Pull ARM updates from Russell King:
"Bigger items included in this update are:
- A series of updates from Arnd for ARM randconfig build failures
- Updates from Dmitry for StrongARM SA-1100 to move IRQ handling to
drivers/irqchip/
- Move ARMs SP804 timer to drivers/clocksource/
- Perf updates from Mark Rutland in preparation to move the ARM perf
code into drivers/ so it can be shared with ARM64.
- MCPM updates from Nicolas
- Add support for taking platform serial number from DT
- Re-implement Keystone2 physical address space switch to conform to
architecture requirements
- Clean up ARMv7 LPAE code, which goes in hand with the Keystone2
changes.
- L2C cleanups to avoid unlocking caches if we're prevented by the
secure support to unlock.
- Avoid cleaning a potentially dirty cache containing stale data on
CPU initialisation
- Add ARM-only entry point for secondary startup (for machines that
can only call into a Thumb kernel in ARM mode). Same thing is also
done for the resume entry point.
- Provide arch_irqs_disabled via asm-generic
- Enlarge ARMv7M vector table
- Always use BFD linker for VDSO, as gold doesn't accept some of the
options we need.
- Fix an incorrect BSYM (for Thumb symbols) usage, and convert all
BSYM compiler macros to a "badr" (for branch address).
- Shut up compiler warnings provoked by our cmpxchg() implementation.
- Ensure bad xchg sizes fail to link"
* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (75 commits)
ARM: Fix build if CLKDEV_LOOKUP is not configured
ARM: fix new BSYM() usage introduced via for-arm-soc branch
ARM: 8383/1: nommu: avoid deprecated source register on mov
ARM: 8391/1: l2c: add options to overwrite prefetching behavior
ARM: 8390/1: irqflags: Get arch_irqs_disabled from asm-generic
ARM: 8387/1: arm/mm/dma-mapping.c: Add arm_coherent_dma_mmap
ARM: 8388/1: tcm: Don't crash when TCM banks are protected by TrustZone
ARM: 8384/1: VDSO: force use of BFD linker
ARM: 8385/1: VDSO: group link options
ARM: cmpxchg: avoid warnings from macro-ized cmpxchg() implementations
ARM: remove __bad_xchg definition
ARM: 8369/1: ARMv7M: define size of vector table for Vybrid
ARM: 8382/1: clocksource: make ARM_TIMER_SP804 depend on GENERIC_SCHED_CLOCK
ARM: 8366/1: move Dual-Timer SP804 driver to drivers/clocksource
ARM: 8365/1: introduce sp804_timer_disable and remove arm_timer.h inclusion
ARM: 8364/1: fix BE32 module loading
ARM: 8360/1: add secondary_startup_arm prototype in header file
ARM: 8359/1: correct secondary_startup_arm mode
ARM: proc-v7: sanitise and document registers around errata
ARM: proc-v7: clean up MIDR access
...
Merge second patchbomb from Andrew Morton:
- most of the rest of MM
- lots of misc things
- procfs updates
- printk feature work
- updates to get_maintainer, MAINTAINERS, checkpatch
- lib/ updates
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (96 commits)
exit,stats: /* obey this comment */
coredump: add __printf attribute to cn_*printf functions
coredump: use from_kuid/kgid when formatting corename
fs/reiserfs: remove unneeded cast
NILFS2: support NFSv2 export
fs/befs/btree.c: remove unneeded initializations
fs/minix: remove unneeded cast
init/do_mounts.c: add create_dev() failure log
kasan: remove duplicate definition of the macro KASAN_FREE_PAGE
fs/efs: femove unneeded cast
checkpatch: emit "NOTE: <types>" message only once after multiple files
checkpatch: emit an error when there's a diff in a changelog
checkpatch: validate MODULE_LICENSE content
checkpatch: add multi-line handling for PREFER_ETHER_ADDR_COPY
checkpatch: suggest using eth_zero_addr() and eth_broadcast_addr()
checkpatch: fix processing of MEMSET issues
checkpatch: suggest using ether_addr_equal*()
checkpatch: avoid NOT_UNIFIED_DIFF errors on cover-letter.patch files
checkpatch: remove local from codespell path
checkpatch: add --showfile to allow input via pipe to show filenames
...
* acpi-video:
ACPI / video: Inline acpi_video_set_dmi_backlight_type
* device-properties:
ACPI / OF: Rename of_node() and acpi_node() to to_of_node() and to_acpi_node()
* pm-sleep:
PM / sleep: Increase default DPM watchdog timeout to 60
PM / hibernate: re-enable nonboot cpus on disable_nonboot_cpus() failure
* pm-cpuidle:
tick/idle/powerpc: Do not register idle states with CPUIDLE_FLAG_TIMER_STOP set in periodic mode
There is a helpful comment in do_exit() that states we sync the mm's RSS
info before statistics gathering.
The function that does the statistics gathering is called right above that
comment.
Change the code to obey the comment.
Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Part of the disassembly of do_blk_trace_setup:
231b: e8 00 00 00 00 callq 2320 <do_blk_trace_setup+0x50>
231c: R_X86_64_PC32 strlen+0xfffffffffffffffc
2320: eb 0a jmp 232c <do_blk_trace_setup+0x5c>
2322: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1)
2328: 48 83 c3 01 add $0x1,%rbx
232c: 48 39 d8 cmp %rbx,%rax
232f: 76 47 jbe 2378 <do_blk_trace_setup+0xa8>
2331: 41 80 3c 1c 2f cmpb $0x2f,(%r12,%rbx,1)
2336: 75 f0 jne 2328 <do_blk_trace_setup+0x58>
2338: 41 c6 04 1c 5f movb $0x5f,(%r12,%rbx,1)
233d: 4c 89 e7 mov %r12,%rdi
2340: e8 00 00 00 00 callq 2345 <do_blk_trace_setup+0x75>
2341: R_X86_64_PC32 strlen+0xfffffffffffffffc
2345: eb e1 jmp 2328 <do_blk_trace_setup+0x58>
Yep, that's right: gcc isn't smart enough to realize that replacing '/' by
'_' cannot change the strlen(), so we call it again and again (at least
when a '/' is found). Even if gcc were that smart, this construction
would still loop over the string twice, once for the initial strlen() call
and then the open-coded loop.
Let's simply use strreplace() instead.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Liked-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There's no point in starting over every time we see a ','...
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch fixes drawbacks in heck_syslog_permissions() noticed by AKPM:
"from_file handling makes me cry.
That's not a boolean - it's an enumerated value with two values
currently defined.
But the code in check_syslog_permissions() treats it as a boolean and
also hardwires the knowledge that SYSLOG_FROM_PROC == 1 (or == `true`).
And the name is wrong: it should be called from_proc to match
SYSLOG_FROM_PROC."
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The final version of commit 637241a900 ("kmsg: honor dmesg_restrict
sysctl on /dev/kmsg") lost few hooks, as result security_syslog() are
processed incorrectly:
- open of /dev/kmsg checks syslog access permissions by using
check_syslog_permissions() where security_syslog() is not called if
dmesg_restrict is set.
- syslog syscall and /proc/kmsg calls do_syslog() where security_syslog
can be executed twice (inside check_syslog_permissions() and then
directly in do_syslog())
With this patch security_syslog() is called once only in all
syslog-related operations regardless of dmesg_restrict value.
Fixes: 637241a900 ("kmsg: honor dmesg_restrict sysctl on /dev/kmsg")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
printk log_buf keeps various metadata for each message including its
sequence number and timestamp. The metadata is currently available only
through /dev/kmsg and stripped out before passed onto console drivers. We
want this metadata to be available to console drivers too so that console
consumers can get full information including the metadata and dictionary,
which among other things can be used to detect whether messages got lost
in transit.
This patch implements support for extended console drivers. Consoles can
indicate that they want extended messages by setting the new CON_EXTENDED
flag and they'll be fed messages formatted the same way as /dev/kmsg.
"<level>,<sequnum>,<timestamp>,<contflag>;<message text>\n"
If extended consoles exist, in-kernel fragment assembly is disabled. This
ensures that all messages emitted to consoles have full metadata including
sequence number. The contflag carries enough information to reassemble
the fragments from the reader side trivially. Note that this only affects
/dev/kmsg. Regular console and /proc/kmsg outputs are not affected by
this change.
* Extended message formatting for console drivers is enabled iff there
are registered extended consoles.
* Comment describing /dev/kmsg message format updated to add missing
contflag field and help distinguishing variable from verbatim terms.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David Miller <davem@davemloft.net>
Cc: Kay Sievers <kay@vrfy.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The extended message formatting used for /dev/kmsg will be used implement
extended consoles. Factor out msg_print_ext_header() and
msg_print_ext_body() from devkmsg_read().
This is pure restructuring.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David Miller <davem@davemloft.net>
Cc: Kay Sievers <kay@vrfy.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patchset updates netconsole so that it can emit messages with the
same header as used in /dev/kmsg which gives neconsole receiver full log
information which enables things like structured logging and detection
of lost messages.
This patch (of 7):
devkmsg_read() uses 8k buffer and assumes that the formatted output
message won't overrun which seems safe given LOG_LINE_MAX, the current use
of dict and the escaping method being used; however, we're planning to use
devkmsg formatting wider and accounting for the buffer size properly isn't
that complicated.
This patch defines CONSOLE_EXT_LOG_MAX as 8192 and updates devkmsg_read()
so that it limits output accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David Miller <davem@davemloft.net>
Cc: Kay Sievers <kay@vrfy.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
clone has some of the quirkiest syscall handling in the kernel, with a
pile of special cases, historical curiosities, and architecture-specific
calling conventions. In particular, clone with CLONE_SETTLS accepts a
parameter "tls" that the C entry point completely ignores and some
assembly entry points overwrite; instead, the low-level arch-specific
code pulls the tls parameter out of the arch-specific register captured
as part of pt_regs on entry to the kernel. That's a massive hack, and
it makes the arch-specific code only work when called via the specific
existing syscall entry points; because of this hack, any new clone-like
system call would have to accept an identical tls argument in exactly
the same arch-specific position, rather than providing a unified system
call entry point across architectures.
The first patch allows architectures to handle the tls argument via
normal C parameter passing, if they opt in by selecting
HAVE_COPY_THREAD_TLS. The second patch makes 32-bit and 64-bit x86 opt
into this.
These two patches came out of the clone4 series, which isn't ready for
this merge window, but these first two cleanup patches were entirely
uncontroversial and have acks. I'd like to go ahead and submit these
two so that other architectures can begin building on top of this and
opting into HAVE_COPY_THREAD_TLS. However, I'm also happy to wait and
send these through the next merge window (along with v3 of clone4) if
anyone would prefer that.
This patch (of 2):
clone with CLONE_SETTLS accepts an argument to set the thread-local
storage area for the new thread. sys_clone declares an int argument
tls_val in the appropriate point in the argument list (based on the
various CLONE_BACKWARDS variants), but doesn't actually use or pass along
that argument. Instead, sys_clone calls do_fork, which calls
copy_process, which calls the arch-specific copy_thread, and copy_thread
pulls the corresponding syscall argument out of the pt_regs captured at
kernel entry (knowing what argument of clone that architecture passes tls
in).
Apart from being awful and inscrutable, that also only works because only
one code path into copy_thread can pass the CLONE_SETTLS flag, and that
code path comes from sys_clone with its architecture-specific
argument-passing order. This prevents introducing a new version of the
clone system call without propagating the same architecture-specific
position of the tls argument.
However, there's no reason to pull the argument out of pt_regs when
sys_clone could just pass it down via C function call arguments.
