Re: SMP question w.r.t. reading kernel variables

2011-04-20 Thread Rick Macklem
> [good stuff snipped for brevity] > > > > 1. Set MNTK_UNMOUNTF > > 2. Acquire a standard FreeBSD mutex "m". > > 3. Update some data structures. > > 4. Release mutex "m". > > > > Then, other threads that acquire "m" after step 4 has occurred will > > see > > MNTK_UNMOUNTF as set. But, other threads

Re: SMP question w.r.t. reading kernel variables

2011-04-20 Thread Rick Macklem
[good stuff snipped for brevity] > > 1. Set MNTK_UNMOUNTF > 2. Acquire a standard FreeBSD mutex "m". > 3. Update some data structures. > 4. Release mutex "m". > > Then, other threads that acquire "m" after step 4 has occurred will > see > MNTK_UNMOUNTF as set. But, other threads that beat thread

Re: SMP question w.r.t. reading kernel variables

2011-04-20 Thread Alan Cox
On Wed, Apr 20, 2011 at 7:42 AM, Rick Macklem wrote: > > On Tue, Apr 19, 2011 at 12:00:29PM +, > > freebsd-hackers-requ...@freebsd.org wrote: > > > Subject: Re: SMP question w.r.t. reading kernel variables > > > To: Rick Macklem > > > Cc: freebsd-hackers@freebsd.org > > > Message-ID: <201104

Re: SMP question w.r.t. reading kernel variables

2011-04-20 Thread Rick Macklem
> On Tue, Apr 19, 2011 at 12:00:29PM +, > freebsd-hackers-requ...@freebsd.org wrote: > > Subject: Re: SMP question w.r.t. reading kernel variables > > To: Rick Macklem > > Cc: freebsd-hackers@freebsd.org > > Message-ID: <201104181712.14457@freebsd.org> > > [John Baldwin] > > On Monday, Ap