Date: Fri, 16 Jan 2004 11:10:28 -0800 (PST) From: John Baldwin <jhb@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 45452 for review Message-ID: <200401161910.i0GJAS9E012411@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=45452 Change 45452 by jhb@jhb_slimer on 2004/01/16 11:09:55 Use a cv rather than a semaphore. Less lock operations that way. Affected files ... .. //depot/projects/smpng/sys/kern/kern_ktrace.c#36 edit Differences ... ==== //depot/projects/smpng/sys/kern/kern_ktrace.c#36 (text+ko) ==== @@ -54,7 +54,6 @@ #include <sys/unistd.h> #include <sys/vnode.h> #include <sys/ktrace.h> -#include <sys/sema.h> #include <sys/sx.h> #include <sys/sysctl.h> #include <sys/syslog.h> @@ -108,7 +107,7 @@ static int print_message = 1; struct mtx ktrace_mtx; -static struct sema ktrace_sema; +static struct cv ktrace_cv; static void ktrace_init(void *dummy); static int sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS); @@ -129,7 +128,7 @@ int i; mtx_init(&ktrace_mtx, "ktrace", NULL, MTX_DEF | MTX_QUIET); - sema_init(&ktrace_sema, 0, "ktrace"); + cv_init(&ktrace_cv, "ktrace"); STAILQ_INIT(&ktr_todo); STAILQ_INIT(&ktr_free); for (i = 0; i < ktr_requestpool; i++) { @@ -263,8 +262,8 @@ mtx_lock(&ktrace_mtx); STAILQ_INSERT_TAIL(&ktr_todo, req, ktr_list); + cv_signal(&ktrace_cv); mtx_unlock(&ktrace_mtx); - sema_post(&ktrace_sema); curthread->td_pflags &= ~TDP_INKTRACE; } @@ -296,8 +295,9 @@ td = curthread; cred = td->td_ucred; for (;;) { - sema_wait(&ktrace_sema); mtx_lock(&ktrace_mtx); + while (STAILQ_EMPTY(&ktr_todo)) + cv_wait(&ktrace_cv, &ktrace_mtx); req = STAILQ_FIRST(&ktr_todo); STAILQ_REMOVE_HEAD(&ktr_todo, ktr_list); KASSERT(req != NULL, ("got a NULL request"));
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