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-rw-r--r--nptl/tpp.c172
1 files changed, 172 insertions, 0 deletions
diff --git a/nptl/tpp.c b/nptl/tpp.c
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index 0000000000..367dd8162a
--- /dev/null
+++ b/nptl/tpp.c
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+/* 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;
+}