Commit Graph

616315 Commits

Author SHA1 Message Date
Mike Travis 5a52e8f822 x86/platform/UV: Fix kernel panic running RHEL kdump kernel on UV systems
The latest UV kernel support panics when RHEL7 kexec's the kdump kernel
to make a dumpfile.  This patch fixes the problem by turning off all UV
support if NUMA is off.

Tested-by: Frank Ramsay <framsay@sgi.com>
Tested-by: John Estabrook <estabrook@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Nathan Zimmer <nzimmer@sgi.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Banman <abanman@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160801184050.577755634@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 15:55:39 +02:00
Mike Travis 22ac2bca92 x86/platform/UV: Fix problem with UV4 BIOS providing incorrect PXM values
There are some circumstances where the UV4 BIOS cannot provide the
correct Proximity Node values to associate with specific Sockets and
Physical Nodes.  The decision was made to remove these values from BIOS
and for the kernel to get these values from the standard ACPI tables.

Tested-by: Frank Ramsay <framsay@sgi.com>
Tested-by: John Estabrook <estabrook@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Nathan Zimmer <nzimmer@sgi.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Banman <abanman@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160801184050.414210079@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 15:55:38 +02:00
Mike Travis e363d24c2b x86/platform/UV: Fix bug with iounmap() of the UV4 EFI System Table causing a crash
Save the uv_systab::size field before doing the iounmap()
of the struct pointer, to avoid a NULL dereference crash.

Tested-by: Frank Ramsay <framsay@sgi.com>
Tested-by: John Estabrook <estabrook@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Nathan Zimmer <nzimmer@sgi.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Banman <abanman@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160801184050.250424783@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 15:55:38 +02:00
Mike Travis 054f621fd5 x86/platform/UV: Fix problem with UV4 Socket IDs not being contiguous
The UV4 Socket IDs are not guaranteed to equate to Node values which
can cause the GAM (Global Addressable Memory) table lookups to fail.
Fix this by using an independent index into the GAM table instead of
the Socket ID to reference the base address.

Tested-by: Frank Ramsay <framsay@sgi.com>
Tested-by: John Estabrook <estabrook@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Nathan Zimmer <nzimmer@sgi.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andrew Banman <abanman@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160801184050.048755337@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 15:55:38 +02:00
Borislav Petkov 3e03530587 x86/entry: Clarify the RF saving/restoring situation with SYSCALL/SYSRET
Clarify why exactly RF cannot be restored properly by SYSRET to avoid
confusion.

No functionality change.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160803171429.GA2590@nazgul.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 15:53:43 +02:00
Sebastian Andrzej Siewior 5cf0791da5 x86/mm: Disable preemption during CR3 read+write
There's a subtle preemption race on UP kernels:

Usually current->mm (and therefore mm->pgd) stays the same during the
lifetime of a task so it does not matter if a task gets preempted during
the read and write of the CR3.

But then, there is this scenario on x86-UP:

TaskA is in do_exit() and exit_mm() sets current->mm = NULL followed by:

 -> mmput()
 -> exit_mmap()
 -> tlb_finish_mmu()
 -> tlb_flush_mmu()
 -> tlb_flush_mmu_tlbonly()
 -> tlb_flush()
 -> flush_tlb_mm_range()
 -> __flush_tlb_up()
 -> __flush_tlb()
 ->  __native_flush_tlb()

At this point current->mm is NULL but current->active_mm still points to
the "old" mm.

Let's preempt taskA _after_ native_read_cr3() by taskB. TaskB has its
own mm so CR3 has changed.

Now preempt back to taskA. TaskA has no ->mm set so it borrows taskB's
mm and so CR3 remains unchanged. Once taskA gets active it continues
where it was interrupted and that means it writes its old CR3 value
back. Everything is fine because userland won't need its memory
anymore.

Now the fun part:

Let's preempt taskA one more time and get back to taskB. This
time switch_mm() won't do a thing because oldmm (->active_mm)
is the same as mm (as per context_switch()). So we remain
with a bad CR3 / PGD and return to userland.

The next thing that happens is handle_mm_fault() with an address for
the execution of its code in userland. handle_mm_fault() realizes that
it has a PTE with proper rights so it returns doing nothing. But the
CPU looks at the wrong PGD and insists that something is wrong and
faults again. And again. And one more time…

This pagefault circle continues until the scheduler gets tired of it and
puts another task on the CPU. It gets little difficult if the task is a
RT task with a high priority. The system will either freeze or it gets
fixed by the software watchdog thread which usually runs at RT-max prio.
But waiting for the watchdog will increase the latency of the RT task
which is no good.

Fix this by disabling preemption across the critical code section.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1470404259-26290-1-git-send-email-bigeasy@linutronix.de
[ Prettified the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 15:37:16 +02:00
Michael Ellerman ca49e64f0c selftests/powerpc: Specify we expect to build with std=gnu99
We have some tests that assume we're using std=gnu99, which is fine on
most compilers, but some old compilers use a different default.

So make it explicit that we want to use std=gnu99.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-10 23:21:37 +10:00
Takashi Iwai a52ff34e5e ALSA: hda - Manage power well properly for resume
For SKL and later Intel chips, we control the power well per codec
basis via link_power callback since the commit [03b135cebc47: ALSA:
hda - remove dependency on i915 power well for SKL].
However, there are a few exceptional cases where the gfx registers are
accessed from the audio driver: namely the wakeup override bit
toggling at (both system and runtime) resume.  This seems causing a
kernel warning when accessed during the power well down (and likely
resulting in the bogus register accesses).

This patch puts the proper power up / down sequence around the resume
code so that the wakeup bit is fiddled properly while the power is
up.  (The other callback, sync_audio_rate, is used only in the PCM
callback, so it's guaranteed in the power-on.)

Also, by this proper power up/down, the instantaneous flip of wakeup
bit in the resume callback that was introduced by the commit
[033ea349a7cd: ALSA: hda - Fix Skylake codec timeout] becomes
superfluous, as snd_hdac_display_power() already does it.  So we can
clean it up together.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96214
Fixes: 03b135cebc ('ALSA: hda - remove dependency on i915 power well for SKL')
Cc: <stable@vger.kernel.org> # v4.2+
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2016-08-10 15:05:17 +02:00
Nicholas Piggin b9a4a0d02c powerpc/vdso: Fix build rules to rebuild vdsos correctly
When using if_changed, we need to add FORCE as a dependency (see
Documentation/kbuild/makefiles.txt) otherwise we don't get command line
change checking amongst other things. This has resulted in vdsos not
being rebuilt when switching between big and little endian.

The vdso64/32ld commands have to be changed around to avoid pulling
FORCE into the linker command line (code copied from x86).

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-10 23:04:12 +10:00
Michael Ellerman 164af597ce powerpc/Makefile: Use cflags-y/aflags-y for setting endian options
When we introduced the little endian support, we added the endian flags
to CC directly using override. I don't know the history of why we did
that, I suspect no one does.

Although this mostly works, it has one bug, which is that CROSS32CC
doesn't get -mbig-endian. That means when the compiler is little endian
by default and the user is building big endian, vdso32 is incorrectly
compiled as little endian and the kernel fails to build.

Instead we can add the endian flags to cflags-y/aflags-y, and then
append those to KBUILD_CFLAGS/KBUILD_AFLAGS.

This has the advantage of being 1) less ugly, 2) the documented way of
adding flags in the arch Makefile and 3) it fixes building vdso32 with a
LE toolchain.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-10 23:01:53 +10:00
Thomas Garnier fb754f958f x86/mm/KASLR: Increase BRK pages for KASLR memory randomization
Default implementation expects 6 pages maximum are needed for low page
allocations. If KASLR memory randomization is enabled, the worse case
of e820 layout would require 12 pages (no large pages). It is due to the
PUD level randomization and the variable e820 memory layout.

This bug was found while doing extensive testing of KASLR memory
randomization on different type of hardware.

