Author: kib
Date: Sun Sep 30 13:32:48 2012
New Revision: 241071
URL: http://svn.freebsd.org/changeset/base/241071
Log:
MFC r240813:
Do not skip two elements of the tid_buffer when reusing the buffer
slot. This eventually results in exhaustion of the tid space, causing
new threads get tid -1 as identifier.
MFC r240951:
Make the updates of the tid ring buffer' head and tail pointers
explicit by moving them into separate statements from the buffer
element accesses.
Modified:
stable/9/sys/kern/kern_thread.c
Directory Properties:
stable/9/sys/ (props changed)
Modified: stable/9/sys/kern/kern_thread.c
==============================================================================
--- stable/9/sys/kern/kern_thread.c Sun Sep 30 13:17:33 2012
(r241070)
+++ stable/9/sys/kern/kern_thread.c Sun Sep 30 13:32:48 2012
(r241071)
@@ -102,8 +102,8 @@ tid_alloc(void)
mtx_unlock(&tid_lock);
return (-1);
}
- tid = tid_buffer[tid_head++];
- tid_head %= TID_BUFFER_SIZE;
+ tid = tid_buffer[tid_head];
+ tid_head = (tid_head + 1) % TID_BUFFER_SIZE;
mtx_unlock(&tid_lock);
return (tid);
}
@@ -115,11 +115,11 @@ tid_free(lwpid_t tid)
mtx_lock(&tid_lock);
if ((tid_tail + 1) % TID_BUFFER_SIZE == tid_head) {
- tmp_tid = tid_buffer[tid_head++];
+ tmp_tid = tid_buffer[tid_head];
tid_head = (tid_head + 1) % TID_BUFFER_SIZE;
}
- tid_buffer[tid_tail++] = tid;
- tid_tail %= TID_BUFFER_SIZE;
+ tid_buffer[tid_tail] = tid;
+ tid_tail = (tid_tail + 1) % TID_BUFFER_SIZE;
mtx_unlock(&tid_lock);
if (tmp_tid != -1)
free_unr(tid_unrhdr, tmp_tid);
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