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Diffstat (limited to 'nptl/tpp.c')
| -rw-r--r-- | nptl/tpp.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/nptl/tpp.c b/nptl/tpp.c new file mode 100644 index 0000000..367dd81 --- /dev/null +++ b/nptl/tpp.c @@ -0,0 +1,172 @@ +/* Thread Priority Protect helpers. + Copyright (C) 2006 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Jakub Jelinek <jakub@redhat.com>, 2006. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <assert.h> +#include <atomic.h> +#include <errno.h> +#include <pthreadP.h> +#include <sched.h> +#include <stdlib.h> + + +int __sched_fifo_min_prio = -1; +int __sched_fifo_max_prio = -1; + +void +__init_sched_fifo_prio (void) +{ + __sched_fifo_max_prio = sched_get_priority_max (SCHED_FIFO); + atomic_write_barrier (); + __sched_fifo_min_prio = sched_get_priority_min (SCHED_FIFO); +} + +int +__pthread_tpp_change_priority (int previous_prio, int new_prio) +{ + struct pthread *self = THREAD_SELF; + struct priority_protection_data *tpp = THREAD_GETMEM (self, tpp); + + if (tpp == NULL) + { + if (__sched_fifo_min_prio == -1) + __init_sched_fifo_prio (); + + size_t size = sizeof *tpp; + size += (__sched_fifo_max_prio - __sched_fifo_min_prio + 1) + * sizeof (tpp->priomap[0]); + tpp = calloc (size, 1); + if (tpp == NULL) + return ENOMEM; + tpp->priomax = __sched_fifo_min_prio - 1; + THREAD_SETMEM (self, tpp, tpp); + } + + assert (new_prio == -1 + || (new_prio >= __sched_fifo_min_prio + && new_prio <= __sched_fifo_max_prio)); + assert (previous_prio == -1 + || (previous_prio >= __sched_fifo_min_prio + && previous_prio <= __sched_fifo_max_prio)); + + int priomax = tpp->priomax; + int newpriomax = priomax; + if (new_prio != -1) + { + if (tpp->priomap[new_prio - __sched_fifo_min_prio] + 1 == 0) + return EAGAIN; + ++tpp->priomap[new_prio - __sched_fifo_min_prio]; + if (new_prio > priomax) + newpriomax = new_prio; + } + + if (previous_prio != -1) + { + if (--tpp->priomap[previous_prio - __sched_fifo_min_prio] == 0 + && priomax == previous_prio + && previous_prio > new_prio) + { + int i; + for (i = previous_prio - 1; i >= __sched_fifo_min_prio; --i) + if (tpp->priomap[i - __sched_fifo_min_prio]) + break; + newpriomax = i; + } + } + + if (priomax == newpriomax) + return 0; + + lll_lock (self->lock); + + tpp->priomax = newpriomax; + + int result = 0; + + if ((self->flags & ATTR_FLAG_SCHED_SET) == 0) + { + if (__sched_getparam (self->tid, &self->schedparam) != 0) + result = errno; + else + self->flags |= ATTR_FLAG_SCHED_SET; + } + + if ((self->flags & ATTR_FLAG_POLICY_SET) == 0) + { + self->schedpolicy = __sched_getscheduler (self->tid); + if (self->schedpolicy == -1) + result = errno; + else + self->flags |= ATTR_FLAG_POLICY_SET; + } + + if (result == 0) + { + struct sched_param sp = self->schedparam; + if (sp.sched_priority < newpriomax || sp.sched_priority < priomax) + { + if (sp.sched_priority < newpriomax) + sp.sched_priority = newpriomax; + + if (__sched_setscheduler (self->tid, self->schedpolicy, &sp) < 0) + result = errno; + } + } + + lll_unlock (self->lock); + + return result; +} + +int +__pthread_current_priority (void) +{ + struct pthread *self = THREAD_SELF; + if ((self->flags & (ATTR_FLAG_POLICY_SET | ATTR_FLAG_SCHED_SET)) + == (ATTR_FLAG_POLICY_SET | ATTR_FLAG_SCHED_SET)) + return self->schedparam.sched_priority; + + int result = 0; + + lll_lock (self->lock); + + if ((self->flags & ATTR_FLAG_SCHED_SET) == 0) + { + if (__sched_getparam (self->tid, &self->schedparam) != 0) + result = -1; + else + self->flags |= ATTR_FLAG_SCHED_SET; + } + + if ((self->flags & ATTR_FLAG_POLICY_SET) == 0) + { + self->schedpolicy = __sched_getscheduler (self->tid); + if (self->schedpolicy == -1) + result = -1; + else + self->flags |= ATTR_FLAG_POLICY_SET; + } + + if (result != -1) + result = self->schedparam.sched_priority; + + lll_unlock (self->lock); + + return result; +} |