Impact: Optimize a bit the function return tracer
This patch changes the calling convention of prepare_ftrace_return to
pass its arguments by register. This will optimize it a bit and
prepare it to support dynamic tracing.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: remove spinlocks and irq disabling in function return tracer.
I've tried to figure out all of the race condition that could happen
when the tracer pushes or pops a return address trace to/from the
current thread_info.
Theory:
_ One thread can only execute on one cpu at a time. So this code
doesn't need to be SMP-safe. Just drop the spinlock.
_ The only race could happen between the current thread and an
interrupt. If an interrupt is raised, it will increase the index of
the return stack storage and then execute until the end of the
tracing to finally free the index it used. We don't need to disable
irqs.
This is theorical. In practice, I've tested it with a two-core SMP and
had no problem at all. Perhaps -tip testing could confirm it.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: name change of unlikely tracer and profiler
Ingo Molnar suggested changing the config from UNLIKELY_PROFILE
to BRANCH_PROFILING. I never did like the "unlikely" name so I
went one step farther, and renamed all the unlikely configurations
to a "BRANCH" variant.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix bootup crash
the branch tracer missed arch/x86/vdso/vclock_gettime.c from
disabling tracing, which caused such bootup crashes:
[ 201.840097] init[1]: segfault at 7fffed3fe7c0 ip 00007fffed3fea2e sp 000077
also clean up the ugly ifdefs in arch/x86/kernel/vsyscall_64.c by
creating DISABLE_UNLIKELY_PROFILE facility for code to turn off
instrumentation on a per file basis.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: new unlikely/likely profiler
Andrew Morton recently suggested having an in-kernel way to profile
likely and unlikely macros. This patch achieves that goal.
When configured, every(*) likely and unlikely macro gets a counter attached
to it. When the condition is hit, the hit and misses of that condition
are recorded. These numbers can later be retrieved by:
/debugfs/tracing/profile_likely - All likely markers
/debugfs/tracing/profile_unlikely - All unlikely markers.
# cat /debug/tracing/profile_unlikely | head
correct incorrect % Function File Line
------- --------- - -------- ---- ----
2167 0 0 do_arch_prctl process_64.c 832
0 0 0 do_arch_prctl process_64.c 804
2670 0 0 IS_ERR err.h 34
71230 5693 7 __switch_to process_64.c 673
76919 0 0 __switch_to process_64.c 639
43184 33743 43 __switch_to process_64.c 624
12740 64181 83 __switch_to process_64.c 594
12740 64174 83 __switch_to process_64.c 590
# cat /debug/tracing/profile_unlikely | \
awk '{ if ($3 > 25) print $0; }' |head -20
44963 35259 43 __switch_to process_64.c 624
12762 67454 84 __switch_to process_64.c 594
12762 67447 84 __switch_to process_64.c 590
1478 595 28 syscall_get_error syscall.h 51
0 2821 100 syscall_trace_leave ptrace.c 1567
0 1 100 native_smp_prepare_cpus smpboot.c 1237
86338 265881 75 calc_delta_fair sched_fair.c 408
210410 108540 34 calc_delta_mine sched.c 1267
0 54550 100 sched_info_queued sched_stats.h 222
51899 66435 56 pick_next_task_fair sched_fair.c 1422
6 10 62 yield_task_fair sched_fair.c 982
7325 2692 26 rt_policy sched.c 144
0 1270 100 pre_schedule_rt sched_rt.c 1261
1268 48073 97 pick_next_task_rt sched_rt.c 884
0 45181 100 sched_info_dequeued sched_stats.h 177
0 15 100 sched_move_task sched.c 8700
0 15 100 sched_move_task sched.c 8690
53167 33217 38 schedule sched.c 4457
0 80208 100 sched_info_switch sched_stats.h 270
30585 49631 61 context_switch sched.c 2619
# cat /debug/tracing/profile_likely | awk '{ if ($3 > 25) print $0; }'
39900 36577 47 pick_next_task sched.c 4397
20824 15233 42 switch_mm mmu_context_64.h 18
0 7 100 __cancel_work_timer workqueue.c 560
617 66484 99 clocksource_adjust timekeeping.c 456
0 346340 100 audit_syscall_exit auditsc.c 1570
38 347350 99 audit_get_context auditsc.c 732
0 345244 100 audit_syscall_entry auditsc.c 1541
38 1017 96 audit_free auditsc.c 1446
0 1090 100 audit_alloc auditsc.c 862
2618 1090 29 audit_alloc auditsc.c 858
0 6 100 move_masked_irq migration.c 9
1 198 99 probe_sched_wakeup trace_sched_switch.c 58
2 2 50 probe_wakeup trace_sched_wakeup.c 227
0 2 100 probe_wakeup_sched_switch trace_sched_wakeup.c 144
4514 2090 31 __grab_cache_page filemap.c 2149
12882 228786 94 mapping_unevictable pagemap.h 50
4 11 73 __flush_cpu_slab slub.c 1466
627757 330451 34 slab_free slub.c 1731
2959 61245 95 dentry_lru_del_init dcache.c 153
946 1217 56 load_elf_binary binfmt_elf.c 904
102 82 44 disk_put_part genhd.h 206
1 1 50 dst_gc_task dst.c 82
0 19 100 tcp_mss_split_point tcp_output.c 1126
As you can see by the above, there's a bit of work to do in rethinking
the use of some unlikelys and likelys. Note: the unlikely case had 71 hits
that were more than 25%.