Introduce a new CONFIG_HAVE_COPY_THREAD_TLS for architectures to opt into,
and a new copy_thread_tls that accepts the tls parameter as an additional
unsigned long (syscall-argument-sized) argument. Change sys_clone's tls
argument to an unsigned long (which does not change the ABI), and pass
that down to copy_thread_tls.
Architectures that don't opt into copy_thread_tls will continue to ignore
the C argument to sys_clone in favor of the pt_regs captured at kernel
entry, and thus will be unable to introduce new versions of the clone
syscall.
Patch co-authored by Josh Triplett and Thiago Macieira.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thiago Macieira <thiago.macieira@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Individual prctl(PR_SET_MM_*) calls do some checking to maintain a
consistent view of mm->arg_start et al fields, but not enough. In
particular PR_SET_MM_ARG_START/PR_SET_MM_ARG_END/ R_SET_MM_ENV_START/
PR_SET_MM_ENV_END only check that the address lies in an existing VMA,
but don't check that the start address is lower than the end address _at
all_.
Consolidate all consistency checks, so there will be no difference in
the future between PR_SET_MM_MAP and individual PR_SET_MM_* calls.
The program below makes both ARGV and ENVP areas be reversed. It makes
/proc/$PID/cmdline show garbage (it doesn't oops by luck).
#include <sys/mman.h>
#include <sys/prctl.h>
#include <unistd.h>
enum {PAGE_SIZE=4096};
int main(void)
{
void *p;
p = mmap(NULL, PAGE_SIZE, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
#define PR_SET_MM 35
#define PR_SET_MM_ARG_START 8
#define PR_SET_MM_ARG_END 9
#define PR_SET_MM_ENV_START 10
#define PR_SET_MM_ENV_END 11
prctl(PR_SET_MM, PR_SET_MM_ARG_START, (unsigned long)p + PAGE_SIZE - 1, 0, 0);
prctl(PR_SET_MM, PR_SET_MM_ARG_END, (unsigned long)p, 0, 0);
prctl(PR_SET_MM, PR_SET_MM_ENV_START, (unsigned long)p + PAGE_SIZE - 1, 0, 0);
prctl(PR_SET_MM, PR_SET_MM_ENV_END, (unsigned long)p, 0, 0);
pause();
return 0;
}
[akpm@linux-foundation.org: tidy code, tweak comment]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Jarod Wilson <jarod@redhat.com>
Cc: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The trace.h header when called without CONFIG_EVENT_TRACING enabled
(seldom done), will not compile because of a typo in the protocol
of trace_event_enum_update().
Cc: stable@vger.kernel.org # 4.1+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
While debugging a WARN_ON() for filtering, I found that it is possible
for the filter string to be referenced after its end. With the filter:
# echo '>' > /sys/kernel/debug/events/ext4/ext4_truncate_exit/filter
The filter_parse() function can call infix_get_op() which calls
infix_advance() that updates the infix filter pointers for the cnt
and tail without checking if the filter is already at the end, which
will put the cnt to zero and the tail beyond the end. The loop then calls
infix_next() that has
ps->infix.cnt--;
return ps->infix.string[ps->infix.tail++];
The cnt will now be below zero, and the tail that is returned is
already passed the end of the filter string. So far the allocation
of the filter string usually has some buffer that is zeroed out, but
if the filter string is of the exact size of the allocated buffer
there's no guarantee that the charater after the nul terminating
character will be zero.
Luckily, only root can write to the filter.
Cc: stable@vger.kernel.org # 2.6.33+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When testing the fix for the trace filter, I could not come up with
a scenario where the operand count goes below zero, so I added a
WARN_ON_ONCE(cnt < 0) to the logic. But there is legitimate case
that it can happen (although the filter would be wrong).
# echo '>' > /sys/kernel/debug/events/ext4/ext4_truncate_exit/filter
That is, a single operation without any operands will hit the path
where the WARN_ON_ONCE() can trigger. Although this is harmless,
and the filter is reported as a error. But instead of spitting out
a warning to the kernel dmesg, just fail nicely and report it via
the proper channels.
Link: http://lkml.kernel.org/r/558C6082.90608@oracle.com
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: stable@vger.kernel.org # 2.6.33+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull core block IO update from Jens Axboe:
"Nothing really major in here, mostly a collection of smaller
optimizations and cleanups, mixed with various fixes. In more detail,
this contains:
- Addition of policy specific data to blkcg for block cgroups. From
Arianna Avanzini.
- Various cleanups around command types from Christoph.
- Cleanup of the suspend block I/O path from Christoph.
- Plugging updates from Shaohua and Jeff Moyer, for blk-mq.
- Eliminating atomic inc/dec of both remaining IO count and reference
count in a bio. From me.
- Fixes for SG gap and chunk size support for data-less (discards)
IO, so we can merge these better. From me.
- Small restructuring of blk-mq shared tag support, freeing drivers
from iterating hardware queues. From Keith Busch.
- A few cfq-iosched tweaks, from Tahsin Erdogan and me. Makes the
IOPS mode the default for non-rotational storage"
* 'for-4.2/core' of git://git.kernel.dk/linux-block: (35 commits)
cfq-iosched: fix other locations where blkcg_to_cfqgd() can return NULL
cfq-iosched: fix sysfs oops when attempting to read unconfigured weights
cfq-iosched: move group scheduling functions under ifdef
cfq-iosched: fix the setting of IOPS mode on SSDs
blktrace: Add blktrace.c to BLOCK LAYER in MAINTAINERS file
block, cgroup: implement policy-specific per-blkcg data
block: Make CFQ default to IOPS mode on SSDs
block: add blk_set_queue_dying() to blkdev.h
blk-mq: Shared tag enhancements
block: don't honor chunk sizes for data-less IO
block: only honor SG gap prevention for merges that contain data
block: fix returnvar.cocci warnings
block, dm: don't copy bios for request clones
block: remove management of bi_remaining when restoring original bi_end_io
block: replace trylock with mutex_lock in blkdev_reread_part()
block: export blkdev_reread_part() and __blkdev_reread_part()
suspend: simplify block I/O handling
block: collapse bio bit space
block: remove unused BIO_RW_BLOCK and BIO_EOF flags
block: remove BIO_EOPNOTSUPP
...
Merge first patchbomb from Andrew Morton:
- a few misc things
- ocfs2 udpates
- kernel/watchdog.c feature work (took ages to get right)
- most of MM. A few tricky bits are held up and probably won't make 4.2.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (91 commits)
mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
mm, thp: respect MPOL_PREFERRED policy with non-local node
tmpfs: truncate prealloc blocks past i_size
mm/memory hotplug: print the last vmemmap region at the end of hot add memory
mm/mmap.c: optimization of do_mmap_pgoff function
mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan
mm: kmemleak: avoid deadlock on the kmemleak object insertion error path
mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()
mm: kmemleak: fix delete_object_*() race when called on the same memory block
mm: kmemleak: allow safe memory scanning during kmemleak disabling
memcg: convert mem_cgroup->under_oom from atomic_t to int
memcg: remove unused mem_cgroup->oom_wakeups
frontswap: allow multiple backends
x86, mirror: x86 enabling - find mirrored memory ranges
mm/memblock: allocate boot time data structures from mirrored memory
mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute
mm: do not ignore mapping_gfp_mask in page cache allocation paths
mm/cma.c: fix typos in comments
mm/oom_kill.c: print points as unsigned int
mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages
...
Rename unmark_oom_victim() to exit_oom_victim(). Marking and unmarking
are related in functionality, but the interface is not symmetrical at
all: one is an internal OOM killer function used during the killing, the
other is for an OOM victim to signal its own death on exit later on.
This has locking implications, see follow-up changes.
While at it, rename mark_tsk_oom_victim() to mark_oom_victim(), which
is easier on the eye.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change the default behavior of watchdog so it only runs on the
housekeeping cores when nohz_full is enabled at build and boot time.
Allow modifying the set of cores the watchdog is currently running on
with a new kernel.watchdog_cpumask sysctl.
In the current system, the watchdog subsystem runs a periodic timer that
schedules the watchdog kthread to run. However, nohz_full cores are
designed to allow userspace application code running on those cores to
have 100% access to the CPU. So the watchdog system prevents the
nohz_full application code from being able to run the way it wants to,
thus the motivation to suppress the watchdog on nohz_full cores, which
this patchset provides by default.
However, if we disable the watchdog globally, then the housekeeping
cores can't benefit from the watchdog functionality. So we allow
disabling it only on some cores. See Documentation/lockup-watchdogs.txt
for more information.
[jhubbard@nvidia.com: fix a watchdog crash in some configurations]
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch series allows the watchdog to run by default only on the
housekeeping cores when nohz_full is in effect; this seems to be a good
compromise short of turning it off completely (since the nohz_full cores
can't tolerate a watchdog).
To provide customizability, we add /proc/sys/kernel/watchdog_cpumask so
that the set of cores running the watchdog can be tuned to different
values after bootup.
To implement this customizability, we add a new
smpboot_update_cpumask_percpu_thread() API to the smpboot_thread
subsystem that lets us park or unpark "unwanted" threads.
And now that threads can be parked for long periods of time, we tweak the
/proc/<pid>/stat and /proc/<pid>/status code so parked threads aren't
reported as running, which is otherwise confusing.
This patch (of 3):
This change allows some cores to be excluded from running the
smp_hotplug_thread tasks. The following commit to update
kernel/watchdog.c to use this functionality is the motivating example, and
more information on the motivation is provided there.
A new smp_hotplug_thread field is introduced, "cpumask", which is cpumask
field managed by the smpboot subsystem that indicates whether or not the
given smp_hotplug_thread should run on that core; the cpumask is checked
when deciding whether to unpark the thread.
To limit the cpumask to less than cpu_possible, you must call
smpboot_update_cpumask_percpu_thread() after registering.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull networking updates from David Miller:
1) Add TX fast path in mac80211, from Johannes Berg.
2) Add TSO/GRO support to ibmveth, from Thomas Falcon
3) Move away from cached routes in ipv6, just like ipv4, from Martin
KaFai Lau.
4) Lots of new rhashtable tests, from Thomas Graf.
5) Run ingress qdisc lockless, from Alexei Starovoitov.
6) Allow servers to fetch TCP packet headers for SYN packets of new
connections, for fingerprinting. From Eric Dumazet.
7) Add mode parameter to pktgen, for testing receive. From Alexei
Starovoitov.
8) Cache access optimizations via simplifications of build_skb(), from
Alexander Duyck.
9) Move page frag allocator under mm/, also from Alexander.
10) Add xmit_more support to hv_netvsc, from KY Srinivasan.
11) Add a counter guard in case we try to perform endless reclassify
loops in the packet scheduler.
12) Extern flow dissector to be programmable and use it in new "Flower"
classifier. From Jiri Pirko.
13) AF_PACKET fanout rollover fixes, performance improvements, and new
statistics. From Willem de Bruijn.
14) Add netdev driver for GENEVE tunnels, from John W Linville.
15) Add ingress netfilter hooks and filtering, from Pablo Neira Ayuso.
16) Fix handling of epoll edge triggers in TCP, from Eric Dumazet.
17) Add an ECN retry fallback for the initial TCP handshake, from Daniel
Borkmann.
18) Add tail call support to BPF, from Alexei Starovoitov.
19) Add several pktgen helper scripts, from Jesper Dangaard Brouer.
20) Add zerocopy support to AF_UNIX, from Hannes Frederic Sowa.
21) Favor even port numbers for allocation to connect() requests, and
odd port numbers for bind(0), in an effort to help avoid
ip_local_port_range exhaustion. From Eric Dumazet.
22) Add Cavium ThunderX driver, from Sunil Goutham.
