profiling: remove profile=sleep support

The kernel sleep profile is no longer working due to a recursive locking
bug introduced by commit 42a20f86dc19 ("sched: Add wrapper for get_wchan()
to keep ta

profiling: remove profile=sleep support

The kernel sleep profile is no longer working due to a recursive locking
bug introduced by commit 42a20f86dc19 ("sched: Add wrapper for get_wchan()
to keep task blocked")

Booting with the 'profile=sleep' kernel command line option added or
executing

# echo -n sleep > /sys/kernel/profiling

after boot causes the system to lock up.

Lockdep reports

kthreadd/3 is trying to acquire lock:
ffff93ac82e08d58 (&p->pi_lock){....}-{2:2}, at: get_wchan+0x32/0x70

but task is already holding lock:
ffff93ac82e08d58 (&p->pi_lock){....}-{2:2}, at: try_to_wake_up+0x53/0x370

with the call trace being

lock_acquire+0xc8/0x2f0
get_wchan+0x32/0x70
__update_stats_enqueue_sleeper+0x151/0x430
enqueue_entity+0x4b0/0x520
enqueue_task_fair+0x92/0x6b0
ttwu_do_activate+0x73/0x140
try_to_wake_up+0x213/0x370
swake_up_locked+0x20/0x50
complete+0x2f/0x40
kthread+0xfb/0x180

However, since nobody noticed this regression for more than two years,
let's remove 'profile=sleep' support based on the assumption that nobody
needs this functionality.

Fixes: 42a20f86dc19 ("sched: Add wrapper for get_wchan() to keep task blocked")
Cc: [email protected] # v5.16+
Signed-off-by: Tetsuo Handa <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

profiling: remove stale percpu flip buffer variables

For some reason I didn't see this issue on my arm64 or x86-64 builds,
but Stephen Rothwell reports that commit 2accfdb7eff6 ("profiling:
attempt

profiling: remove stale percpu flip buffer variables

For some reason I didn't see this issue on my arm64 or x86-64 builds,
but Stephen Rothwell reports that commit 2accfdb7eff6 ("profiling:
attempt to remove per-cpu profile flip buffer") left these static
variables around, and the powerpc build is unhappy about them:

kernel/profile.c:52:28: warning: 'cpu_profile_flip' defined but not used [-Wunused-variable]
52 | static DEFINE_PER_CPU(int, cpu_profile_flip);
| ^~~~~~~~~~~~~~~~
..

So remove these stale left-over remnants too.

Fixes: 2accfdb7eff6 ("profiling: attempt to remove per-cpu profile flip buffer")
Reported-by: Stephen Rothwell <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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profiling: attempt to remove per-cpu profile flip buffer

This is the really old legacy kernel profiling code, which has long
since been obviated by "real profiling" (ie 'prof' and company), and
main

profiling: attempt to remove per-cpu profile flip buffer

This is the really old legacy kernel profiling code, which has long
since been obviated by "real profiling" (ie 'prof' and company), and
mainly remains as a source of syzbot reports.

There are anecdotal reports that people still use it for boot-time
profiling, but it's unlikely that such use would care about the old NUMA
optimizations in this code from 2004 (commit ad02973d42: "profile: 512x
Altix timer interrupt livelock fix" in the BK import archive at [1])

So in order to head off future syzbot reports, let's try to simplify
this code and get rid of the per-cpu profile buffers that are quite a
large portion of the complexity footprint of this thing (including CPU
hotplug callbacks etc).

It's unlikely anybody will actually notice, or possibly, as Thomas put
it: "Only people who indulge in nostalgia will notice :)".

That said, if it turns out that this code is actually actively used by
somebody, we can always revert this removal. Thus the "attempt" in the
summary line.

