There was an amusing bogosity in ac_rw calculation - it tried to
do encode_comp_t(encode_comp_t(0) / 1024). Seeing that comp_t is
a 3-bit exponent + 13-bit mantissa... it's a good thing that 0 is
represented by all-bits-clear.
The history of that one is interesting - it was introduced in
2.1.68pre1, when acct.c had been reworked and moved to separate
file. Two months later (2.1.86) somebody has noticed that the
sucker won't compile - there was no task_struct::io_usage.
At which point the ac_io calculation had changed from
encode_comp_t(current->io_usage) to encode_comp_t(0) and the
bug in the next line (absolutely real back then, had it ever
managed to compile) become a harmless bogosity. Looks like
nobody has ever noticed until now.
Anyway, let's bury that idiocy now that it got noticed. 17 years
is long enough...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Merge incoming from Andrew Morton:
- Various misc things.
- arch/sh updates.
- Part of ocfs2. Review is slow.
- Slab updates.
- Most of -mm.
- printk updates.
- lib/ updates.
- checkpatch updates.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (226 commits)
checkpatch: update $declaration_macros, add uninitialized_var
checkpatch: warn on missing spaces in broken up quoted
checkpatch: fix false positives for --strict "space after cast" test
checkpatch: fix false positive MISSING_BREAK warnings with --file
checkpatch: add test for native c90 types in unusual order
checkpatch: add signed generic types
checkpatch: add short int to c variable types
checkpatch: add for_each tests to indentation and brace tests
checkpatch: fix brace style misuses of else and while
checkpatch: add --fix option for a couple OPEN_BRACE misuses
checkpatch: use the correct indentation for which()
checkpatch: add fix_insert_line and fix_delete_line helpers
checkpatch: add ability to insert and delete lines to patch/file
checkpatch: add an index variable for fixed lines
checkpatch: warn on break after goto or return with same tab indentation
checkpatch: emit a warning on file add/move/delete
checkpatch: add test for commit id formatting style in commit log
checkpatch: emit fewer kmalloc_array/kcalloc conversion warnings
checkpatch: improve "no space after cast" test
checkpatch: allow multiple const * types
...
Pull ACPI and power management updates from Rafael Wysocki:
"Again, ACPICA leads the pack (47 commits), followed by cpufreq (18
commits) and system suspend/hibernation (9 commits).
From the new code perspective, the ACPICA update brings ACPI 5.1 to
the table, including a new device configuration object called _DSD
(Device Specific Data) that will hopefully help us to operate device
properties like Device Trees do (at least to some extent) and changes
related to supporting ACPI on ARM.
Apart from that we have hibernation changes making it use radix trees
to store memory bitmaps which should speed up some operations carried
out by it quite significantly. We also have some power management
changes related to suspend-to-idle (the "freeze" sleep state) support
and more preliminary changes needed to support ACPI on ARM (outside of
ACPICA).
The rest is fixes and cleanups pretty much everywhere.
Specifics:
- ACPICA update to upstream version 20140724. That includes ACPI 5.1
material (support for the _CCA and _DSD predefined names, changes
related to the DMAR and PCCT tables and ARM support among other
things) and cleanups related to using ACPICA's header files. A
major part of it is related to acpidump and the core code used by
that utility. Changes from Bob Moore, David E Box, Lv Zheng,
Sascha Wildner, Tomasz Nowicki, Hanjun Guo.
- Radix trees for memory bitmaps used by the hibernation core from
Joerg Roedel.
- Support for waking up the system from suspend-to-idle (also known
as the "freeze" sleep state) using ACPI-based PCI wakeup signaling
(Rafael J Wysocki).
- Fixes for issues related to ACPI button events (Rafael J Wysocki).
- New device ID for an ACPI-enumerated device included into the
Wildcat Point PCH from Jie Yang.
- ACPI video updates related to backlight handling from Hans de Goede
and Linus Torvalds.
- Preliminary changes needed to support ACPI on ARM from Hanjun Guo
and Graeme Gregory.
- ACPI PNP core cleanups from Arjun Sreedharan and Zhang Rui.
- Cleanups related to ACPI_COMPANION() and ACPI_HANDLE() macros
(Rafael J Wysocki).
- ACPI-based device hotplug cleanups from Wei Yongjun and Rafael J
Wysocki.