23) Allow bpf programs to access skb_iif and dev->ifindex SKB metadata,
from Alexei Starovoitov.
24) Add support for T6 chips in cxgb4vf driver, from Hariprasad Shenai.
25) Double TCP Small Queues default to 256K to accomodate situations
like the XEN driver and wireless aggregation. From Wei Liu.
26) Add more entropy inputs to flow dissector, from Tom Herbert.
27) Add CDG congestion control algorithm to TCP, from Kenneth Klette
Jonassen.
28) Convert ipset over to RCU locking, from Jozsef Kadlecsik.
29) Track and act upon link status of ipv4 route nexthops, from Andy
Gospodarek.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1670 commits)
bridge: vlan: flush the dynamically learned entries on port vlan delete
bridge: multicast: add a comment to br_port_state_selection about blocking state
net: inet_diag: export IPV6_V6ONLY sockopt
stmmac: troubleshoot unexpected bits in des0 & des1
net: ipv4 sysctl option to ignore routes when nexthop link is down
net: track link-status of ipv4 nexthops
net: switchdev: ignore unsupported bridge flags
net: Cavium: Fix MAC address setting in shutdown state
drivers: net: xgene: fix for ACPI support without ACPI
ip: report the original address of ICMP messages
net/mlx5e: Prefetch skb data on RX
net/mlx5e: Pop cq outside mlx5e_get_cqe
net/mlx5e: Remove mlx5e_cq.sqrq back-pointer
net/mlx5e: Remove extra spaces
net/mlx5e: Avoid TX CQE generation if more xmit packets expected
net/mlx5e: Avoid redundant dev_kfree_skb() upon NOP completion
net/mlx5e: Remove re-assignment of wq type in mlx5e_enable_rq()
net/mlx5e: Use skb_shinfo(skb)->gso_segs rather than counting them
net/mlx5e: Static mapping of netdev priv resources to/from netdev TX queues
net/mlx4_en: Use HW counters for rx/tx bytes/packets in PF device
...
Many harddisks (mostly WD ones) have firmware problems and take too
long, more than 10 seconds, to resume from suspend. And this often
exceeds the default DPM watchdog timeout (12 seconds), resulting in a
kernel panic out of sudden.
Since most distros just take the default as is, we should give a bit
more safer value. This patch increases the default value from 12
seconds to one minute, which has been confirmed to be long enough for
such problematic disks.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=91921
Fixes: 70fea60d88 (PM / Sleep: Detect device suspend/resume lockup and log event)
Cc: 3.13+ <stable@vger.kernel.org> # 3.13+
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull scheduler updates from Thomas Gleixner:
"This series of scheduler updates depends on sched/core and timers/core
branches, which are already in your tree:
- Scheduler balancing overhaul to plug a hard to trigger race which
causes an oops in the balancer (Peter Zijlstra)
- Lockdep updates which are related to the balancing updates (Peter
Zijlstra)"
* 'sched-hrtimers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched,lockdep: Employ lock pinning
lockdep: Implement lock pinning
lockdep: Simplify lock_release()
sched: Streamline the task migration locking a little
sched: Move code around
sched,dl: Fix sched class hopping CBS hole
sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance callbacks
sched,dl: Remove return value from pull_dl_task()
sched, rt: Convert switched_{from, to}_rt() / prio_changed_rt() to balance callbacks
sched,rt: Remove return value from pull_rt_task()
sched: Allow balance callbacks for check_class_changed()
sched: Use replace normalize_task() with __sched_setscheduler()
sched: Replace post_schedule with a balance callback list
When disable_nonboot_cpus() fails on some cpu it doesn't bring back all
cpus it managed to offline, a consequent call to enable_nonboot_cpus() is
expected. In hibernation_platform_enter() we don't call
enable_nonboot_cpus() on error so cpus stay offlined.
create_image() and resume_target_kernel() functions handle
disable_nonboot_cpus() faults correctly, hibernation_platform_enter()
is the only one which is doing it wrong.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull locking updates from Thomas Gleixner:
"These locking updates depend on the alreay merged sched/core branch:
- Lockless top waiter wakeup for rtmutex (Davidlohr)
- Reduce hash bucket lock contention for PI futexes (Sebastian)
- Documentation update (Davidlohr)"
* 'sched-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rtmutex: Update stale plist comments
futex: Lower the lock contention on the HB lock during wake up
locking/rtmutex: Implement lockless top-waiter wakeup
- ACPICA update to upstream revision 20150515 including basic
support for ACPI 6 features: new ACPI tables introduced by
ACPI 6 (STAO, XENV, WPBT, NFIT, IORT), changes related to the
other tables (DTRM, FADT, LPIT, MADT), new predefined names
(_BTH, _CR3, _DSD, _LPI, _MTL, _PRR, _RDI, _RST, _TFP, _TSN),
fixes and cleanups (Bob Moore, Lv Zheng).
- ACPI device power management core code update to follow ACPI 6
which reflects the ACPI device power management implementation
in Windows (Rafael J Wysocki).
- Rework of the backlight interface selection logic to reduce the
number of kernel command line options and improve the handling
of DMI quirks that may be involved in that and to make the
code generally more straightforward (Hans de Goede).
- Fixes for the ACPI Embedded Controller (EC) driver related to
the handling of EC transactions (Lv Zheng).
- Fix for a regression related to the ACPI resources management
and resulting from a recent change of ACPI initialization code
ordering (Rafael J Wysocki).
- Fix for a system initialization regression related to ACPI
introduced during the 3.14 cycle and caused by running the
code that switches the platform over to the ACPI mode too
early in the initialization sequence (Rafael J Wysocki).
- Support for the ACPI _CCA device configuration object related
to DMA cache coherence (Suravee Suthikulpanit).
- ACPI/APEI fixes and cleanups (Jiri Kosina, Borislav Petkov).
- ACPI battery driver cleanups (Luis Henriques, Mathias Krause).
- ACPI processor driver cleanups (Hanjun Guo).
- Cleanups and documentation update related to the ACPI device
properties interface based on _DSD (Rafael J Wysocki).
- ACPI device power management fixes (Rafael J Wysocki).
- Assorted cleanups related to ACPI (Dominik Brodowski. Fabian
Frederick, Lorenzo Pieralisi, Mathias Krause, Rafael J Wysocki).
- Fix for a long-standing issue causing General Protection Faults
to be generated occasionally on return to user space after resume
from ACPI-based suspend-to-RAM on 32-bit x86 (Ingo Molnar).
- Fix to make the suspend core code return -EBUSY consistently in
all cases when system suspend is aborted due to wakeup detection
(Ruchi Kandoi).
- Support for automated device wakeup IRQ handling allowing drivers
to make their PM support more starightforward (Tony Lindgren).
- New tracepoints for suspend-to-idle tracing and rework of the
prepare/complete callbacks tracing in the PM core (Todd E Brandt,
Rafael J Wysocki).
- Wakeup sources framework enhancements (Jin Qian).
- New macro for noirq system PM callbacks (Grygorii Strashko).
- Assorted cleanups related to system suspend (Rafael J Wysocki).
- cpuidle core cleanups to make the code more efficient (Rafael J
Wysocki).
- powernv/pseries cpuidle driver update (Shilpasri G Bhat).
- cpufreq core fixes related to CPU online/offline that should
reduce the overhead of these operations quite a bit, unless the
CPU in question is physically going away (Viresh Kumar, Saravana
Kannan).
- Serialization of cpufreq governor callbacks to avoid race
conditions in some cases (Viresh Kumar).
- intel_pstate driver fixes and cleanups (Doug Smythies, Prarit
Bhargava, Joe Konno).
- cpufreq driver (arm_big_little, cpufreq-dt, qoriq) updates (Sudeep
Holla, Felipe Balbi, Tang Yuantian).
- Assorted cleanups in cpufreq drivers and core (Shailendra Verma,
Fabian Frederick, Wang Long).
- New Device Tree bindings for representing Operating Performance
Points (Viresh Kumar).
- Updates for the common clock operations support code in the PM
core (Rajendra Nayak, Geert Uytterhoeven).
- PM domains core code update (Geert Uytterhoeven).
- Intel Knights Landing support for the RAPL (Running Average Power
Limit) power capping driver (Dasaratharaman Chandramouli).
- Fixes related to the floor frequency setting on Atom SoCs in the
RAPL power capping driver (Ajay Thomas).
- Runtime PM framework documentation update (Ben Dooks).
- cpupower tool fix (Herton R Krzesinski).
/
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Merge tag 'pm+acpi-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management and ACPI updates from Rafael Wysocki:
"The rework of backlight interface selection API from Hans de Goede
stands out from the number of commits and the number of affected
places perspective. The cpufreq core fixes from Viresh Kumar are
quite significant too as far as the number of commits goes and because
they should reduce CPU online/offline overhead quite a bit in the
majority of cases.
From the new featues point of view, the ACPICA update (to upstream
revision 20150515) adding support for new ACPI 6 material to ACPICA is
the one that matters the most as some new significant features will be
based on it going forward. Also included is an update of the ACPI
device power management core to follow ACPI 6 (which in turn reflects
the Windows' device PM implementation), a PM core extension to support
wakeup interrupts in a more generic way and support for the ACPI _CCA
device configuration object.
The rest is mostly fixes and cleanups all over and some documentation
updates, including new DT bindings for Operating Performance Points.
There is one fix for a regression introduced in the 4.1 cycle, but it
adds quite a number of lines of code, it wasn't really ready before
Thursday and you were on vacation, so I refrained from pushing it on
the last minute for 4.1.
Specifics:
- ACPICA update to upstream revision 20150515 including basic support
for ACPI 6 features: new ACPI tables introduced by ACPI 6 (STAO,
XENV, WPBT, NFIT, IORT), changes related to the other tables (DTRM,
FADT, LPIT, MADT), new predefined names (_BTH, _CR3, _DSD, _LPI,
_MTL, _PRR, _RDI, _RST, _TFP, _TSN), fixes and cleanups (Bob Moore,
Lv Zheng).
- ACPI device power management core code update to follow ACPI 6
which reflects the ACPI device power management implementation in
Windows (Rafael J Wysocki).
- rework of the backlight interface selection logic to reduce the
number of kernel command line options and improve the handling of
DMI quirks that may be involved in that and to make the code
generally more straightforward (Hans de Goede).
- fixes for the ACPI Embedded Controller (EC) driver related to the
handling of EC transactions (Lv Zheng).
- fix for a regression related to the ACPI resources management and
resulting from a recent change of ACPI initialization code ordering
(Rafael J Wysocki).
- fix for a system initialization regression related to ACPI
introduced during the 3.14 cycle and caused by running the code
that switches the platform over to the ACPI mode too early in the
initialization sequence (Rafael J Wysocki).
- support for the ACPI _CCA device configuration object related to
DMA cache coherence (Suravee Suthikulpanit).
- ACPI/APEI fixes and cleanups (Jiri Kosina, Borislav Petkov).
- ACPI battery driver cleanups (Luis Henriques, Mathias Krause).
- ACPI processor driver cleanups (Hanjun Guo).
- cleanups and documentation update related to the ACPI device
properties interface based on _DSD (Rafael J Wysocki).
- ACPI device power management fixes (Rafael J Wysocki).
- assorted cleanups related to ACPI (Dominik Brodowski, Fabian
Frederick, Lorenzo Pieralisi, Mathias Krause, Rafael J Wysocki).
- fix for a long-standing issue causing General Protection Faults to
be generated occasionally on return to user space after resume from
ACPI-based suspend-to-RAM on 32-bit x86 (Ingo Molnar).
