Re: x86: 4kstacks default
From: Alexander E. Patrakov
Date: Sun Apr 20 2008 - 23:30:26 EST
Adrian Bunk wrote:
On Sun, Apr 20, 2008 at 08:41:27AM -0700, Arjan van de Ven wrote:
...
yes. Adrian is waay off in the weeds on this one. Nobody but him is suggesting to remove
8Kb stacks. I think everyone else agrees that having both options is valuable; and there
are better ways to find+fix stack bloat than removing this config option.
I'm not arguing for removing the option immediately, but long-term we
shouldn't need it.
This comes from my experience of removing obsolete drivers for hardware
for which also a more recent driver exists:
As long as there is some workaround (e.g. using an older driver or
8k stacks) the workaround will be used instead of the getting proper
bug reports and fixes.
As far as I know all problems that are known with 4k stacks are some
nested things with XFS in the trace.
This "as far as I know" is a problem itself. Is it possible to implement (e.g.,
using some form of memory protection in hardware, but I am not an expert here)
an option with 8k stacks that, however, spams the log if the actual usage goes
above 4k, and have this as a default for some time? If 4k stacks are the goal
that is almost achieved, then this debugging option should have zero impact on
performance.
--
Alexander E. Patrakov
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