[ Note: in a small nod to "the profiling code can cause NUMA problems",
this also removes the "increment the last entry in the profiling array
on any unknown hits" logic. That would account any program counter in
a module to that single counter location, and might exacerbate any
NUMA cacheline bouncing issues ]

Link: https://lore.kernel.org/all/CAHk-=wgs52BxT4Zjmjz8aNvHWKxf5_ThBY4bYL1Y6CTaNL2dTw@mail.gmail.com/
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git [1]
Cc: Thomas Gleixner <[email protected]>
Cc: Tetsuo Handa <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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profiling: remove prof_cpu_mask

syzbot is reporting uninit-value at profile_hits(), for there is a race
window between

if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL))
return -ENOMEM;
cp

profiling: remove prof_cpu_mask

syzbot is reporting uninit-value at profile_hits(), for there is a race
window between

if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL))
return -ENOMEM;
cpumask_copy(prof_cpu_mask, cpu_possible_mask);

in profile_init() and

cpumask_available(prof_cpu_mask) &&
cpumask_test_cpu(smp_processor_id(), prof_cpu_mask))

in profile_tick(); prof_cpu_mask remains uninitialzed until cpumask_copy()
completes while cpumask_available(prof_cpu_mask) returns true as soon as
alloc_cpumask_var(&prof_cpu_mask) completes.

We could replace alloc_cpumask_var() with zalloc_cpumask_var() and
call cpumask_copy() from create_proc_profile() on only UP kernels, for
profile_online_cpu() calls cpumask_set_cpu() as needed via
cpuhp_setup_state(CPUHP_AP_ONLINE_DYN) on SMP kernels. But this patch
removes prof_cpu_mask because it seems unnecessary.

The cpumask_test_cpu(smp_processor_id(), prof_cpu_mask) test
in profile_tick() is likely always true due to

a CPU cannot call profile_tick() if that CPU is offline

and

cpumask_set_cpu(cpu, prof_cpu_mask) is called when that CPU becomes
online and cpumask_clear_cpu(cpu, prof_cpu_mask) is called when that
CPU becomes offline

. This test could be false during transition between online and offline.

But according to include/linux/cpuhotplug.h , CPUHP_PROFILE_PREPARE
belongs to PREPARE section, which means that the CPU subjected to
profile_dead_cpu() cannot be inside profile_tick() (i.e. no risk of
use-after-free bug) because interrupt for that CPU is disabled during
PREPARE section. Therefore, this test is guaranteed to be true, and
can be removed. (Since profile_hits() checks prof_buffer != NULL, we
don't need to check prof_buffer != NULL here unless get_irq_regs() or
user_mode() is such slow that we want to avoid when prof_buffer == NULL).

do_profile_hits() is called from profile_tick() from timer interrupt
only if cpumask_test_cpu(smp_processor_id(), prof_cpu_mask) is true and
prof_buffer is not NULL. But syzbot is also reporting that sometimes
do_profile_hits() is called while current thread is still doing vzalloc(),
where prof_buffer must be NULL at this moment. This indicates that multiple
threads concurrently tried to write to /sys/kernel/profiling interface,
which caused that somebody else try to re-allocate prof_buffer despite
somebody has already allocated prof_buffer. Fix this by using
serialization.

Reported-by: syzbot <[email protected]>
Closes: https://syzkaller.appspot.com/bug?extid=b1a83ab2a9eb9321fbdd
Signed-off-by: Tetsuo Handa <[email protected]>
Tested-by: syzbot <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

profiling: Remove create_prof_cpu_mask().

create_prof_cpu_mask() is no longer used after commit 1f44a225777e ("s390:
convert interrupt handling to use generic hardirq").

Signed-off-by: Tetsuo Handa

profiling: Remove create_prof_cpu_mask().

create_prof_cpu_mask() is no longer used after commit 1f44a225777e ("s390:
convert interrupt handling to use generic hardirq").

Signed-off-by: Tetsuo Handa <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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kernel/profile.c: simplify duplicated code in profile_setup()

The code to parse option string "schedule/sleep/kvm" of cmdline in
function profile_setup is redundant, so simplify that.

