From fce05250f93362ea3cac7e272465fd011a8b48fe Mon Sep 17 00:00:00 2001 From: chs Date: Mon, 19 Jul 1999 03:21:11 +0000 Subject: [PATCH] more cleanup: remove simplelockrecurse, lockpausetime and PAUSE(): none of these serve any purpose anymore. in the LOCKDEBUG functions, expand the splhigh() region to cover the entire function. without this there can still be races. --- sys/kern/kern_lock.c | 116 +++++++++++-------------------------------- 1 file changed, 29 insertions(+), 87 deletions(-) diff --git a/sys/kern/kern_lock.c b/sys/kern/kern_lock.c index 1211000dcb97..ec791231bc89 100644 --- a/sys/kern/kern_lock.c +++ b/sys/kern/kern_lock.c @@ -1,4 +1,4 @@ -/* $NetBSD: kern_lock.c,v 1.17 1999/05/04 15:58:53 sommerfe Exp $ */ +/* $NetBSD: kern_lock.c,v 1.18 1999/07/19 03:21:11 chs Exp $ */ /* * Copyright (c) 1995 @@ -40,6 +40,7 @@ */ #include "opt_lockdebug.h" +#include "opt_ddb.h" #include #include @@ -58,47 +59,10 @@ #define COUNT(p, x) #endif -#if 0 /*#was defined(MULTIPROCESSOR)*/ -/*- - -This macro is Bad Style and it doesn't work either... [pk, 10-14-1998] - --* - * For multiprocessor system, try spin lock first. - * - * This should be inline expanded below, but we cannot have #if - * inside a multiline define. - */ - -int lock_wait_time = 100; -#define PAUSE(lkp, wanted) \ - if (lock_wait_time > 0) { \ - int i; \ - \ - simple_unlock(&lkp->lk_interlock); \ - for (i = lock_wait_time; i > 0; i--) \ - if (!(wanted)) \ - break; \ - simple_lock(&lkp->lk_interlock); \ - } \ - if (!(wanted)) \ - break; - -#else /* ! MULTIPROCESSOR */ - -/* - * It is an error to spin on a uniprocessor as nothing will ever cause - * the simple lock to clear while we are executing. - */ -#define PAUSE(lkp, wanted) - -#endif /* MULTIPROCESSOR */ - /* * Acquire a resource. */ #define ACQUIRE(lkp, error, extflags, wanted) \ - PAUSE(lkp, wanted); \ for (error = 0; wanted; ) { \ (lkp)->lk_waitcount++; \ simple_unlock(&(lkp)->lk_interlock); \ @@ -409,9 +373,6 @@ lockmgr(lkp, flags, interlkp) error = EBUSY; break; } - PAUSE(lkp, ((lkp->lk_flags & - (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)) || - lkp->lk_sharecount != 0 || lkp->lk_waitcount != 0)); for (error = 0; ((lkp->lk_flags & (LK_HAVE_EXCL | LK_WANT_EXCL | LK_WANT_UPGRADE)) || lkp->lk_sharecount != 0 || lkp->lk_waitcount != 0); ) { @@ -469,13 +430,8 @@ lockmgr_printinfo(lkp) } #if defined(LOCKDEBUG) && !defined(MULTIPROCESSOR) -#include -#include -#include -int lockpausetime = 0; -struct ctldebug debug2 = { "lockpausetime", &lockpausetime }; -int simplelockrecurse; LIST_HEAD(slocklist, simplelock) slockdebuglist; +int simple_lock_debugger = 0; /* * Simple lock functions so that the debugger can see from whence @@ -501,8 +457,7 @@ _simple_lock(alp, id, l) { int s; - if (simplelockrecurse) - return; + s = splhigh(); if (alp->lock_data == 1) { printf("simple_lock: lock held\n"); printf("currently at: %s:%d\n", id, l); @@ -510,30 +465,19 @@ _simple_lock(alp, id, l) alp->lock_file, alp->lock_line); printf("last unlocked: %s:%d\n", alp->unlock_file, alp->unlock_line); - if (lockpausetime == -1) - panic("simple_lock: lock held"); - if (lockpausetime == 1) { -#ifdef BACKTRACE - BACKTRACE(curproc); -#endif - } else if (lockpausetime > 1) { - printf("simple_lock: lock held, pausing..."); - tsleep(&lockpausetime, PCATCH | PPAUSE, "slock", - lockpausetime * hz); - printf(" continuing\n"); + if (simple_lock_debugger) { + Debugger(); } + splx(s); return; } - - s = splhigh(); LIST_INSERT_HEAD(&slockdebuglist, (struct simplelock *)alp, list); - splx(s); - alp->lock_data = 1; alp->lock_file = id; alp->lock_line = l; if (curproc) curproc->p_simple_locks++; + splx(s); } int @@ -544,20 +488,29 @@ _simple_lock_try(alp, id, l) { int s; - if (alp->lock_data) + s = splhigh(); + if (alp->lock_data != 0) { + printf("simple_lock_try: lock held\n"); + printf("currently at: %s:%d\n", id, l); + printf("last locked: %s:%d\n", + alp->lock_file, alp->lock_line); + printf("last unlocked: %s:%d\n", + alp->unlock_file, alp->unlock_line); + if (simple_lock_debugger) { + Debugger(); + } + splx(s); return (0); - if (simplelockrecurse) - return (1); + } + alp->lock_data = 1; alp->lock_file = id; alp->lock_line = l; - - s = splhigh(); LIST_INSERT_HEAD(&slockdebuglist, (struct simplelock *)alp, list); - splx(s); - if (curproc) curproc->p_simple_locks++; + splx(s); + return (1); } @@ -569,8 +522,7 @@ _simple_unlock(alp, id, l) { int s; - if (simplelockrecurse) - return; + s = splhigh(); if (alp->lock_data == 0) { printf("simple_unlock: lock not held\n"); printf("currently at: %s:%d\n", id, l); @@ -578,32 +530,22 @@ _simple_unlock(alp, id, l) alp->lock_file, alp->lock_line); printf("last unlocked: %s:%d\n", alp->unlock_file, alp->unlock_line); - if (lockpausetime == -1) - panic("simple_unlock: lock not held"); - if (lockpausetime == 1) { -#ifdef BACKTRACE - BACKTRACE(curproc); -#endif - } else if (lockpausetime > 1) { - printf("simple_unlock: lock not held, pausing..."); - tsleep(&lockpausetime, PCATCH | PPAUSE, "sunlock", - lockpausetime * hz); - printf(" continuing\n"); + if (simple_lock_debugger) { + Debugger(); } + splx(s); return; } - s = splhigh(); LIST_REMOVE(alp, list); alp->list.le_next = NULL; alp->list.le_prev = NULL; - splx(s); - alp->lock_data = 0; alp->unlock_file = id; alp->unlock_line = l; if (curproc) curproc->p_simple_locks--; + splx(s); } void