Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-19 Thread Andy Lutomirski
On Wed, Aug 19, 2015 at 10:18 AM, Frederic Weisbecker wrote: > On Tue, Aug 18, 2015 at 03:40:20PM -0700, Andy Lutomirski wrote: >> >> I sure hope not, unless it nests inside an NMI-like thing. It's >> conceivable that this might happen due to perf NMIs causing a failed >> MSR read or similar. We

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-19 Thread Frederic Weisbecker
On Tue, Aug 18, 2015 at 03:40:20PM -0700, Andy Lutomirski wrote: > On Tue, Aug 18, 2015 at 3:34 PM, Frederic Weisbecker > wrote: > >> If we switched back to exception_enter, we'd have to remember the > >> previous state, and, with a single exception right now, I think that's > >> unnecessary. > >

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-18 Thread Andy Lutomirski
On Tue, Aug 18, 2015 at 3:34 PM, Frederic Weisbecker wrote: > On Wed, Aug 12, 2015 at 07:59:44AM -0700, Andy Lutomirski wrote: >> On Wed, Aug 12, 2015 at 6:32 AM, Frederic Weisbecker >> wrote: >> > Right, and doing it the way we did previously was safe wrt. that. >> > >> > Can't we have exceptio

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-18 Thread Frederic Weisbecker
On Wed, Aug 12, 2015 at 07:59:44AM -0700, Andy Lutomirski wrote: > On Wed, Aug 12, 2015 at 6:32 AM, Frederic Weisbecker > wrote: > > Right, and doing it the way we did previously was safe wrt. that. > > > > Can't we have exceptions slow path just like the way we do it in syscalls? > > > > Then th

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-12 Thread Andy Lutomirski
On Wed, Aug 12, 2015 at 6:32 AM, Frederic Weisbecker wrote: > On Tue, Aug 11, 2015 at 04:33:05PM -0700, Andy Lutomirski wrote: >> On Tue, Aug 11, 2015 at 4:22 PM, Frederic Weisbecker >> wrote: >> > >> > On Tue, Aug 11, 2015 at 03:51:26PM -0700, Andy Lutomirski wrote: >> >> On Tue, Aug 11, 2015 a

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-12 Thread Frederic Weisbecker
On Tue, Aug 11, 2015 at 04:33:05PM -0700, Andy Lutomirski wrote: > On Tue, Aug 11, 2015 at 4:22 PM, Frederic Weisbecker > wrote: > > > > On Tue, Aug 11, 2015 at 03:51:26PM -0700, Andy Lutomirski wrote: > >> On Tue, Aug 11, 2015 at 3:38 PM, Frederic Weisbecker > >> wrote: > >> > > >> > This make

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-12 Thread Frederic Weisbecker
On Tue, Aug 11, 2015 at 03:59:37PM -0700, Andy Lutomirski wrote: > On Tue, Aug 11, 2015 at 3:49 PM, Frederic Weisbecker > wrote: > > On Tue, Aug 11, 2015 at 03:25:04PM -0700, Andy Lutomirski wrote: > >> Can you explain to me what context tracking does that rcu_irq_enter > >> and vtime_account_irq

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-11 Thread Paul E. McKenney
On Tue, Aug 11, 2015 at 03:59:37PM -0700, Andy Lutomirski wrote: > On Tue, Aug 11, 2015 at 3:49 PM, Frederic Weisbecker > wrote: > > On Tue, Aug 11, 2015 at 03:25:04PM -0700, Andy Lutomirski wrote: > >> Can you explain to me what context tracking does that rcu_irq_enter > >> and vtime_account_irq

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-11 Thread Andy Lutomirski
On Tue, Aug 11, 2015 at 4:22 PM, Frederic Weisbecker wrote: > > On Tue, Aug 11, 2015 at 03:51:26PM -0700, Andy Lutomirski wrote: >> On Tue, Aug 11, 2015 at 3:38 PM, Frederic Weisbecker >> wrote: >> > >> > This makes me very nervous as well! >> > >> > It means that instead of using the context tr