Link: https:/

kernel/profile.c: simplify duplicated code in profile_setup()

The code to parse option string "schedule/sleep/kvm" of cmdline in
function profile_setup is redundant, so simplify that.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: wuchi <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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profile: setup_profiling_timer() is moslty not implemented

The setup_profiling_timer() is mostly un-implemented by many
architectures. In many places it isn't guarded by CONFIG_PROFILE which is
nee

profile: setup_profiling_timer() is moslty not implemented

The setup_profiling_timer() is mostly un-implemented by many
architectures. In many places it isn't guarded by CONFIG_PROFILE which is
needed for it to be used. Make it a weak symbol in kernel/profile.c and
remove the 'return -EINVAL' implementations from the kenrel.

There are a couple of architectures which do return 0 from the
setup_profiling_timer() function but they don't seem to do anything else
with it. To keep the /proc compatibility for now, leave these for a
future update or removal.

On ARM, this fixes the following sparse warning:
arch/arm/kernel/smp.c:793:5: warning: symbol 'setup_profiling_timer' was not declared. Should it be static?

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ben Dooks <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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profiling: fix shift too large makes kernel panic

2d186afd04d6 ("profiling: fix shift-out-of-bounds bugs") limits shift
value by [0, BITS_PER_LONG -1], which means [0, 63].

However, syzbot found th

profiling: fix shift too large makes kernel panic

2d186afd04d6 ("profiling: fix shift-out-of-bounds bugs") limits shift
value by [0, BITS_PER_LONG -1], which means [0, 63].

However, syzbot found that the max shift value should be the bit number of
(_etext - _stext). If shift is outside of this, the "buffer_bytes" will
be zero and will cause kzalloc(0). Then the kernel panics due to
dereferencing the returned pointer 16.

This can be easily reproduced by passing a large number like 60 to enable
profiling and then run readprofile.

LOGS:
BUG: kernel NULL pointer dereference, address: 0000000000000010
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 6148067 P4D 6148067 PUD 6142067 PMD 0
PREEMPT SMP
CPU: 4 PID: 184 Comm: readprofile Not tainted 5.18.0+ #162
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:read_profile+0x104/0x220
RSP: 0018:ffffc900006fbe80 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888006150000 RSI: 0000000000000001 RDI: ffffffff82aba4a0
RBP: 000000000188bb60 R08: 0000000000000010 R09: ffff888006151000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82aba4a0
R13: 0000000000000000 R14: ffffc900006fbf08 R15: 0000000000020c30
FS: 000000000188a8c0(0000) GS:ffff88803ed00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000000006144000 CR4: 00000000000006e0
Call Trace:
<TASK>
proc_reg_read+0x56/0x70
vfs_read+0x9a/0x1b0
ksys_read+0xa1/0xe0
? fpregs_assert_state_consistent+0x1e/0x40
do_syscall_64+0x3a/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x4d4b4e
RSP: 002b:00007ffebb668d58 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000000000188a8a0 RCX: 00000000004d4b4e
RDX: 0000000000000400 RSI: 000000000188bb60 RDI: 0000000000000003
RBP: 0000000000000003 R08: 000000000000006e R09: 0000000000000000
R10: 0000000000000041 R11: 0000000000000246 R12: 000000000188bb60
R13: 0000000000000400 R14: 0000000000000000 R15: 000000000188bb60
</TASK>
Modules linked in:
CR2: 0000000000000010
Killed
---[ end trace 0000000000000000 ]---

Check prof_len in profile_init() to prevent it be zero.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Chen Zhongjin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

exit: Remove profile_handoff_task

All profile_handoff_task does is notify the task_free_notifier chain.
The helpers task_handoff_register and task_handoff_unregister are used
to add and delete entri

exit: Remove profile_handoff_task

All profile_handoff_task does is notify the task_free_notifier chain.
The helpers task_handoff_register and task_handoff_unregister are used
to add and delete entries from that chain and are never called.

So remove the dead code and make it much easier to read and reason
about __put_task_struct.

