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Diffstat (limited to 'rt/aio_misc.c')
| -rw-r--r-- | rt/aio_misc.c | 708 |
1 files changed, 0 insertions, 708 deletions
diff --git a/rt/aio_misc.c b/rt/aio_misc.c deleted file mode 100644 index 1026e061c8..0000000000 --- a/rt/aio_misc.c +++ /dev/null @@ -1,708 +0,0 @@ -/* Handle general operations. - Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Library General Public License as - published by the Free Software Foundation; either version 2 of the - License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Library General Public License for more details. - - You should have received a copy of the GNU Library General Public - License along with the GNU C Library; see the file COPYING.LIB. If not, - write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ - -#include <aio.h> -#include <assert.h> -#include <errno.h> -#include <limits.h> -#include <pthread.h> -#include <stdlib.h> -#include <unistd.h> -#include <sys/stat.h> -#include <sys/time.h> - -#include "aio_misc.h" - -static void add_request_to_runlist (struct requestlist *newrequest); - -/* Pool of request list entries. */ -static struct requestlist **pool; - -/* Number of total and allocated pool entries. */ -static size_t pool_max_size; -static size_t pool_size; - -/* We implement a two dimensional array but allocate each row separately. - The macro below determines how many entries should be used per row. - It should better be a power of two. */ -#define ENTRIES_PER_ROW 32 - -/* How many rows we allocate at once. */ -#define ROWS_STEP 8 - -/* List of available entries. */ -static struct requestlist *freelist; - -/* List of request waiting to be processed. */ -static struct requestlist *runlist; - -/* Structure list of all currently processed requests. */ -static struct requestlist *requests; - -/* Number of threads currently running. */ -static int nthreads; - -/* Number of threads waiting for work to arrive. */ -static int idle_thread_count; - - -/* These are the values used to optimize the use of AIO. The user can - overwrite them by using the `aio_init' function. */ -static struct aioinit optim = -{ - 20, /* int aio_threads; Maximal number of threads. */ - 64, /* int aio_num; Number of expected simultanious requests. */ - 0, - 0, - 0, - 0, - 1, - 0 -}; - - -/* Since the list is global we need a mutex protecting it. */ -pthread_mutex_t __aio_requests_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP; - -/* When you add a request to the list and there are idle threads present, - you signal this condition variable. When a thread finishes work, it waits - on this condition variable for a time before it actually exits. */ -pthread_cond_t __aio_new_request_notification = PTHREAD_COND_INITIALIZER; - - -/* Functions to handle request list pool. */ -static struct requestlist * -get_elem (void) -{ - struct requestlist *result; - - if (freelist == NULL) - { - struct requestlist *new_row; - int cnt; - - assert (sizeof (struct aiocb) == sizeof (struct aiocb64)); - - if (pool_size + 1 >= pool_max_size) - { - size_t new_max_size = pool_max_size + ROWS_STEP; - struct requestlist **new_tab; - - new_tab = (struct requestlist **) - realloc (pool, new_max_size * sizeof (struct requestlist *)); - - if (new_tab == NULL) - return NULL; - - pool_max_size = new_max_size; - pool = new_tab; - } - - /* Allocate the new row. */ - cnt = pool_size == 0 ? optim.aio_num : ENTRIES_PER_ROW; - new_row = (struct requestlist *) calloc (cnt, - sizeof (struct requestlist)); - if (new_row == NULL) - return NULL; - - pool[pool_size++] = new_row; - - /* Put all the new entries in the freelist. */ - do - { - new_row->next_prio = freelist; - freelist = new_row++; - } - while (--cnt > 0); - } - - result = freelist; - freelist = freelist->next_prio; - - return result; -} - - -void -internal_function -__aio_free_request (struct requestlist *elem) -{ - elem->running = no; - elem->next_prio = freelist; - freelist = elem; -} - - -struct requestlist * -internal_function -__aio_find_req (aiocb_union *elem) -{ - struct requestlist *runp = requests; - int fildes = elem->aiocb.aio_fildes; - - while (runp != NULL && runp->aiocbp->aiocb.aio_fildes < fildes) - runp = runp->next_fd; - - if (runp != NULL) - { - if (runp->aiocbp->aiocb.aio_fildes != fildes) - runp = NULL; - else - while (runp != NULL && runp->aiocbp != elem) - runp = runp->next_prio; - } - - return runp; -} - - -struct requestlist * -internal_function -__aio_find_req_fd (int fildes) -{ - struct requestlist *runp = requests; - - while (runp != NULL && runp->aiocbp->aiocb.aio_fildes < fildes) - runp = runp->next_fd; - - return (runp != NULL && runp->aiocbp->aiocb.aio_fildes == fildes - ? runp : NULL); -} - - -void -internal_function -__aio_remove_request (struct requestlist *last, struct requestlist *req, - int all) -{ - assert (req->running == yes || req->running == queued - || req->running == done); - - if (last != NULL) - last->next_prio = all ? NULL : req->next_prio; - else - { - if (all || req->next_prio == NULL) - { - if (req->last_fd != NULL) - req->last_fd->next_fd = req->next_fd; - else - requests = req->next_fd; - if (req->next_fd != NULL) - req->next_fd->last_fd = req->last_fd; - } - else - { - if (req->last_fd != NULL) - req->last_fd->next_fd = req->next_prio; - else - requests = req->next_prio; - - if (req->next_fd != NULL) - req->next_fd->last_fd = req->next_prio; - - req->next_prio->last_fd = req->last_fd; - req->next_prio->next_fd = req->next_fd; - - /* Mark this entry as runnable. */ - req->next_prio->running = yes; - } - - if (req->running == yes) - { - struct requestlist *runp = runlist; - - last = NULL; - while (runp != NULL) - { - if (runp == req) - { - if (last == NULL) - runlist = runp->next_run; - else - last->next_run = runp->next_run; - break; - } - last = runp; - runp = runp->next_run; - } - } - } -} - - -/* The thread handler. */ -static void *handle_fildes_io (void *arg); - - -/* User optimization. */ -void -__aio_init (const struct aioinit *init) -{ - /* Get the mutex. */ - pthread_mutex_lock (&__aio_requests_mutex); - - /* Only allow writing new values if the table is not yet allocated. */ - if (pool == NULL) - { - optim.aio_threads = init->aio_threads < 1 ? 1 : init->aio_threads; - optim.aio_num = (init->aio_num < ENTRIES_PER_ROW - ? ENTRIES_PER_ROW - : init->aio_num & ~ENTRIES_PER_ROW); - } - - if (init->aio_idle_time != 0) - optim.aio_idle_time = init->aio_idle_time; - - /* Release the mutex. */ - pthread_mutex_unlock (&__aio_requests_mutex); -} -weak_alias (__aio_init, aio_init) - - -/* The main function of the async I/O handling. It enqueues requests - and if necessary starts and handles threads. */ -struct requestlist * -internal_function -__aio_enqueue_request (aiocb_union *aiocbp, int operation) -{ - int result = 0; - int policy, prio; - struct sched_param param; - struct requestlist *last, *runp, *newp; - int running = no; - - if (operation == LIO_SYNC || operation == LIO_DSYNC) - aiocbp->aiocb.aio_reqprio = 0; - else if (aiocbp->aiocb.aio_reqprio < 0 - || aiocbp->aiocb.aio_reqprio > AIO_PRIO_DELTA_MAX) - { - /* Invalid priority value. */ - __set_errno (EINVAL); - aiocbp->aiocb.__error_code = EINVAL; - aiocbp->aiocb.