Re: [PATCH RFC] time: drop do_sys_times spinlock

[Rik van Riel]

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On 08/13/2014 01:40 PM, Peter Zijlstra wrote:

> So the problem with the above is the lack of fwd progress; if
> there's enough clone()/exit() happening in the thread group (and
> the more CPUs the more possible), we'll keep repeating.

We can fall back to taking the lock if we circle around,
or if there is a writer active when we are in seqcount_read,
similar to what the semaphore (ipc/sem.c) code is doing.

read_seqbegin_or_lock would do the trick...
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