Suggested-by: Al Viro <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: "Eric W. Biederman" <[email protected]>

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exit: Remove profile_task_exit & profile_munmap

When I say remove I mean remove. All profile_task_exit and
profile_munmap do is call a blocking notifier chain. The helpers
profile_task_register an

exit: Remove profile_task_exit & profile_munmap

When I say remove I mean remove. All profile_task_exit and
profile_munmap do is call a blocking notifier chain. The helpers
profile_task_register and profile_task_unregister are not called
anywhere in the tree. Which means this is all dead code.

So remove the dead code and make it easier to read do_exit.

Reviewed-by: Christoph Hellwig <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: "Eric W. Biederman" <[email protected]>

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profiling: fix shift-out-of-bounds bugs

Syzbot reported shift-out-of-bounds bug in profile_init().
The problem was in incorrect prof_shift. Since prof_shift value comes from
userspace we need to cla

profiling: fix shift-out-of-bounds bugs

Syzbot reported shift-out-of-bounds bug in profile_init().
The problem was in incorrect prof_shift. Since prof_shift value comes from
userspace we need to clamp this value into [0, BITS_PER_LONG -1]
boundaries.

Second possible shiht-out-of-bounds was found by Tetsuo:
sample_step local variable in read_profile() had "unsigned int" type,
but prof_shift allows to make a BITS_PER_LONG shift. So, to prevent
possible shiht-out-of-bounds sample_step type was changed to
"unsigned long".

Also, "unsigned short int" will be sufficient for storing
[0, BITS_PER_LONG] value, that's why there is no need for
"unsigned long" prof_shift.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-and-tested-by: [email protected]
Suggested-by: Tetsuo Handa <[email protected]>
Signed-off-by: Pavel Skripkin <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Steven Rostedt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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kernel: Initialize cpumask before parsing

KMSAN complains that new_value at cpumask_parse_user() from
write_irq_affinity() from irq_affinity_proc_write() is uninitialized.

[ 148.133411][ T5509]

kernel: Initialize cpumask before parsing

KMSAN complains that new_value at cpumask_parse_user() from
write_irq_affinity() from irq_affinity_proc_write() is uninitialized.

[ 148.133411][ T5509] =====================================================
[ 148.135383][ T5509] BUG: KMSAN: uninit-value in find_next_bit+0x325/0x340
[ 148.137819][ T5509]
[ 148.138448][ T5509] Local variable ----new_value.i@irq_affinity_proc_write created at:
[ 148.140768][ T5509] irq_affinity_proc_write+0xc3/0x3d0
[ 148.142298][ T5509] irq_affinity_proc_write+0xc3/0x3d0
[ 148.143823][ T5509] =====================================================

Since bitmap_parse() from cpumask_parse_user() calls find_next_bit(),
any alloc_cpumask_var() + cpumask_parse_user() sequence has possibility
that find_next_bit() accesses uninitialized cpu mask variable. Fix this
problem by replacing alloc_cpumask_var() with zalloc_cpumask_var().

Signed-off-by: Tetsuo Handa <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Steven Rostedt (VMware) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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proc: convert everything to "struct proc_ops"

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

llseek => proc_lseek
unlocked_ioctl => proc_ioctl

proc: convert everything to "struct proc_ops"

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

llseek => proc_lseek
unlocked_ioctl => proc_ioctl

xxx => proc_xxx

delete ".owner = THIS_MODULE" line

[[email protected]: fix drivers/isdn/capi/kcapi_proc.c]
[[email protected]: fix kernel/sched/psi.c]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Stephen Rothwell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

kernel/profile.c: use cpumask_available to check for NULL cpumask

When building with clang + -Wtautological-pointer-compare, these
instances pop up:

kernel/profile.c:339:6: warning: comparison of

kernel/profile.c: use cpumask_available to check for NULL cpumask

When building with clang + -Wtautological-pointer-compare, these
instances pop up:

kernel/profile.c:339:6: warning: comparison of array 'prof_cpu_mask' not equal to a null pointer is always true [-Wtautological-pointer-compare]
if (prof_cpu_mask != NULL)
^~~~~~~~~~~~~ ~~~~
kernel/profile.c:376:6: warning: comparison of array 'prof_cpu_mask' not equal to a null pointer is always true [-Wtautological-pointer-compare]
if (prof_cpu_mask != NULL)
^~~~~~~~~~~~~ ~~~~
kernel/profile.c:406:26: warning: comparison of array 'prof_cpu_mask' not equal to a null pointer is always true [-Wtautological-pointer-compare]
if (!user_mode(regs) && prof_cpu_mask != NULL &&
^~~~~~~~~~~~~ ~~~~
3 warnings generated.

