Add a macro that clears the want_resched flag that need_resched sets.

Right now when mi_switch picks up the same proc, we didn't clear the
flag which would mean that every time we service an AST we would attempt
a context switch. For some architectures, amd64 being probably the
most extreme, that meant attempting to context switch for every
trap and interrupt.

Now we clear_resched explicitly after every context switch, even if it
didn't do anything. Which also allows us to remove some more code
in cpu_switchto (not done yet).

miod@ ok

diff --git a/sys/arch/alpha/include/cpu.h b/sys/arch/alpha/include/cpu.h
index 5937dbd..9e393ff 100644 (file)
--- a/sys/arch/alpha/include/cpu.h
+++ b/sys/arch/alpha/include/cpu.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: cpu.h,v 1.32 2008/06/26 05:42:08 ray Exp $ */
+/* $OpenBSD: cpu.h,v 1.33 2008/07/18 23:43:31 art Exp $ */
 /* $NetBSD: cpu.h,v 1.45 2000/08/21 02:03:12 thorpej Exp $ */
 
 /*-
@@ -282,12 +282,14 @@ do {                                                                      \
        ci->ci_want_resched = 1;                                        \
        aston(curcpu());                                                \
 } while (/*CONSTCOND*/0)
+#define clear_resched(ci) (ci)->ci_want_resched = 0
 #else
 #define        need_resched(ci)                                                \
 do {                                                                   \
        curcpu()->ci_want_resched = 1;                                  \
        aston(curcpu());                                                \
 } while (/*CONSTCOND*/0)
+#define clear_resched(ci) curcpu()->ci_want_resched = 0
 #endif
 
 /*

diff --git a/sys/arch/amd64/include/cpu.h b/sys/arch/amd64/include/cpu.h
index 2516fdd..248a965 100644 (file)
--- a/sys/arch/amd64/include/cpu.h
+++ b/sys/arch/amd64/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.36 2008/06/10 02:55:39 weingart Exp $       */
+/*     $OpenBSD: cpu.h,v 1.37 2008/07/18 23:43:31 art Exp $    */
 /*     $NetBSD: cpu.h,v 1.1 2003/04/26 18:39:39 fvdl Exp $     */
 
 /*-
@@ -161,6 +161,7 @@ extern struct cpu_info *cpu_info_list;
  * or after the current trap/syscall if in system mode.
  */
 extern void need_resched(struct cpu_info *);
+#define clear_resched(ci) (ci)->ci_want_resched = 0
 
 #if defined(MULTIPROCESSOR)
 

diff --git a/sys/arch/arm/include/cpu.h b/sys/arch/arm/include/cpu.h
index 9aa2166..0c418dc 100644 (file)
--- a/sys/arch/arm/include/cpu.h
+++ b/sys/arch/arm/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.18 2007/08/14 15:18:07 deraadt Exp $        */
+/*     $OpenBSD: cpu.h,v 1.19 2008/07/18 23:43:31 art Exp $    */
 /*     $NetBSD: cpu.h,v 1.34 2003/06/23 11:01:08 martin Exp $  */
 
 /*
@@ -256,6 +256,7 @@ extern int astpending;
  */
 extern int want_resched;       /* resched() was called */
 #define        need_resched(ci)        (want_resched = 1, setsoftast())
+#define clear_resched(ci)      want_resched = 0
 
 /*
  * Give a profiling tick to the current process when the user profiling

diff --git a/sys/arch/hp300/include/cpu.h b/sys/arch/hp300/include/cpu.h
index 76afb0a..a524d1c 100644 (file)
--- a/sys/arch/hp300/include/cpu.h
+++ b/sys/arch/hp300/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.35 2007/11/02 19:18:54 martin Exp $ */
+/*     $OpenBSD: cpu.h,v 1.36 2008/07/18 23:43:31 art Exp $    */
 /*     $NetBSD: cpu.h,v 1.28 1998/02/13 07:41:51 scottr Exp $  */
 