Signed-off-by: Thomas Garnier <thgarnie@google.com>
Cc: Aleksey Makarov <aleksey.makarov@linaro.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lv Zheng <lv.zheng@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: kernel-hardening@lists.openwall.com
Fixes: 021182e52f ("Enable KASLR for physical mapping memory regions")
Link: http://lkml.kernel.org/r/1470762665-88032-2-git-send-email-thgarnie@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:45:19 +02:00
Thomas Garnier c7d2361f75 x86/mm/KASLR: Fix physical memory calculation on KASLR memory randomization
Initialize KASLR memory randomization after max_pfn is initialized. Also
ensure the size is rounded up. It could create problems on machines
with more than 1Tb of memory on certain random addresses.

Signed-off-by: Thomas Garnier <thgarnie@google.com>
Cc: Aleksey Makarov <aleksey.makarov@linaro.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fabian Frederick <fabf@skynet.be>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lv Zheng <lv.zheng@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: kernel-hardening@lists.openwall.com
Fixes: 021182e52f ("Enable KASLR for physical mapping memory regions")
Link: http://lkml.kernel.org/r/1470762665-88032-1-git-send-email-thgarnie@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:45:19 +02:00
Arnd Bergmann 22cc1ca3c5 x86/hpet: Fix /dev/rtc breakage caused by RTC cleanup
Ville Syrjälä reports "The first time I run hwclock after rebooting
I get this:

 open("/dev/rtc", O_RDONLY)              = 3
 ioctl(3, PHN_SET_REGS or RTC_UIE_ON, 0) = 0
 select(4, [3], NULL, NULL, {10, 0})     = 0 (Timeout)
 ioctl(3, PHN_NOT_OH or RTC_UIE_OFF, 0)  = 0
 close(3)                                = 0

On all subsequent runs I get this:

 open("/dev/rtc", O_RDONLY)              = 3
 ioctl(3, PHN_SET_REGS or RTC_UIE_ON, 0) = -1 EINVAL (Invalid argument)
 ioctl(3, RTC_RD_TIME, 0x7ffd76b3ae70)   = -1 EINVAL (Invalid argument)
 close(3)                                = 0"

This was caused by a stupid typo in a patch that should have been
a simple rename to move around contents of a header file, but
accidentally wrote zeroes into the rtc rather than reading from
it:

  463a86304c ("char/genrtc: x86: remove remnants of asm/rtc.h")

Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: rtc-linux@googlegroups.com
Fixes: 463a86304c ("char/genrtc: x86: remove remnants of asm/rtc.h")
Link: http://lkml.kernel.org/r/20160809195528.1604312-1-arnd@arndb.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:37:06 +02:00
Ingo Molnar fdbdfefbab Merge branch 'linus' into timers/urgent, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:36:23 +02:00
Alexander Potapenko 469f002312 x86, kasan, ftrace: Put APIC interrupt handlers into .irqentry.text
Dmitry Vyukov has reported unexpected KASAN stackdepot growth:

  https://github.com/google/kasan/issues/36

... which is caused by the APIC handlers not being present in .irqentry.text:

When building with CONFIG_FUNCTION_GRAPH_TRACER=y or CONFIG_KASAN=y, put the
APIC interrupt handlers into the .irqentry.text section. This is needed
because both KASAN and function graph tracer use __irqentry_text_start and
__irqentry_text_end to determine whether a function is an IRQ entry point.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: aryabinin@virtuozzo.com
Cc: kasan-dev@googlegroups.com
Cc: kcc@google.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/1468575763-144889-1-git-send-email-glider@google.com
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:19:33 +02:00
Pan Xinhui c2ace36b88 locking/pvqspinlock: Fix a bug in qstat_read()
It's obviously wrong to set stat to NULL. So lets remove it.
Otherwise it is always zero when we check the latency of kick/wake.

Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <Waiman.Long@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1468405414-3700-1-git-send-email-xinhui.pan@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:13:29 +02:00
Wanpeng Li 229ce63157 locking/pvqspinlock: Fix double hash race
When the lock holder vCPU is racing with the queue head:

   CPU 0 (lock holder)    CPU1 (queue head)
   ===================    =================
   spin_lock();           spin_lock();
    pv_kick_node():        pv_wait_head_or_lock():
                            if (!lp) {
                             lp = pv_hash(lock, pn);
                             xchg(&l->locked, _Q_SLOW_VAL);
                            }
                            WRITE_ONCE(pn->state, vcpu_halted);
     cmpxchg(&pn->state,
      vcpu_halted, vcpu_hashed);
     WRITE_ONCE(l->locked, _Q_SLOW_VAL);
     (void)pv_hash(lock, pn);

In this case, lock holder inserts the pv_node of queue head into the
hash table and set _Q_SLOW_VAL unnecessary. This patch avoids it by
restoring/setting vcpu_hashed state after failing adaptive locking
spinning.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hpe.com>
Link: http://lkml.kernel.org/r/1468484156-4521-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:13:28 +02:00
pan xinhui 2db34e8bf9 locking/qrwlock: Fix write unlock bug on big endian systems
This patch aims to get rid of endianness in queued_write_unlock(). We
want to set  __qrwlock->wmode to NULL, however the address is not
&lock->cnts in big endian machine. That causes queued_write_unlock()
write NULL to the wrong field of __qrwlock.

So implement __qrwlock_write_byte() which returns the correct
__qrwlock->wmode address.

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hpe.com
Cc: arnd@arndb.de
Cc: boqun.feng@gmail.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1468835259-4486-1-git-send-email-xinhui.pan@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:13:27 +02:00
Ingo Molnar a2071cd765 Merge branch 'linus' into locking/urgent, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:11:54 +02:00
Wanpeng Li c0c8c9fa21 sched/deadline: Fix lock pinning warning during CPU hotplug
The following warning can be triggered by hot-unplugging the CPU
on which an active SCHED_DEADLINE task is running on:

  WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3531 lock_release+0x690/0x6a0
  releasing a pinned lock
  Call Trace:
   dump_stack+0x99/0xd0
   __warn+0xd1/0xf0
   ? dl_task_timer+0x1a1/0x2b0
   warn_slowpath_fmt+0x4f/0x60
   ? sched_clock+0x13/0x20
   lock_release+0x690/0x6a0
   ? enqueue_pushable_dl_task+0x9b/0xa0
   ? enqueue_task_dl+0x1ca/0x480
   _raw_spin_unlock+0x1f/0x40
   dl_task_timer+0x1a1/0x2b0
   ? push_dl_task.part.31+0x190/0x190
  WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3649 lock_unpin_lock+0x181/0x1a0
  unpinning an unpinned lock
  Call Trace:
   dump_stack+0x99/0xd0
   __warn+0xd1/0xf0
   warn_slowpath_fmt+0x4f/0x60
   lock_unpin_lock+0x181/0x1a0
   dl_task_timer+0x127/0x2b0
   ? push_dl_task.part.31+0x190/0x190

As per the comment before this code, its safe to drop the RQ lock
here, and since we (potentially) change rq, unpin and repin to avoid
the splat.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
[ Rewrote changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470274940-17976-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:02:55 +02:00
Giovanni Gherdovich 6075620b05 sched/cputime: Mitigate performance regression in times()/clock_gettime()
Commit:

  6e998916df ("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency")

fixed a problem whereby clock_nanosleep() followed by clock_gettime() could
allow a task to wake early. It addressed the problem by calling the scheduling
classes update_curr() when the cputimer starts.

Said change induced a considerable performance regression on the syscalls
times() and clock_gettimes(CLOCK_PROCESS_CPUTIME_ID). There are some
debuggers and applications that monitor their own performance that
accidentally depend on the performance of these specific calls.

This patch mitigates the performace loss by prefetching data in the CPU
cache, as stalls due to cache misses appear to be where most time is spent
in our benchmarks.

