in ticks. Optional. If 0 is passed, this
* function may call spdk_get_ticks() to get the current time.
*
* \return 1 if work was done. 0 if no work was done. -1 if thread has exited.
*/
int spdk_thread_poll(struct spdk_thread *thread, uint32_t max_msgs, uint64_t now);
/**
* Return the number of ticks until the next timed poller
* would expire. Timed pollers are pollers for which
* period_microseconds is greater than 0.
*
* \param thread The thread to check poller expiration times on
*
* \return Number of ticks. If no timed pollers, return 0.
*/
uint64_t spdk_thread_next_poller_expiration(struct spdk_thread *thread);
/**
* Returns whether there are any active pollers (pollers for which
* period_microseconds equals 0) registered to be run on the thread.
*
* \param thread The thread to check.
*
* \return 1 if there is at least one active poller, 0 otherwise.
*/
int spdk_thread_has_active_pollers(struct spdk_thread *thread);
/**
* Returns whether there are any pollers registered to be run
* on the thread.
*
* \param thread The thread to check.
*
* \return true if there is any active poller, false otherwise.
*/
bool spdk_thread_has_pollers(struct spdk_thread *thread);
/**
* Returns whether there are scheduled operations to be run on the thread.
*
* \param thread The thread to check.
*
* \return true if there are no scheduled operations, false otherwise.
*/
bool spdk_thread_is_idle(struct spdk_thread *thread);
/**
* Get count of allocated threads.
*/
uint32_t spdk_thread_get_count(void);
/**
* Get a handle to the current thread.
*
* This handle may be passed to other threads and used as the target of
* spdk_thread_send_msg().
*
* \sa spdk_io_channel_get_thread()
*
* \return a pointer to the current thread on success or NULL on failure.
*/
struct spdk_thread *spdk_get_thread(void);
/**
* Get a thread's name.
*
* \param thread Thread to query.
*
* \return the name of the thread.
*/
const char *spdk_thread_get_name(const struct spdk_thread *thread);
struct spdk_thread_stats {
uint64_t busy_tsc;
uint64_t idle_tsc;
};
/**
* Get statistics about the current thread.
*
* Copy cumulative thread stats values to the provided thread stats structure.
*
* \param stats User's thread_stats structure.
*/
int spdk_thread_get_stats(struct spdk_thread_stats *stats);
/**
* Send a message to the given thread.
*
* The message may be sent asynchronously - i.e. spdk_thread_send_msg may return
* prior to `fn` being called.
*
* \param thread The target thread.
* \param fn This function will be called on the given thread.
* \param ctx This context will be passed to fn when called.
*/
void spdk_thread_send_msg(const struct spdk_thread *thread, spdk_msg_fn fn, void *ctx);
/**
* Send a message to each thread, serially.
*
* The message is sent asynchronously - i.e. spdk_for_each_thread will return
* prior to `fn` being called on each thread.
*
* \param fn This is the function that will be called on each thread.
* \param ctx This context will be passed to fn when called.
* \param cpl This will be called on the originating thread after `fn` has been
* called on each thread.
*/
void spdk_for_each_thread(spdk_msg_fn fn, void *ctx, spdk_msg_fn cpl);
/**
* Register a poller on the current thread.
*
* The poller can be unregistered by calling spdk_poller_unregister().
*
* \param fn This function will be called every `period_microseconds`.
* \param arg Argument passed to fn.
* \param period_microseconds How often to call `fn`. If 0, call `fn` as often
* as possible.
*
* \return a pointer to the poller registered on the current thread on success
* or NULL on failure.
*/
struct spdk_poller *spdk_poller_register(spdk_poller_fn fn,
void *arg,
uint64_t period_microseconds);
/**
* Unregister a poller on the current thread.
*
* \param ppoller The poller to unregister.
*/
void spdk_poller_unregister(struct spdk_poller **ppoller);
/**
* Register the opaque io_device context as an I/O device.
*
* After an I/O device is registered, it can return I/O channels using the
* spdk_get_io_channel() function.
*
* \param io_device The pointer to io_device context.
* \param create_cb Callback function invoked to allocate any resources required
* for a new I/O channel.
* \param destroy_cb Callback function invoked to release the resources for an
* I/O channel.
* \param ctx_size The size of the context buffer allocated to store references
* to allocated I/O channel resources.
* \param name A string name for the device used only for debugging. Optional -
* may be NULL.
