Reorganize perf kernel side

Reorganize perf kernel side

[Borislav Petkov]

Hi guys,

so I've had my eyes on this for a long time now and it has managed to
get on my nerves just enough to do something about it :-)

So how about moving perf stuff to arch/x86/perf/ and get rid of the
prefixes in the filenames. This also flattens our folder structure which
is a good thing and which we've been talking about in the past.

In order to diminish churn, I can do the whole thing in 4-5 patches'
sets, after having run enough *config smoke tests and 0day bot too.
Anyway, something like that.

perf_event_<vendor>_<type>.c

can then move to arch/x86/perf/<vendor>/type.c

and have much saner structure.

Thoughts?

---
 arch/x86/Kbuild                            | 2 ++
 arch/x86/kernel/cpu/Makefile               | 2 --
 arch/x86/perf/Makefile                     | 1 +
 arch/x86/{kernel/cpu => perf}/perf_event.c | 2 +-
 4 files changed, 4 insertions(+), 3 deletions(-)
 create mode 100644 arch/x86/perf/Makefile
 rename arch/x86/{kernel/cpu => perf}/perf_event.c (99%)

diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild
index 1538562cc720..cd85aa30ad14 100644
--- a/arch/x86/Kbuild
+++ b/arch/x86/Kbuild
@@ -1,6 +1,8 @@
 
 obj-y += entry/
 
+obj-$(CONFIG_PERF_EVENTS) += perf/
+
 obj-$(CONFIG_KVM) += kvm/
 
 # Xen paravirtualization support
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index 58031303e304..77000d54fcd1 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -30,8 +30,6 @@ obj-$(CONFIG_CPU_SUP_CENTAUR)		+= centaur.o
 obj-$(CONFIG_CPU_SUP_TRANSMETA_32)	+= transmeta.o
 obj-$(CONFIG_CPU_SUP_UMC_32)		+= umc.o
 
-obj-$(CONFIG_PERF_EVENTS)		+= perf_event.o
-
 ifdef CONFIG_PERF_EVENTS
 obj-$(CONFIG_CPU_SUP_AMD)		+= perf_event_amd.o perf_event_amd_uncore.o
 ifdef CONFIG_AMD_IOMMU
diff --git a/arch/x86/perf/Makefile b/arch/x86/perf/Makefile
new file mode 100644
index 000000000000..3b2566aa58e5
--- /dev/null
+++ b/arch/x86/perf/Makefile
@@ -0,0 +1 @@
+obj-y		+= perf_event.o
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/perf/perf_event.c
similarity index 99%
rename from arch/x86/kernel/cpu/perf_event.c
rename to arch/x86/perf/perf_event.c
index 9dfbba5ce6e8..ccbf7242307c 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/perf/perf_event.c
@@ -37,7 +37,7 @@
 #include <asm/desc.h>
 #include <asm/ldt.h>
 
-#include "perf_event.h"
+#include "../kernel/cpu/perf_event.h"
 
 struct x86_pmu x86_pmu __read_mostly;
 
-- 
2.3.5


-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

Re: Reorganize perf kernel side

[Peter Zijlstra]

On Fri, Dec 04, 2015 at 10:17:56PM +0100, Borislav Petkov wrote:
> Hi guys,
> 
> so I've had my eyes on this for a long time now and it has managed to
> get on my nerves just enough to do something about it :-)
> 
> So how about moving perf stuff to arch/x86/perf/ and get rid of the
> prefixes in the filenames. This also flattens our folder structure which
> is a good thing and which we've been talking about in the past.
> 
> In order to diminish churn, I can do the whole thing in 4-5 patches'
> sets, after having run enough *config smoke tests and 0day bot too.
> Anyway, something like that.
> 
> perf_event_<vendor>_<type>.c
> 
> can then move to arch/x86/perf/<vendor>/type.c
> 
> and have much saner structure.
> 
> Thoughts?

I _will_ blame you for at least a month after every time I mistype a
pathname because of this ;-)

git blame --follow must keep working. That is, git had better be able to
understand this code movement, loosing history is just a total PITA.

Also, a script that can auto-convert patches would be nice.

