From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Correct nr_processes() when CPUs have been unplugged
Date: Tue, 3 Nov 2009 07:51:25 -0800 (PST) [thread overview]
Message-ID: <alpine.LFD.2.01.0911030748430.31845@localhost.localdomain> (raw)
In-Reply-To: <1257243074.23110.779.camel@zakaz.uk.xensource.com>
On Tue, 3 Nov 2009, Ian Campbell wrote:
>
> Therefore calculating the sum of process_counts over only the online
> CPUs omits the processes which were started or stopped on any CPU which
> has since been unplugged. Only the sum of process_counts across all
> possible CPUs has meaning.
I think your patch is fine, but I also suspect that we could/should
instead fix it by doing something like
per_cpu(process_counts, this_cpu) += per_cpu(process_counts, down_cpu);
per_cpu(process_counts, down_cpu) = 0;
in the CPU off-lining case after having quieted 'down_cpu'. That way we
could always use online CPU's rather than possible CPU's. I think that
just sounds nicer.
So I'll apply the patch, but I get the feeling it could be done better.
Linus
next prev parent reply other threads:[~2009-11-03 15:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-03 10:11 Ian Campbell
2009-11-03 15:51 ` Linus Torvalds [this message]
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
2009-11-04 11:10 ` Ian Campbell
2009-11-04 8:34 ` Rusty Russell
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