__return_value = -1; - return NULL; - } - - /* Compute priority for this request. */ - pthread_getschedparam (pthread_self (), &policy, ¶m); - prio = param.sched_priority - aiocbp->aiocb.aio_reqprio; - - /* Get the mutex. */ - pthread_mutex_lock (&__aio_requests_mutex); - - last = NULL; - runp = requests; - /* First look whether the current file descriptor is currently - worked with. */ - while (runp != NULL - && runp->aiocbp->aiocb.aio_fildes < aiocbp->aiocb.aio_fildes) - { - last = runp; - runp = runp->next_fd; - } - - /* Get a new element for the waiting list. */ - newp = get_elem (); - if (newp == NULL) - { - pthread_mutex_unlock (&__aio_requests_mutex); - __set_errno (EAGAIN); - return NULL; - } - newp->aiocbp = aiocbp; - newp->caller_pid = (aiocbp->aiocb.aio_sigevent.sigev_notify == SIGEV_SIGNAL - ? getpid () : 0); - newp->waiting = NULL; - - aiocbp->aiocb.__abs_prio = prio; - aiocbp->aiocb.__policy = policy; - aiocbp->aiocb.aio_lio_opcode = operation; - aiocbp->aiocb.__error_code = EINPROGRESS; - aiocbp->aiocb.__return_value = 0; - - if (runp != NULL - && runp->aiocbp->aiocb.aio_fildes == aiocbp->aiocb.aio_fildes) - { - /* The current file descriptor is worked on. It makes no sense - to start another thread since this new thread would fight - with the running thread for the resources. But we also cannot - say that the thread processing this desriptor shall immediately - after finishing the current job process this request if there - are other threads in the running queue which have a higher - priority. */ - - /* Simply enqueue it after the running one according to the - priority. */ - while (runp->next_prio != NULL - && runp->next_prio->aiocbp->aiocb.__abs_prio >= prio) - runp = runp->next_prio; - - newp->next_prio = runp->next_prio; - runp->next_prio = newp; - - running = queued; - } - else - { - running = yes; - /* Enqueue this request for a new descriptor. */ - if (last == NULL) - { - newp->last_fd = NULL; - newp->next_fd = requests; - if (requests != NULL) - requests->last_fd = newp; - requests = newp; - } - else - { - newp->next_fd = last->next_fd; - newp->last_fd = last; - last->next_fd = newp; - if (newp->next_fd != NULL) - newp->next_fd->last_fd = newp; - } - - newp->next_prio = NULL; - } - - if (running == yes) - { - /* We try to create a new thread for this file descriptor. The - function which gets called will handle all available requests - for this descriptor and when all are processed it will - terminate. - - If no new thread can be created or if the specified limit of - threads for AIO is reached we queue the request. */ - - /* See if we need to and are able to create a thread. */ - if (nthreads < optim.aio_threads && idle_thread_count == 0) - { - pthread_t thid; - pthread_attr_t attr; - - /* Make sure the thread is created detached. */ - pthread_attr_init (&attr); - pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); - - running = newp->running = allocated; - - /* Now try to start a thread. */ - if (pthread_create (&thid, &attr, handle_fildes_io, newp) == 0) - /* We managed to enqueue the request. All errors which can - happen now can be recognized by calls to `aio_return' and - `aio_error'. */ - ++nthreads; - else - { - /* Reset the running flag. The new request is not running. */ - running = newp->running = yes; - - if (nthreads == 0) - /* We cannot create a thread in the moment and there is - also no thread running. This is a problem. `errno' is - set to EAGAIN if this is only a temporary problem. */ - result = -1; - } - } - } - - /* Enqueue the request in the run queue if it is not yet running. */ - if (running == yes && result == 0) - { - add_request_to_runlist (newp); - - /* If there is a thread waiting for work, then let it know that we - have just given it something to do. */ - if (idle_thread_count > 0) - pthread_cond_signal (&__aio_new_request_notification); - } - - if (result == 0) - newp->running = running; - else - { - /* Something went wrong. */ - __aio_free_request (newp); - newp = NULL; - } - - /* Release the mutex. */ - pthread_mutex_unlock (&__aio_requests_mutex); - - return newp; -} - - -static void * -__attribute__ ((noreturn)) -handle_fildes_io (void *arg) -{ - pthread_t self = pthread_self (); - struct sched_param param; - struct requestlist *runp = (struct requestlist *) arg; - aiocb_union *aiocbp; - int policy; - int fildes; - - pthread_getschedparam (self, &policy, ¶m); - - do - { - /* If runp is NULL, then we were created to service the work queue - in general, not to handle any particular request. In that case we - skip the "do work" stuff on the first pass, and go directly to the - "get work off the work queue" part of this loop, which is near the - end. */ - if (runp == NULL) - pthread_mutex_lock (&__aio_requests_mutex); - else - { - /* Hopefully this request is marked as running. */ - assert (runp->running == allocated); - - /* Update our variables. */ - aiocbp = runp->aiocbp; - fildes = aiocbp->aiocb.aio_fildes; - - /* Change the priority to the requested value (if necessary). */ - if (aiocbp->aiocb.__abs_prio != param.sched_priority - || aiocbp->aiocb.__policy != policy) - { - param.sched_priority = aiocbp->aiocb.__abs_prio; - policy = aiocbp->aiocb.__policy; - pthread_setschedparam (self, policy, ¶m); - } - - /* Process request pointed to by RUNP. We must not be disturbed - by signals. */ - if ((aiocbp->aiocb.aio_lio_opcode & 127) == LIO_READ) - { - if (aiocbp->aiocb.aio_lio_opcode & 128) - aiocbp->aiocb.__return_value = - TEMP_FAILURE_RETRY (__pread64 (fildes, (void *) - aiocbp->aiocb64.aio_buf, - aiocbp->aiocb64.aio_nbytes, - aiocbp->aiocb64.aio_offset)); - else - aiocbp->aiocb.__return_value = - TEMP_FAILURE_RETRY (pread (fildes, - (void *) aiocbp->aiocb.aio_buf, - aiocbp->aiocb.aio_nbytes, - aiocbp->aiocb.aio_offset)); - - if (aiocbp->aiocb.__return_value == -1 && errno == ESPIPE) - /* The Linux kernel is different from others. It returns - ESPIPE if using pread on a socket. Other platforms - simply ignore the offset parameter and behave like - read. */ - aiocbp->aiocb.__return_value = - TEMP_FAILURE_RETRY (read (fildes, - (void *) aiocbp->aiocb64.aio_buf, - aiocbp->aiocb64.aio_nbytes)); - } - else if ((aiocbp->aiocb.aio_lio_opcode & 127) == LIO_WRITE) - { - if (aiocbp->aiocb.aio_lio_opcode & 128) - aiocbp->aiocb.__return_value = - TEMP_FAILURE_RETRY (__pwrite64 (fildes, (const void *) - aiocbp->aiocb64.aio_buf, - aiocbp->aiocb64.aio_nbytes, - aiocbp->aiocb64.aio_offset)); - else - aiocbp->aiocb.__return_value = - TEMP_FAILURE_RETRY (pwrite (fildes, (const void *) - aiocbp->aiocb.aio_buf, - aiocbp->aiocb.aio_nbytes, - aiocbp->aiocb.aio_offset)); - - if (aiocbp->aiocb.__return_value == -1 && errno == ESPIPE) - /* The Linux kernel is different from others. It returns - ESPIPE if using pwrite on a socket. Other platforms - simply ignore the offset parameter and behave like - write. */ - aiocbp->aiocb.__return_value = - TEMP_FAILURE_RETRY (write (fildes, - (void *) aiocbp->aiocb64.aio_buf, - aiocbp->aiocb64.aio_nbytes)); - } - else if (aiocbp->aiocb.aio_lio_opcode == LIO_DSYNC) - aiocbp->aiocb.__return_value = - TEMP_FAILURE_RETRY (fdatasync (fildes)); - else if (aiocbp->aiocb.aio_lio_opcode == LIO_SYNC) - aiocbp->aiocb.__return_value = - TEMP_FAILURE_RETRY (fsync (fildes)); - else - { - /* This is an invalid opcode. */ - aiocbp->aiocb.__return_value = -1; - __set_errno (EINVAL); - } - - /* Get the mutex. */ - pthread_mutex_lock (&__aio_requests_mutex); - - /* In theory we would need here a write memory barrier since the - callers test using aio_error() whether the request finished - and once this value != EINPROGRESS the field __return_value - must be committed to memory. - - But since the pthread_mutex_lock call involves write memory - barriers as well it is not necessary. */ - - if (aiocbp->aiocb.