From: Oleg Nesterov <oleg@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Jan Beulich <jbeulich@suse.com>, Ingo Molnar <mingo@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Sebastian Lackner <sebastian@fds-team.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Chuck Ebbert <cebbert.lkml@gmail.com>,
Anish Bhatt <anish@chelsio.com>,
Thomas Gleixner <tglx@linutronix.de>,
"linux-tip-commits@vger.kernel.org"
<linux-tip-commits@vger.kernel.org>
Subject: Re: [tip:x86/asm] sched/x86_64: Don't save flags on context switch
Date: Wed, 5 Nov 2014 00:09:41 +0100 [thread overview]
Message-ID: <20141104230941.GA30569@redhat.com> (raw)
In-Reply-To: <CALCETrUMLaz_McO=f-v6JmPY7pJSU4M4g1+p1un1UiVcNf+4XQ@mail.gmail.com>
Didn't notice this part yesterday...
On 11/03, Andy Lutomirski wrote:
>
> On Mon, Nov 3, 2014 at 1:58 PM, Oleg Nesterov <oleg@redhat.com> wrote:
> > On 11/03, Oleg Nesterov wrote:
> >>
> >> On 11/03, Andy Lutomirski wrote:
> >> >
> >> > Also, what's with 'jmp exit_intr' at the end of retint_kernel? Why
> >> > isn't that 'jmp retint_kernel'?
> >>
> >> Even better, why not "jmp retint_restore_args" ?
> >>
> >> preempt_schedule_irq() checks need_resched() and returns with irqs
> >> disabled, not need to to recheck test_preempt_need_resched() ?
>
> Seems reasonable to me. Want to write the patch?
OK, will try to do tomorrow.
And it seems that we can do a bit more, although I need to recheck.
retint_kernel() no longer needs rcx == threadinfo, it doesn't check
TIF_NEED_RESCHED. This means we can shift/remove some GET_THREAD_INFO()'s
under retint_check.
Oleg.
next prev parent reply other threads:[~2014-11-04 23:09 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-01 18:28 [PATCH v3 0/2] x86_64,entry: Clear NT on entry and speed up switch_to Andy Lutomirski
2014-10-01 18:28 ` [PATCH v3 1/2] x86_64,entry: Filter RFLAGS.NT on entry from userspace Andy Lutomirski
2014-10-01 18:28 ` [PATCH v3 2/2] x86_64: Don't save flags on context switch Andy Lutomirski
2014-10-01 18:35 ` H. Peter Anvin
2014-10-01 18:44 ` Andy Lutomirski
2014-10-20 18:52 ` Andy Lutomirski
2014-10-28 11:14 ` [tip:x86/asm] sched/x86_64: " tip-bot for Andy Lutomirski
2014-11-03 21:11 ` Andy Lutomirski
2014-11-03 21:47 ` Oleg Nesterov
2014-11-03 21:58 ` Oleg Nesterov
2014-11-03 22:37 ` Andy Lutomirski
2014-11-03 22:57 ` Oleg Nesterov
2014-11-03 23:02 ` Andy Lutomirski
2014-11-03 23:10 ` Oleg Nesterov
2014-11-04 23:09 ` Oleg Nesterov [this message]
2014-11-03 22:17 ` H. Peter Anvin
2014-10-01 18:34 ` [PATCH v3 0/2] x86_64,entry: Clear NT on entry and speed up switch_to H. Peter Anvin
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