 /*
@@ -92,6 +92,7 @@ struct clockframe {
  */
 extern int want_resched;       /* resched() was called */
 #define        need_resched(ci)        { want_resched = 1; aston(); }
+#define clear_resched(ci)      want_resched = 0
 
 /*
  * Give a profiling tick to the current process when the user profiling

diff --git a/sys/arch/hppa/include/cpu.h b/sys/arch/hppa/include/cpu.h
index f4b45f4..d80bae1 100644 (file)
--- a/sys/arch/hppa/include/cpu.h
+++ b/sys/arch/hppa/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.53 2008/07/14 13:39:06 miod Exp $   */
+/*     $OpenBSD: cpu.h,v 1.54 2008/07/18 23:43:31 art Exp $    */
 
 /*
  * Copyright (c) 2000-2004 Michael Shalayeff
@@ -151,6 +151,7 @@ extern register_t kpsw;
 
 #define        signotify(p)            (setsoftast())
 #define        need_resched(ci)        (want_resched = 1, setsoftast())
+#define clear_resched(ci)      want_resched = 0
 #define        need_proftick(p)        setsoftast()
 #define        PROC_PC(p)              ((p)->p_md.md_regs->tf_iioq_head)
 

diff --git a/sys/arch/hppa64/include/cpu.h b/sys/arch/hppa64/include/cpu.h
index ddc35e3..b34705b 100644 (file)
--- a/sys/arch/hppa64/include/cpu.h
+++ b/sys/arch/hppa64/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.11 2007/05/16 19:37:06 thib Exp $   */
+/*     $OpenBSD: cpu.h,v 1.12 2008/07/18 23:43:31 art Exp $    */
 
 /*
  * Copyright (c) 2005 Michael Shalayeff
@@ -196,6 +196,7 @@ extern int cpu_hvers;
 
 #define        signotify(p)            (setsoftast())
 #define        need_resched(ci)        (want_resched = 1, setsoftast())
+#define clear_resched(ci)      want_resched = 0
 #define        need_proftick(p)        setsoftast()
 
 #ifndef _LOCORE

diff --git a/sys/arch/i386/include/cpu.h b/sys/arch/i386/include/cpu.h
index 7632dbb..62209b1 100644 (file)
--- a/sys/arch/i386/include/cpu.h
+++ b/sys/arch/i386/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.102 2008/06/09 20:43:43 miod Exp $  */
+/*     $OpenBSD: cpu.h,v 1.103 2008/07/18 23:43:31 art Exp $   */
 /*     $NetBSD: cpu.h,v 1.35 1996/05/05 19:29:26 christos Exp $        */
 
 /*-
@@ -230,6 +230,7 @@ extern void cpu_init_idle_pcbs(void);
  * or after the current trap/syscall if in system mode.
  */
 extern void need_resched(struct cpu_info *);
+#define clear_resched(ci) (ci)->ci_want_resched = 0
 
 #define        CLKF_USERMODE(frame)    USERMODE((frame)->if_cs, (frame)->if_eflags)
 #define        CLKF_PC(frame)          ((frame)->if_eip)

diff --git a/sys/arch/m88k/include/cpu.h b/sys/arch/m88k/include/cpu.h
index aa3acd6..2e19692 100644 (file)
--- a/sys/arch/m88k/include/cpu.h
+++ b/sys/arch/m88k/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.34 2008/01/13 20:20:29 miod Exp $ */
+/*     $OpenBSD: cpu.h,v 1.35 2008/07/18 23:43:31 art Exp $ */
 /*
  * Copyright (c) 1996 Nivas Madhur
  * Copyright (c) 1992, 1993
@@ -241,6 +241,7 @@ do {                                                                        \
        if (ci->ci_curproc != NULL)                                     \
                aston(ci->ci_curproc);                                  \
 } while (0)
+#define clear_resched(ci)      (ci)->ci_want_resched = 0
 