Here are the performance gain of this patch over v4.7-rc7 on a Sandy Bridge
box with 32 logical cores and 2 NUMA nodes. The test is repeated with a
variable number of threads, from 2 to 4*num_cpus; the results are in
seconds and correspond to the average of 10 runs; the percentage gain is
computed with (before-after)/before so a positive value is an improvement
(it's faster). The improvement varies between a few percents for 5-20
threads and more than 10% for 2 or >20 threads.

pound_clock_gettime:

    threads       4.7-rc7     patched 4.7-rc7
    [num]         [secs]      [secs (percent)]
      2           3.48        3.06 ( 11.83%)
      5           3.33        3.25 (  2.40%)
      8           3.37        3.26 (  3.30%)
     12           3.32        3.37 ( -1.60%)
     21           4.01        3.90 (  2.74%)
     30           3.63        3.36 (  7.41%)
     48           3.71        3.11 ( 16.27%)
     79           3.75        3.16 ( 15.74%)
    110           3.81        3.25 ( 14.80%)
    128           3.88        3.31 ( 14.76%)

pound_times:

    threads       4.7-rc7     patched 4.7-rc7
    [num]         [secs]      [secs (percent)]
      2           3.65        3.25 ( 11.03%)
      5           3.45        3.17 (  7.92%)
      8           3.52        3.22 (  8.69%)
     12           3.29        3.36 ( -2.04%)
     21           4.07        3.92 (  3.78%)
     30           3.87        3.40 ( 12.17%)
     48           3.79        3.16 ( 16.61%)
     79           3.88        3.28 ( 15.42%)
    110           3.90        3.38 ( 13.35%)
    128           4.00        3.38 ( 15.45%)

pound_clock_gettime and pound_clock_gettime are two benchmarks included in
the MMTests framework. They launch a given number of threads which
repeatedly call times() or clock_gettimes(). The results above can be
reproduced with cloning MMTests from github.com and running the "poundtime"
workload:

  $ git clone https://github.com/gormanm/mmtests.git
  $ cd mmtests
  $ cp configs/config-global-dhp__workload_poundtime config
  $ ./run-mmtests.sh --run-monitor $(uname -r)

The above will run "poundtime" measuring the kernel currently running on
the machine; Once a new kernel is installed and the machine rebooted,
running again

  $ cd mmtests
  $ ./run-mmtests.sh --run-monitor $(uname -r)

will produce results to compare with. A comparison table will be output
with:

  $ cd mmtests/work/log
  $ ../../compare-kernels.sh

the table will contain a lot of entries; grepping for "Amean" (as in
"arithmetic mean") will give the tables presented above. The source code
for the two benchmarks is reported at the end of this changelog for
clairity.

The cache misses addressed by this patch were found using a combination of
`perf top`, `perf record` and `perf annotate`. The incriminated lines were
found to be

    struct sched_entity *curr = cfs_rq->curr;

and

    delta_exec = now - curr->exec_start;

in the function update_curr() from kernel/sched/fair.c. This patch
prefetches the data from memory just before update_curr is called in the
interested execution path.

A comparison of the total number of cycles before and after the patch
follows; the data is obtained using `perf stat -r 10 -ddd <program>`
running over the same sequence of number of threads used above (a positive
gain is an improvement):

  threads   cycles before                 cycles after                gain

    2      19,699,563,964  +-1.19%      17,358,917,517  +-1.85%      11.88%
    5      47,401,089,566  +-2.96%      45,103,730,829  +-0.97%       4.85%
    8      80,923,501,004  +-3.01%      71,419,385,977  +-0.77%      11.74%
   12     112,326,485,473  +-0.47%     110,371,524,403  +-0.47%       1.74%
   21     193,455,574,299  +-0.72%     180,120,667,904  +-0.36%       6.89%
   30     315,073,519,013  +-1.64%     271,222,225,950  +-1.29%      13.92%
   48     321,969,515,332  +-1.48%     273,353,977,321  +-1.16%      15.10%
   79     337,866,003,422  +-0.97%     289,462,481,538  +-1.05%      14.33%
  110     338,712,691,920  +-0.78%     290,574,233,170  +-0.77%      14.21%
  128     348,384,794,006  +-0.50%     292,691,648,206  +-0.66%      15.99%

A comparison of cache miss vs total cache loads ratios, before and after
the patch (again from the `perf stat -r 10 -ddd <program>` tables):

  threads   L1 misses/total*100     L1 misses/total*100            gain
		         before                   after
      2           7.43  +-4.90%           7.36  +-4.70%           0.94%
      5          13.09  +-4.74%          13.52  +-3.73%          -3.28%
      8          13.79  +-5.61%          12.90  +-3.27%           6.45%
     12          11.57  +-2.44%           8.71  +-1.40%          24.72%
     21          12.39  +-3.92%           9.97  +-1.84%          19.53%
     30          13.91  +-2.53%          11.73  +-2.28%          15.67%
     48          13.71  +-1.59%          12.32  +-1.97%          10.14%
     79          14.44  +-0.66%          13.40  +-1.06%           7.20%
    110          15.86  +-0.50%          14.46  +-0.59%           8.83%
    128          16.51  +-0.32%          15.06  +-0.78%           8.78%

As a final note, the following shows the evolution of performance figures
in the "poundtime" benchmark and pinpoints commit 6e998916df
("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency") as a
major source of degradation, mostly unaddressed to this day (figures
expressed in seconds).

pound_clock_gettime:

  threads   parent of         6e998916df        4.7-rc7
	    6e998916df            itself
    2        2.23          3.68 ( -64.56%)        3.48 (-55.48%)
    5        2.83          3.78 ( -33.42%)        3.33 (-17.43%)
    8        2.84          4.31 ( -52.12%)        3.37 (-18.76%)
    12       3.09          3.61 ( -16.74%)        3.32 ( -7.17%)
    21       3.14          4.63 ( -47.36%)        4.01 (-27.71%)
    30       3.28          5.75 ( -75.37%)        3.63 (-10.80%)
    48       3.02          6.05 (-100.56%)        3.71 (-22.99%)
    79       2.88          6.30 (-118.90%)        3.75 (-30.26%)
    110      2.95          6.46 (-119.00%)        3.81 (-29.24%)
    128      3.05          6.42 (-110.08%)        3.88 (-27.04%)

pound_times:

  threads   parent of         6e998916df        4.7-rc7
	    6e998916df            itself
    2        2.27          3.73 ( -64.71%)        3.65 (-61.14%)
    5        2.78          3.77 ( -35.56%)        3.45 (-23.98%)
    8        2.79          4.41 ( -57.71%)        3.52 (-26.05%)
    12       3.02          3.56 ( -17.94%)        3.29 ( -9.08%)
    21       3.10          4.61 ( -48.74%)        4.07 (-31.34%)
    30       3.33          5.75 ( -72.53%)        3.87 (-16.01%)
    48       2.96          6.06 (-105.04%)        3.79 (-28.10%)
    79       2.88          6.24 (-116.83%)        3.88 (-34.81%)
    110      2.98          6.37 (-114.08%)        3.90 (-31.12%)
    128      3.10          6.35 (-104.61%)        4.00 (-28.87%)

The source code of the two benchmarks follows. To compile the two:

  NR_THREADS=42
  for FILE in pound_times pound_clock_gettime; do
      gcc -lrt -O2 -lpthread -DNUM_THREADS=$NR_THREADS $FILE.c -o $FILE
  done

==== BEGIN pound_times.c ====

struct tms start;

void *pound (void *threadid)
{
  struct tms end;
  int oldutime = 0;
  int utime;
  int i;
  for (i = 0; i < 5000000 / NUM_THREADS; i++) {
          times(&end);
          utime = ((int)end.tms_utime - (int)start.tms_utime);
          if (oldutime > utime) {
            printf("utime decreased, was %d, now %d!\n", oldutime, utime);
          }
          oldutime = utime;
  }
  pthread_exit(NULL);
}

int main()
{
  pthread_t th[NUM_THREADS];
  long i;
  times(&start);
  for (i = 0; i < NUM_THREADS; i++) {
    pthread_create (&th[i], NULL, pound, (void *)i);
  }
  pthread_exit(NULL);
  return 0;
}
==== END pound_times.c ====

