On 06/08/2014 01:28 AM, Kalle Valo wrote:
Ben Greear <greearb@xxxxxxxxxxxxxxx> writes:
On 06/07/2014 05:55 AM, Kalle Valo wrote:
Ben Greear <greearb@xxxxxxxxxxxxxxx> writes:
I'm a bit leery of adding spin-locks in the dump routine just for
this, but I can add and use a new spin-lock if you prefer.
Why a new spinlock? I didn't review the locking requirements, but I
would first check ar->data_lock can be used.
I think it has to be a spin-lock because the crash dump is gathered
in the irq handler, so I can't use a mutex as far as I know...
I'll work on adding such a lock today.
I asked why add a _new_ spinlock as ar->data_lock is already a spinlock.
Surely we do not want to impede traffic flow just to dump debug info?
I don't see data_lock being used anywhere in hotpath, but of course I
might have missed something. Anyway, if for optimisation reasons we need
to introduce a new lock that should happen for a specific case in hot
path. Handling firmware debug log events is not in that category.
And, it is easier to review a specific spinlock rather than use one big
global-ish lock and have to review every use of that lock for issues.
Sure, it's easier for you to just add a new lock and then forget :) But
not for me who would have to maintain 20 different locks for years to
come. My view is that a new lock should be added on very exceptional
cases and with good justifications.
I have the opposite opinion on what makes it easy to maintain
locks, but I'll switch to the data-spinlock as you suggest.
Thanks,
Ben
--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
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