 /*
  * Give a profiling tick to the current process when the user profiling

diff --git a/sys/arch/mac68k/include/cpu.h b/sys/arch/mac68k/include/cpu.h
index f3562fb..4ad125d 100644 (file)
--- a/sys/arch/mac68k/include/cpu.h
+++ b/sys/arch/mac68k/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.46 2007/11/02 19:18:54 martin Exp $ */
+/*     $OpenBSD: cpu.h,v 1.47 2008/07/18 23:43:31 art Exp $    */
 /*     $NetBSD: cpu.h,v 1.45 1997/02/10 22:13:40 scottr Exp $  */
 
 /*
@@ -105,6 +105,7 @@ struct clockframe {
  */
 extern int want_resched;       /* resched() was called */
 #define        need_resched(ci)        { want_resched = 1; aston(); }
+#define clear_resched(ci)      want_resched = 0
 
 /*
  * Give a profiling tick to the current process from the softclock

diff --git a/sys/arch/mips64/include/cpu.h b/sys/arch/mips64/include/cpu.h
index d320ef5..3a5d6d9 100644 (file)
--- a/sys/arch/mips64/include/cpu.h
+++ b/sys/arch/mips64/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.24 2008/04/07 22:37:16 miod Exp $   */
+/*     $OpenBSD: cpu.h,v 1.25 2008/07/18 23:43:31 art Exp $    */
 
 /*-
  * Copyright (c) 1992, 1993
@@ -409,6 +409,7 @@ extern int int_nest_cntr;
  * or after the current trap/syscall if in system mode.
  */
 #define        need_resched(info)      { want_resched = 1; aston(); }
+#define clear_resched(ci)      want_resched = 0
 
 /*
  * Give a profiling tick to the current process when the user profiling

diff --git a/sys/arch/mvme68k/include/cpu.h b/sys/arch/mvme68k/include/cpu.h
index 99f07c8..727b817 100644 (file)
--- a/sys/arch/mvme68k/include/cpu.h
+++ b/sys/arch/mvme68k/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.27 2007/05/30 17:10:44 miod Exp $ */
+/*     $OpenBSD: cpu.h,v 1.28 2008/07/18 23:43:31 art Exp $ */
 
 /*
  * Copyright (c) 1995 Theo de Raadt
@@ -115,6 +115,7 @@ struct clockframe {
  */
 extern int want_resched;
 #define        need_resched(ci)        { want_resched = 1; aston(); }
+#define clear_resched(ci)      want_resched = 0
 
 /*
  * Give a profiling tick to the current process when the user profiling

diff --git a/sys/arch/powerpc/include/cpu.h b/sys/arch/powerpc/include/cpu.h
index e95b065..4a6d2ed 100644 (file)
--- a/sys/arch/powerpc/include/cpu.h
+++ b/sys/arch/powerpc/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.37 2008/05/04 20:54:22 drahn Exp $  */
+/*     $OpenBSD: cpu.h,v 1.38 2008/07/18 23:43:31 art Exp $    */
 /*     $NetBSD: cpu.h,v 1.1 1996/09/30 16:34:21 ws Exp $       */
 
 /*
@@ -151,6 +151,7 @@ do {                                                                        \
        if (ci->ci_curproc != NULL)                                     \
                aston(ci->ci_curproc);                                  \
 } while (0)
+#define clear_resched(ci) (ci)->ci_want_resched = 0
 
 #define        need_proftick(p)        aston(p)
 

diff --git a/sys/arch/sh/include/cpu.h b/sys/arch/sh/include/cpu.h
index 2b8a0d5..dd2cd31 100644 (file)
--- a/sys/arch/sh/include/cpu.h
+++ b/sys/arch/sh/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.13 2008/05/21 19:45:37 miod Exp $   */
+/*     $OpenBSD: cpu.h,v 1.14 2008/07/18 23:43:31 art Exp $    */
 /*     $NetBSD: cpu.h,v 1.41 2006/01/21 04:24:12 uwe Exp $     */
 