==== BEGIN pound_clock_gettime.c ====

void *pound (void *threadid)
{
	struct timespec ts;
	int rc, i;
	unsigned long prev = 0, this = 0;

	for (i = 0; i < 5000000 / NUM_THREADS; i++) {
		rc = clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
		if (rc < 0)
			perror("clock_gettime");
		this = (ts.tv_sec * 1000000000) + ts.tv_nsec;
		if (0 && this < prev)
			printf("%lu ns timewarp at iteration %d\n", prev - this, i);
		prev = this;
	}
	pthread_exit(NULL);
}

int main()
{
	pthread_t th[NUM_THREADS];
	long rc, i;
	pid_t pgid;

	for (i = 0; i < NUM_THREADS; i++) {
		rc = pthread_create(&th[i], NULL, pound, (void *)i);
		if (rc < 0)
			perror("pthread_create");
	}

	pthread_exit(NULL);
	return 0;
}
==== END pound_clock_gettime.c ====

Suggested-by: Mike Galbraith <mgalbraith@suse.de>
Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1470385316-15027-2-git-send-email-ggherdovich@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:32:56 +02:00
Xunlei Pang b8922125e4 sched/fair: Fix typo in sync_throttle()
We should update cfs_rq->throttled_clock_task, not
pcfs_rq->throttle_clock_task.

The effects of this bug was probably occasionally erratic
group scheduling, particularly in cgroups-intense workloads.

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
[ Added changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 55e16d30bd ("sched/fair: Rework throttle_count sync")
Link: http://lkml.kernel.org/r/1468050862-18864-1-git-send-email-xlpang@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:32:55 +02:00
Tommaso Cucinotta a23eadfae2 sched/deadline: Fix wrap-around in DL heap
Current code in cpudeadline.c has a bug in re-heapifying when adding a
new element at the end of the heap, because a deadline value of 0 is
temporarily set in the new elem, then cpudl_change_key() is called
with the actual elem deadline as param.

However, the function compares the new deadline to set with the one
previously in the elem, which is 0.  So, if current absolute deadlines
grew so much to have negative values as s64, the comparison in
cpudl_change_key() makes the wrong decision.  Instead, as from
dl_time_before(), the kernel should handle correctly abs deadlines
wrap-arounds.

This patch fixes the problem with a minimally invasive change that
forces cpudl_change_key() to heapify up in this case.

Signed-off-by: Tommaso Cucinotta <tommaso.cucinotta@sssup.it>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Luca Abeni <luca.abeni@unitn.it>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1468921493-10054-2-git-send-email-tommaso.cucinotta@sssup.it
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:32:55 +02:00
David Carrillo-Cisneros db4a835601 perf/core: Set cgroup in CPU contexts for new cgroup events
There's a perf stat bug easy to observer on a machine with only one cgroup:

  $ perf stat -e cycles -I 1000 -C 0 -G /
  #          time             counts unit events
      1.000161699      <not counted>      cycles                    /
      2.000355591      <not counted>      cycles                    /
      3.000565154      <not counted>      cycles                    /
      4.000951350      <not counted>      cycles                    /

We'd expect some output there.

The underlying problem is that there is an optimization in
perf_cgroup_sched_{in,out}() that skips the switch of cgroup events
if the old and new cgroups in a task switch are the same.

This optimization interacts with the current code in two ways
that cause a CPU context's cgroup (cpuctx->cgrp) to be NULL even if a
cgroup event matches the current task. These are:

  1. On creation of the first cgroup event in a CPU: In current code,
  cpuctx->cpu is only set in perf_cgroup_sched_in, but due to the
  aforesaid optimization, perf_cgroup_sched_in will run until the next
  cgroup switches in that CPU. This may happen late or never happen,
  depending on system's number of cgroups, CPU load, etc.

  2. On deletion of the last cgroup event in a cpuctx: In list_del_event,
  cpuctx->cgrp is set NULL. Any new cgroup event will not be sched in
  because cpuctx->cgrp == NULL until a cgroup switch occurs and
  perf_cgroup_sched_in is executed (updating cpuctx->cgrp).

This patch fixes both problems by setting cpuctx->cgrp in list_add_event,
mirroring what list_del_event does when removing a cgroup event from CPU
context, as introduced in:

  commit 68cacd2916 ("perf_events: Fix stale ->cgrp pointer in update_cgrp_time_from_cpuctx()")

With this patch, cpuctx->cgrp is always set/clear when installing/removing
the first/last cgroup event in/from the CPU context. With cpuctx->cgrp
correctly set, event_filter_match works as intended when events are
sched in/out.

After the fix, the output is as expected:

  $ perf stat -e cycles -I 1000 -a -G /
  #         time             counts unit events
     1.004699159          627342882      cycles                    /
     2.007397156          615272690      cycles                    /
     3.010019057          616726074      cycles                    /

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1470124092-113192-1-git-send-email-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:05:52 +02:00
Peter Zijlstra 0b8f1e2e26 perf/core: Fix sideband list-iteration vs. event ordering NULL pointer deference crash
Vegard Nossum reported that perf fuzzing generates a NULL
pointer dereference crash:

> Digging a bit deeper into this, it seems the event itself is getting
> created by perf_event_open() and it gets added to the pmu_event_list
> through:
>
> perf_event_open()
>  - perf_event_alloc()
>     - account_event()
>        - account_pmu_sb_event()
>           - attach_sb_event()
>
> so at this point the event is being attached but its ->ctx is still
> NULL. It seems like ->ctx is set just a bit later in
> perf_event_open(), though.
>
> But before that, __schedule() comes along and creates a stack trace
> similar to the one above:
>
> __schedule()
>  - __perf_event_task_sched_out()
>    - perf_iterate_sb()
>      - perf_iterate_sb_cpu()
>         - event_filter_match()
>           - perf_cgroup_match()
>             - __get_cpu_context()
>               - (dereference ctx which is NULL)
>
> So I guess the question is... should the event be attached (= put on
> the list) before ->ctx gets set? Or should the cgroup code check for a
> NULL ->ctx?

The latter seems like the simplest solution. Moving the list-add later
creates a bit of a mess.

Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: f2fb6bef92 ("perf/core: Optimize side-band event delivery")
Link: http://lkml.kernel.org/r/20160804123724.GN6862@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 13:05:51 +02:00
Nicolai Stange 6731b0d611 x86/timers/apic: Inform TSC deadline clockevent device about recalibration
This patch eliminates a source of imprecise APIC timer interrupts,
which imprecision may result in double interrupts or even late
interrupts.

The TSC deadline clockevent devices' configuration and registration
happens before the TSC frequency calibration is refined in
tsc_refine_calibration_work().

This results in the TSC clocksource and the TSC deadline clockevent
devices being configured with slightly different frequencies: the former
gets the refined one and the latter are configured with the inaccurate
frequency detected earlier by means of the "Fast TSC calibration using PIT".

Within the APIC code, introduce the notifier function
lapic_update_tsc_freq() which reconfigures all per-CPU TSC deadline
clockevent devices with the current tsc_khz.

Call it from the TSC code after TSC calibration refinement has happened.

Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christopher S. Hall <christopher.s.hall@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Link: http://lkml.kernel.org/r/20160714152255.18295-3-nicstange@gmail.com
[ Pushed #ifdef CONFIG_X86_LOCAL_APIC into header, improved changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 12:38:12 +02:00
Nicolai Stange 1a9e4c564a x86/timers/apic: Fix imprecise timer interrupts by eliminating TSC clockevents frequency roundoff error
I noticed the following bug/misbehavior on certain Intel systems: with a
single task running on a NOHZ CPU on an Intel Haswell, I recognized
that I did not only get the one expected local_timer APIC interrupt, but
two per second at minimum. (!)

Further tracing showed that the first one precedes the programmed deadline
by up to ~50us and hence, it did nothing except for reprogramming the TSC
deadline clockevent device to trigger shortly thereafter again.