- fix to make the suspend core code return -EBUSY consistently in all
cases when system suspend is aborted due to wakeup detection (Ruchi
Kandoi).
- support for automated device wakeup IRQ handling allowing drivers
to make their PM support more starightforward (Tony Lindgren).
- new tracepoints for suspend-to-idle tracing and rework of the
prepare/complete callbacks tracing in the PM core (Todd E Brandt,
Rafael J Wysocki).
- wakeup sources framework enhancements (Jin Qian).
- new macro for noirq system PM callbacks (Grygorii Strashko).
- assorted cleanups related to system suspend (Rafael J Wysocki).
- cpuidle core cleanups to make the code more efficient (Rafael J
Wysocki).
- powernv/pseries cpuidle driver update (Shilpasri G Bhat).
- cpufreq core fixes related to CPU online/offline that should reduce
the overhead of these operations quite a bit, unless the CPU in
question is physically going away (Viresh Kumar, Saravana Kannan).
- serialization of cpufreq governor callbacks to avoid race
conditions in some cases (Viresh Kumar).
- intel_pstate driver fixes and cleanups (Doug Smythies, Prarit
Bhargava, Joe Konno).
- cpufreq driver (arm_big_little, cpufreq-dt, qoriq) updates (Sudeep
Holla, Felipe Balbi, Tang Yuantian).
- assorted cleanups in cpufreq drivers and core (Shailendra Verma,
Fabian Frederick, Wang Long).
- new Device Tree bindings for representing Operating Performance
Points (Viresh Kumar).
- updates for the common clock operations support code in the PM core
(Rajendra Nayak, Geert Uytterhoeven).
- PM domains core code update (Geert Uytterhoeven).
- Intel Knights Landing support for the RAPL (Running Average Power
Limit) power capping driver (Dasaratharaman Chandramouli).
- fixes related to the floor frequency setting on Atom SoCs in the
RAPL power capping driver (Ajay Thomas).
- runtime PM framework documentation update (Ben Dooks).
- cpupower tool fix (Herton R Krzesinski)"
* tag 'pm+acpi-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (194 commits)
cpuidle: powernv/pseries: Auto-promotion of snooze to deeper idle state
x86: Load __USER_DS into DS/ES after resume
PM / OPP: Add binding for 'opp-suspend'
PM / OPP: Allow multiple OPP tables to be passed via DT
PM / OPP: Add new bindings to address shortcomings of existing bindings
ACPI: Constify ACPI device IDs in documentation
ACPI / enumeration: Document the rules regarding the PRP0001 device ID
ACPI / video: Make acpi_video_unregister_backlight() private
acpi-video-detect: Remove old API
toshiba-acpi: Port to new backlight interface selection API
thinkpad-acpi: Port to new backlight interface selection API
sony-laptop: Port to new backlight interface selection API
samsung-laptop: Port to new backlight interface selection API
msi-wmi: Port to new backlight interface selection API
msi-laptop: Port to new backlight interface selection API
intel-oaktrail: Port to new backlight interface selection API
ideapad-laptop: Port to new backlight interface selection API
fujitsu-laptop: Port to new backlight interface selection API
eeepc-laptop: Port to new backlight interface selection API
dell-wmi: Port to new backlight interface selection API
...
Pull livepatching fixes from Jiri Kosina:
- symbol lookup locking fix, from Miroslav Benes
- error handling improvements in case of failure of the module coming
notifier, from Minfei Huang
- we were too pessimistic when kASLR has been enabled on x86 and were
dropping address hints on the floor unnecessarily in such case. Fix
from Jiri Kosina
- a few other small fixes and cleanups
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
livepatch: add module locking around kallsyms calls
livepatch: annotate klp_init() with __init
livepatch: introduce patch/func-walking helpers
livepatch: make kobject in klp_object statically allocated
livepatch: Prevent patch inconsistencies if the coming module notifier fails
livepatch: match return value to function signature
x86: kaslr: fix build due to missing ALIGN definition
livepatch: x86: make kASLR logic more accurate
x86: introduce kaslr_offset()
Add a "param_lock" mutex to each module, and update params.c to use
the correct built-in or module mutex while locking kernel params.
Remove the kparam_block_sysfs_r/w() macros, replace them with direct
calls to kernel_param_[un]lock(module).
The kernel param code currently uses a single mutex to protect
modification of any and all kernel params. While this generally works,
there is one specific problem with it; a module callback function
cannot safely load another module, i.e. with request_module() or even
with indirect calls such as crypto_has_alg(). If the module to be
loaded has any of its params configured (e.g. with a /etc/modprobe.d/*
config file), then the attempt will result in a deadlock between the
first module param callback waiting for modprobe, and modprobe trying to
lock the single kernel param mutex to set the new module's param.
This fixes that by using per-module mutexes, so that each individual module
is protected against concurrent changes in its own kernel params, but is
not blocked by changes to other module params. All built-in modules
continue to use the built-in mutex, since they will always be loaded at
runtime and references (e.g. request_module(), crypto_has_alg()) to them
will never cause load-time param changing.
This also simplifies the interface used by modules to block sysfs access
to their params; while there are currently functions to block and unblock
sysfs param access which are split up by read and write and expect a single
kernel param to be passed, their actual operation is identical and applies
to all params, not just the one passed to them; they simply lock and unlock
the global param mutex. They are replaced with direct calls to
kernel_param_[un]lock(THIS_MODULE), which locks THIS_MODULE's param_lock, or
if the module is built-in, it locks the built-in mutex.
Suggested-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Change the struct kernel_param.perm field to a const, as it should never
be changed.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (cut from larger patch)
It shouldn't fail due to OOM (it's boot time), and already warns if we
get two identical names. But you never know what the future holds, and
WARN_ON_ONCE() keeps gcc happy with minimal code.
Reported-by: Louis Langholtz <lou_langholtz@me.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Pull irq updates from Thomas Gleixner:
"The irq departement delivers:
- plug a potential race related to chained interrupt handlers
- core updates which address the needs of the x86 irqdomain conversion
- new irqchip callback to support affinity settings for VCPUs
- the usual pile of updates to interrupt chip drivers
- a few helper functions to allow further cleanups and
simplifications
I have a largish pile of coccinelle scripted/verified cleanups and
simplifications pending on top of that, but I prefer to send that
towards the end of the merge window when the arch/driver changes have
hit your tree to avoid API change wreckage as far as possible"
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
genirq: Remove bogus restriction in irq_move_mask_irq()
irqchip: atmel-aic5: Add sama5d2 support
irq: spear-shirq: Fix race in installing chained IRQ handler
irq: irq-keystone: Fix race in installing chained IRQ handler
gpio: gpio-tegra: Fix race in installing chained IRQ handler
gpio: gpio-mxs: Fix race in installing chained IRQ handler
gpio: gpio-mxc: Fix race in installing chained IRQ handler
ARM: gemini: Fix race in installing GPIO chained IRQ handler
GPU: ipu: Fix race in installing IPU chained IRQ handler
ARM: sa1100: convert SA11x0 related code to use new chained handler helper
irq: Add irq_set_chained_handler_and_data()
irqchip: exynos-combiner: Save IRQ enable set on suspend
genirq: Introduce helper function irq_data_get_affinity_mask()
genirq: Introduce helper function irq_data_get_node()
genirq: Introduce struct irq_common_data to host shared irq data
genirq: Prevent crash in irq_move_irq()
genirq: Enhance irq_data_to_desc() to support hierarchy irqdomain
irqchip: gic: Simplify gic_configure_irq by using IRQCHIP_SET_TYPE_MASKED
irqchip: renesas: intc-irqpin: Improve binding documentation
genirq: Set IRQCHIP_SKIP_SET_WAKE for no_irq_chip
...
Pull NOHZ updates from Thomas Gleixner:
"A few updates to the nohz infrastructure:
- recursion protection for context tracking
- make the TIF_NOHZ inheritance smarter
- isolate cpus which belong to the NOHZ full set"
* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
nohz: Set isolcpus when nohz_full is set
nohz: Add tick_nohz_full_add_cpus_to() API
context_tracking: Inherit TIF_NOHZ through forks instead of context switches
context_tracking: Protect against recursion
Pull timer updates from Thomas Gleixner:
"A rather largish update for everything time and timer related:
- Cache footprint optimizations for both hrtimers and timer wheel
- Lower the NOHZ impact on systems which have NOHZ or timer migration
disabled at runtime.
- Optimize run time overhead of hrtimer interrupt by making the clock
offset updates smarter
- hrtimer cleanups and removal of restrictions to tackle some
problems in sched/perf
- Some more leap second tweaks
- Another round of changes addressing the 2038 problem
- First step to change the internals of clock event devices by
introducing the necessary infrastructure
- Allow constant folding for usecs/msecs_to_jiffies()
- The usual pile of clockevent/clocksource driver updates
The hrtimer changes contain updates to sched, perf and x86 as they
depend on them plus changes all over the tree to cleanup API changes
and redundant code, which got copied all over the place. The y2038
changes touch s390 to remove the last non 2038 safe code related to
boot/persistant clock"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
clocksource: Increase dependencies of timer-stm32 to limit build wreckage
timer: Minimize nohz off overhead
timer: Reduce timer migration overhead if disabled
timer: Stats: Simplify the flags handling
timer: Replace timer base by a cpu index
timer: Use hlist for the timer wheel hash buckets
timer: Remove FIFO "guarantee"
timers: Sanitize catchup_timer_jiffies() usage
hrtimer: Allow hrtimer::function() to free the timer
seqcount: Introduce raw_write_seqcount_barrier()
seqcount: Rename write_seqcount_barrier()
hrtimer: Fix hrtimer_is_queued() hole
hrtimer: Remove HRTIMER_STATE_MIGRATE
selftest: Timers: Avoid signal deadlock in leap-a-day
timekeeping: Copy the shadow-timekeeper over the real timekeeper last
clockevents: Check state instead of mode in suspend/resume path
selftests: timers: Add leap-second timer edge testing to leap-a-day.c
ntp: Do leapsecond adjustment in adjtimex read path
time: Prevent early expiry of hrtimers[CLOCK_REALTIME] at the leap second edge
ntp: Introduce and use SECS_PER_DAY macro instead of 86400
...
Pull x86 core updates from Ingo Molnar:
"There were so many changes in the x86/asm, x86/apic and x86/mm topics
in this cycle that the topical separation of -tip broke down somewhat -
so the result is a more traditional architecture pull request,
collected into the 'x86/core' topic.
The topics were still maintained separately as far as possible, so
bisectability and conceptual separation should still be pretty good -
but there were a handful of merge points to avoid excessive
dependencies (and conflicts) that would have been poorly tested in the
end.
The next cycle will hopefully be much more quiet (or at least will
have fewer dependencies).
The main changes in this cycle were:
* x86/apic changes, with related IRQ core changes: (Jiang Liu, Thomas
Gleixner)
- This is the second and most intrusive part of changes to the x86
interrupt handling - full conversion to hierarchical interrupt
domains:
[IOAPIC domain] -----
|
[MSI domain] --------[Remapping domain] ----- [ Vector domain ]
| (optional) |
[HPET MSI domain] ----- |
|
[DMAR domain] -----------------------------
|
[Legacy domain] -----------------------------
This now reflects the actual hardware and allowed us to distangle
the domain specific code from the underlying parent domain, which
can be optional in the case of interrupt remapping. It's a clear
separation of functionality and removes quite some duct tape
constructs which plugged the remap code between ioapic/msi/hpet
and the vector management.
