diff options
| author | dillon <dillon@FreeBSD.org> | 1999-11-19 16:49:30 +0000 |
|---|---|---|
| committer | dillon <dillon@FreeBSD.org> | 1999-11-19 16:49:30 +0000 |
| commit | 1ac9471dbc55b5fa42d36aa8041ffbe7f64bf917 (patch) | |
| tree | a4124d514335e75961eb168aa446f957cbedfe22 /sys/i386/isa/ipl.s | |
| parent | 3544d646b5ba034af1430a8d204a232f969894de (diff) | |
| download | FreeBSD-src-1ac9471dbc55b5fa42d36aa8041ffbe7f64bf917.zip FreeBSD-src-1ac9471dbc55b5fa42d36aa8041ffbe7f64bf917.tar.gz | |
Optimize two cases in the MP locking code. First, it is not necessary
to use a locked cmpexg when unlocking a lock that we already hold, since
nobody else can touch the lock while we hold it. Second, it is not
necessary to use a locked cmpexg when locking a lock that we already
hold, for the same reason. These changes will allow MP locks to be used
recursively without impacting performance.
Modify two procedures that are called only by assembly and are already
NOPROF entries to pass a critical argument in %edx instead of on the
stack, removing a significant amount of code from the critical path
as a consequence.
Reviewed by: Alfred Perlstein <bright@wintelcom.net>, Peter Wemm <peter@netplex.com.au>
Diffstat (limited to 'sys/i386/isa/ipl.s')
| -rw-r--r-- | sys/i386/isa/ipl.s | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/sys/i386/isa/ipl.s b/sys/i386/isa/ipl.s index 964834d..7c1fca1 100644 --- a/sys/i386/isa/ipl.s +++ b/sys/i386/isa/ipl.s @@ -174,9 +174,8 @@ doreti_exit: #error code needed here to decide which lock to release, INTR or giant #endif /* release the kernel lock */ - pushl $_mp_lock /* GIANT_LOCK */ - call _MPrellock - add $4, %esp + movl $_mp_lock, %edx /* GIANT_LOCK */ + call _MPrellock_edx #endif /* SMP */ .globl doreti_popl_fs |