The reason for this is imprecise calibration, the timeout we program into
the APIC results in 'too short' timer interrupts. The core (hr)timer code
notices this (because it has a precise ktime source and sees the short
interrupt) and fixes it up by programming an additional very short
interrupt period.

This is obviously suboptimal.

The reason for the imprecise calibration is twofold, and this patch
fixes the first reason:

In setup_APIC_timer(), the registered clockevent device's frequency
is calculated by first dividing tsc_khz by TSC_DIVISOR and multiplying
it with 1000 afterwards:

  (tsc_khz / TSC_DIVISOR) * 1000

The multiplication with 1000 is done for converting from kHz to Hz and the
division by TSC_DIVISOR is carried out in order to make sure that the final
result fits into an u32.

However, with the order given in this calculation, the roundoff error
introduced by the division gets magnified by a factor of 1000 by the
following multiplication.

To fix it, reversing the order of the division and the multiplication a la:

  (tsc_khz * 1000) / TSC_DIVISOR

... reduces the roundoff error already.

Furthermore, if TSC_DIVISOR divides 1000, associativity holds:

  (tsc_khz * 1000) / TSC_DIVISOR = tsc_khz * (1000 / TSC_DIVISOR)

and thus, the roundoff error even vanishes and the whole operation can be
carried out within 32 bits.

The powers of two that divide 1000 are 2, 4 and 8. A value of 8 for
TSC_DIVISOR still allows for TSC frequencies up to
2^32 / 10^9ns * 8 = 34.4GHz which is way larger than anything to expect
in the next years.

Thus we also replace the current TSC_DIVISOR value of 32 by 8. Reverse
the order of the divison and the multiplication in the calculation of
the registered clockevent device's frequency.

Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christopher S. Hall <christopher.s.hall@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Link: http://lkml.kernel.org/r/20160714152255.18295-2-nicstange@gmail.com
[ Improved changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 12:37:38 +02:00
Benjamin Herrenschmidt 97f6e0cc35 powerpc/32: Fix crash during static key init
We cannot do those initializations from apply_feature_fixups() as
this function runs in a very restricted environment on 32-bit where
the kernel isn't running at its linked address and the PTRRELOC()
macro must be used for any global accesss.

Instead, split them into a separtate steup_feature_keys() function
which is called in a more suitable spot on ppc32.

Fixes: 309b315b6e ("powerpc: Call jump_label_init() in apply_feature_fixups()")
Reported-and-tested-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-10 19:41:58 +10:00
Benjamin Herrenschmidt f9cc1d1f80 powerpc: Update obsolete comment in setup_32.c about early_init()
We don't identify the machine type anymore...

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-10 19:38:02 +10:00
Benjamin Herrenschmidt 7d70c63c71 powerpc: Print the kernel load address at the end of prom_init()
This makes it easier to debug crashes that happen very early before
the kernel takes over Open Firmware by allowing us to relate the OF
reported crashing addresses to offsets within the kernel.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-10 19:37:43 +10:00
Cyril Bur c7a318ba86 powerpc/ptrace: Fix coredump since ptrace TM changes
Commit 8d460f6156 ("powerpc/process: Add the function
flush_tmregs_to_thread") added flush_tmregs_to_thread() and included
the assumption that it would only be called for a task which is not
current.

Although this is correct for ptrace, when generating a core dump, some
of the routines which call flush_tmregs_to_thread() are called. This
leads to a WARNing such as:

  Not expecting ptrace on self: TM regs may be incorrect
  ------------[ cut here ]------------
  WARNING: CPU: 123 PID: 7727 at arch/powerpc/kernel/process.c:1088 flush_tmregs_to_thread+0x78/0x80
  CPU: 123 PID: 7727 Comm: libvirtd Not tainted 4.8.0-rc1-gcc6x-g61e8a0d #1
  task: c000000fe631b600 task.stack: c000000fe63b0000
  NIP: c00000000001a1a8 LR: c00000000001a1a4 CTR: c000000000717780
  REGS: c000000fe63b3420 TRAP: 0700   Not tainted  (4.8.0-rc1-gcc6x-g61e8a0d)
  MSR: 900000010282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]>  CR: 28004222  XER: 20000000
  ...
  NIP [c00000000001a1a8] flush_tmregs_to_thread+0x78/0x80
  LR [c00000000001a1a4] flush_tmregs_to_thread+0x74/0x80
  Call Trace:
   flush_tmregs_to_thread+0x74/0x80 (unreliable)
   vsr_get+0x64/0x1a0
   elf_core_dump+0x604/0x1430
   do_coredump+0x5fc/0x1200
   get_signal+0x398/0x740
   do_signal+0x54/0x2b0
   do_notify_resume+0x98/0xb0
   ret_from_except_lite+0x70/0x74

So fix flush_tmregs_to_thread() to detect the case where it is called on
current, and a transaction is active, and in that case flush the TM regs
to the thread_struct.

This patch also moves flush_tmregs_to_thread() into ptrace.c as it is
only called from that file.

Fixes: 8d460f6156 ("powerpc/process: Add the function flush_tmregs_to_thread")
Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
[mpe: Flesh out change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-10 16:34:20 +10:00
Christophe Leroy 1bc8b816cb powerpc/32: Fix csum_partial_copy_generic()
Commit 7aef413656 ("powerpc32: rewrite csum_partial_copy_generic()
based on copy_tofrom_user()") introduced a bug when destination
address is odd and initial csum is not null

In that (rare) case the initial csum value has to be rotated one byte
as well as the resulting value is

This patch also fixes related comments

Fixes: 7aef413656 ("powerpc32: rewrite csum_partial_copy_generic() based on copy_tofrom_user()")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-10 14:52:45 +10:00
Frederic Barrat c6d2ee09c2 cxl: Set psl_fir_cntl to production environment value
Switch the setting of psl_fir_cntl from debug to production
environment recommended value. It mostly affects the PSL behavior when
an error is raised in psl_fir1/2.

Tested with cxlflash.

Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-10 14:02:45 +10:00
Konstantin Khlebnikov 51350ea0d7 mm, writeback: flush plugged IO in wakeup_flusher_threads()
I've found funny live-lock between raid10 barriers during resync and
memory controller hard limits. Inside mpage_readpages() task holds on to
its plug bio which blocks the barrier in raid10. Its memory cgroup have
no free memory thus the task goes into reclaimer but all reclaimable
pages are dirty and cannot be written because raid10 is rebuilding and
stuck on the barrier.

Common flush of such IO in schedule() never happens, because the caller
doesn't go to sleep.

Lock is 'live' because changing memory limit or killing tasks which
holds that stuck bio unblock whole progress.

That was what happened in 3.18.x but I see no difference in upstream
logic.  Theoretically this might happen even without memory cgroup.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-09 19:58:06 -06:00
Ingo Molnar 69766c40c3 perf/urgent fixes:
User visible fixes:
 
 - Fix the lookup for a kernel module in 'perf probe', fixing for instance, the
   erroneous return of "[raid10]" when looking for "[raid1]"  (Konstantin Khlebnikov)
 
 - Disable counters in a group before reading them in 'perf stat', to avoid skew (Mark Rutland)
 
 - Fix adding probes to function aliases in systems using kaslr (Masami Hiramatsu)
 
 - Trip libtraceevent trace_seq buffers, removing unnecessary memory usage that could
   bring a system using tracepoint events with 'perf top' to a crawl, as the trace_seq
   buffers start at a whooping 4 KB, which is very rarely used in perf's usecases,
   so realloc it to the really used space as a last measure after using libtraceevent
   functions to format the fields of tracepoint events (Arnaldo Carvalho de Melo)
 
 - Fix 'perf probe' location when using DWARF on ppc64le (Ravi Bangoria)
 
 Improvement:
 
 - Allow specifying signedness casts to a 'perf probe' variable, to shorten
   the number of steps to see signed values that otherwise would always appear
   as hex values (Naohiro Aota)
 
 Documentation fixes:
 
 - Add 'bpf-output' field to 'perf script' usage message (Brendan Gregg)
 
 Infrastructure fixes:
 
 - Sync kernel header files: cpufeatures.h, {disabled,required}-features.h,
   bpf.h and vmx.h, so that we get a clean build, without warnings about files
   being different from the kernel counterparts.
 
