Author: attilio
Date: Sat Jan 28 14:00:21 2012
New Revision: 230643
URL: http://svn.freebsd.org/changeset/base/230643
Log:
Avoid to check the same cache line/variable from all the locking
primitives by breaking stop_scheduler into a per-thread variable.
Also, store the new td_stopsched very close to td_*locks members as
they will be accessed mostly in the same codepaths as td_stopsched and
this results in avoiding a further cache-line pollution, possibly.
STOP_SCHEDULER() was pondered to use a new 'thread' argument, in order to
take advantage of already cached curthread, but in the end there should
not really be a performance benefit, while introducing a KPI breakage.
In collabouration with: flo
Reviewed by: avg
MFC after: 3 months (or never)
X-MFC: r228424
Modified:
head/sys/dev/usb/usb_transfer.c
head/sys/geom/geom_bsd.c
head/sys/geom/geom_mbr.c
head/sys/geom/geom_pc98.c
head/sys/geom/mountver/g_mountver.c
head/sys/kern/kern_shutdown.c
head/sys/sys/proc.h
head/sys/sys/systm.h
Modified: head/sys/dev/usb/usb_transfer.c
==============================================================================
--- head/sys/dev/usb/usb_transfer.c Sat Jan 28 13:41:34 2012
(r230642)
+++ head/sys/dev/usb/usb_transfer.c Sat Jan 28 14:00:21 2012
(r230643)
@@ -42,6 +42,7 @@
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>
+#include <sys/proc.h>
#include <dev/usb/usb.h>
#include <dev/usb/usbdi.h>
Modified: head/sys/geom/geom_bsd.c
==============================================================================
--- head/sys/geom/geom_bsd.c Sat Jan 28 13:41:34 2012 (r230642)
+++ head/sys/geom/geom_bsd.c Sat Jan 28 14:00:21 2012 (r230643)
@@ -57,6 +57,7 @@ __FBSDID("$FreeBSD$");
#include <sys/errno.h>
#include <sys/disklabel.h>
#include <sys/gpt.h>
+#include <sys/proc.h>
#include <sys/sbuf.h>
#include <sys/uuid.h>
#include <geom/geom.h>
Modified: head/sys/geom/geom_mbr.c
==============================================================================
--- head/sys/geom/geom_mbr.c Sat Jan 28 13:41:34 2012 (r230642)
+++ head/sys/geom/geom_mbr.c Sat Jan 28 14:00:21 2012 (r230643)
@@ -45,6 +45,7 @@ __FBSDID("$FreeBSD$");
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/md5.h>
+#include <sys/proc.h>
#include <sys/diskmbr.h>
#include <sys/sbuf.h>
Modified: head/sys/geom/geom_pc98.c
==============================================================================
--- head/sys/geom/geom_pc98.c Sat Jan 28 13:41:34 2012 (r230642)
+++ head/sys/geom/geom_pc98.c Sat Jan 28 14:00:21 2012 (r230643)
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
#include <sys/bio.h>
#include <sys/lock.h>
#include <sys/mutex.h>
+#include <sys/proc.h>
#include <sys/sbuf.h>
#include <sys/diskpc98.h>
Modified: head/sys/geom/mountver/g_mountver.c
==============================================================================
--- head/sys/geom/mountver/g_mountver.c Sat Jan 28 13:41:34 2012
(r230642)
+++ head/sys/geom/mountver/g_mountver.c Sat Jan 28 14:00:21 2012
(r230643)
@@ -36,6 +36,7 @@ __FBSDID("$FreeBSD$");
#include <sys/mutex.h>
#include <sys/bio.h>
#include <sys/disk.h>
+#include <sys/proc.h>
#include <sys/sbuf.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
Modified: head/sys/kern/kern_shutdown.c
==============================================================================
--- head/sys/kern/kern_shutdown.c Sat Jan 28 13:41:34 2012
(r230642)
+++ head/sys/kern/kern_shutdown.c Sat Jan 28 14:00:21 2012
(r230643)
@@ -145,7 +145,6 @@ SYSCTL_INT(_kern_shutdown, OID_AUTO, sho
*/
const char *panicstr;
-int stop_scheduler; /* system stopped CPUs for panic */
int dumping; /* system is dumping */
int rebooting; /* system is rebooting */
static struct dumperinfo dumper; /* our selected dumper */
@@ -597,7 +596,7 @@ panic(const char *fmt, ...)
* stop_scheduler_on_panic is true, then stop_scheduler will
* always be set. Even if panic has been entered from kdb.
*/
- stop_scheduler = 1;
+ td->td_stopsched = 1;
}
#endif
Modified: head/sys/sys/proc.h
==============================================================================
--- head/sys/sys/proc.h Sat Jan 28 13:41:34 2012 (r230642)
+++ head/sys/sys/proc.h Sat Jan 28 14:00:21 2012 (r230643)
@@ -235,6 +235,7 @@ struct thread {
short td_locks; /* (k) Count of non-spin locks. */
short td_rw_rlocks; /* (k) Count of rwlock read locks. */
short td_lk_slocks; /* (k) Count of lockmgr shared locks. */
+ short td_stopsched; /* (k) Scheduler stopped. */
struct turnstile *td_blocked; /* (t) Lock thread is blocked on. */
const char *td_lockname; /* (t) Name of lock blocked on. */
LIST_HEAD(, turnstile) td_contested; /* (q) Contested locks. */
Modified: head/sys/sys/systm.h
==============================================================================
--- head/sys/sys/systm.h Sat Jan 28 13:41:34 2012 (r230642)
+++ head/sys/sys/systm.h Sat Jan 28 14:00:21 2012 (r230643)
@@ -47,7 +47,6 @@
extern int cold; /* nonzero if we are doing a cold boot */
extern int rebooting; /* kern_reboot() has been called. */
-extern int stop_scheduler; /* only one thread runs after panic */
extern const char *panicstr; /* panic message */
extern char version[]; /* system version */
extern char copyright[]; /* system copyright */
@@ -113,7 +112,7 @@ enum VM_GUEST { VM_GUEST_NO = 0, VM_GUES
* Otherwise, the kernel will deadlock since the scheduler isn't
* going to run the thread that holds any lock we need.
*/
-#define SCHEDULER_STOPPED() __predict_false(stop_scheduler)
+#define SCHEDULER_STOPPED() __predict_false(curthread->td_stopsched)
/*
* XXX the hints declarations are even more misplaced than most declarations
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