 /*-
@@ -101,6 +101,7 @@ do {                                                                        \
        if (curproc != NULL)                                            \
                aston(curproc);                                 \
 } while (/*CONSTCOND*/0)
+#define clear_resched(ci)      want_resched = 0
 
 /*
  * Give a profiling tick to the current process when the user profiling

diff --git a/sys/arch/sparc/include/cpu.h b/sys/arch/sparc/include/cpu.h
index 4468696..5d44640 100644 (file)
--- a/sys/arch/sparc/include/cpu.h
+++ b/sys/arch/sparc/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.29 2007/05/08 07:23:18 art Exp $    */
+/*     $OpenBSD: cpu.h,v 1.30 2008/07/18 23:43:31 art Exp $    */
 /*     $NetBSD: cpu.h,v 1.24 1997/03/15 22:25:15 pk Exp $ */
 
 /*
@@ -131,6 +131,7 @@ extern void raise(int, int);
  */
 extern int     want_resched;           /* resched() was called */
 #define        need_resched(ci)                (want_resched = 1, want_ast = 1)
+#define clear_resched(ci)      want_resched = 0
 extern int     want_ast;
 
 /*

diff --git a/sys/arch/sparc64/include/cpu.h b/sys/arch/sparc64/include/cpu.h
index 7091658..a6251de 100644 (file)
--- a/sys/arch/sparc64/include/cpu.h
+++ b/sys/arch/sparc64/include/cpu.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cpu.h,v 1.62 2008/07/04 22:03:30 kettenis Exp $       */
+/*     $OpenBSD: cpu.h,v 1.63 2008/07/18 23:43:31 art Exp $    */
 /*     $NetBSD: cpu.h,v 1.28 2001/06/14 22:56:58 thorpej Exp $ */
 
 /*
@@ -223,6 +223,7 @@ void setsoftnet(void);
  * or after the current trap/syscall if in system mode.
  */
 extern void need_resched(struct cpu_info *);
+#define clear_resched(ci) (ci)->ci_want_resched = 0
 
 /*
  * This is used during profiling to integrate system time.

diff --git a/sys/arch/vax/include/cpu.h b/sys/arch/vax/include/cpu.h
index dc6ec20..4dc1b5a 100644 (file)
--- a/sys/arch/vax/include/cpu.h
+++ b/sys/arch/vax/include/cpu.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: cpu.h,v 1.26 2007/10/10 15:53:53 art Exp $      */
+/*      $OpenBSD: cpu.h,v 1.27 2008/07/18 23:43:31 art Exp $      */
 /*      $NetBSD: cpu.h,v 1.41 1999/10/21 20:01:36 ragge Exp $      */
 
 /*
@@ -107,6 +107,7 @@ extern int bootdev;
        want_resched++; \
        mtpr(AST_OK,PR_ASTLVL); \
        }
+#define clear_resched(ci)      want_resched = 0
 
 /*
  * Notify the current process (p) that it has a signal pending,

diff --git a/sys/kern/sched_bsd.c b/sys/kern/sched_bsd.c
index 2bfbadb..e7babbb 100644 (file)
--- a/sys/kern/sched_bsd.c
+++ b/sys/kern/sched_bsd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: sched_bsd.c,v 1.16 2008/05/22 14:07:14 thib Exp $     */
+/*     $OpenBSD: sched_bsd.c,v 1.17 2008/07/18 23:43:31 art Exp $      */
 /*     $NetBSD: kern_synch.c,v 1.37 1996/04/22 01:38:37 christos Exp $ */
 
 /*-
@@ -415,6 +415,8 @@ mi_switch(void)
                p->p_stat = SONPROC;
        }
 
+       clear_resched(curcpu());
+
        SCHED_ASSERT_LOCKED();
 
        /*