__return_value == -1) - aiocbp->aiocb.__error_code = errno; - else - aiocbp->aiocb.__error_code = 0; - - /* Send the signal to notify about finished processing of the - request. */ - __aio_notify (runp); - - /* For debugging purposes we reset the running flag of the - finished request. */ - assert (runp->running == allocated); - runp->running = done; - - /* Now dequeue the current request. */ - __aio_remove_request (NULL, runp, 0); - if (runp->next_prio != NULL) - add_request_to_runlist (runp->next_prio); - - /* Free the old element. */ - __aio_free_request (runp); - } - - runp = runlist; - - /* If the runlist is empty, then we sleep for a while, waiting for - something to arrive in it. */ - if (runp == NULL && optim.aio_idle_time >= 0) - { - struct timeval now; - struct timespec wakeup_time; - - ++idle_thread_count; - gettimeofday (&now, NULL); - wakeup_time.tv_sec = now.tv_sec + optim.aio_idle_time; - wakeup_time.tv_nsec = now.tv_usec * 1000; - if (wakeup_time.tv_nsec > 1000000000) - { - wakeup_time.tv_nsec -= 1000000000; - ++wakeup_time.tv_sec; - } - pthread_cond_timedwait (&__aio_new_request_notification, - &__aio_requests_mutex, - &wakeup_time); - --idle_thread_count; - runp = runlist; - } - - if (runp == NULL) - --nthreads; - else - { - assert (runp->running == yes); - runp->running = allocated; - runlist = runp->next_run; - - /* If we have a request to process, and there's still another in - the run list, then we need to either wake up or create a new - thread to service the request that is still in the run list. */ - if (runlist != NULL) - { - /* There are at least two items in the work queue to work on. - If there are other idle threads, then we should wake them - up for these other work elements; otherwise, we should try - to create a new thread. */ - if (idle_thread_count > 0) - pthread_cond_signal (&__aio_new_request_notification); - else if (nthreads < optim.aio_threads) - { - pthread_t thid; - pthread_attr_t attr; - - /* Make sure the thread is created detached. */ - pthread_attr_init (&attr); - pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); - - /* Now try to start a thread. If we fail, no big deal, - because we know that there is at least one thread (us) - that is working on AIO operations. */ - if (pthread_create (&thid, &attr, handle_fildes_io, NULL) - == 0) - ++nthreads; - } - } - } - - /* Release the mutex. */ - pthread_mutex_unlock (&__aio_requests_mutex); - } - while (runp != NULL); - - pthread_exit (NULL); -} - - -/* Free allocated resources. */ -static void -__attribute__ ((unused)) -free_res (void) -{ - size_t row; - - for (row = 0; row < pool_max_size; ++row) - free (pool[row]); - - free (pool); -} -text_set_element (__libc_subfreeres, free_res); - - -/* Add newrequest to the runlist. The __abs_prio flag of newrequest must - be correctly set to do this. Also, you had better set newrequest's - "running" flag to "yes" before you release your lock or you'll throw an - assertion. */ -static void -add_request_to_runlist (struct requestlist *newrequest) -{ - int prio = newrequest->aiocbp->aiocb.__abs_prio; - struct requestlist *runp; - - if (runlist == NULL || runlist->aiocbp->aiocb.__abs_prio < prio) - { - newrequest->next_run = runlist; - runlist = newrequest; - } - else - { - runp = runlist; - - while (runp->next_run != NULL - && runp->next_run->aiocbp->aiocb.__abs_prio >= prio) - runp = runp->next_run; - - newrequest->next_run = runp->next_run; - runp->next_run = newrequest; - } -} |