   A verification of the need or desirability of changes in tools/ based on what
   was done in the kernel changesets was made and documented in the respective
   file sync changesets (Arnaldo Carvalho de Melo)
 
 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2
 
 iQIcBAABCAAGBQJXqfpSAAoJENZQFvNTUqpAkJUQALGxbMIZmCOE2O/lok7t6PDZ
 VUsq0vs3V1mPqdin1UnNsfMCvWQExeJZQ4P8EUTSLoMbpiifq2BY5696xs35LUtl
 +UTTtVgtN+/W5gLiQ78U8kEkG8Q/PiMeWKyLLKgBSAEtibC4pOLnQCu/g4DP3e3c
 oYQTaoaSq4eBQMQaDKF2Y6EVQFEdQs4PI1JUIsGn9zTfR5qtRiKwZxrNkAfmNAVO
 opDN42JR3HewwXiOKWuoAVHDi5QVsHgDUnPuYlFujbx306WV+EiypRpzA4Rbr0Cu
 AZrtkqQdSkKYVhEop3Az5kW9m3qZ6DRcZfJNVmD0Cax637gQNbOyIVVxo2KiS5JQ
 8kZknTuQoR8GTARUwlUlQVydwKaRXsox4M1o71FVAOuvEKzBFpIUF46c+Ljgj4O0
 zo1q9I2GnmxjakP0528oLrtT4UyndWTxjK0bwPcr+AwFGVfICT5OteUoTkLSbTAO
 WdqfIhtS1PL+yJmy9iQkaPtTWVtgHmJbQ8PtBVBZZjwvDbx2sDv84/83picwUM+u
 4g0WaqEzKMhRznDHXjc6EkSWRcP20AFqAotRNn8Uxhinx6OvLMs2C6TLzt1lHuw/
 Zsz6wJnM3qaOs9Oxe1U8J04Zm47C8y6iVx5zpJkgFaAf49mJ475me89NratFrAfq
 T1OsSy9dejfB4xrBvOjk
 =/B7T
 -----END PGP SIGNATURE-----

Merge tag 'perf-urgent-for-mingo-20160809' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull perf/urgent fixes from Arnaldo Carvalho de Melo:

User visible fixes:

- Fix the lookup for a kernel module in 'perf probe', fixing for instance, the
  erroneous return of "[raid10]" when looking for "[raid1]"  (Konstantin Khlebnikov)

- Disable counters in a group before reading them in 'perf stat', to avoid skew (Mark Rutland)

- Fix adding probes to function aliases in systems using kaslr (Masami Hiramatsu)

- Trip libtraceevent trace_seq buffers, removing unnecessary memory usage that could
  bring a system using tracepoint events with 'perf top' to a crawl, as the trace_seq
  buffers start at a whooping 4 KB, which is very rarely used in perf's usecases,
  so realloc it to the really used space as a last measure after using libtraceevent
  functions to format the fields of tracepoint events (Arnaldo Carvalho de Melo)

- Fix 'perf probe' location when using DWARF on ppc64le (Ravi Bangoria)

- Allow specifying signedness casts to a 'perf probe' variable, to shorten
  the number of steps to see signed values that otherwise would always appear
  as hex values (Naohiro Aota)

Documentation fixes:

- Add 'bpf-output' field to 'perf script' usage message (Brendan Gregg)

Infrastructure fixes:

- Sync kernel header files: cpufeatures.h, {disabled,required}-features.h,
  bpf.h and vmx.h, so that we get a clean build, without warnings about files
  being different from the kernel counterparts.

  A verification of the need or desirability of changes in tools/ based on what
  was done in the kernel changesets was made and documented in the respective
  file sync changesets (Arnaldo Carvalho de Melo)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-09 21:11:00 +02:00
Linus Torvalds a0cba2179e Revert "printk: create pr_<level> functions"
This reverts commit 874f9c7da9.

Geert Uytterhoeven reports:
 "This change seems to have an (unintendent?) side-effect.

  Before, pr_*() calls without a trailing newline characters would be
  printed with a newline character appended, both on the console and in
  the output of the dmesg command.

  After this commit, no new line character is appended, and the output
  of the next pr_*() call of the same type may be appended, like in:

    - Truncating RAM at 0x0000000040000000-0x00000000c0000000 to -0x0000000070000000
    - Ignoring RAM at 0x0000000200000000-0x0000000240000000 (!CONFIG_HIGHMEM)
    + Truncating RAM at 0x0000000040000000-0x00000000c0000000 to -0x0000000070000000Ignoring RAM at 0x0000000200000000-0x0000000240000000 (!CONFIG_HIGHMEM)"

Joe Perches says:
 "No, that is not intentional.

  The newline handling code inside vprintk_emit is a bit involved and
  for now I suggest a revert until this has all the same behavior as
  earlier"

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Requested-by: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-09 10:48:18 -07:00
Linus Torvalds 84bd8d33a9 Luiz Capitulino noticed that the tick_stop tracepoint wasn't being parsed
properly by the tracing user space tools. This was due to the
 TRACE_DEFINE_ENUM() being set to a define, when it should have been set
 to the enum itself. The define was of the MASK that used the BIT to shift.
 The BIT was the enum and by adding that, everything gets converted nicely.
 The MASK is still kept just in case it gets converted to an enum in the
 future.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQEcBAABAgAGBQJXqeA/AAoJEKKk/i67LK/8wLAH/0nD8L5pxtn+pZi3mQnWNwbn
 qEBtfKK8cvnt0IWH2HlKmRKLAiIJfp8UrkGoPiLT7Nb83PlKaw3UT868t7eDmknu
 b29SsZroMgvJ1MeeNH9Yzk7cK3/K213VO02P4ce8EWSELYCqFlxJDE3dhl52K9Lj
 clJSoZbIGTLlx4pk6zZnPksTt3Z9WZXcVJITwxEiz/Cr+CKAWZpLoPPUaqJOmA4j
 9oS6d++0DYZdz3cWCmYBBkphmc5IQkBNZWGMYLcAR+M+m5fsN+baWlP3Dhq4j7he
 WknHwu4WDFMk6a2Kh0Ggi6yUWVUIkLNY2Z4QUF2gNmJT1g/FH5lZka4/kIxjvKw=
 =rgBA
 -----END PGP SIGNATURE-----

Merge tag 'trace-v4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fix from Steven Rostedt:
 "Fix tick_stop tracepoint symbols for user export.

  Luiz Capitulino noticed that the tick_stop tracepoint wasn't being
  parsed properly by the tracing user space tools.

  This was due to the TRACE_DEFINE_ENUM() being set to a define, when it
  should have been set to the enum itself.  The define was of the MASK
  that used the BIT to shift.  The BIT was the enum and by adding that,
  everything gets converted nicely.  The MASK is still kept just in case
  it gets converted to an enum in the future"

