Date: Fri, 18 Jan 2008 09:29:44 -0500 From: John Baldwin <jhb@freebsd.org> To: "Attilio Rao" <attilio@freebsd.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, David Xu <davidxu@freebsd.org>, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/kern kern_time.c Message-ID: <200801180929.45123.jhb@freebsd.org> In-Reply-To: <3bbf2fe10801180534y7f97f39meb0b12624e0b919a@mail.gmail.com> References: <200801181300.m0ID0SMi041767@repoman.freebsd.org> <3bbf2fe10801180534y7f97f39meb0b12624e0b919a@mail.gmail.com>
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On Friday 18 January 2008 08:34:57 am Attilio Rao wrote: > 2008/1/18, David Xu <davidxu@freebsd.org>: > > davidxu 2008-01-18 13:00:28 UTC > > > > FreeBSD src repository > > > > Modified files: > > sys/kern kern_time.c > > Log: > > Make sure reading td_runtime in critical section since thread may be > > preempted and td_runtime will be modified. > > If you don't need the operation to be atomical with other operations > inside the critical path (and I don't expect so) this change is > pointless as our reading are always atomic. Not on 32-bit archs like i386. They may do two 32-bit reads and you could have problems if the lower 32 wraps in between the reads. -- John Baldwin
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