- Cleanups and improvements related to system suspend from Lan
Tianyu, Randy Dunlap and Rafael J Wysocki.
- ACPI battery cleanup from Wei Yongjun.
- cpufreq core fixes from Viresh Kumar.
- Elimination of a deadband effect from the cpufreq ondemand governor
and intel_pstate driver cleanups from Stratos Karafotis.
- 350MHz CPU support for the powernow-k6 cpufreq driver from Mikulas
Patocka.
- Fix for the imx6 cpufreq driver from Anson Huang.
- cpuidle core and governor cleanups from Daniel Lezcano, Sandeep
Tripathy and Mohammad Merajul Islam Molla.
- Build fix for the big_little cpuidle driver from Sachin Kamat.
- Configuration fix for the Operation Performance Points (OPP)
framework from Mark Brown.
- APM cleanup from Jean Delvare.
- cpupower utility fixes and cleanups from Peter Senna Tschudin,
Andrey Utkin, Himangi Saraogi, Rickard Strandqvist, Thomas
Renninger"
* tag 'pm+acpi-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (118 commits)
ACPI / LPSS: add LPSS device for Wildcat Point PCH
ACPI / PNP: Replace faulty is_hex_digit() by isxdigit()
ACPICA: Update version to 20140724.
ACPICA: ACPI 5.1: Update for PCCT table changes.
ACPICA/ARM: ACPI 5.1: Update for GTDT table changes.
ACPICA/ARM: ACPI 5.1: Update for MADT changes.
ACPICA/ARM: ACPI 5.1: Update for FADT changes.
ACPICA: ACPI 5.1: Support for the _CCA predifined name.
ACPICA: ACPI 5.1: New notify value for System Affinity Update.
ACPICA: ACPI 5.1: Support for the _DSD predefined name.
ACPICA: Debug object: Add current value of Timer() to debug line prefix.
ACPICA: acpihelp: Add UUID support, restructure some existing files.
ACPICA: Utilities: Fix local printf issue.
ACPICA: Tables: Update for DMAR table changes.
ACPICA: Remove some extraneous printf arguments.
ACPICA: Update for comments/formatting. No functional changes.
ACPICA: Disassembler: Add support for the ToUUID opererator (macro).
ACPICA: Remove a redundant cast to acpi_size for ACPI_OFFSET() macro.
ACPICA: Work around an ancient GCC bug.
ACPI / processor: Make it possible to get local x2apic id via _MAT
...
Pull SCSI updates from James Bottomley:
"This patch set consists of the usual driver updates (ufs, storvsc,
pm8001 hpsa). It also has removal of the user space target driver
code (everyone is using LIO now), a partial PCI MSI-X update, more
multi-queue updates, conversion to 64 bit LUNs (so we could
theoretically cope with any LUN returned by a device) and placeholder
support for the ZBC device type (Shingle drives), plus an assortment
of minor updates and bug fixes"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (143 commits)
scsi: do not issue SCSI RSOC command to Promise Vtrak E610f
vmw_pvscsi: Use pci_enable_msix_exact() instead of pci_enable_msix()
pm8001: Fix invalid return when request_irq() failed
lpfc: Remove superfluous call to pci_disable_msix()
isci: Use pci_enable_msix_exact() instead of pci_enable_msix()
bfa: Use pci_enable_msix_exact() instead of pci_enable_msix()
bfa: Cleanup bfad_setup_intr() function
bfa: Do not call pci_enable_msix() after it failed once
fnic: Use pci_enable_msix_exact() instead of pci_enable_msix()
scsi: use short driver name for per-driver cmd slab caches
scsi_debug: support scsi-mq, queues and locks
Drivers: add blist flags
scsi: ufs: fix endianness sparse warnings
scsi: ufs: make undeclared functions static
bnx2i: Update driver version to 2.7.10.1
pm8001: fix a memory leak in nvmd_resp
pm8001: fix update_flash
pm8001: fix a memory leak in flash_update
pm8001: Cleaning up uninitialized variables
pm8001: Fix to remove null pointer checks that could never happen
...