- Intel IOMMU IRQ remapping enhancements, to allow direct interrupt
injection into guests (Feng Wu)
* x86/asm changes:
- Tons of cleanups and small speedups, micro-optimizations. This
is in preparation to move a good chunk of the low level entry
code from assembly to C code (Denys Vlasenko, Andy Lutomirski,
Brian Gerst)
- Moved all system entry related code to a new home under
arch/x86/entry/ (Ingo Molnar)
- Removal of the fragile and ugly CFI dwarf debuginfo annotations.
Conversion to C will reintroduce many of them - but meanwhile
they are only getting in the way, and the upstream kernel does
not rely on them (Ingo Molnar)
- NOP handling refinements. (Borislav Petkov)
* x86/mm changes:
- Big PAT and MTRR rework: making the code more robust and
preparing to phase out exposing direct MTRR interfaces to drivers -
in favor of using PAT driven interfaces (Toshi Kani, Luis R
Rodriguez, Borislav Petkov)
- New ioremap_wt()/set_memory_wt() interfaces to support
Write-Through cached memory mappings. This is especially
important for good performance on NVDIMM hardware (Toshi Kani)
* x86/ras changes:
- Add support for deferred errors on AMD (Aravind Gopalakrishnan)
This is an important RAS feature which adds hardware support for
poisoned data. That means roughly that the hardware marks data
which it has detected as corrupted but wasn't able to correct, as
poisoned data and raises an APIC interrupt to signal that in the
form of a deferred error. It is the OS's responsibility then to
take proper recovery action and thus prolonge system lifetime as
far as possible.
- Add support for Intel "Local MCE"s: upcoming CPUs will support
CPU-local MCE interrupts, as opposed to the traditional system-
wide broadcasted MCE interrupts (Ashok Raj)
- Misc cleanups (Borislav Petkov)
* x86/platform changes:
- Intel Atom SoC updates
... and lots of other cleanups, fixlets and other changes - see the
shortlog and the Git log for details"
* 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (222 commits)
x86/hpet: Use proper hpet device number for MSI allocation
x86/hpet: Check for irq==0 when allocating hpet MSI interrupts
x86/mm/pat, drivers/infiniband/ipath: Use arch_phys_wc_add() and require PAT disabled
x86/mm/pat, drivers/media/ivtv: Use arch_phys_wc_add() and require PAT disabled
x86/platform/intel/baytrail: Add comments about why we disabled HPET on Baytrail
genirq: Prevent crash in irq_move_irq()
genirq: Enhance irq_data_to_desc() to support hierarchy irqdomain
iommu, x86: Properly handle posted interrupts for IOMMU hotplug
iommu, x86: Provide irq_remapping_cap() interface
iommu, x86: Setup Posted-Interrupts capability for Intel iommu
iommu, x86: Add cap_pi_support() to detect VT-d PI capability
iommu, x86: Avoid migrating VT-d posted interrupts
iommu, x86: Save the mode (posted or remapped) of an IRTE
iommu, x86: Implement irq_set_vcpu_affinity for intel_ir_chip
iommu: dmar: Provide helper to copy shared irte fields
iommu: dmar: Extend struct irte for VT-d Posted-Interrupts
iommu: Add new member capability to struct irq_remap_ops
x86/asm/entry/64: Disentangle error_entry/exit gsbase/ebx/usermode code
x86/asm/entry/32: Shorten __audit_syscall_entry() args preparation
x86/asm/entry/32: Explain reloading of registers after __audit_syscall_entry()
...
Pull x86 FPU updates from Ingo Molnar:
"This tree contains two main changes:
- The big FPU code rewrite: wide reaching cleanups and reorganization
that pulls all the FPU code together into a clean base in
arch/x86/fpu/.
The resulting code is leaner and faster, and much easier to
understand. This enables future work to further simplify the FPU
code (such as removing lazy FPU restores).
By its nature these changes have a substantial regression risk: FPU
code related bugs are long lived, because races are often subtle
and bugs mask as user-space failures that are difficult to track
back to kernel side backs. I'm aware of no unfixed (or even
suspected) FPU related regression so far.
- MPX support rework/fixes. As this is still not a released CPU
feature, there were some buglets in the code - should be much more
robust now (Dave Hansen)"
* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (250 commits)
x86/fpu: Fix double-increment in setup_xstate_features()
x86/mpx: Allow 32-bit binaries on 64-bit kernels again
x86/mpx: Do not count MPX VMAs as neighbors when unmapping
x86/mpx: Rewrite the unmap code
x86/mpx: Support 32-bit binaries on 64-bit kernels
x86/mpx: Use 32-bit-only cmpxchg() for 32-bit apps
x86/mpx: Introduce new 'directory entry' to 'addr' helper function
x86/mpx: Add temporary variable to reduce masking
x86: Make is_64bit_mm() widely available
x86/mpx: Trace allocation of new bounds tables
x86/mpx: Trace the attempts to find bounds tables
x86/mpx: Trace entry to bounds exception paths
x86/mpx: Trace #BR exceptions
x86/mpx: Introduce a boot-time disable flag
x86/mpx: Restrict the mmap() size check to bounds tables
x86/mpx: Remove redundant MPX_BNDCFG_ADDR_MASK
x86/mpx: Clean up the code by not passing a task pointer around when unnecessary
x86/mpx: Use the new get_xsave_field_ptr()API
x86/fpu/xstate: Wrap get_xsave_addr() to make it safer
x86/fpu/xstate: Fix up bad get_xsave_addr() assumptions
...
Pull scheduler updates from Ingo Molnar:
"The main changes are:
- lockless wakeup support for futexes and IPC message queues
(Davidlohr Bueso, Peter Zijlstra)
- Replace spinlocks with atomics in thread_group_cputimer(), to
improve scalability (Jason Low)
- NUMA balancing improvements (Rik van Riel)
- SCHED_DEADLINE improvements (Wanpeng Li)
- clean up and reorganize preemption helpers (Frederic Weisbecker)
- decouple page fault disabling machinery from the preemption
counter, to improve debuggability and robustness (David
Hildenbrand)
- SCHED_DEADLINE documentation updates (Luca Abeni)
- topology CPU masks cleanups (Bartosz Golaszewski)
- /proc/sched_debug improvements (Srikar Dronamraju)"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits)
sched/deadline: Remove needless parameter in dl_runtime_exceeded()
sched: Remove superfluous resetting of the p->dl_throttled flag
sched/deadline: Drop duplicate init_sched_dl_class() declaration
sched/deadline: Reduce rq lock contention by eliminating locking of non-feasible target
sched/deadline: Make init_sched_dl_class() __init
sched/deadline: Optimize pull_dl_task()
sched/preempt: Add static_key() to preempt_notifiers
sched/preempt: Fix preempt notifiers documentation about hlist_del() within unsafe iteration
sched/stop_machine: Fix deadlock between multiple stop_two_cpus()
sched/debug: Add sum_sleep_runtime to /proc/<pid>/sched
sched/debug: Replace vruntime with wait_sum in /proc/sched_debug
sched/debug: Properly format runnable tasks in /proc/sched_debug
sched/numa: Only consider less busy nodes as numa balancing destinations
Revert 095bebf61a ("sched/numa: Do not move past the balance point if unbalanced")
sched/fair: Prevent throttling in early pick_next_task_fair()
preempt: Reorganize the notrace definitions a bit
preempt: Use preempt_schedule_context() as the official tracing preemption point
sched: Make preempt_schedule_context() function-tracing safe
x86: Remove cpu_sibling_mask() and cpu_core_mask()
x86: Replace cpu_**_mask() with topology_**_cpumask()
...
Pull perf fixes from Ingo Molnar:
"These are the left over fixes from the v4.1 cycle"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf tools: Fix build breakage if prefix= is specified
perf/x86: Honor the architectural performance monitoring version
perf/x86/intel: Fix PMI handling for Intel PT
perf/x86/intel/bts: Fix DS area sharing with x86_pmu events
perf/x86: Add more Broadwell model numbers
perf: Fix ring_buffer_attach() RCU sync, again
Pull perf updates from Ingo Molnar:
"Kernel side changes mostly consist of work on x86 PMU drivers:
- x86 Intel PT (hardware CPU tracer) improvements (Alexander
Shishkin)
- x86 Intel CQM (cache quality monitoring) improvements (Thomas
Gleixner)
- x86 Intel PEBSv3 support (Peter Zijlstra)
- x86 Intel PEBS interrupt batching support for lower overhead
sampling (Zheng Yan, Kan Liang)
- x86 PMU scheduler fixes and improvements (Peter Zijlstra)
There's too many tooling improvements to list them all - here are a
few select highlights:
'perf bench':
- Introduce new 'perf bench futex' benchmark: 'wake-parallel', to
measure parallel waker threads generating contention for kernel
locks (hb->lock). (Davidlohr Bueso)
'perf top', 'perf report':
- Allow disabling/enabling events dynamicaly in 'perf top':
a 'perf top' session can instantly become a 'perf report'
one, i.e. going from dynamic analysis to a static one,
returning to a dynamic one is possible, to toogle the
modes, just press 'f' to 'freeze/unfreeze' the sampling. (Arnaldo Carvalho de Melo)
- Make Ctrl-C stop processing on TUI, allowing interrupting the load of big
perf.data files (Namhyung Kim)
'perf probe': (Masami Hiramatsu)
- Support glob wildcards for function name
- Support $params special probe argument: Collect all function arguments
- Make --line checks validate C-style function name.
- Add --no-inlines option to avoid searching inline functions
- Greatly speed up 'perf probe --list' by caching debuginfo.
- Improve --filter support for 'perf probe', allowing using its arguments
on other commands, as --add, --del, etc.
'perf sched':
- Add option in 'perf sched' to merge like comms to lat output (Josef Bacik)
Plus tons of infrastructure work - in particular preparation for
upcoming threaded perf report support, but also lots of other work -
and fixes and other improvements. See (much) more details in the
shortlog and in the git log"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (305 commits)
perf tools: Configurable per thread proc map processing time out
perf tools: Add time out to force stop proc map processing
perf report: Fix sort__sym_cmp to also compare end of symbol
perf hists browser: React to unassigned hotkey pressing
perf top: Tell the user how to unfreeze events after pressing 'f'
perf hists browser: Honour the help line provided by builtin-{top,report}.c
perf hists browser: Do not exit when 'f' is pressed in 'report' mode
perf top: Replace CTRL+z with 'f' as hotkey for enable/disable events
perf annotate: Rename source_line_percent to source_line_samples
perf annotate: Display total number of samples with --show-total-period
perf tools: Ensure thread-stack is flushed
perf top: Allow disabling/enabling events dynamicly
perf evlist: Add toggle_enable() method
perf trace: Fix race condition at the end of started workloads
perf probe: Speed up perf probe --list by caching debuginfo
perf probe: Show usage even if the last event is skipped
perf tools: Move libtraceevent dynamic list to separated LDFLAGS variable
perf tools: Fix a problem when opening old perf.data with different byte order
perf tools: Ignore .config-detected in .gitignore
perf probe: Fix to return error if no probe is added
...
