Messages in this thread | | | Date | Fri, 3 Oct 2014 23:16:10 +0200 | From | Oleg Nesterov <> | Subject | Re: [tip:x86/asm] x86: Speed up ___preempt_schedule*() by using THUNK helpers |
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Hi Sasha,
On 10/03, Sasha Levin wrote: > > On 09/24/2014 11:02 AM, tip-bot for Oleg Nesterov wrote: > > Commit-ID: 0ad6e3c5199be12c9745da8f8b9e3c9f8066c235 > > Gitweb: http://git.kernel.org/tip/0ad6e3c5199be12c9745da8f8b9e3c9f8066c235 > > Author: Oleg Nesterov <oleg@redhat.com> > > AuthorDate: Sun, 21 Sep 2014 20:41:53 +0200 > > Committer: Ingo Molnar <mingo@kernel.org> > > CommitDate: Wed, 24 Sep 2014 15:15:38 +0200 > > > > x86: Speed up ___preempt_schedule*() by using THUNK helpers > > > > ___preempt_schedule() does SAVE_ALL/RESTORE_ALL but this is > > suboptimal, we do not need to save/restore the callee-saved > > register. And we already have arch/x86/lib/thunk_*.S which > > implements the similar asm wrappers, so it makes sense to > > redefine ___preempt_schedule() as "THUNK ..." and remove > > preempt.S altogether. > > > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > > Reviewed-by: Andy Lutomirski <luto@amacapital.net> > > Cc: Denys Vlasenko <dvlasenk@redhat.com> > > Cc: Peter Zijlstra <peterz@infradead.org> > > Cc: Linus Torvalds <torvalds@linux-foundation.org> > > Link: http://lkml.kernel.org/r/20140921184153.GA23727@redhat.com > > Signed-off-by: Ingo Molnar <mingo@kernel.org> > > --- > > Hi Oleg, > > I *think* that this patch is causing the following trace (arch/x86/lib/thunk_64.S:44 > is new code introduced by this patch):
Not sure, but I'm afraid your guess can be correct...
> [ 921.908530] kernel BUG at kernel/sched/core.c:2702!
OK, this is schedule_debug() -> BUG_ON(unlikely(task_stack_end_corrupted(prev))) in linux-next.
But at first glance this doesn't match the disassembled code... Could you send me (privately) your kernel/sched/core.c just in case? And .config please. And, if possible, kernel/sched/core.s
Oleg.
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