Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On 18/12/15 17:00, Daniel Thompson wrote: The MCE handlers should only call printk() when they decide to panic and *after* busting the spinlocks. At this point deferring printk() until it is safe is not very helpful. When we bust the spinlocks we should probably restore the normal printk()

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On 18/12/15 17:00, Daniel Thompson wrote: The MCE handlers should only call printk() when they decide to panic and *after* busting the spinlocks. At this point deferring printk() until it is safe is not very helpful. When we bust the spinlocks we should probably restore the normal printk()

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, 18 Dec 2015 13:11:41 +0100 Peter Zijlstra wrote: > On Fri, Dec 18, 2015 at 12:29:02PM +0100, Peter Zijlstra wrote: > > On Fri, Dec 18, 2015 at 10:18:08AM +, Daniel Thompson wrote: > > > I'm not entirely sure that this is an improvement. > > > > What I do these days is delete

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On 18/12/15 14:52, Petr Mladek wrote: On Fri 2015-12-18 10:18:08, Daniel Thompson wrote: On 11/12/15 23:26, Jiri Kosina wrote: On Fri, 11 Dec 2015, Russell King - ARM Linux wrote: I'm personally happy with the existing code, and I've been wondering why there's this effort to apply further

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Thu 2015-12-17 14:38:58, Andrew Morton wrote: > On Tue, 15 Dec 2015 15:26:21 +0100 Petr Mladek wrote: > > > > OK, thanks. So "not needed at present, might be needed in the future, > > > useful for out-of-tree debug code"? > > > > It is possible that I got it a wrong way on arm. The NMI

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri 2015-12-18 10:18:08, Daniel Thompson wrote: > On 11/12/15 23:26, Jiri Kosina wrote: > >On Fri, 11 Dec 2015, Russell King - ARM Linux wrote: > > > >>I'm personally happy with the existing code, and I've been wondering why > >>there's this effort to apply further cleanups - to me, the

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, Dec 18, 2015 at 12:29:02PM +0100, Peter Zijlstra wrote: > On Fri, Dec 18, 2015 at 10:18:08AM +, Daniel Thompson wrote: > > I'm not entirely sure that this is an improvement. > > What I do these days is delete everything in vprintk_emit() and simply > call early_printk(). On that,

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, Dec 18, 2015 at 10:18:08AM +, Daniel Thompson wrote: > I'm not entirely sure that this is an improvement. What I do these days is delete everything in vprintk_emit() and simply call early_printk(). Kill the useless kmsg buffer crap and locking, just pound bytes to the UART registers

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On 11/12/15 23:26, Jiri Kosina wrote: On Fri, 11 Dec 2015, Russell King - ARM Linux wrote: I'm personally happy with the existing code, and I've been wondering why there's this effort to apply further cleanups - to me, the changelogs don't seem to make that much sense, unless we want to start

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On 11/12/15 23:26, Jiri Kosina wrote: On Fri, 11 Dec 2015, Russell King - ARM Linux wrote: I'm personally happy with the existing code, and I've been wondering why there's this effort to apply further cleanups - to me, the changelogs don't seem to make that much sense, unless we want to start

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, Dec 18, 2015 at 10:18:08AM +, Daniel Thompson wrote: > I'm not entirely sure that this is an improvement. What I do these days is delete everything in vprintk_emit() and simply call early_printk(). Kill the useless kmsg buffer crap and locking, just pound bytes to the UART registers

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, Dec 18, 2015 at 12:29:02PM +0100, Peter Zijlstra wrote: > On Fri, Dec 18, 2015 at 10:18:08AM +, Daniel Thompson wrote: > > I'm not entirely sure that this is an improvement. > > What I do these days is delete everything in vprintk_emit() and simply > call early_printk(). On that,

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri 2015-12-18 10:18:08, Daniel Thompson wrote: > On 11/12/15 23:26, Jiri Kosina wrote: > >On Fri, 11 Dec 2015, Russell King - ARM Linux wrote: > > > >>I'm personally happy with the existing code, and I've been wondering why > >>there's this effort to apply further cleanups - to me, the