We need interrupts disabled when calling console_trylock_for_printk()
only so that cpu id we pass to can_use_console() remains valid (for
other things console_sem provides all the exclusion we need and
deadlocks on console_sem due to interrupts are impossible because we use
down_trylock()). However if we are rescheduled, we are guaranteed to
run on an online cpu so we can easily just get the cpu id in
can_use_console().
We can lose a bit of performance when we enable interrupts in
vprintk_emit() and then disable them again in console_unlock() but OTOH
it can somewhat reduce interrupt latency caused by console_unlock().
We differ from (reverted) commit 939f04bec1 in that we avoid calling
console_unlock() from vprintk_emit() with lockdep enabled as that has
unveiled quite some bugs leading to system freezes during boot (e.g.
https://lkml.org/lkml/2014/5/30/242,
https://lkml.org/lkml/2014/6/28/521).
Signed-off-by: Jan Kara <jack@suse.cz>
Tested-by: Andreas Bombe <aeb@debian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some small cleanups to kernel/printk/printk.c. None of them should
cause any change in behavior.
- When CONFIG_PRINTK is defined, parenthesize the value of LOG_LINE_MAX.
- When CONFIG_PRINTK is *not* defined, there is an extra LOG_LINE_MAX
definition; delete it.
- Pull an assignment out of a conditional expression in console_setup().
- Use isdigit() in console_setup() rather than open coding it.
- In update_console_cmdline(), drop a NUL-termination assignment;
the strlcpy() call that precedes it guarantees it's not needed.
- Simplify some logic in printk_timed_ratelimit().
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jan Kara <jack@suse.cz>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit a8fe19ebfb ("kernel/printk: use symbolic defines for console
loglevels") makes consistent use of symbolic values for printk() log
levels.
The naming scheme used is different from the one used for
DEFAULT_MESSAGE_LOGLEVEL though. Change that symbol name to be
MESSAGE_LOGLEVEL_DEFAULT for consistency. And because the value of that
symbol comes from a similarly-named config option, rename
CONFIG_DEFAULT_MESSAGE_LOGLEVEL as well.
Signed-off-by: Alex Elder <elder@linaro.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jan Kara <jack@suse.cz>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In do_syslog() there's a path used by kmsg_poll() and kmsg_read() that
only needs to know whether there's any data available to read (and not
its size). These callers only check for non-zero return. As a
shortcut, do_syslog() returns the difference between what has been
logged and what has been "seen."
The comments say that the "count of records" should be returned but it's
not. Instead it returns (log_next_idx - syslog_idx), which is a
difference between buffer offsets--and the result could be negative.
The behavior is the same (it'll be zero or not in the same cases), but
the count of records is more meaningful and it matches what the comments
say. So change the code to return that.
Signed-off-by: Alex Elder <elder@linaro.org>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The default size of the ring buffer is too small for machines with a
large amount of CPUs under heavy load. What ends up happening when
debugging is the ring buffer overlaps and chews up old messages making
debugging impossible unless the size is passed as a kernel parameter.
An idle system upon boot up will on average spew out only about one or
two extra lines but where this really matters is on heavy load and that
will vary widely depending on the system and environment.
There are mechanisms to help increase the kernel ring buffer for tracing
through debugfs, and those interfaces even allow growing the kernel ring
buffer per CPU. We also have a static value which can be passed upon
boot. Relying on debugfs however is not ideal for production, and
relying on the value passed upon bootup is can only used *after* an
issue has creeped up. Instead of being reactive this adds a proactive
measure which lets you scale the amount of contributions you'd expect to
the kernel ring buffer under load by each CPU in the worst case
scenario.
We use num_possible_cpus() to avoid complexities which could be
introduced by dynamically changing the ring buffer size at run time,
num_possible_cpus() lets us use the upper limit on possible number of
CPUs therefore avoiding having to deal with hotplugging CPUs on and off.
This introduces the kernel configuration option LOG_CPU_MAX_BUF_SHIFT
which is used to specify the maximum amount of contributions to the
kernel ring buffer in the worst case before the kernel ring buffer flips
over, the size is specified as a power of 2. The total amount of
contributions made by each CPU must be greater than half of the default
kernel ring buffer size (1 << LOG_BUF_SHIFT bytes) in order to trigger
an increase upon bootup. The kernel ring buffer is increased to the
next power of two that would fit the required minimum kernel ring buffer
size plus the additional CPU contribution. For example if LOG_BUF_SHIFT
is 18 (256 KB) you'd require at least 128 KB contributions by other CPUs
in order to trigger an increase of the kernel ring buffer. With a
LOG_CPU_BUF_SHIFT of 12 (4 KB) you'd require at least anything over > 64
possible CPUs to trigger an increase. If you had 128 possible CPUs the
amount of minimum required kernel ring buffer bumps to:
((1 << 18) + ((128 - 1) * (1 << 12))) / 1024 = 764 KB
Since we require the ring buffer to be a power of two the new required
size would be 1024 KB.
