2001-10-01 04:21:24

by Robert Love

[permalink] [raw]
Subject: [PATCH] (Updated) Preemptible Kernel

Updated patches for 2.4.10, 2.4.11-pre1, and 2.4.10-ac1 are at
http://tech9.net/rml/linux

Note that the 2.4.10 patch is updated over previous patches.

It's been awhile, because a lot has changed. Please give this a good
once (and twice) -over. For those of you using preempt-stats, I suggest
not keeping that patch compiled in during regular use and certainly not
during any benchmarking.

What's New:

Most notably, George Anzinger of MontaVista rewrote how we keep track of
whether a task is preempted or not. The "preempt bit" has been moved
from a task's status flag to the preempt_count (per-task_struct)
variable. The resulting code is cleaner and simpler, and as a bonus the
race with ptrace and signals (and any undetected similar problems) has
been fixed, so we don't need explicit fixes.

I also renamed our namespace, cleaning things up, and trying to stick to
a prefix of "preempt." Most important, ctx_sw_on and ctx_sw_off are now
preempt_enable and preempt_disable.

The ChangeLog since the last official release:

20010928
- have spin_lock_prefetch prefetch the preempt_count, too,
since its incremented on each spin_lock
- some more ifdef and namespace cleanups

20010925
- modify our handling of the "preemption bit": move from the
task's status to the preempt_count
- the above removes the risk of race in ptrace and SIGSTOP
signal handling, so we can back out those fixes.
- rearrange our namespace. most notably, ctx_sw_on/off
is now preempt_enable/disable.
- cleanup some defines

20010923
- fix strace race: make ptrace preempt safe
- fix job control race: make SIGSTOP signal preempt
safe
- fix adfs compile bug: add sched.h include to
fs/adfs/map.c

--
Robert M. Love
rml at ufl.edu
rml at tech9.net


2001-10-01 05:34:08

by Steve Kieu

[permalink] [raw]
Subject: Re: [PATCH] (Updated) Preemptible Kernel

--- Robert Love <[email protected]> wrote: > Updated
patches for 2.4.10, 2.4.11-pre1, and
> 2.4.10-ac1 are at
> http://tech9.net/rml/linux

Sorry it seems that your patches has not uploaded yet
:-)

Cheers,



=====
S.KIEU

http://travel.yahoo.com.au - Yahoo! Travel
- Got Itchy feet? Get inspired!

2001-10-01 05:45:58

by Robert Love

[permalink] [raw]
Subject: Re: [PATCH] (Updated) Preemptible Kernel

On Mon, 2001-10-01 at 01:34, Steve Kieu wrote:
> Sorry it seems that your patches has not uploaded yet
> :-)

Hm, check again -- I see them. I've already gotten emails about them,
so I guess others do, too :)

>From http://tech9.net/rml/linux, the patches are at:

http://tech9.net/rml/linux/patch-rml-2.4.10-ac1-preempt-kernel-1
http://tech9.net/rml/linux/patch-rml-2.4.11-pre1-preempt-kernel-1
http://tech9.net/rml/linux/patch-rml-2.4.10-preempt-kernel-5

--
Robert M. Love
rml at ufl.edu
rml at tech9.net