This can be addressed with the cpumask_available helper, introduced in
commit f7e30f01a9e2 ("cpumask: Add helper cpumask_available()") to fix
warnings like this while keeping the code the same.

Link: https://github.com/ClangBuiltLinux/linux/issues/747
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Nathan Chancellor <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was use

treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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mm: remove include/linux/bootmem.h

Move remaining definitions and declarations from include/linux/bootmem.h
into include/linux/memblock.h and remove the redundant header.

The includes were replaced

mm: remove include/linux/bootmem.h

Move remaining definitions and declarations from include/linux/bootmem.h
into include/linux/memblock.h and remove the redundant header.

The includes were replaced with the semantic patch below and then
semi-automated removal of duplicated '#include <linux/memblock.h>

@@
@@
- #include <linux/bootmem.h>
+ #include <linux/memblock.h>

[[email protected]: dma-direct: fix up for the removal of linux/bootmem.h]
Link: http://lkml.kernel.org/r/[email protected]
[[email protected]: powerpc: fix up for removal of linux/bootmem.h]
Link: http://lkml.kernel.org/r/[email protected]
[[email protected]: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Mike Rapoport <[email protected]>
Signed-off-by: Stephen Rothwell <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Chris Zankel <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Greentime Hu <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Guan Xuetao <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Jonas Bonn <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Ley Foon Tan <[email protected]>
Cc: Mark Salter <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Burton <[email protected]>
Cc: Richard Kuo <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Rich Felker <[email protected]>
Cc: Russell King <[email protected]>
Cc: Serge Semin <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h>

But first update usage sites with the new header dependency.

Acked-by: Linu

sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h>

But first update usage sites with the new header dependency.

Acked-by: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PA

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

This was entirely automated, using the script by Al:

PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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profile: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs. A lot of code is removed because
the for-loop

profile: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs. A lot of code is removed because
the for-loop is used and create_hash_tables() is removed since its purpose
is covered by the startup / teardown hooks.

Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Anna-Maria Gleixner <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

show more ...

profile: hide unused functions when !CONFIG_PROC_FS

A couple of functions and variables in the profile implementation are
used only on SMP systems by the procfs code, but are unused if either
procfs

profile: hide unused functions when !CONFIG_PROC_FS

A couple of functions and variables in the profile implementation are
used only on SMP systems by the procfs code, but are unused if either
procfs is disabled or in uniprocessor kernels. gcc prints a harmless
warning about the unused symbols:

kernel/profile.c:243:13: error: 'profile_flip_buffers' defined but not used [-Werror=unused-function]
static void profile_flip_buffers(void)
^
kernel/profile.c:266:13: error: 'profile_discard_flip_buffers' defined but not used [-Werror=unused-function]
static void profile_discard_flip_buffers(void)
^
kernel/profile.c:330:12: error: 'profile_cpu_callback' defined but not used [-Werror=unused-function]
static int profile_cpu_callback(struct notifier_block *info,
^

This adds further #ifdef to the file, to annotate exactly in which cases
they are used. I have done several thousand ARM randconfig kernels with
this patch applied and no longer get any warnings in this file.

Signed-off-by: Arnd Bergmann <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Robin Holt <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Tejun Heo <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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sched/debug: Make schedstats a runtime tunable that is disabled by default

schedstats is very useful during debugging and performance tuning but it
incurs overhead to calculate the stats. As such, e

sched/debug: Make schedstats a runtime tunable that is disabled by default

schedstats is very useful during debugging and performance tuning but it
incurs overhead to calculate the stats. As such, even though it can be
disabled at build time, it is often enabled as the information is useful.