* tag 'trace-v4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix tick_stop tracepoint symbols for user export
2016-08-09 10:34:09 -07:00
Linus Torvalds b79f34d6ae Several fixes/improvements for the gcc plugin infrastructure:
- Fixes a problem with gcc plugins interfering with cc-option tests.
 - Aborts more gracefully when gcc plugin headers or compiler support is
   missing.
 - Improves the gcc plugin rule generation to be more dynamic, pass arguments,
   and build from subdirectories.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 Comment: Kees Cook <kees@outflux.net>
 
 iQIbBAABCgAGBQJXqSsEAAoJEIly9N/cbcAmf+gP+LkBnio5aJrhQwsw2pJ44xC+
 XTYeypDJswjA2EZsCLJXRFkRr46/SDUXF9sE428o/i47udglOPDyvRtb4/yekBTC
 ao9INrXqmpfkwM2QAZRQH6bTDmxoJF4/u1Z+KgF0e2CX+23ZEUjNVuQwsGcBWGJ8
 ktvF3agyT/Of97scbiKmxmbyvGF4lqCdEUWr2Aq0kYd2XKRzKvDO5JvqB+Sz7uWQ
 ipy4GdcVgEJG6XyjirEyneqcH4Kp0XLf7pYV4V8cdBm1ORBx7igLVgm1mnPwIiAH
 xzlRLD/CHG8bLttvd/6iJ3RvTUYhoBFzfiijH4CTKEd/M7wWqzXhdQEGChvD1OCS
 DJIrZZZfWP+9IfPMdFBuq3eZ7O5wyroQf8n8jbF2Nql3qZfWy8CeNTwINxCivEHs
 PJnXMiug8yNuBBiXagKNlAVUb91ij/VzsQ0Zikh7wQB6odOi680p16xEUrvoNC5V
 H+zST1Ep+BI8O7WiYPH3YyoDZtIJcPGYLT4j0ZGY7U3UrPAgF5Wnu6pcCHDD6Azl
 zisde72+DWcUXTsIdFLvK1lvy4aC2lkgyqBwTvUQ8s4O0IDymywo+WacuCk1JURL
 5dkGsRT8Q31XOvJjp7rf4NZvB8blwHFkwTR4yB5qjiTVCl8x2d+xfq2tDxLw60MT
 d/R0RGahDEBddJwmN04=
 =Jwmy
 -----END PGP SIGNATURE-----

Merge tag 'gcc-plugin-infrastructure-v4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull gcc plugin improvements from Kees Cook:
 "Several fixes/improvements for the gcc plugin infrastructure:

   - fix a problem with gcc plugins interfering with cc-option tests.

   - abort more gracefully when gcc plugin headers or compiler support
     is missing.

   - improve the gcc plugin rule generation to be more dynamic, pass
     arguments, and build from subdirectories"

* tag 'gcc-plugin-infrastructure-v4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  gcc-plugins: Add support for plugin subdirectories
  gcc-plugins: Automate make rule generation
  gcc-plugins: Add support for passing plugin arguments
  gcc-plugins: abort builds cleanly when not supported
  kbuild: no gcc-plugins during cc-option tests
2016-08-09 10:30:07 -07:00
Linus Torvalds e1d009eab4 platform-drivers-x86 for 4.8-3
dell-wmi:
  - Ignore WMI event 0xe00e
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQEcBAABAgAGBQJXqNDLAAoJEKbMaAwKp364NG8H/jmcdVk8QDGLVvTQJ624CsL6
 VWKEkIBj1HnxW7zukwXcPlypjccbHcGKG+Q98pwpKKBw2bHc3dVIpVhc1k2fVZdc
 ny5JNg8gJBwNUFTl+i4yzbOo9UAwSJApScc3l5c2x892/1v6x10IoVdjygD0uMOK
 P9mQ4z2w0D9kpeUpgjFwZrgdePlUKeykg4byGwGu/WyuEMisQE31QaJstDdyc/VE
 EqYpir2dQ4czAKgXOSG12xvTsvqdadyDhoh1ln7tmfMNkRjLAwHYidBdUBnjVcJ2
 tN1ppAc2gz1a/5yKxHEAz+jjqrx4t8CCbLIH83SFOH8GCmUH1XMhdLnzvp1NBbY=
 =UulL
 -----END PGP SIGNATURE-----

Merge tag 'platform-drivers-x86-v4.8-3' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86

Pull x86 platform driver update from Darren Hart:
 "dell-wmi: ignore battery remove/insert event"

* tag 'platform-drivers-x86-v4.8-3' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86:
  dell-wmi: Ignore WMI event 0xe00e
2016-08-09 10:26:14 -07:00
Linus Torvalds cb0d93aaf0 Merge tag 'drm-fixes-for-4.8-rc2' of git://people.freedesktop.org/~airlied/linux
Pull drm fixes from Dave Airlie:
 "This contains a bunch of amdgpu fixes, and some i915 regression fixes.

  It also contains some fixes for an older regression with some EDID
  changes and some 6bpc panels.

  Then there are the lockdep, cirrus and rcar-du regression fixes from
  this window"

* tag 'drm-fixes-for-4.8-rc2' of git://people.freedesktop.org/~airlied/linux:
  drm/cirrus: Fix NULL pointer dereference when registering the fbdev
  drm/edid: Set 8 bpc color depth for displays with "DFP 1.x compliant TMDS".
  drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown"
  drm/edid: Add 6 bpc quirk for display AEO model 0.
  drm: Paper over locking inversion after registration rework
  drm: rcar-du: Link HDMI encoder with bridge
  drm/ttm: Wait for a BO to become idle before unbinding it from GTT
  drm/i915/fbdev: Check for the framebuffer before use
  drm/amdgpu: update golden setting of polaris10
  drm/amdgpu: update golden setting of stoney
  drm/amdgpu: update golden setting of polaris11
  drm/amdgpu: update golden setting of carrizo
  drm/amdgpu: update golden setting of iceland
  drm/amd/amdgpu: change pptable output format from ASCII to binary
  drm/amdgpu/ci: add mullins to default case for smc ucode
  drm/amdgpu/gmc7: add missing mullins case
  drm/i915: Never fully mask the the EI up rps interrupt on SNB/IVB
  drm/i915: Wait up to 3ms for the pcu to ack the cdclk change request on SKL
2016-08-09 10:20:21 -07:00
Brian King a3d1ddd932 ipr: Fix sync scsi scan
Commit b195d5e2bf ("ipr: Wait to do async scan until scsi host is
initialized") fixed async scan for ipr, but broke sync scan for ipr.

This fixes sync scan back up.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Reported-and-tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-09 10:17:42 -07:00
Vladimir Davydov c4159a75b6 mm: memcontrol: only mark charged pages with PageKmemcg
To distinguish non-slab pages charged to kmemcg we mark them PageKmemcg,
which sets page->_mapcount to -512.  Currently, we set/clear PageKmemcg
in __alloc_pages_nodemask()/free_pages_prepare() for any page allocated
with __GFP_ACCOUNT, including those that aren't actually charged to any
cgroup, i.e. allocated from the root cgroup context.  To avoid overhead
in case cgroups are not used, we only do that if memcg_kmem_enabled() is
true.  The latter is set iff there are kmem-enabled memory cgroups
(online or offline).  The root cgroup is not considered kmem-enabled.

As a result, if a page is allocated with __GFP_ACCOUNT for the root
cgroup when there are kmem-enabled memory cgroups and is freed after all
kmem-enabled memory cgroups were removed, e.g.

  # no memory cgroups has been created yet, create one
  mkdir /sys/fs/cgroup/memory/test
  # run something allocating pages with __GFP_ACCOUNT, e.g.
  # a program using pipe
  dmesg | tail
  # remove the memory cgroup
  rmdir /sys/fs/cgroup/memory/test

we'll get bad page state bug complaining about page->_mapcount != -1:

  BUG: Bad page state in process swapper/0  pfn:1fd945c
  page:ffffea007f651700 count:0 mapcount:-511 mapping:          (null) index:0x0
  flags: 0x1000000000000000()

To avoid that, let's mark with PageKmemcg only those pages that are
actually charged to and hence pin a non-root memory cgroup.

Fixes: 4949148ad4 ("mm: charge/uncharge kmemcg from generic page allocator paths")
Reported-and-tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-09 10:14:10 -07:00
Marc Zyngier 7f1d642fbb drivers/perf: arm-pmu: Fix handling of SPI lacking "interrupt-affinity" property
Patch 19a469a587 ("drivers/perf: arm-pmu: Handle per-interrupt
affinity mask") added support for partitionned PPI setups, but
inadvertently broke setups using SPIs without the "interrupt-affinity"
property (which is the case for UP platforms).

This patch restore the broken functionnality by testing whether the
interrupt is percpu or not instead of relying on the using_spi flag
that really means "SPI *and* interrupt-affinity property".