Pull locking updates from Ingo Molnar:
"The main changes are:
- 'qspinlock' support, enabled on x86: queued spinlocks - these are
now the spinlock variant used by x86 as they outperform ticket
spinlocks in every category. (Waiman Long)
- 'pvqspinlock' support on x86: paravirtualized variant of queued
spinlocks. (Waiman Long, Peter Zijlstra)
- 'qrwlock' support, enabled on x86: queued rwlocks. Similar to
queued spinlocks, they are now the variant used by x86:
CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y
CONFIG_QUEUED_SPINLOCKS=y
CONFIG_ARCH_USE_QUEUED_RWLOCKS=y
CONFIG_QUEUED_RWLOCKS=y
- various lockdep fixlets
- various locking primitives cleanups, further WRITE_ONCE()
propagation"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
locking/lockdep: Remove hard coded array size dependency
locking/qrwlock: Don't contend with readers when setting _QW_WAITING
lockdep: Do not break user-visible string
locking/arch: Rename set_mb() to smp_store_mb()
locking/arch: Add WRITE_ONCE() to set_mb()
rtmutex: Warn if trylock is called from hard/softirq context
arch: Remove __ARCH_HAVE_CMPXCHG
locking/rtmutex: Drop usage of __HAVE_ARCH_CMPXCHG
locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS
locking/pvqspinlock: Rename QUEUED_SPINLOCK to QUEUED_SPINLOCKS
locking/pvqspinlock: Replace xchg() by the more descriptive set_mb()
locking/pvqspinlock, x86: Enable PV qspinlock for Xen
locking/pvqspinlock, x86: Enable PV qspinlock for KVM
locking/pvqspinlock, x86: Implement the paravirt qspinlock call patching
locking/pvqspinlock: Implement simple paravirt support for the qspinlock
locking/qspinlock: Revert to test-and-set on hypervisors
locking/qspinlock: Use a simple write to grab the lock
locking/qspinlock: Optimize for smaller NR_CPUS
locking/qspinlock: Extract out code snippets for the next patch
locking/qspinlock: Add pending bit
...
Pull RCU updates from Ingo Molnar:
- Continued initialization/Kconfig updates: hide most Kconfig options
from unsuspecting users.
There's now a single high level configuration option:
*
* RCU Subsystem
*
Make expert-level adjustments to RCU configuration (RCU_EXPERT) [N/y/?] (NEW)
Which if answered in the negative, leaves us with a single
interactive configuration option:
Offload RCU callback processing from boot-selected CPUs (RCU_NOCB_CPU) [N/y/?] (NEW)
All the rest of the RCU options are configured automatically. Later
on we'll remove this single leftover configuration option as well.
- Remove all uses of RCU-protected array indexes: replace the
rcu_[access|dereference]_index_check() APIs with READ_ONCE() and
rcu_lockdep_assert()
- RCU CPU-hotplug cleanups
- Updates to Tiny RCU: a race fix and further code shrinkage.
- RCU torture-testing updates: fixes, speedups, cleanups and
documentation updates.
- Miscellaneous fixes
- Documentation updates
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
rcutorture: Allow repetition factors in Kconfig-fragment lists
rcutorture: Display "make oldconfig" errors
rcutorture: Update TREE_RCU-kconfig.txt
rcutorture: Make rcutorture scripts force RCU_EXPERT
rcutorture: Update configuration fragments for rcutree.rcu_fanout_exact
rcutorture: TASKS_RCU set directly, so don't explicitly set it
rcutorture: Test SRCU cleanup code path
rcutorture: Replace barriers with smp_store_release() and smp_load_acquire()
locktorture: Change longdelay_us to longdelay_ms
rcutorture: Allow negative values of nreaders to oversubscribe
rcutorture: Exchange TREE03 and TREE08 NR_CPUS, speed up CPU hotplug
rcutorture: Exchange TREE03 and TREE04 geometries
locktorture: fix deadlock in 'rw_lock_irq' type
rcu: Correctly handle non-empty Tiny RCU callback list with none ready
rcutorture: Test both RCU-sched and RCU-bh for Tiny RCU
rcu: Further shrink Tiny RCU by making empty functions static inlines
rcu: Conditionally compile RCU's eqs warnings
rcu: Remove prompt for RCU implementation
rcu: Make RCU able to tolerate undefined CONFIG_RCU_KTHREAD_PRIO
rcu: Make RCU able to tolerate undefined CONFIG_RCU_FANOUT_LEAF
...
If an interrupt is marked with the no balancing flag, we still allow
setting the affinity for such an interrupt from the kernel itself, but
for interrupts which move the affinity from interrupt context via
irq_move_mask_irq() this runs into a check for the no balancing flag,
which in turn ends up with an endless storm of stack dumps because the
move pending flag is not reset.
Allow the move for interrupts which have the no balancing flag set and
clear the move pending bit before checking for interrupts with the per
cpu flag set.
Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1506201002570.4107@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
... as of fb00aca474 (rtmutex: Turn the plist into an rb-tree) we
no longer use plists for queuing any waiters. Update stale comments.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1432056298-18738-4-git-send-email-dave@stgolabs.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
wake_futex_pi() wakes the task before releasing the hash bucket lock
(HB). The first thing the woken up task usually does is to acquire the
lock which requires the HB lock. On SMP Systems this leads to blocking
on the HB lock which is released by the owner shortly after.
This patch rearranges the unlock path by first releasing the HB lock and
then waking up the task.
[ tglx: Fixed up the rtmutex unlock path ]
Originally-from: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Link: http://lkml.kernel.org/r/20150617083350.GA2433@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If nohz is disabled on the kernel command line the [hr]timer code
still calls wake_up_nohz_cpu() and tick_nohz_full_cpu(), a pretty
pointless exercise. Cache nohz_active in [hr]timer per cpu bases and
avoid the overhead.
Before:
48.10% hog [.] main
15.25% [kernel] [k] _raw_spin_lock_irqsave
9.76% [kernel] [k] _raw_spin_unlock_irqrestore
6.50% [kernel] [k] mod_timer
6.44% [kernel] [k] lock_timer_base.isra.38
3.87% [kernel] [k] detach_if_pending
3.80% [kernel] [k] del_timer
2.67% [kernel] [k] internal_add_timer
1.33% [kernel] [k] __internal_add_timer
0.73% [kernel] [k] timerfn
0.54% [kernel] [k] wake_up_nohz_cpu
After:
48.73% hog [.] main
15.36% [kernel] [k] _raw_spin_lock_irqsave
9.77% [kernel] [k] _raw_spin_unlock_irqrestore
6.61% [kernel] [k] lock_timer_base.isra.38
6.42% [kernel] [k] mod_timer
3.90% [kernel] [k] detach_if_pending
3.76% [kernel] [k] del_timer
2.41% [kernel] [k] internal_add_timer
1.39% [kernel] [k] __internal_add_timer
0.76% [kernel] [k] timerfn
We probably should have a cached value for nohz full in the per cpu
bases as well to avoid the cpumask check. The base cache line is hot
already, the cpumask not necessarily.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Link: http://lkml.kernel.org/r/20150526224512.207378134@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Eric reported that the timer_migration sysctl is not really nice
performance wise as it needs to check at every timer insertion whether
the feature is enabled or not. Further the check does not live in the
timer code, so we have an extra function call which checks an extra
cache line to figure out that it is disabled.
We can do better and store that information in the per cpu (hr)timer
bases. I pondered to use a static key, but that's a nightmare to
update from the nohz code and the timer base cache line is hot anyway
when we select a timer base.
The old logic enabled the timer migration unconditionally if
CONFIG_NO_HZ was set even if nohz was disabled on the kernel command
line.
With this modification, we start off with migration disabled. The user
visible sysctl is still set to enabled. If the kernel switches to NOHZ
migration is enabled, if the user did not disable it via the sysctl
prior to the switch. If nohz=off is on the kernel command line,
migration stays disabled no matter what.
Before:
47.76% hog [.] main
14.84% [kernel] [k] _raw_spin_lock_irqsave
9.55% [kernel] [k] _raw_spin_unlock_irqrestore
6.71% [kernel] [k] mod_timer
6.24% [kernel] [k] lock_timer_base.isra.38
3.76% [kernel] [k] detach_if_pending
3.71% [kernel] [k] del_timer
2.50% [kernel] [k] internal_add_timer
1.51% [kernel] [k] get_nohz_timer_target
1.28% [kernel] [k] __internal_add_timer
0.78% [kernel] [k] timerfn
0.48% [kernel] [k] wake_up_nohz_cpu
After:
48.10% hog [.] main
15.25% [kernel] [k] _raw_spin_lock_irqsave
9.76% [kernel] [k] _raw_spin_unlock_irqrestore
6.50% [kernel] [k] mod_timer
6.44% [kernel] [k] lock_timer_base.isra.38
3.87% [kernel] [k] detach_if_pending
3.80% [kernel] [k] del_timer
2.67% [kernel] [k] internal_add_timer
1.33% [kernel] [k] __internal_add_timer
0.73% [kernel] [k] timerfn
0.54% [kernel] [k] wake_up_nohz_cpu
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Link: http://lkml.kernel.org/r/20150526224512.127050787@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Simplify the handling of the flag storage for the timer statistics. No
intermediate storage anymore. Just hand over the flags field.
I left the printout of 'deferrable' for now because changing this
would be an ABI update and I have no idea how strong people feel about
that. OTOH, I wonder whether we should kill the whole timer stats
stuff because all of that information can be retrieved via ftrace/perf
as well.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Link: http://lkml.kernel.org/r/20150526224512.046626248@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Instead of storing a pointer to the per cpu tvec_base we can simply
cache a CPU index in the timer_list and use that to get hold of the
correct per cpu tvec_base. This is only used in lock_timer_base() and
the slightly larger code is peanuts versus the spinlock operation and
the d-cache foot print of the timer wheel.
Aside of that this allows to get rid of following nuisances:
- boot_tvec_base
That statically allocated 4k bss data is just kept around so the
timer has a home when it gets statically initialized. It serves no
other purpose.
With the CPU index we assign the timer to CPU0 at static
initialization time and therefor can avoid the whole boot_tvec_base
dance. That also simplifies the init code, which just can use the
per cpu base.
Before:
text data bss dec hex filename
17491 9201 4160 30852 7884 ../build/kernel/time/timer.o
After:
text data bss dec hex filename
17440 9193 0 26633 6809 ../build/kernel/time/timer.o
- Overloading the base pointer with various flags
The CPU index has enough space to hold the flags (deferrable,
irqsafe) so we can get rid of the extra masking and bit fiddling
with the base pointer.
As a benefit we reduce the size of struct timer_list on 64 bit
machines. 4 - 8 bytes, a size reduction up to 15% per struct timer_list,
which is a real win as we have tons of them embedded in other structs.
This changes also the newly added deferrable printout of the timer
start trace point to capture and print all timer->flags, which allows
us to decode the target cpu of the timer as well.
We might have used bitfields for this, but that would change the
static initializers and the init function for no value to accomodate
big endian bitfields.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Badhri Jagan Sridharan <Badhri@google.com>
Link: http://lkml.kernel.org/r/20150526224511.950084301@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This reduces the size of struct tvec_base by 50% and results in
slightly smaller code as well.
Before:
struct tvec_base: size: 8256, cachelines: 129
text data bss dec hex filename
17698 13297 8256 39251 9953 ../build/kernel/time/timer.o
After:
struct tvec_base: 4160, cachelines: 65
text data bss dec hex filename
17491 9201 4160 30852 7884 ../build/kernel/time/timer.o
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Link: http://lkml.kernel.org/r/20150526224511.854731214@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The FIFO guarantee is only there if two timers are queued into the
same bucket at the same jiffie on the same cpu:
- The slack value depends on the delta between expiry and enqueue
time, so the resulting expiry time can be different for timers
which are queued in different jiffies.
- Timers which are queued into the secondary array end up after a
later queued timer which was queued into the primary array due to
cascading.
- Timers can end up on different cpus due to the NOHZ target moving
around. Obviously there is no guarantee of expiry ordering between
cpus.
So anything which relies on FIFO behaviour of the timer wheel is
broken already.
This is a preparatory patch for converting the timer wheel to hlist
which reduces the memory foot print of the wheel by 50%.