This patch adds a kernel command-line and sysctl tunable to enable or
disable schedstats on demand (when it's built in). It is disabled
by default as someone who knows they need it can also learn to enable
it when necessary.

The benefits are dependent on how scheduler-intensive the workload is.
If it is then the patch reduces the number of cycles spent calculating
the stats with a small benefit from reducing the cache footprint of the
scheduler.

These measurements were taken from a 48-core 2-socket
machine with Xeon(R) E5-2670 v3 cpus although they were also tested on a
single socket machine 8-core machine with Intel i7-3770 processors.

netperf-tcp
4.5.0-rc1 4.5.0-rc1
vanilla nostats-v3r1
Hmean 64 560.45 ( 0.00%) 575.98 ( 2.77%)
Hmean 128 766.66 ( 0.00%) 795.79 ( 3.80%)
Hmean 256 950.51 ( 0.00%) 981.50 ( 3.26%)
Hmean 1024 1433.25 ( 0.00%) 1466.51 ( 2.32%)
Hmean 2048 2810.54 ( 0.00%) 2879.75 ( 2.46%)
Hmean 3312 4618.18 ( 0.00%) 4682.09 ( 1.38%)
Hmean 4096 5306.42 ( 0.00%) 5346.39 ( 0.75%)
Hmean 8192 10581.44 ( 0.00%) 10698.15 ( 1.10%)
Hmean 16384 18857.70 ( 0.00%) 18937.61 ( 0.42%)

Small gains here, UDP_STREAM showed nothing intresting and neither did
the TCP_RR tests. The gains on the 8-core machine were very similar.

tbench4
4.5.0-rc1 4.5.0-rc1
vanilla nostats-v3r1
Hmean mb/sec-1 500.85 ( 0.00%) 522.43 ( 4.31%)
Hmean mb/sec-2 984.66 ( 0.00%) 1018.19 ( 3.41%)
Hmean mb/sec-4 1827.91 ( 0.00%) 1847.78 ( 1.09%)
Hmean mb/sec-8 3561.36 ( 0.00%) 3611.28 ( 1.40%)
Hmean mb/sec-16 5824.52 ( 0.00%) 5929.03 ( 1.79%)
Hmean mb/sec-32 10943.10 ( 0.00%) 10802.83 ( -1.28%)
Hmean mb/sec-64 15950.81 ( 0.00%) 16211.31 ( 1.63%)
Hmean mb/sec-128 15302.17 ( 0.00%) 15445.11 ( 0.93%)
Hmean mb/sec-256 14866.18 ( 0.00%) 15088.73 ( 1.50%)
Hmean mb/sec-512 15223.31 ( 0.00%) 15373.69 ( 0.99%)
Hmean mb/sec-1024 14574.25 ( 0.00%) 14598.02 ( 0.16%)
Hmean mb/sec-2048 13569.02 ( 0.00%) 13733.86 ( 1.21%)
Hmean mb/sec-3072 12865.98 ( 0.00%) 13209.23 ( 2.67%)

Small gains of 2-4% at low thread counts and otherwise flat. The
gains on the 8-core machine were slightly different

tbench4 on 8-core i7-3770 single socket machine
Hmean mb/sec-1 442.59 ( 0.00%) 448.73 ( 1.39%)
Hmean mb/sec-2 796.68 ( 0.00%) 794.39 ( -0.29%)
Hmean mb/sec-4 1322.52 ( 0.00%) 1343.66 ( 1.60%)
Hmean mb/sec-8 2611.65 ( 0.00%) 2694.86 ( 3.19%)
Hmean mb/sec-16 2537.07 ( 0.00%) 2609.34 ( 2.85%)
Hmean mb/sec-32 2506.02 ( 0.00%) 2578.18 ( 2.88%)
Hmean mb/sec-64 2511.06 ( 0.00%) 2569.16 ( 2.31%)
Hmean mb/sec-128 2313.38 ( 0.00%) 2395.50 ( 3.55%)
Hmean mb/sec-256 2110.04 ( 0.00%) 2177.45 ( 3.19%)
Hmean mb/sec-512 2072.51 ( 0.00%) 2053.97 ( -0.89%)