Note: After submitting my first version of this patch, Andrew Morton
showed me a version written by Daniel Walker, where I picked up
the following ideas from:
1) Using __builtin_constant_p to avoid profiling fixed values.
2) Using __FILE__ instead of instruction pointers.
3) Using the preprocessor to stop all profiling of likely
annotations from vsyscall_64.c.
Thanks to Andrew Morton, Arjan van de Ven, Theodore Tso and Ingo Molnar
for their feed back on this patch.
(*) Not ever unlikely is recorded, those that are used by vsyscalls
(a few of them) had to have profiling disabled.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
timers: handle HRTIMER_CB_IRQSAFE_UNLOCKED correctly from softirq context
nohz: disable tick_nohz_kick_tick() for now
irq: call __irq_enter() before calling the tick_idle_check
x86: HPET: enter hpet_interrupt_handler with interrupts disabled
x86: HPET: read from HPET_Tn_CMP() not HPET_T0_CMP
x86: HPET: convert WARN_ON to WARN_ON_ONCE
fix:
arch/x86/kernel/ftrace.c: In function 'ftrace_return_to_handler':
arch/x86/kernel/ftrace.c:112: error: implicit declaration of function 'cpu_clock'
cpu_clock() is implicitly included via a number of ways, but its real
location is sched.h. (Build failure is triggerable if enough other
kernel components are turned off.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
fix:
arch/x86/kernel/ftrace.c: Assembler messages:
arch/x86/kernel/ftrace.c:140: Error: missing ')'
arch/x86/kernel/ftrace.c:140: Error: junk `(%ebp))' after expression
arch/x86/kernel/ftrace.c:141: Error: missing ')'
arch/x86/kernel/ftrace.c:141: Error: junk `(%ebp))' after expression
the [parent_replaced] is used in an =rm fashion, so that constraint
is correct in isolation - but [parent_old] aliases register %0 and uses
it in an addressing mode that is only valid with registers - so change
the constraint from =rm to =r.
This fixes the build failure.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add infrastructure for function-return tracing
Add low level support for ftrace return tracing.
This plug-in stores return addresses on the thread_info structure of
the current task.
The index of the current return address is initialized when the task
is the first one (init) and when a process forks (the child). It is
not needed when a task does a sys_execve because after this syscall,
it still needs to return on the kernel functions it called.
Note that the code of return_to_handler has been suggested by Steven
Rostedt as almost all of the ideas of improvements in this V3.
For purpose of security, arch/x86/kernel/process_32.c is not traced
because __switch_to() changes the current task during its execution.
That could cause inconsistency in the stored return address of this
function even if I didn't have any crash after testing with tracing on
this function enabled.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Turned off CONFIG_PCI_LEGACY and turned on EXT4, and otherwise mostly
took the defaults. This also updates ppc6xx_defconfig, which covers
the 6xx/7xx/7xxx-based embedded boards.
Signed-off-by: Paul Mackerras <paulus@samba.org>
The new context may not be 16-byte aligned, so the real address of the
mcontext structure should be read from the uc_regs pointer instead of
directly using the (unaligned) uc_mcontext field.
Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
While investigating the failure of hibernation on 32-bit x86 with
CONFIG_NUMA set, as described in this message
http://marc.info/?l=linux-kernel&m=122634118116226&w=4
I asked some people for help and I was told that it wasn't really
worth the effort, because CONFIG_NUMA was generally broken on 32-bit
x86 systems and it shouldn't be used in such configs. For this
reason, make CONFIG_NUMA depend on BROKEN instead of EXPERIMENTAL on
x86-32.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Pavel Machek <pavel@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 8dd9453737.
This fixes a boot failure reported by Robert Reif.
The code above the section change expects to fallthrough, so
we can't make such a section change here.
Some functions that may be called from this handler require that
interrupts are disabled. Also, combining IRQF_DISABLED and
IRQF_SHARED does not reliably disable interrupts in a handler, so
remove IRQF_SHARED from the irq flags (this irq is not shared anyway).