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On 18/12/15 14:52, Petr Mladek wrote: On Fri 2015-12-18 10:18:08, Daniel Thompson wrote: On 11/12/15 23:26, Jiri Kosina wrote: On Fri, 11 Dec 2015, Russell King - ARM Linux wrote: I'm personally happy with the existing code, and I've been wondering why there's this effort to apply further

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Thu 2015-12-17 14:38:58, Andrew Morton wrote: > On Tue, 15 Dec 2015 15:26:21 +0100 Petr Mladek wrote: > > > > OK, thanks. So "not needed at present, might be needed in the future, > > > useful for out-of-tree debug code"? > > > > It is possible that I got it a wrong way on

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, 18 Dec 2015 13:11:41 +0100 Peter Zijlstra wrote: > On Fri, Dec 18, 2015 at 12:29:02PM +0100, Peter Zijlstra wrote: > > On Fri, Dec 18, 2015 at 10:18:08AM +, Daniel Thompson wrote: > > > I'm not entirely sure that this is an improvement. > > > > What I do these

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Tue, 15 Dec 2015 15:26:21 +0100 Petr Mladek wrote: > > OK, thanks. So "not needed at present, might be needed in the future, > > useful for out-of-tree debug code"? > > It is possible that I got it a wrong way on arm. The NMI buffer is > usable there on two locations. > > First, the

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Tue, 15 Dec 2015 15:26:21 +0100 Petr Mladek wrote: > > OK, thanks. So "not needed at present, might be needed in the future, > > useful for out-of-tree debug code"? > > It is possible that I got it a wrong way on arm. The NMI buffer is > usable there on two locations. > >

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri 2015-12-11 15:30:54, Andrew Morton wrote: > On Fri, 11 Dec 2015 23:21:13 + Russell King - ARM Linux > wrote: > > > On Fri, Dec 11, 2015 at 02:57:25PM -0800, Andrew Morton wrote: > > > This is a bit messy. NEED_PRINTK_NMI is an added-on hack for one > > > particular arm variant.

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri 2015-12-11 15:30:54, Andrew Morton wrote: > On Fri, 11 Dec 2015 23:21:13 + Russell King - ARM Linux > wrote: > > > On Fri, Dec 11, 2015 at 02:57:25PM -0800, Andrew Morton wrote: > > > This is a bit messy. NEED_PRINTK_NMI is an added-on hack for one > > >

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On 11/12/15 23:21, Russell King - ARM Linux wrote: As I explained when I did that work, the vast majority of ARM platforms are unable to trigger anything like a NMI - the FIQ is something that's generally a property of the secure monitor, and is not accessible to Linux. However, there are

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On 11/12/15 23:21, Russell King - ARM Linux wrote: As I explained when I did that work, the vast majority of ARM platforms are unable to trigger anything like a NMI - the FIQ is something that's generally a property of the secure monitor, and is not accessible to Linux. However, there are

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, 11 Dec 2015 23:21:13 + Russell King - ARM Linux wrote: > On Fri, Dec 11, 2015 at 02:57:25PM -0800, Andrew Morton wrote: > > This is a bit messy. NEED_PRINTK_NMI is an added-on hack for one > > particular arm variant. From the changelog: > > > >"One exception is arm where the

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, 11 Dec 2015, Russell King - ARM Linux wrote: > I'm personally happy with the existing code, and I've been wondering why > there's this effort to apply further cleanups - to me, the changelogs > don't seem to make that much sense, unless we want to start using > printk() extensively in NMI

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, Dec 11, 2015 at 02:57:25PM -0800, Andrew Morton wrote: > This is a bit messy. NEED_PRINTK_NMI is an added-on hack for one > particular arm variant. From the changelog: > >"One exception is arm where the deferred printing is used for > printing backtraces even without NMI. For

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, 11 Dec 2015 13:41:59 +0100 Petr Mladek wrote: > On Fri 2015-12-11 12:10:02, Geert Uytterhoeven wrote: > > On Wed, Dec 9, 2015 at 2:21 PM, Petr Mladek wrote: > > > --- a/init/Kconfig > > > +++ b/init/Kconfig > > > @@ -866,6 +866,28 @@ config LOG_CPU_MAX_BUF_SHIFT > > >

