Date: Thu, 23 Feb 2012 00:42:54 +0100 From: Jilles Tjoelker <jilles@stack.nl> To: David Xu <davidxu@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r231989 - in head: lib/libthr/thread sys/kern sys/sys Message-ID: <20120222234254.GC95122@stack.nl> In-Reply-To: <201202220322.q1M3MoFE032330@svn.freebsd.org> References: <201202220322.q1M3MoFE032330@svn.freebsd.org>
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On Wed, Feb 22, 2012 at 03:22:50AM +0000, David Xu wrote: > Author: davidxu > Date: Wed Feb 22 03:22:49 2012 > New Revision: 231989 > URL: http://svn.freebsd.org/changeset/base/231989 > Log: > Use unused fourth argument of umtx_op to pass flags to kernel for operation > UMTX_OP_WAIT. Upper 16bits is enough to hold a clock id, and lower > 16bits is used to pass flags. The change saves a clock_gettime() syscall > from libthr. > Modified: > head/lib/libthr/thread/thr_umtx.c > head/sys/kern/kern_umtx.c > head/sys/sys/umtx.h > > Modified: head/lib/libthr/thread/thr_umtx.c > ============================================================================== > --- head/lib/libthr/thread/thr_umtx.c Wed Feb 22 01:50:13 2012 (r231988) > +++ head/lib/libthr/thread/thr_umtx.c Wed Feb 22 03:22:49 2012 (r231989) > @@ -200,20 +200,10 @@ int > + abstime != NULL ? (void *)(uintptr_t)((clockid << 16) | UMTX_WAIT_ABSTIME) : 0, Please check that this shift does not lose any information (i.e., clockid >= 0 && clockid <= 0xFFFF) before doing it. Implementing clock_getcpuclockid() will require clockids greater than 65535 because such clockids contain a process id. -- Jilles Tjoelker
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