Re: [3/4] [PATCH]Diskdump - yet another crash dump function

From: Nobuhiro Tachino
Date: Mon Jun 21 2004 - 15:42:36 EST


Takao Indoh wrote:
On Thu, 17 Jun 2004 14:13:56 +0200, Ingo Molnar wrote:


but there's another possible method (suggested by Alan Cox) that
requires no changes to the timer API hotpaths: 'clear' all timer lists
upon a crash [once all CPUs have stopped and irqs are disabled] and just
let the drivers use the normal timer APIs. Drive timer execution via a
polling method.

this basically approximates your polling based implementation but uses
the existing kernel timer data structures and timer mechanism so should
be robust and compatible. It doesnt rely on any previous state (because
all currently pending timers are discarded) so it's as crash-safe as
possible.


This is a test patch for clearing timer/tasklet and executing it
during dumping.
This patch does not work yet. I tried dumping using this patch, but
aic7xxx is unstable...

Your new dump_run_timers() calls __run_timers() directly. I think that's
the reason of unstability. __run_timers() calls spin_unlock_irq()
and enables IRQ, but diskdump expects everything runs with IRQ
disabled.
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