Signed-off-by: Matt Fleming <mjf@gentoo.org>
Cc: mingo@elte.hu
Cc: venkatesh.pallipadi@intel.com
Cc: "Will Newton" <will.newton@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
In hpet_next_event() we check that the value we just wrote to
HPET_Tn_CMP(timer) has reached the chip. Currently, we're checking that
the value we wrote to HPET_Tn_CMP(timer) is in HPET_T0_CMP, which, if
timer is anything other than timer 0, is likely to fail.
Signed-off-by: Matt Fleming <mjf@gentoo.org>
Cc: mingo@elte.hu
Cc: venkatesh.pallipadi@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
It is possible to flood the console with call traces if the WARN_ON
condition is true because of the frequency with which this function is
called.
Signed-off-by: Matt Fleming <mjf@gentoo.org>
Cc: mingo@elte.hu
Cc: venkatesh.pallipadi@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
unset CONFIG_PCI_LEGACY in the defconfigs as none of them enable
ISDN drivers which seem to be the only place we are using pci_find_device
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Fixes following build error:
CC drivers/usb/gadget/fsl_qe_udc.o
drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_eprx_stall_change':
drivers/usb/gadget/fsl_qe_udc.c:156: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c:163: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_eptx_stall_change':
drivers/usb/gadget/fsl_qe_udc.c:173: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c:180: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_eprx_nack':
drivers/usb/gadget/fsl_qe_udc.c:201: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c:201: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_eprx_normal':
drivers/usb/gadget/fsl_qe_udc.c:218: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c:218: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_ep_reset':
drivers/usb/gadget/fsl_qe_udc.c:325: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c:342: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c: In function 'qe_ep_register_init':
drivers/usb/gadget/fsl_qe_udc.c:515: error: 'struct usb_ctlr' has no member named 'usb_usep'
drivers/usb/gadget/fsl_qe_udc.c: In function 'ch9getstatus':
drivers/usb/gadget/fsl_qe_udc.c:1981: error: 'struct usb_ctlr' has no member named 'usb_usep'
make[2]: *** [drivers/usb/gadget/fsl_qe_udc.o] Error 1
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This patch corrects the bus-frequency value provided in the SBC610's dts.
Signed-off-by: Martyn Welch <martyn.welch@gefanuc.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: optimize sched_clock() a bit
sched: improve sched_clock() performance
sched_clock() uses cycles_2_ns() needlessly - which is an irq-disabling
variant of __cycles_2_ns().
Most of the time sched_clock() is called with irqs disabled already.
The few places that call it with irqs enabled need to be updated.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
in scheduler-intense workloads native_read_tsc() overhead accounts for
20% of the system overhead:
659567 system_call 41222.9375
686796 schedule 435.7843
718382 __switch_to 665.1685
823875 switch_mm 4526.7857
1883122 native_read_tsc 55385.9412
9761990 total 2.8468
this is large part due to the rdtsc_barrier() that is done before
and after reading the TSC.
But sched_clock() is not a precise clock in the GTOD sense, using such
barriers is completely pointless. So remove the barriers and only use
them in vget_cycles().
This improves lat_ctx performance by about 5%.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
[IA64] Reserve elfcorehdr memory in CONFIG_CRASH_DUMP
[IA64] fix boot panic caused by offline CPUs
[IA64] reorder Kconfig options to match x86
[IA64] Build VT-D iommu support into generic kernel
[IA64] remove dead BIO_VMERGE_BOUNDARY definition
[IA64] remove duplicated #include from pci-dma.c
[IA64] use common header for software IO/TLB
[IA64] fix the difference between node_mem_map and node_start_pfn
[IA64] Add error_recovery_info field to SAL section header
[IA64] Add UV watchlist support.
[IA64] Simplify SGI uv vs. sn2 driver issues
IA64 kdump kernel failed to initialize /proc/vmcore in 2.6.28-rc2.
A bug was introduced in this patch commit:
d9a9855d0b
always reserve elfcore header memory in crash kernel
The problem was that the call to reserve_elfcorehdr() should be placed
in CONFIG_CRASH_DUMP rather than in CONFIG_CRASH_KERNEL, which does
not exist.
Signed-off-by: Jay Lan <jlan@sgi.com>
Acked-by: Simon Hormon <horms@verge.net.au>
Signed-off-by: Tony Luck <tony.luck@intel.com>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, xen: fix use of pgd_page now that it really does return a page
Fix the counter overflow check for CPUs with counter width > 32
I had a similar change in a different patch that I didn't submit
and I didn't notice the problem earlier because it was always
tested together.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Xen requires that all mappings of pagetable pages are read-only, so
that they can't be updated illegally. As a result, if a page is being
turned into a pagetable page, we need to make sure all its mappings
are RO.