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, Dec 11, 2015 at 1:41 PM, Petr Mladek wrote: > On Fri 2015-12-11 12:10:02, Geert Uytterhoeven wrote: >> On Wed, Dec 9, 2015 at 2:21 PM, Petr Mladek wrote: >> > --- a/init/Kconfig >> > +++ b/init/Kconfig >> > @@ -866,6 +866,28 @@ config LOG_CPU_MAX_BUF_SHIFT >> > 13 =>

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Friday 11 December 2015 13:41:59 Petr Mladek wrote: > diff --git a/init/Kconfig b/init/Kconfig > index efcff25a112d..61cfd96a3c96 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -870,7 +870,7 @@ config NMI_LOG_BUF_SHIFT > int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri 2015-12-11 12:10:02, Geert Uytterhoeven wrote: > On Wed, Dec 9, 2015 at 2:21 PM, Petr Mladek wrote: > > --- a/init/Kconfig > > +++ b/init/Kconfig > > @@ -866,6 +866,28 @@ config LOG_CPU_MAX_BUF_SHIFT > > 13 => 8 KB for each CPU > > 12 => 4 KB

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Wed, Dec 9, 2015 at 2:21 PM, Petr Mladek wrote: > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -866,6 +866,28 @@ config LOG_CPU_MAX_BUF_SHIFT > 13 => 8 KB for each CPU > 12 => 4 KB for each CPU > > +config NMI_LOG_BUF_SHIFT > + int "Temporary

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Wed, Dec 9, 2015 at 2:21 PM, Petr Mladek wrote: > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -866,6 +866,28 @@ config LOG_CPU_MAX_BUF_SHIFT > 13 => 8 KB for each CPU > 12 => 4 KB for each CPU > > +config NMI_LOG_BUF_SHIFT > +

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri 2015-12-11 12:10:02, Geert Uytterhoeven wrote: > On Wed, Dec 9, 2015 at 2:21 PM, Petr Mladek wrote: > > --- a/init/Kconfig > > +++ b/init/Kconfig > > @@ -866,6 +866,28 @@ config LOG_CPU_MAX_BUF_SHIFT > > 13 => 8 KB for each CPU > >

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Friday 11 December 2015 13:41:59 Petr Mladek wrote: > diff --git a/init/Kconfig b/init/Kconfig > index efcff25a112d..61cfd96a3c96 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -870,7 +870,7 @@ config NMI_LOG_BUF_SHIFT > int "Temporary per-CPU NMI log buffer size (12 => 4KB, 13

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, Dec 11, 2015 at 02:57:25PM -0800, Andrew Morton wrote: > This is a bit messy. NEED_PRINTK_NMI is an added-on hack for one > particular arm variant. From the changelog: > >"One exception is arm where the deferred printing is used for > printing backtraces even without NMI. For

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, 11 Dec 2015 13:41:59 +0100 Petr Mladek wrote: > On Fri 2015-12-11 12:10:02, Geert Uytterhoeven wrote: > > On Wed, Dec 9, 2015 at 2:21 PM, Petr Mladek wrote: > > > --- a/init/Kconfig > > > +++ b/init/Kconfig > > > @@ -866,6 +866,28 @@ config

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, 11 Dec 2015 23:21:13 + Russell King - ARM Linux wrote: > On Fri, Dec 11, 2015 at 02:57:25PM -0800, Andrew Morton wrote: > > This is a bit messy. NEED_PRINTK_NMI is an added-on hack for one > > particular arm variant. From the changelog: > > > >"One

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, 11 Dec 2015, Russell King - ARM Linux wrote: > I'm personally happy with the existing code, and I've been wondering why > there's this effort to apply further cleanups - to me, the changelogs > don't seem to make that much sense, unless we want to start using > printk() extensively in NMI

Re: [PATCH v3 4/4] printk/nmi: Increase the size of NMI buffer and make it configurable

On Fri, Dec 11, 2015 at 1:41 PM, Petr Mladek wrote: > On Fri 2015-12-11 12:10:02, Geert Uytterhoeven wrote: >> On Wed, Dec 9, 2015 at 2:21 PM, Petr Mladek wrote: >> > --- a/init/Kconfig >> > +++ b/init/Kconfig >> > @@ -866,6 +866,28 @@ config