*/
void spdk_io_device_register(void *io_device, spdk_io_channel_create_cb create_cb,
spdk_io_channel_destroy_cb destroy_cb, uint32_t ctx_size,
const char *name);
/**
* Unregister the opaque io_device context as an I/O device.
*
* The actual unregistration might be deferred until all active I/O channels are
* destroyed.
*
* \param io_device The pointer to io_device context.
* \param unregister_cb An optional callback function invoked to release any
* references to this I/O device.
*/
void spdk_io_device_unregister(void *io_device, spdk_io_device_unregister_cb unregister_cb);
/**
* Get an I/O channel for the specified io_device to be used by the calling thread.
*
* The io_device context pointer specified must have previously been registered
* using spdk_io_device_register(). If an existing I/O channel does not exist
* yet for the given io_device on the calling thread, it will allocate an I/O
* channel and invoke the create_cb function pointer specified in spdk_io_device_register().
* If an I/O channel already exists for the given io_device on the calling thread,
* its reference is returned rather than creating a new I/O channel.
*
* \param io_device The pointer to io_device context.
*
* \return a pointer to the I/O channel for this device on success or NULL on failure.
*/
struct spdk_io_channel *spdk_get_io_channel(void *io_device);
/**
* Release a reference to an I/O channel. This happens asynchronously.
*
* Actual release will happen on the same thread that called spdk_get_io_channel()
* for the specified I/O channel. If this releases the last reference to the
* I/O channel, The destroy_cb function specified in spdk_io_device_register()
* will be invoked to release any associated resources.
*
* \param ch I/O channel to release a reference.
*/
void spdk_put_io_channel(struct spdk_io_channel *ch);
/**
* Get the context buffer associated with an I/O channel.
*
* \param ch I/O channel.
*
* \return a pointer to the context buffer.
*/
static inline void *
spdk_io_channel_get_ctx(struct spdk_io_channel *ch)
{
return (uint8_t *)ch + sizeof(*ch);
}
/**
* Get I/O channel from the context buffer. This is the inverse of
* spdk_io_channel_get_ctx().
*
* \param ctx The pointer to the context buffer.
*
* \return a pointer to the I/O channel associated with the context buffer.
*/
struct spdk_io_channel *spdk_io_channel_from_ctx(void *ctx);
/**
* Get the thread associated with an I/O channel.
*
* \param ch I/O channel.
*
* \return a pointer to the thread associated with the I/O channel
*/
struct spdk_thread *spdk_io_channel_get_thread(struct spdk_io_channel *ch);
/**
* Call 'fn' on each channel associated with io_device.
*
* This happens asynchronously, so fn may be called after spdk_for_each_channel
* returns. 'fn' will be called for each channel serially, such that two calls
* to 'fn' will not overlap in time. After 'fn' has been called, call
* spdk_for_each_channel_continue() to continue iterating.
*
* \param io_device 'fn' will be called on each channel associated with this io_device.
* \param fn Called on the appropriate thread for each channel associated with io_device.
* \param ctx Context buffer registered to spdk_io_channel_iter that can be obatined
* form the function spdk_io_channel_iter_get_ctx().
* \param cpl Called on the thread that spdk_for_each_channel was initially called
* from when 'fn' has been called on each channel.
*/
void spdk_for_each_channel(void *io_device, spdk_channel_msg fn, void *ctx,
spdk_channel_for_each_cpl cpl);
/**
* Get io_device from the I/O channel iterator.
*
* \param i I/O channel iterator.
*
* \return a pointer to the io_device.
*/
void *spdk_io_channel_iter_get_io_device(struct spdk_io_channel_iter *i);
/**
* Get I/O channel from the I/O channel iterator.
*
* \param i I/O channel iterator.
*
* \return a pointer to the I/O channel.
*/
struct spdk_io_channel *spdk_io_channel_iter_get_channel(struct spdk_io_channel_iter *i);
/**
* Get context buffer from the I/O channel iterator.
*
* \param i I/O channel iterator.
*
* \return a pointer to the context buffer.
*/
void *spdk_io_channel_iter_get_ctx(struct spdk_io_channel_iter *i);
/**
* Helper function to iterate all channels for spdk_for_each_channel().
*
* \param i I/O channel iterator.
* \param status Status for the I/O channel iterator.
*/
void spdk_for_each_channel_continue(struct spdk_io_channel_iter *i, int status);
#ifdef __cplusplus
}
#endif
#endif /* SPDK_THREAD_H_ */