svn commit: r211176 - in head/sys: amd64/amd64 i386/i386
attilio at freebsd.org
Wed Aug 11 11:21:48 UTC 2010
2010/8/11 Kostik Belousov <kostikbel at gmail.com>:
> On Wed, Aug 11, 2010 at 10:51:27AM +0000, Attilio Rao wrote:
>> Author: attilio
>> Date: Wed Aug 11 10:51:27 2010
>> New Revision: 211176
>> URL: http://svn.freebsd.org/changeset/base/211176
>> IPI handlers may run generally with interrupts disabled because they
>> are served via an interrupt gate.
>> However, that doesn't explicitly prevent preemption and thread
>> migration thus scheduler pinning may be necessary in some handlers.
>> Fix that.
> How the preemption is supposed to happen ? Aside from the explicit
> calls to mi_switch() from e.g. critical_exit().
IIRC it should be hardclock() willing to schedule the softclock(). It
is the critical_exit() in the thread_unlock() that may trigger it
(sorry for not digging more, it was a while back that I hacked this
part, but I guess you can verify on your own).
We already have other points within the kernel that take care of
dealing with preemption/migration like lapic_handle_timer(), for
Peace can only be achieved by understanding - A. Einstein
More information about the svn-src-all