Date: Sun, 27 Jun 1999 23:22:33 -0500 From: Alan Cox <alc@cs.rice.edu> To: smp@freebsd.org Subject: try this... Message-ID: <19990627232233.K2738@cs.rice.edu>
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This patch eliminates pointless lock acquires/releases from critical
sections in the ipl code that consist of single atomic read-modify-write
instruction.
When I hear a few positive reports, I'll commit this patch.
Alan
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Index: i386/isa/ipl_funcs.c
===================================================================
RCS file: /home/ncvs/src/sys/i386/isa/ipl_funcs.c,v
retrieving revision 1.20
diff -c -r1.20 ipl_funcs.c
*** ipl_funcs.c 1999/05/09 23:40:29 1.20
--- ipl_funcs.c 1999/06/27 18:30:02
***************
*** 35,62 ****
/*
* The volatile bitmap variables must be set atomically. This normally
* involves using a machine-dependent bit-set or `or' instruction.
*/
- #ifndef SMP
-
#define DO_SETBITS(name, var, bits) \
void name(void) \
{ \
setbits(var, bits); \
}
#else /* !SMP */
!
! #define DO_SETBITS(name, var, bits) \
! void name(void) \
! { \
! IFCPL_LOCK(); \
! setbits(var, bits); \
! IFCPL_UNLOCK(); \
}
-
#endif /* !SMP */
- DO_SETBITS(setdelayed, &ipending, loadandclear(&idelayed))
DO_SETBITS(setsoftast, &ipending, SWI_AST_PENDING)
DO_SETBITS(setsoftcamnet,&ipending, SWI_CAMNET_PENDING)
DO_SETBITS(setsoftcambio,&ipending, SWI_CAMBIO_PENDING)
--- 35,60 ----
/*
* The volatile bitmap variables must be set atomically. This normally
* involves using a machine-dependent bit-set or `or' instruction.
+ *
+ * If setbits is atomic, this is MP-safe.
*/
#define DO_SETBITS(name, var, bits) \
void name(void) \
{ \
setbits(var, bits); \
}
+ #ifndef SMP
+ DO_SETBITS(setdelayed, &ipending, loadandclear(&idelayed))
#else /* !SMP */
! void setdelayed(void)
! {
! IFCPL_LOCK();
! setbits(&ipending, loadandclear(&idelayed));
! IFCPL_UNLOCK();
}
#endif /* !SMP */
DO_SETBITS(setsoftast, &ipending, SWI_AST_PENDING)
DO_SETBITS(setsoftcamnet,&ipending, SWI_CAMNET_PENDING)
DO_SETBITS(setsoftcambio,&ipending, SWI_CAMBIO_PENDING)
***************
*** 71,84 ****
DO_SETBITS(schedsofttty, &idelayed, SWI_TTY_PENDING)
DO_SETBITS(schedsoftvm, &idelayed, SWI_VM_PENDING)
- #ifndef SMP
-
unsigned
softclockpending(void)
{
return (ipending & SWI_CLOCK_PENDING);
}
#define GENSPL(name, set_cpl) \
unsigned name(void) \
{ \
--- 69,82 ----
DO_SETBITS(schedsofttty, &idelayed, SWI_TTY_PENDING)
DO_SETBITS(schedsoftvm, &idelayed, SWI_VM_PENDING)
unsigned
softclockpending(void)
{
return (ipending & SWI_CLOCK_PENDING);
}
+ #ifndef SMP
+
#define GENSPL(name, set_cpl) \
unsigned name(void) \
{ \
***************
*** 142,160 ****
#define POSTCODE_LO(X)
#define POSTCODE_HI(X)
#endif /* SPL_DEBUG_POSTCODE */
-
-
- unsigned
- softclockpending(void)
- {
- unsigned x;
-
- IFCPL_LOCK();
- x = ipending & SWI_CLOCK_PENDING;
- IFCPL_UNLOCK();
-
- return (x);
- }
/*
--- 140,145 ----
--J2SCkAp4GZ/dPZZf--
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