Re: Reorganize perf kernel side

[Borislav Petkov]

On Fri, Dec 04, 2015 at 11:09:07PM +0100, Peter Zijlstra wrote:
> I _will_ blame you for at least a month after every time I mistype a
> pathname because of this ;-)

Oh boy, I probably shouldn't do it after all out of fear of you coming
over ... :-)

> git blame --follow must keep working. That is, git had better be able to
> understand this code movement, loosing history is just a total PITA.

Well, I did

git annotate arch/x86/kernel/cpu/perf_event.c > blame.before

git annotate arch/x86/perf/perf_event.c > blame.after

The diff is:

--- /tmp/blame.before   2015-12-04 23:30:28.502701279 +0100
+++ /tmp/blame.after    2015-12-04 23:29:53.618702295 +0100
@@ -37,7 +37,7 @@ e3f3541c19c89 (Peter Zijlstra 2011-11-21
 d07bdfd322d30  (Peter Zijlstra 2012-07-10 09:42:15 +0200       37)#include <asm/desc.h>
 d07bdfd322d30  (Peter Zijlstra 2012-07-10 09:42:15 +0200       38)#include <asm/ldt.h>
 241771ef016b5  (Ingo Molnar    2008-12-03 10:39:53 +0100       39)
-de0428a7ad485  (Kevin Winchester       2011-08-30 20:41:05 -0300       40)#include "perf_event.h"
+b5e0c1bab8637  (Borislav Petkov        2015-12-04 22:02:51 +0100       40)#include "../kernel/cpu/perf_event.h"
 de0428a7ad485  (Kevin Winchester       2011-08-30 20:41:05 -0300       41)
 de0428a7ad485  (Kevin Winchester       2011-08-30 20:41:05 -0300       42)struct x86_pmu x86_pmu __read_mostly;
 efc9f05df2dd1  (Stephane Eranian       2011-06-06 16:57:03 +0200       43)

and that include file change is only temporary in order to keep the
churn at the lowest level.

Is this what you had in mind?

> Also, a script that can auto-convert patches would be nice.

Sure, I can do that.

Also, I was thinking of doing this in 4-5 patches sets only so that we
can keep everything easily manageable.

For sure, I don't want to do one insane move in one go and cause
needless churn and regressions.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

Re: Reorganize perf kernel side

[Ingo Molnar]

* Borislav Petkov <bp@alien8.de> wrote:

> Hi guys,
> 
> so I've had my eyes on this for a long time now and it has managed to
> get on my nerves just enough to do something about it :-)
> 
> So how about moving perf stuff to arch/x86/perf/ and get rid of the
> prefixes in the filenames. This also flattens our folder structure which
> is a good thing and which we've been talking about in the past.
> 
> In order to diminish churn, I can do the whole thing in 4-5 patches'
> sets, after having run enough *config smoke tests and 0day bot too.
> Anyway, something like that.
> 
> perf_event_<vendor>_<type>.c
> 
> can then move to arch/x86/perf/<vendor>/type.c
> 
> and have much saner structure.
> 
> Thoughts?

Yeah, it would be lovely if you could do that - but could we please name it 
'events' instead of 'perf', to follow the existing namespace pattern we are using 
for the core bits, where we have kernel/events/ for the core bits, not 
kernel/perf/?

Also, how about naming the core x86 bits like this:

  arch/x86/events/core.c

which would give us a clear path to split-out core functionality eventually, such 
as:

  arch/x86/events/sched.c
  arch/x86/events/constraints.c
  ...etc...
  ...

Just like we've already split out functionality from kernel/events/core.c into 
kernel/events/ring_buffer.c.

Btw., kernel/sched/ is using a similar approach, there's core.c, and various 
split-out sub-modules. We are slowly migrating from the original humunguous 
kernel/sched.c to a more finegrained kernel/sched/subsys.c structure.

... and as you suggested, the x86 vendor dependent bits would be in their own, but 
easily accessible directory close to the core, as you suggested:

  arch/x86/events/intel/
  arch/x86/events/amd/
  ...

as a lot of work is happening in that space, so promoting it up in the namespace 
helps.

So, as an example, we'd have renames like this:

     arch/x86/kernel/cpu/perf_event_intel_uncore_nhmex.c
  => arch/x86/events/intel/uncore_nhmex.c

which will be 30% easier to type! Once our muscle memory has re-trained that is. ;-)

Thanks,

	Ingo