[rfc] use ext3 instead of ext2

Bryan Kadzban bryan at kadzban.is-a-geek.net
Fri Jul 16 09:55:15 PDT 2004


On Fri, Jul 16, 2004 at 05:03:00PM +0100, Ian Molton wrote:
> On Fri, 16 Jul 2004 07:01:52 -0400
> Bryan Kadzban <bryan at kadzban.is-a-geek.net> wrote:
> 
> > Does low latency even matter with a preemptible kernel?
> 
> yes. what preempt alleviates is the problem of one task making others
> waiting to enter the kernel.

I thought preempt allowed other tasks to execute (in any mode) while one
was in kernel mode?  I didn't think it had anything to do with *entering*
the kernel (executing an INT 80h (on x86 anyway) to run a syscall), I
thought it allowed syscalls (or whatever) to be interrupted by higher-
priority processes, and then resumed later.

But this understanding is not based on reading the code, just the
documentation that's attached to CONFIG_PREEMPT.

Also, let me play dumb here -- what does low-latency alleviate?  All
that the low-latency patches do is make the kernel functions give up
their locks at certain predefined "OK" points, right?  Or is that not
the case anymore?  (IIRC, it used to be, though I may not.)



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