Acked-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Fixes: 19a469a587 ("drivers/perf: arm-pmu: Handle per-interrupt affinity mask")
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-08-09 17:57:39 +01:00
Sudeep Holla a026bb12cc drivers/perf: arm-pmu: convert arm_pmu_mutex to spinlock
arm_pmu_mutex is never held long and we don't want to sleep while the
lock is being held as it's executed in the context of hotplug notifiers.
So it can be converted to a simple spinlock instead.

Without this patch we get the following warning:

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620
in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/2
no locks held by swapper/2/0.
irq event stamp: 381314
hardirqs last  enabled at (381313): _raw_spin_unlock_irqrestore+0x7c/0x88
hardirqs last disabled at (381314): cpu_die+0x28/0x48
softirqs last  enabled at (381294): _local_bh_enable+0x28/0x50
softirqs last disabled at (381293): irq_enter+0x58/0x78
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.7.0 #12
Call trace:
 dump_backtrace+0x0/0x220
 show_stack+0x24/0x30
 dump_stack+0xb4/0xf0
 ___might_sleep+0x1d8/0x1f0
 __might_sleep+0x5c/0x98
 mutex_lock_nested+0x54/0x400
 arm_perf_starting_cpu+0x34/0xb0
 cpuhp_invoke_callback+0x88/0x3d8
 notify_cpu_starting+0x78/0x98
 secondary_start_kernel+0x108/0x1a8

This patch converts the mutex to spinlock to eliminate the above
warnings. This constraints pmu->reset to be non-blocking call which is
the case with all the ARM PMU backends.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Fixes: 37b502f121 ("arm/perf: Fix hotplug state machine conversion")
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-08-09 17:33:38 +01:00
Ilya Dryomov 4eacd4cb3a ceph: initialize pathbase in the !dentry case in encode_caps_cb()
pathbase is the base inode; set it to 0 if we've got no path.

Coverity-id: 146348
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
2016-08-09 17:26:56 +02:00
Ilya Dryomov d8734849d8 rbd: nuke the 32-bit pool id check
ceph_file_layout::pool_id is now s64.  rbd_add_get_pool_id() and
ceph_pg_poolid_by_name() both return an int, so it's bogus anyway.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
2016-08-09 17:26:47 +02:00
Ravi Bangoria 99e608b595 perf probe ppc64le: Fix probe location when using DWARF
Powerpc has Global Entry Point and Local Entry Point for functions.  LEP
catches call from both the GEP and the LEP. Symbol table of ELF contains
GEP and Offset from which we can calculate LEP, but debuginfo does not
have LEP info.

Currently, perf prioritize symbol table over dwarf to probe on LEP for
ppc64le. But when user tries to probe with function parameter, we fall
back to using dwarf(i.e. GEP) and when function called via LEP, probe
will never hit.

For example:

  $ objdump -d vmlinux
    ...
    do_sys_open():
    c0000000002eb4a0:       e8 00 4c 3c     addis   r2,r12,232
    c0000000002eb4a4:       60 00 42 38     addi    r2,r2,96
    c0000000002eb4a8:       a6 02 08 7c     mflr    r0
    c0000000002eb4ac:       d0 ff 41 fb     std     r26,-48(r1)

  $ sudo ./perf probe do_sys_open
  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
    p:probe/do_sys_open _text+3060904

  $ sudo ./perf probe 'do_sys_open filename:string'
  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
    p:probe/do_sys_open _text+3060896 filename_string=+0(%gpr4):string

For second case, perf probed on GEP. So when function will be called via
LEP, probe won't hit.

  $ sudo ./perf record -a -e probe:do_sys_open ls
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.195 MB perf.data ]

To resolve this issue, let's not prioritize symbol table, let perf
decide what it wants to use. Perf is already converting GEP to LEP when
it uses symbol table. When perf uses debuginfo, let it find LEP offset
form symbol table. This way we fall back to probe on LEP for all cases.

After patch:

  $ sudo ./perf probe 'do_sys_open filename:string'
  $ sudo cat /sys/kernel/debug/tracing/kprobe_events
    p:probe/do_sys_open _text+3060904 filename_string=+0(%gpr4):string

  $ sudo ./perf record -a -e probe:do_sys_open ls
    [ perf record: Woken up 1 times to write data ]
    [ perf record: Captured and wrote 0.197 MB perf.data (11 samples) ]

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1470723805-5081-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-08-09 12:14:29 -03:00
Ravi Bangoria d820456dc7 perf probe: Add function to post process kernel trace events
Instead of inline code, introduce function to post process kernel
probe trace events.

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1470723805-5081-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-08-09 12:09:59 -03:00
Arnaldo Carvalho de Melo 840b49ba55 tools: Sync cpufeatures headers with the kernel
Due to:

  1e61f78baf ("x86/cpufeature: Make sure DISABLED/REQUIRED macros are updated")

No changes to tools using those headers (tools/arch/x86/lib/mem{set,cpu}_64.S)
seems necessary.

Detected by the tools build header drift checker:

  $ make -C tools/perf O=/tmp/build/perf
  make: Entering directory '/home/acme/git/linux/tools/perf'
    BUILD:   Doing 'make -j4' parallel build
    GEN      /tmp/build/perf/common-cmds.h
  Warning: tools/arch/x86/include/asm/disabled-features.h differs from kernel
  Warning: tools/arch/x86/include/asm/required-features.h differs from kernel
  Warning: tools/arch/x86/include/asm/cpufeatures.h differs from kernel
    CC       /tmp/build/perf/util/probe-finder.o
    CC       /tmp/build/perf/builtin-help.o
  <SNIP>
  ^C$

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-ja75m7zk8j0jkzmrv16i5ehw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-08-09 11:56:33 -03:00
Arnaldo Carvalho de Melo 791cceb89f toops: Sync tools/include/uapi/linux/bpf.h with the kernel
The way we're using kernel headers in tools/ now, with a copy that is
made to the same path prefixed by "tools/" plus checking if that copy
got stale, i.e. if the kernel counterpart changed, helps in keeping
track with new features that may be useful for tools to exploit.

For instance, looking at all the changes to bpf.h since it was last
copied to tools/include brings this to toolers' attention:

Need to investigate this one to check how to run a program via perf, setting up
a BPF event, that will take advantage of the way perf already calls clang/LLVM,
sets up the event and runs the workload in a single command line, helping in
debugging such semi cooperative programs:

  96ae522795 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers")

This one needs further investigation about using the feature it improves
in 'perf trace' to do some tcpdumpin' mixed with syscalls, tracepoints,
probe points, callgraphs, etc:

  555c8a8623 ("bpf: avoid stack copy and use skb ctx for event output")

Add tracing just packets that are related to some container to that mix:

  4a482f34af ("cgroup: bpf: Add bpf_skb_in_cgroup_proto")
  4ed8ec521e ("cgroup: bpf: Add BPF_MAP_TYPE_CGROUP_ARRAY")

Definetely needs to have example programs accessing task_struct from a bpf proggie
started from 'perf trace':

  606274c5ab ("bpf: introduce bpf_get_current_task() helper")

Core networking related, XDP:

  6ce96ca348 ("bpf: add XDP_TX xdp_action for direct forwarding")
  6a773a15a1 ("bpf: add XDP prog type for early driver filter")
  13c5c240f7 ("bpf: add bpf_get_hash_recalc helper")
  d2485c4242 ("bpf: add bpf_skb_change_type helper")
  6578171a7f ("bpf: add bpf_skb_change_proto helper")

Changes detected by the tools build system:

  $ make -C tools/perf O=/tmp/build/perf install-bin
  make: Entering directory '/home/acme/git/linux/tools/perf'
    BUILD:   Doing 'make -j4' parallel build
  Warning: tools/include/uapi/linux/bpf.h differs from kernel
    INSTALL  GTK UI
    CC       /tmp/build/perf/bench/mem-memcpy-x86-64-asm.o
  <SNIP>
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Brenden Blanco <bblanco@plumgrid.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-difq4ts1xvww6eyfs9e7zlft@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-08-09 11:48:07 -03:00