From: Rusty Russell <rusty@rustcorp.com.au>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Ian Campbell <Ian.Campbell@citrix.com>, Tejun Heo <tj@kernel.org>,
"Paul E. McKenney" <paulmck@us.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-kernel" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Correct nr_processes() when CPUs have been unplugged
Date: Thu, 5 Nov 2009 11:13:33 +1030 [thread overview]
Message-ID: <200911051113.33889.rusty@rustcorp.com.au> (raw)
In-Reply-To: <alpine.DEB.1.10.0911031324380.32136@V090114053VZO-1>
On Wed, 4 Nov 2009 05:04:32 am Christoph Lameter wrote:
> On Tue, 3 Nov 2009, Ingo Molnar wrote:
>
> > Sidenote: percpu areas currently are kept allocated on x86.
>
> They must be kept allocated for all possible cpus. Arch code cannot decide
> to not allocate per cpu areas.
>
> Search for "for_each_possible_cpu" in the source tree if you want more
> detail.
Yeah, handling onlining/offlining of cpus is a hassle for most code.
But I can see us wanting abstractions for counters which handle being per-cpu
or per-node and doing the folding etc. automagically. It's best that this
be done by looking at all the existing users to see if there's a nice API
which would cover 90%.
Cheers,
Rusty.
next prev parent reply other threads:[~2009-11-05 0:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-03 10:11 [PATCH] Correct nr_processes() when CPUs have been unplugged Ian Campbell
2009-11-03 15:51 ` Linus Torvalds
2009-11-03 16:07 ` Ingo Molnar
2009-11-03 18:34 ` Christoph Lameter
2009-11-04 6:09 ` Paul E. McKenney
2009-11-04 19:37 ` Christoph Lameter
2009-11-04 19:44 ` Paul E. McKenney
2009-11-04 10:42 ` Ingo Molnar
2009-11-05 0:43 ` Rusty Russell [this message]
2009-11-04 11:10 ` Ian Campbell
2009-11-04 8:34 ` Rusty Russell
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