Author: kib
Date: Sat Oct 11 17:49:51 2014
New Revision: 272946
URL: https://svnweb.freebsd.org/changeset/base/272946
Log:
MFC r272536:
Add kernel option KSTACK_USAGE_PROF.
Modified:
stable/10/sys/conf/NOTES
stable/10/sys/conf/options
stable/10/sys/kern/kern_intr.c
stable/10/sys/sys/systm.h
stable/10/sys/vm/vm_glue.c
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/sys/conf/NOTES
==============================================================================
--- stable/10/sys/conf/NOTES Sat Oct 11 17:16:18 2014 (r272945)
+++ stable/10/sys/conf/NOTES Sat Oct 11 17:49:51 2014 (r272946)
@@ -2950,6 +2950,7 @@ options SC_RENDER_DEBUG # syscons rende
options VFS_BIO_DEBUG # VFS buffer I/O debugging
options KSTACK_MAX_PAGES=32 # Maximum pages to give the kernel stack
+options KSTACK_USAGE_PROF
# Adaptec Array Controller driver options
options AAC_DEBUG # Debugging levels:
Modified: stable/10/sys/conf/options
==============================================================================
--- stable/10/sys/conf/options Sat Oct 11 17:16:18 2014 (r272945)
+++ stable/10/sys/conf/options Sat Oct 11 17:49:51 2014 (r272946)
@@ -132,6 +132,7 @@ GEOM_ZERO opt_geom.h
KDTRACE_HOOKS opt_kdtrace.h
KSTACK_MAX_PAGES
KSTACK_PAGES
+KSTACK_USAGE_PROF
KTRACE
KTRACE_REQUEST_POOL opt_ktrace.h
LIBICONV
Modified: stable/10/sys/kern/kern_intr.c
==============================================================================
--- stable/10/sys/kern/kern_intr.c Sat Oct 11 17:16:18 2014
(r272945)
+++ stable/10/sys/kern/kern_intr.c Sat Oct 11 17:49:51 2014
(r272946)
@@ -28,6 +28,7 @@
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
+#include "opt_kstack_usage_prof.h"
#include <sys/param.h>
#include <sys/bus.h>
@@ -1407,6 +1408,10 @@ intr_event_handle(struct intr_event *ie,
td = curthread;
+#ifdef KSTACK_USAGE_PROF
+ intr_prof_stack_use(td, frame);
+#endif
+
/* An interrupt with no event or handlers is a stray interrupt. */
if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers))
return (EINVAL);
Modified: stable/10/sys/sys/systm.h
==============================================================================
--- stable/10/sys/sys/systm.h Sat Oct 11 17:16:18 2014 (r272945)
+++ stable/10/sys/sys/systm.h Sat Oct 11 17:49:51 2014 (r272946)
@@ -443,4 +443,6 @@ bitcount16(uint32_t x)
return (x);
}
+void intr_prof_stack_use(struct thread *td, struct trapframe *frame);
+
#endif /* !_SYS_SYSTM_H_ */
Modified: stable/10/sys/vm/vm_glue.c
==============================================================================
--- stable/10/sys/vm/vm_glue.c Sat Oct 11 17:16:18 2014 (r272945)
+++ stable/10/sys/vm/vm_glue.c Sat Oct 11 17:49:51 2014 (r272946)
@@ -62,6 +62,7 @@ __FBSDID("$FreeBSD$");
#include "opt_vm.h"
#include "opt_kstack_pages.h"
#include "opt_kstack_max_pages.h"
+#include "opt_kstack_usage_prof.h"
#include <sys/param.h>
#include <sys/systm.h>
@@ -98,6 +99,8 @@ __FBSDID("$FreeBSD$");
#include <vm/vm_pager.h>
#include <vm/swap_pager.h>
+#include <machine/cpu.h>
+
#ifndef NO_SWAPPING
static int swapout(struct proc *);
static void swapclear(struct proc *);
@@ -486,6 +489,52 @@ kstack_cache_init(void *nulll)
SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init,
NULL);
+#ifdef KSTACK_USAGE_PROF
+/*
+ * Track maximum stack used by a thread in kernel.
+ */
+static int max_kstack_used;
+
+SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD,
+ &max_kstack_used, 0,
+ "Maxiumum stack depth used by a thread in kernel");
+
+void
+intr_prof_stack_use(struct thread *td, struct trapframe *frame)
+{
+ vm_offset_t stack_top;
+ vm_offset_t current;
+ int used, prev_used;
+
+ /*
+ * Testing for interrupted kernel mode isn't strictly
+ * needed. It optimizes the execution, since interrupts from
+ * usermode will have only the trap frame on the stack.
+ */
+ if (TRAPF_USERMODE(frame))
+ return;
+
+ stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
+ current = (vm_offset_t)(uintptr_t)&stack_top;
+
+ /*
+ * Try to detect if interrupt is using kernel thread stack.
+ * Hardware could use a dedicated stack for interrupt handling.
+ */
+ if (stack_top <= current || current < td->td_kstack)
+ return;
+
+ used = stack_top - current;
+ for (;;) {
+ prev_used = max_kstack_used;
+ if (prev_used >= used)
+ break;
+ if (atomic_cmpset_int(&max_kstack_used, prev_used, used))
+ break;
+ }
+}
+#endif /* KSTACK_USAGE_PROF */
+
#ifndef NO_SWAPPING
/*
* Allow a thread's kernel stack to be paged out.
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