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-11 Thread Frederic Weisbecker
On Tue, Aug 11, 2015 at 03:51:26PM -0700, Andy Lutomirski wrote: > On Tue, Aug 11, 2015 at 3:38 PM, Frederic Weisbecker > wrote: > > > > This makes me very nervous as well! > > > > It means that instead of using the context tracking save/restore model that > > we had > > with exception_enter/ex

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-11 Thread Andy Lutomirski
On Tue, Aug 11, 2015 at 3:49 PM, Frederic Weisbecker wrote: > On Tue, Aug 11, 2015 at 03:25:04PM -0700, Andy Lutomirski wrote: >> Can you explain to me what context tracking does that rcu_irq_enter >> and vtime_account_irq_enter don't do that's expensive? Frankly, I'd >> rather drop everything ex

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-11 Thread Andy Lutomirski
On Tue, Aug 11, 2015 at 3:38 PM, Frederic Weisbecker wrote: > On Tue, Jul 07, 2015 at 03:53:29AM -0700, tip-bot for Andy Lutomirski wrote: >> Commit-ID: 02bc7768fe447ae305e924b931fa629073a4a1b9 >> Gitweb: >> http://git.kernel.org/tip/02bc7768fe447ae305e924b931fa629073a4a1b9 >> Author: An

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-11 Thread Frederic Weisbecker
On Tue, Aug 11, 2015 at 03:25:04PM -0700, Andy Lutomirski wrote: > Can you explain to me what context tracking does that rcu_irq_enter > and vtime_account_irq_enter don't do that's expensive? Frankly, I'd > rather drop everything except the context tracking callback. Irqs have their own hooks in

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-11 Thread Frederic Weisbecker
On Tue, Jul 07, 2015 at 03:53:29AM -0700, tip-bot for Andy Lutomirski wrote: > Commit-ID: 02bc7768fe447ae305e924b931fa629073a4a1b9 > Gitweb: http://git.kernel.org/tip/02bc7768fe447ae305e924b931fa629073a4a1b9 > Author: Andy Lutomirski > AuthorDate: Fri, 3 Jul 2015 12:44:31 -0700 > Committe

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-11 Thread Andy Lutomirski
On Tue, Aug 11, 2015 at 3:18 PM, Frederic Weisbecker wrote: > On Tue, Jul 07, 2015 at 03:53:29AM -0700, tip-bot for Andy Lutomirski wrote: >> Commit-ID: 02bc7768fe447ae305e924b931fa629073a4a1b9 >> Gitweb: >> http://git.kernel.org/tip/02bc7768fe447ae305e924b931fa629073a4a1b9 >> Author: An

Re: [tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-08-11 Thread Frederic Weisbecker
On Tue, Jul 07, 2015 at 03:53:29AM -0700, tip-bot for Andy Lutomirski wrote: > Commit-ID: 02bc7768fe447ae305e924b931fa629073a4a1b9 > Gitweb: http://git.kernel.org/tip/02bc7768fe447ae305e924b931fa629073a4a1b9 > Author: Andy Lutomirski > AuthorDate: Fri, 3 Jul 2015 12:44:31 -0700 > Committe

[tip:x86/asm] x86/asm/entry/64: Migrate error and IRQ exit work to C and remove old assembly code

2015-07-07 Thread tip-bot for Andy Lutomirski
Commit-ID: 02bc7768fe447ae305e924b931fa629073a4a1b9 Gitweb: http://git.kernel.org/tip/02bc7768fe447ae305e924b931fa629073a4a1b9 Author: Andy Lutomirski AuthorDate: Fri, 3 Jul 2015 12:44:31 -0700 Committer: Ingo Molnar CommitDate: Tue, 7 Jul 2015 10:59:08 +0200 x86/asm/entry/64: Migrate