If the page had been used for ioremap or vmalloc, it may still have
left over mappings as a result of not having been lazily unmapped.
This change makes sure we explicitly mop them all up before pinning
the page.
Unlike aliases created by kmap, the there can be vmalloc aliases even
for non-high pages, so we must do the flush unconditionally.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Linux Memory Management List <linux-mm@kvack.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
Revert "x86: default to reboot via ACPI"
x86: align DirectMap in /proc/meminfo
AMD IOMMU: fix lazy IO/TLB flushing in unmap path
x86: add smp_mb() before sending INVALIDATE_TLB_VECTOR
x86: remove VISWS and PARAVIRT around NR_IRQS puzzle
x86: mention ACPI in top-level Kconfig menu
x86: size NR_IRQS on 32-bit systems the same way as 64-bit
x86: don't allow nr_irqs > NR_IRQS
x86/docs: remove noirqbalance param docs
x86: don't use tsc_khz to calculate lpj if notsc is passed
x86, voyager: fix smp_intr_init() compile breakage
AMD IOMMU: fix detection of NP capable IOMMUs
Impact: fix 32-bit Xen guest boot crash
On 32-bit PAE, pud_page, for no good reason, didn't really return a
struct page *. Since Jan Beulich's fix "i386/PAE: fix pud_page()",
pud_page does return a struct page *.
Because PAE has 3 pagetable levels, the pud level is folded into the
pgd level, so pgd_page() is the same as pud_page(), and now returns
a struct page *. Update the xen/mmu.c code which uses pgd_page()
accordingly.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When 'start' and 'end' are less than a cacheline apart and 'start' is
unaligned we are done after cleaning and invalidating the first
cacheline. So check for (start < end) which will not walk off into
invalid address ranges when (start > end).
This issue was caught by drivers/dma/dmatest.
2.6.27 is susceptible.
Cc: <stable@kernel.org>
Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Cc: Lothar WaÃ<9f>mann <LW@KARO-electronics.de>
Cc: Lennert Buytenhek <buytenh@marvell.com>
Cc: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
As a result of the ptebits changes, we ended up marking device mappings
as normal memory on ARMv7 CPUs, resulting in undesirable behaviour with
serial ports and the like. While reviewing the section mapping table
entries, other errors in the memory type settings for devices were
detected and confirmed to prevent Xscale3 platforms booting.
Tested on:
OMAP34xx (ARMv7),
OMAP24xx (ARMv6),
OMAP16xx (ARM926T, ARMv5),
PXA311 (Xscale3),
PXA272 (Xscale),
PXA255 (Xscale),
IXP42x (Xscale),
S3C2410 (ARM920T, ARMv4T),
ARM720T (ARMv4T)
StrongARM-110 (ARMv4)
Acked-by: Tony Lindgren <tony@atomide.com>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Tested-by: Mike Rapoport <mike@compulab.co.il>
Tested-by: Ben Dooks <ben-linux@fluff.org>
Tested-by: Anders Grafström <grfstrm@users.sourceforge.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This fixes a regression introduced by 2c6e6db41f
"Minimize per_cpu reservations." That patch incorrectly used information about
what CPUs are possible that was not yet initialized by ACPI. The end result
was that per_cpu structures for offline CPUs were not initialized causing a
NULL pointer reference.
Since we cannot do the full acpi_boot_init() call any earlier, the simplest
fix is to just parse the MADT for SAPIC entries early to find the CPU
info. This should also allow for some cleanup of the code added by the
"Minimize per_cpu reservations". This patch just fixes the regressions, the
cleanup will come in a later patch.
Signed-off-by: Doug Chapman <doug.chapman@hp.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
CC: Robin Holt <holt@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
No functional change, just reorder some config options and update
the "Power management and ACPI" label to match the defacto x86
standard.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
As of 73bdf0a60e, the kernel needs
to know where modules are located in the virtual address space.
On ARM, we located this region between MODULE_START and MODULE_END.
Unfortunately, everyone else calls it MODULES_VADDR and MODULES_END.
Update ARM to use the same naming, so is_vmalloc_or_module_addr()
can work properly. Also update the comment on mm/vmalloc.c to
reflect that ARM also places modules in a separate region from the
vmalloc space.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This reverts commit c7ffa6c262.
the assumptio of this change was that this would not break
any existing machine. Andrey Borzenkov reported troubles with
the ACPI reboot method: the system would hang on reboot, necessiating
a power cycle. Probably more systems are affected as well.
Also, there are patches queued up for v2.6.29 to disable virtualization
on emergency_restart() - which was the original motivation of
this change.
Reported-by: Andrey Borzenkov <arvidjaar@mail.ru>
Bisected-by: Andrey Borzenkov <arvidjaar@mail.ru>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