This CPU contributions are ignored when the "log_buf_len" kernel
parameter is used as it forces the exact size of the ring buffer to an
expected power of two value.
[pmladek@suse.cz: fix build]
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.cz>
Tested-by: Davidlohr Bueso <davidlohr@hp.com>
Tested-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: Arun KS <arunks.linux@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In practice the power of 2 practice of the size of the kernel ring
buffer remains purely historical but not a requirement, specially now
that we have LOG_ALIGN and use it for both static and dynamic
allocations. It could have helped with implicit alignment back in the
days given the even the dynamically sized ring buffer was guaranteed to
be aligned so long as CONFIG_LOG_BUF_SHIFT was set to produce a
__LOG_BUF_LEN which is architecture aligned, since log_buf_len=n would
be allowed only if it was > __LOG_BUF_LEN and we always ended up
rounding the log_buf_len=n to the next power of 2 with
roundup_pow_of_two(), any multiple of 2 then should be also architecture
aligned. These assumptions of course relied heavily on
CONFIG_LOG_BUF_SHIFT producing an aligned value but users can always
change this.
We now have precise alignment requirements set for the log buffer size
for both static and dynamic allocations, but lets upkeep the old
practice of using powers of 2 for its size to help with easy expected
scalable values and the allocators for dynamic allocations. We'll reuse
this later so move this into a helper.
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: Arun KS <arunks.linux@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have to consider alignment for the ring buffer both for the default
static size, and then also for when an dynamic allocation is made when
the log_buf_len=n kernel parameter is passed to set the size
specifically to a size larger than the default size set by the
architecture through CONFIG_LOG_BUF_SHIFT.
The default static kernel ring buffer can be aligned properly if
architectures set CONFIG_LOG_BUF_SHIFT properly, we provide ranges for
the size though so even if CONFIG_LOG_BUF_SHIFT has a sensible aligned
value it can be reduced to a non aligned value. Commit 6ebb017de9
("printk: Fix alignment of buf causing crash on ARM EABI") by Andrew
Lunn ensures the static buffer is always aligned and the decision of
alignment is done by the compiler by using __alignof__(struct log).
When log_buf_len=n is used we allocate the ring buffer dynamically.
Dynamic allocation varies, for the early allocation called before
setup_arch() memblock_virt_alloc() requests a page aligment and for the
default kernel allocation memblock_virt_alloc_nopanic() requests no
special alignment, which in turn ends up aligning the allocation to
SMP_CACHE_BYTES, which is L1 cache aligned.
Since we already have the required alignment for the kernel ring buffer
though we can do better and request explicit alignment for LOG_ALIGN.
This does that to be safe and make dynamic allocation alignment
explicit.
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Tested-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Petr Mladek <pmladek@suse.cz>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: Arun KS <arunks.linux@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The oom killer scans each process and determines whether it is eligible
for oom kill or whether the oom killer should abort because of
concurrent memory freeing. It will abort when an eligible process is
found to have TIF_MEMDIE set, meaning it has already been oom killed and
we're waiting for it to exit.
Processes with task->mm == NULL should not be considered because they
are either kthreads or have already detached their memory and killing
them would not lead to memory freeing. That memory is only freed after
exit_mm() has returned, however, and not when task->mm is first set to
NULL.
Clear TIF_MEMDIE after exit_mm()'s mmput() so that an oom killed process
is no longer considered for oom kill, but only until exit_mm() has
returned. This was fragile in the past because it relied on
exit_notify() to be reached before no longer considering TIF_MEMDIE
processes.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Al Viro
Linus Torvalds
Neil Zhang
Jan Kara
Alex Elder
Luis R. Rodriguez
Sasha Levin
David Rientjes
Fabian Frederick