PERFORCE change 127810 for review

[John Birrell]

http://perforce.freebsd.org/chv.cgi?CH=127810

Change 127810 by jb at jb_freebsd1 on 2007/10/20 04:09:01

	Allocate extra thread space opaquely.

Affected files ...

.. //depot/projects/dtrace6/src/sys/kern/init_main.c#2 edit
.. //depot/projects/dtrace6/src/sys/kern/kern_thread.c#3 edit
.. //depot/projects/dtrace6/src/sys/sys/proc.h#4 edit

Differences ...

==== //depot/projects/dtrace6/src/sys/kern/init_main.c#2 (text+ko) ====

@@ -98,6 +98,15 @@
 struct	vmspace vmspace0;
 struct	proc *initproc;
 
+/* DTrace data for the primary thread in proc0. */
+char	kdtrace_thread0[KDTRACE_THREAD_SIZE];
+
+/* Offset from 'struct thread *' to the opaque DTrace fields. */
+int	kdtrace_thread_offset;
+
+/* Overall per-thread allocation size. */
+int	kdtrace_thread_size;
+
 int	boothowto = 0;		/* initialized so that it can be patched */
 SYSCTL_INT(_debug, OID_AUTO, boothowto, CTLFLAG_RD, &boothowto, 0, "");
 int	bootverbose;
@@ -177,6 +186,18 @@
 	int verbose;
 #endif
 
+	/* Get the size of 'struct thread' plus 'struct td_sched' */
+	kdtrace_thread_offset = sched_sizeof_thread();
+
+	/*
+	 * Allow for the DTrace-specific thread data after
+	 * struct td_sched. This space is allocated opaquely to
+	 * avoid license issues. The value of KDTRACE_THREAD_SIZE
+	 * set in sys/proc.h must be larger than that required by
+	 * the DTrace kernel modules.
+	 */
+	kdtrace_thread_size = kdtrace_thread_offset + KDTRACE_THREAD_SIZE;
+
 	if (sysinit == NULL) {
 		sysinit = SET_BEGIN(sysinit_set);
 		sysinit_end = SET_LIMIT(sysinit_set);

==== //depot/projects/dtrace6/src/sys/kern/kern_thread.c#3 (text+ko) ====

@@ -303,7 +303,7 @@
 	mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
 	tid_unrhdr = new_unrhdr(PID_MAX + 1, INT_MAX, &tid_lock);
 
-	thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
+	thread_zone = uma_zcreate("THREAD", kdtrace_thread_size,
 	    thread_ctor, thread_dtor, thread_init, thread_fini,
 	    THREAD_ALIGN - 1, 0);
 	ksegrp_zone = uma_zcreate("KSEGRP", sched_sizeof_ksegrp(),

==== //depot/projects/dtrace6/src/sys/sys/proc.h#4 (text+ko) ====

@@ -860,6 +860,21 @@
 extern u_long ps_arg_cache_limit;
 extern int sched_quantum;		/* Scheduling quantum in ticks. */
 
+/*
+ * Space to append to struct thread for DTrace specific thread
+ * variables. This space is after the 'struct td_sched'.
+ */
+#define KDTRACE_THREAD_SIZE 128
+
+/* Offset from 'struct thread *' to the opaque DTrace fields. */
+extern int kdtrace_thread_offset;
+
+/* Overall per-thread allocation size. */
+extern int kdtrace_thread_size;
+
+/* DTrace data for the primary thread in proc0. */
+extern char kdtrace_thread0[];
+
 LIST_HEAD(proclist, proc);
 TAILQ_HEAD(procqueue, proc);
 TAILQ_HEAD(threadqueue, thread);