It's a seperate patch so any (unlikely to happen) regression caused by
this can be identified clearly.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Cc: George Spelvin <linux@horizon.com>
Link: http://lkml.kernel.org/r/20150526224511.757520403@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
catchup_timer_jiffies() has been applied blindly to several functions
without looking for possible better ways to do it.
1) internal_add_timer()
Move the update to base->all_timers before we actually insert the
timer into the wheel.
2) detach_if_pending()
Again the update to base->all_timers allows us to explicitely do
the timer_jiffies update in place, if this was the last timer which
got removed.
3) __run_timers()
We only check on entry, which is silly, because base->timer_jiffies
can be behind - especially on NOHZ kernels - and if there is a
single deferrable timer somewhere between base->timer_jiffies and
jiffies we expire it and then loop until base->timer_jiffies ==
jiffies.
Move it into the loop.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Link: http://lkml.kernel.org/r/20150526224511.662994644@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Sine commit 269ad8015a ("sched/deadline: Avoid double-accounting in
case of missed deadlines), parameter 'rq' is no longer used, so
remove it.
Signed-off-by: Zhiqiang Zhang <zhangzhiqiang.zhang@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <juri.lelli@gmail.com>
Cc: <luca.abeni@unitn.it>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.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/1434338120-43773-1-git-send-email-zhangzhiqiang.zhang@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Resetting the p->dl_throttled flag in rt_mutex_setprio() (for a task that is going
to be boosted) is superfluous, as the natural place to do so is in
replenish_dl_entity().
If the task was on the runqueue and it is boosted by a DL task, it will be enqueued
back with ENQUEUE_REPLENISH flag set, which can guarantee that dl_throttled is
reset in replenish_dl_entity().
This patch drops the resetting of throttled status in function rt_mutex_setprio().
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.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/1431496867-4194-6-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are two init_sched_dl_class() declarations, this patch drops
the duplicate.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.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/1431496867-4194-5-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This patch adds a check that prevents futile attempts to move DL tasks
to a CPU with active tasks of equal or earlier deadline. The same
behavior as commit 80e3d87b2c ("sched/rt: Reduce rq lock contention
by eliminating locking of non-feasible target") for rt class.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.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/1431496867-4194-3-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
pull_dl_task() uses pick_next_earliest_dl_task() to select a migration
candidate; this is sub-optimal since the next earliest task -- as per
the regular runqueue -- might not be migratable at all. This could
result in iterating the entire runqueue looking for a task.
Instead iterate the pushable queue -- this queue only contains tasks
that have at least 2 cpus set in their cpus_allowed mask.
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
[ Improved the changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juri Lelli <juri.lelli@arm.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/1431496867-4194-1-git-send-email-wanpeng.li@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
preempt_notifier_unregister() documents:
"This is safe to call from within a preemption notifier."
However, both fire_sched_in_preempt_notifiers() and
fire_sched_out_preempt_notifiers() are using hlist_for_each_entry(),
which is not safe against entry removal during iteration.
Inspection of the KVM code does not reveal any use of
preempt_notifier_unregister() within the preempt notifiers.
Therefore, fix the comment.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.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/1431881590-1456-1-git-send-email-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Jiri reported a machine stuck in multi_cpu_stop() with
migrate_swap_stop() as function and with the following src,dst cpu
pairs: {11, 4} {13, 11} { 4, 13}
4 11 13
cpuM: queue(4 ,13)
*Ma
cpuN: queue(13,11)
*N Na
*M Mb
cpuO: queue(11, 4)
*O Oa
*Nb
*Ob
Where *X denotes the cpu running the queueing of cpu-X and X[ab] denotes
the first/second queued work.
You'll observe the top of the workqueue for each cpu: 4,11,13 to be work
from cpus: M, O, N resp. IOW. deadlock.
Do away with the queueing trickery and introduce lg_double_lock() to
lock both CPUs and fully serialize the stop_two_cpus() callers instead
of the partial (and buggy) serialization we have now.
Reported-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150605153023.GH19282@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When CONFIG_SCHEDSTATS is enabled, /proc/<pid>/sched prints almost all
sched statistics except sum_sleep_runtime. Since sum_sleep_runtime is
a good info to collect, add this it to /proc/<pid>/sched.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.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/1433751041-11724-4-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Within runnable tasks in /proc/sched_debug, vruntime is printed twice,
once as tree-key and again as exec-runtime.
Since exec-runtime isnt populated in !CONFIG_SCHEDSTATS, use this field
to print wait_sum.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.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/1433751041-11724-3-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With !CONFIG_SCHEDSTATS, runnable tasks in /proc/sched_debug has too
many columns than required. Fix this by printing appropriate columns.
While at this, print sum_exec_runtime, since this information is
available even in !CONFIG_SCHEDSTATS case.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.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/1433751041-11724-2-git-send-email-srikar@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The current cmpxchg() loop in setting the _QW_WAITING flag for writers
in queue_write_lock_slowpath() will contend with incoming readers
causing possibly extra cmpxchg() operations that are wasteful. This
patch changes the code to do a byte cmpxchg() to eliminate contention
with new readers.
A multithreaded microbenchmark running 5M read_lock/write_lock loop
on a 8-socket 80-core Westmere-EX machine running 4.0 based kernel
with the qspinlock patch have the following execution times (in ms)
with and without the patch:
With R:W ratio = 5:1
Threads w/o patch with patch % change
------- --------- ---------- --------
2 990 895 -9.6%
3 2136 1912 -10.5%
4 3166 2830 -10.6%
5 3953 3629 -8.2%
6 4628 4405 -4.8%
7 5344 5197 -2.8%
8 6065 6004 -1.0%
9 6826 6811 -0.2%
10 7599 7599 0.0%
15 9757 9766 +0.1%
20 13767 13817 +0.4%
With small number of contending threads, this patch can improve
locking performance by up to 10%. With more contending threads,
however, the gain diminishes.
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Douglas Hatch <doug.hatch@hp.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1433863153-30722-3-git-send-email-Waiman.Long@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
While looking for other users of get_state/cond_sync. I Found
ring_buffer_attach() and it looks obviously buggy?
Don't we need to ensure that we have "synchronize" _between_
list_del() and list_add() ?
IOW. Suppose that ring_buffer_attach() preempts right_after
get_state_synchronize_rcu() and gp completes before spin_lock().
In this case cond_synchronize_rcu() does nothing and we reuse
->rb_entry without waiting for gp in between?
It also moves the ->rcu_pending check under "if (rb)", to make it
more readable imo.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
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: 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: dave@stgolabs.net
Cc: der.herr@hofr.at
Cc: josh@joshtriplett.org
Cc: tj@kernel.org
Fixes: b69cf53640 ("perf: Fix a race between ring_buffer_detach() and ring_buffer_attach()")
Link: http://lkml.kernel.org/r/20150530200425.GA15748@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
* pm-sleep:
PM / sleep: trace_device_pm_callback coverage in dpm_prepare/complete
PM / wakeup: add a dummy wakeup_source to record statistics
PM / sleep: Make suspend-to-idle-specific code depend on CONFIG_SUSPEND
PM / sleep: Return -EBUSY from suspend_enter() on wakeup detection
PM / tick: Add tracepoints for suspend-to-idle diagnostics
PM / sleep: Fix symbol name in a comment in kernel/power/main.c
leds / PM: fix hibernation on arm when gpio-led used with CPU led trigger
ARM: omap-device: use SET_NOIRQ_SYSTEM_SLEEP_PM_OPS
bus: omap_l3_noc: add missed callbacks for suspend-to-disk
PM / sleep: Add macro to define common noirq system PM callbacks
PM / sleep: Refine diagnostic messages in enter_state()
PM / wakeup: validate wakeup source before activating it.
* pm-runtime:
PM / Runtime: Update last_busy in rpm_resume
PM / runtime: add note about re-calling in during device probe()
* pm-cpuidle:
cpuidle: Do not use CPUIDLE_DRIVER_STATE_START in cpuidle.c
cpuidle: Select a different state on tick_broadcast_enter() failures
sched / idle: Call default_idle_call() from cpuidle_enter_state()
sched / idle: Call idle_set_state() from cpuidle_enter_state()
cpuidle: Fix the kerneldoc comment for cpuidle_enter_state()
sched / idle: Eliminate the "reflect" check from cpuidle_idle_call()
cpuidle: Check the sign of index in cpuidle_reflect()
sched / idle: Move the default idle call code to a separate function
Add a lockdep annotation that WARNs if you 'accidentially' unlock a
lock.
This is especially helpful for code with callbacks, where the upper
layer assumes a lock remains taken but a lower layer thinks it maybe
can drop and reacquire the lock.
By unwittingly breaking up the lock, races can be introduced.
Lock pinning is a lockdep annotation that helps with this, when you
lockdep_pin_lock() a held lock, any unlock without a
lockdep_unpin_lock() will produce a WARN. Think of this as a relative
of lockdep_assert_held(), except you don't only assert its held now,
but ensure it stays held until you release your assertion.
RFC: a possible alternative API would be something like:
int cookie = lockdep_pin_lock(&foo);
...
lockdep_unpin_lock(&foo, cookie);
Where we pick a random number for the pin_count; this makes it
impossible to sneak a lock break in without also passing the right
cookie along.
I've not done this because it ends up generating code for !LOCKDEP,
esp. if you need to pass the cookie around for some reason.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124743.906731065@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We still have a few pending issues with the deadline code, one of which
is that switching between scheduling classes can 'leak' CBS state.
Close the hole by retaining the current CBS state when leaving
SCHED_DEADLINE and unconditionally programming the deadline timer.
The timer will then reset the CBS state if the task is still
!SCHED_DEADLINE by the time it hits.
If the task left SCHED_DEADLINE it will not call task_dead_dl() and
we'll not cancel the hrtimer, leaving us a pending timer in free
space. Avoid this by giving the timer a task reference, this avoids
littering the task exit path for this rather uncommon case.
In order to do this, I had to move dl_task_offline_migration() below
the replenishment, such that the task_rq()->lock fully covers that.
While doing this, I noticed that it (was) buggy in assuming a task is
enqueued and or we need to enqueue the task now. Fixing this means
select_task_rq_dl() might encounter an offline rq -- look into that.
As a result this kills cancel_dl_timer() which included a rq->lock
break.
Fixes: 40767b0dc7 ("sched/deadline: Fix deadline parameter modification handling")
Cc: Wanpeng Li <wanpeng.li@linux.intel.com>
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: Luca Abeni <luca.abeni@unitn.it>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124743.574192138@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
In order to remove dropping rq->lock from the
switched_{to,from}()/prio_changed() sched_class methods, run the
balance callbacks after it.
We need to remove dropping rq->lock because its buggy,
suppose using sched_setattr()/sched_setscheduler() to change a running
task from FIFO to OTHER.
By the time we get to switched_from_rt() the task is already enqueued
on the cfs runqueues. If switched_from_rt() does pull_rt_task() and
drops rq->lock, load-balancing can come in and move our task @p to
another rq.
The subsequent switched_to_fair() still assumes @p is on @rq and bad
things will happen.
By using balance callbacks we delay the load-balancing operations
{rt,dl}x{push,pull} until we've done all the important work and the
task is fully set up.
Furthermore, the balance callbacks do not know about @p, therefore
they cannot get confused like this.
Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Link: http://lkml.kernel.org/r/20150611124742.615343911@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Currently an hrtimer callback function cannot free its own timer
because __run_hrtimer() still needs to clear HRTIMER_STATE_CALLBACK
after it. Freeing the timer would result in a clear use-after-free.
