Re: Feedback on preemptible kernel patch

Arjan Filius
2001-09-09T21:08:07Z

Hello Robert,

I tried 2.4.10-pre4+preempt+this-patch.
Just booted up, and don't notice anything unusual.

On 9 Sep 2001, Robert Love wrote:

> Arjan,
>
> the following patch was written by Manfred Spraul to fix your highmem
> bug. I haven't had a chance to go over it, but I would like it if you
> could test it. It can't hurt. Patch it on top of the preempt patch and
> enable CONFIG_PREEMPT, CONFIG_HIGHMEM, and CONFIG_HIGHMEM_DEBUG.

I found i do anly have a '#define HIGHMEM_DEBUG 1' in
./include/asm/highmem.h, which is default in 2.4.10-pre4.

>
> let me know what happens...any relevant messages, etc. please pass
> along. if it does work, id be curious if they are any slowdowns

Booting up, X, compiling kernel.. no problems.
For speed, i DO notice other processes seem not to wait on that one
programm which has much disk-access, so the (real) sluggish feeling has
gone. This is however with the preempt patch, and the ctx_sw_ patch below
seems only to affect stability in positive sense.

Can you advice what and how to test performance/latency?
The grafics/statistics on the websites you named are impressive..

Greatings,

>
>
> --- highmem.h.prev Sun Sep 9 08:59:04 2001
> +++ highmem.h Sun Sep 9 09:00:07 2001
> @@ -88,6 +88,7 @@
> if (page < highmem_start_page)
> return page_address(page);
>
> + ctx_sw_off();
> idx = type + KM_TYPE_NR*smp_processor_id();
> vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
> #if HIGHMEM_DEBUG
> @@ -119,6 +120,7 @@
> pte_clear(kmap_pte-idx);
> __flush_tlb_one(vaddr);
> #endif
> + ctx_sw_on();
> }
>
> #endif /* __KERNEL__ */
>
>
>
>

--
Arjan Filius
mailto:iafilius@xs4all.nl