2003-07-09 09:28:27

by Aurelien Jarno

Subject: Patch preempt and win4lin

Hi all,

I am maintaining the Debian package containing the preemptible kernel
from Robert Love.

A user told me that win4lin stops working when the preemptible patch is
used. He sent me a patch (see below); I have tested it on my computer it
seems to work, however I don't understand exactly what it does.

Could anybody can give me some comments on this patch and the possible
consequences it could generate?

Thanks
Aurelien


##
# This patch will apply to a 2.4.18 tree that has been patched with
# preempt-kernel-rml-2.4.18-5.patch
#
--- linux-2.4.18-orig/arch/i386/kernel/entry.S Mon Feb 25 12:37:53 2002
++++ linux-2.4.18/arch/i386/kernel/entry.S Wed Feb 27 07:16:58
2002
@@ -293,9 +293,8 @@
jnz restore_all
cmpl $0,need_resched(%ebx)
jz restore_all
- movl SYMBOL_NAME(irq_stat)+irq_stat_local_bh_count CPU_INDX,%ecx
- addl SYMBOL_NAME(irq_stat)+irq_stat_local_irq_count
CPU_INDX,%ecx
- jnz restore_all
+ testl $IF_MASK,EFLAGS(%esp) # Ints off (execption path) ?
+ jz restore_all
incl preempt_count(%ebx)
sti
call SYMBOL_NAME(preempt_schedule)

2003-07-09 21:46:10

by Nicholas Wourms

Subject: Re: Patch preempt and win4lin

Aurelien Jarno wrote:

> Hi all,
>
> I am maintaining the Debian package containing the preemptible kernel
> from Robert Love.
>
> A user told me that win4lin stops working when the preemptible patch is
> used. He sent me a patch (see below); I have tested it on my computer it
> seems to work, however I don't understand exactly what it does.
>
> Could anybody can give me some comments on this patch and the possible
> consequences it could generate?

You might want to check with Marc-Christian @WOLK, since he said he
already got a patch awile back from the win4lin people to fix this.

Cheers,
Nicholas