Solve this by using a scheme similar to regular timers; track the
current running timer in hrtimer_clock_base::running.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: wanpeng.li@linux.intel.com
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124743.471563047@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
On traditional hierarchies, if a task has write access to "tasks" or
"cgroup.procs" file of a cgroup and its euid agrees with the target,
it can move the target to the cgroup; however, consider the following
scenario. The owner of each cgroup is in the parentheses.
R (root) - 0 (root) - 00 (user1) - 000 (user1)
| \ 001 (user1)
\ 1 (root) - 10 (user1)
The subtrees of 00 and 10 are delegated to user1; however, while both
subtrees may belong to the same user, it is clear that the two
subtrees are to be isolated - they're under completely separate
resource limits imposed by 0 and 1, respectively. Note that 0 and 1
aren't strictly necessary but added to ease illustrating the issue.
If user1 is allowed to move processes between the two subtrees, the
intention of the hierarchy - keeping a given group of processes under
a subtree with certain resource restrictions while delegating
management of the subtree - can be circumvented by user1.
This happens because migration permission check doesn't consider the
hierarchical nature of cgroups. To fix the issue, this patch adds an
extra permission requirement when userland tries to migrate a process
in the default hierarchy - the issuing task must have write access to
the common ancestor of "cgroup.procs" file of the ancestor in addition
to the destination's.
Conceptually, the issuer must be able to move the target process from
the source cgroup to the common ancestor of source and destination
cgroups and then to the destination. As long as delegation is done in
a proper top-down way, this guarantees that a delegatee can't smuggle
processes across disjoint delegation domains.
The next patch will add documentation on the delegation model on the
default hierarchy.
v2: Fixed missing !ret test. Spotted by Li Zefan.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>
Separate out task / process migration permission check from
__cgroup_procs_write() into cgroup_procs_write_permission().
* Permission check is moved right above the actual migration and no
longer performed while holding rcu_read_lock().
cgroup_procs_write_permission() uses get_task_cred() / put_cred()
instead of __task_cred(). Also, !root trying to migrate kthreadd or
PF_NO_SETAFFINITY tasks will now fail with -EINVAL rather than
-EACCES which should be fine.
* The same permission check is now performed even when moving self by
specifying 0 as pid. This always succeeds so there's no functional
difference. We'll add more permission checks later and the benefits
of keeping both cases consistent outweigh the minute overhead of
doing perm checks on pid 0 case.
Signed-off-by: Tejun Heo <tj@kernel.org>
Mark the task for later wakeup after the wait_lock has been released.
This way, once the next task is awoken, it will have a better chance
to of finding the wait_lock free when continuing executing in
__rt_mutex_slowlock() when trying to acquire the rtmutex, calling
try_to_take_rt_mutex(). Upon contended scenarios, other tasks attempting
take the lock may acquire it first, right after the wait_lock is released,
but (a) this can also occur with the current code, as it relies on the
spinlock fairness, and (b) we are dealing with the top-waiter anyway,
so it will always take the lock next.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1432056298-18738-2-git-send-email-dave@stgolabs.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Driver authors seem to get the ordering of irq_set_chained_handler()
and irq_set_handler_data() wrong - ordering the former before the
latter. This opens a race window where, if there is an interrupt
pending, the handler will be called between these two calls,
potentially resulting in an oops.
Provide a single interface to set both of these together, especially
as that's commonly what is required.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/E1Z4yzs-0002Rw-4B@rmk-PC.arm.linux.org.uk
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The fix in d151832650 (time: Move clock_was_set_seq update
before updating shadow-timekeeper) was unfortunately incomplete.
The main gist of that change was to do the shadow-copy update
last, so that any state changes were properly duplicated, and
we wouldn't accidentally have stale data in the shadow.
Unfortunately in the main update_wall_time() logic, we update
use the shadow-timekeeper to calculate the next update values,
then while holding the lock, copy the shadow-timekeeper over,
then call timekeeping_update() to do some additional
bookkeeping, (skipping the shadow mirror). The bug with this is
the additional bookkeeping isn't all read-only, and some
changes timkeeper state. Thus we might then overwrite this state
change on the next update.
To avoid this problem, do the timekeeping_update() on the
shadow-timekeeper prior to copying the full state over to
the real-timekeeper.
This avoids problems with both the clock_was_set_seq and
next_leap_ktime being overwritten and possibly the
fast-timekeepers as well.
Many thanks to Prarit for his rigorous testing, which discovered
this problem, along with Prarit and Daniel's work validating this
fix.
Reported-by: Prarit Bhargava <prarit@redhat.com>
Tested-by: Prarit Bhargava <prarit@redhat.com>
Tested-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/1434560753-7441-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
CLOCK_EVT_MODE_* macros are present for backward compatibility (as most
of the drivers are still using old ->set_mode() interface).
These macro's shouldn't be used anymore in code, that is common to both
driver interfaces, i.e. ->set_mode() and ->set_state_*().
Drivers implementing ->set_state_*() interface, which have their
clkevt->mode set to 0 (clkevt device structures are normally globally
defined), will not participate in suspend/resume as they will always be
marked as UNUSED.
Fix this by checking state of the clockevent device instead of mode,
which is updated for both the interfaces.
Fixes: ac34ad27fc ("clockevents: Do not suspend/resume if unused")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: alexandre.belloni@free-electrons.com
Cc: sylvain.rochet@finsecur.com
Link: http://lkml.kernel.org/r/a1964eef6e8a47d02b1ff9083c6c91f73f0ff643.1434537215.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
into his fuzzer tests. There's a missing check of balanced
operations when parenthesis are used, and this triggers a WARN_ON()
and when reading the failure, the filter reports no failure occurred.
The operands were not being checked if they match, this adds that.
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Merge tag 'trace-fix-filter-4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing filter fix from Steven Rostedt:
"Vince Weaver reported a warning when he added perf event filters into
his fuzzer tests. There's a missing check of balanced operations when
parenthesis are used, and this triggers a WARN_ON() and when reading
the failure, the filter reports no failure occurred.
The operands were not being checked if they match, this adds that"
* tag 'trace-fix-filter-4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Have filter check for balanced ops
When the following filter is used it causes a warning to trigger:
# cd /sys/kernel/debug/tracing
# echo "((dev==1)blocks==2)" > events/ext4/ext4_truncate_exit/filter
-bash: echo: write error: Invalid argument
# cat events/ext4/ext4_truncate_exit/filter
((dev==1)blocks==2)
^
parse_error: No error
------------[ cut here ]------------
WARNING: CPU: 2 PID: 1223 at kernel/trace/trace_events_filter.c:1640 replace_preds+0x3c5/0x990()
Modules linked in: bnep lockd grace bluetooth ...
CPU: 3 PID: 1223 Comm: bash Tainted: G W 4.1.0-rc3-test+ #450
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012
0000000000000668 ffff8800c106bc98 ffffffff816ed4f9 ffff88011ead0cf0
0000000000000000 ffff8800c106bcd8 ffffffff8107fb07 ffffffff8136b46c
ffff8800c7d81d48 ffff8800d4c2bc00 ffff8800d4d4f920 00000000ffffffea
Call Trace:
[<ffffffff816ed4f9>] dump_stack+0x4c/0x6e
[<ffffffff8107fb07>] warn_slowpath_common+0x97/0xe0
[<ffffffff8136b46c>] ? _kstrtoull+0x2c/0x80
[<ffffffff8107fb6a>] warn_slowpath_null+0x1a/0x20
[<ffffffff81159065>] replace_preds+0x3c5/0x990
[<ffffffff811596b2>] create_filter+0x82/0xb0
[<ffffffff81159944>] apply_event_filter+0xd4/0x180
[<ffffffff81152bbf>] event_filter_write+0x8f/0x120
[<ffffffff811db2a8>] __vfs_write+0x28/0xe0
[<ffffffff811dda43>] ? __sb_start_write+0x53/0xf0
[<ffffffff812e51e0>] ? security_file_permission+0x30/0xc0
[<ffffffff811dc408>] vfs_write+0xb8/0x1b0
[<ffffffff811dc72f>] SyS_write+0x4f/0xb0
[<ffffffff816f5217>] system_call_fastpath+0x12/0x6a
---[ end trace e11028bd95818dcd ]---
Worse yet, reading the error message (the filter again) it says that
there was no error, when there clearly was. The issue is that the
code that checks the input does not check for balanced ops. That is,
having an op between a closed parenthesis and the next token.
This would only cause a warning, and fail out before doing any real
harm, but it should still not caues a warning, and the error reported
should work:
# cd /sys/kernel/debug/tracing
# echo "((dev==1)blocks==2)" > events/ext4/ext4_truncate_exit/filter
-bash: echo: write error: Invalid argument
# cat events/ext4/ext4_truncate_exit/filter
((dev==1)blocks==2)
^
parse_error: Meaningless filter expression
And give no kernel warning.
Link: http://lkml.kernel.org/r/20150615175025.7e809215@gandalf.local.home
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: stable@vger.kernel.org # 2.6.31+
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This lets you build a kernel which can support xen dom0
or xen guests on i386, x86-64 and arm64 by just using:
make xenconfig
You can start from an allnoconfig and then switch to xenconfig.
This also splits out the options which are available currently
to be built with x86 and 'make ARCH=arm64' under a shared config.
Technically xen supports a dom0 kernel and also a guest
kernel configuration but upon review with the xen team
since we don't have many dom0 options its best to just
combine these two into one.
A few generic notes: we enable both of these:
CONFIG_INET=y
CONFIG_BINFMT_ELF=y
although technically not required given you likely will
end up with a pretty useless system otherwise.
A few architectural differences worth noting:
$ make allnoconfig; make xenconfig > /dev/null ; \
grep XEN .config > 64-bit-config
$ make ARCH=i386 allnoconfig; make ARCH=i386 xenconfig > /dev/null; \
grep XEN .config > 32-bit-config
$ make ARCH=arm64 allnoconfig; make ARCH=arm64 xenconfig > /dev/null; \
grep XEN .config > arm64-config
Since the options are already split up with a generic config and
architecture specific configs you anything on the x86 configs
are known to only work right now on x86. For instance arm64 doesn't
support MEMORY_HOTPLUG yet as such although we try to enabe it
generically arm64 doesn't have it yet, so we leave the xen
specific kconfig option XEN_BALLOON_MEMORY_HOTPLUG on x86's config
file to set expecations correctly.
Then on x86 we have differences between i386 and x86-64. The difference
between 64-bit-config and 32-bit-config is you don't get XEN_MCE_LOG as
this is only supported on 64-bit. You also do not get on i386
XEN_BALLOON_MEMORY_HOTPLUG, there does not seem to be any technical
reasons to not allow this but I gave up after a few attempts.
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: penberg@kernel.org
Cc: levinsasha928@gmail.com
Cc: mtosatti@redhat.com
Cc: fengguang.wu@intel.com
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xenproject.org
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Michal Marek <mmarek@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
The functions irq_move_irq() and irq_move_masked_irq() expect that the
caller passes the top-level irq_data to them when hierarchical
irqdomains are enabled. But that's not true when called from
apic_ack_edge(), which results in a null pointer dereference by
idata->chip->irq_mask(idata).
Instead of fixing callers to passing top-level irq_data, we rather
change irq_move_irq()/irq_move_masked_irq() to accept any irq_data.
Fixes: 52f518a3a7 'x86/MSI: Use hierarchical irqdomains to manage MSI interrupts'
Reported-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/1433145945-789-3-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
For irq associated with hierarchy irqdomains, there will be multiple
irq_datas for one irq_desc. So enhance irq_data_to_desc() to support
hierarchy irqdomain. Also export irq_data_to_desc() as an inline
function for later reuse.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/1433145945-789-2-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
It's useful to do per-cpu histograms.
Suggested-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