In constract, this shows a relatively steady 2-3% gain at higher thread
counts. Due to the nature of the patch and the type of workload, it's
not a surprise that the result will depend on the CPU used.

hackbench-pipes
4.5.0-rc1 4.5.0-rc1
vanilla nostats-v3r1
Amean 1 0.0637 ( 0.00%) 0.0660 ( -3.59%)
Amean 4 0.1229 ( 0.00%) 0.1181 ( 3.84%)
Amean 7 0.1921 ( 0.00%) 0.1911 ( 0.52%)
Amean 12 0.3117 ( 0.00%) 0.2923 ( 6.23%)
Amean 21 0.4050 ( 0.00%) 0.3899 ( 3.74%)
Amean 30 0.4586 ( 0.00%) 0.4433 ( 3.33%)
Amean 48 0.5910 ( 0.00%) 0.5694 ( 3.65%)
Amean 79 0.8663 ( 0.00%) 0.8626 ( 0.43%)
Amean 110 1.1543 ( 0.00%) 1.1517 ( 0.22%)
Amean 141 1.4457 ( 0.00%) 1.4290 ( 1.16%)
Amean 172 1.7090 ( 0.00%) 1.6924 ( 0.97%)
Amean 192 1.9126 ( 0.00%) 1.9089 ( 0.19%)

Some small gains and losses and while the variance data is not included,
it's close to the noise. The UMA machine did not show anything particularly
different

pipetest
4.5.0-rc1 4.5.0-rc1
vanilla nostats-v2r2
Min Time 4.13 ( 0.00%) 3.99 ( 3.39%)
1st-qrtle Time 4.38 ( 0.00%) 4.27 ( 2.51%)
2nd-qrtle Time 4.46 ( 0.00%) 4.39 ( 1.57%)
3rd-qrtle Time 4.56 ( 0.00%) 4.51 ( 1.10%)
Max-90% Time 4.67 ( 0.00%) 4.60 ( 1.50%)
Max-93% Time 4.71 ( 0.00%) 4.65 ( 1.27%)
Max-95% Time 4.74 ( 0.00%) 4.71 ( 0.63%)
Max-99% Time 4.88 ( 0.00%) 4.79 ( 1.84%)
Max Time 4.93 ( 0.00%) 4.83 ( 2.03%)
Mean Time 4.48 ( 0.00%) 4.39 ( 1.91%)
Best99%Mean Time 4.47 ( 0.00%) 4.39 ( 1.91%)
Best95%Mean Time 4.46 ( 0.00%) 4.38 ( 1.93%)
Best90%Mean Time 4.45 ( 0.00%) 4.36 ( 1.98%)
Best50%Mean Time 4.36 ( 0.00%) 4.25 ( 2.49%)
Best10%Mean Time 4.23 ( 0.00%) 4.10 ( 3.13%)
Best5%Mean Time 4.19 ( 0.00%) 4.06 ( 3.20%)
Best1%Mean Time 4.13 ( 0.00%) 4.00 ( 3.39%)

Small improvement and similar gains were seen on the UMA machine.

The gain is small but it stands to reason that doing less work in the
scheduler is a good thing. The downside is that the lack of schedstats and
tracepoints may be surprising to experts doing performance analysis until
they find the existence of the schedstats= parameter or schedstats sysctl.
It will be automatically activated for latencytop and sleep profiling to
alleviate the problem. For tracepoints, there is a simple warning as it's
not safe to activate schedstats in the context when it's known the tracepoint
may be wanted but is unavailable.

Signed-off-by: Mel Gorman <[email protected]>
Reviewed-by: Matt Fleming <[email protected]>
Reviewed-by: Srikar Dronamraju <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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mm: rename alloc_pages_exact_node() to __alloc_pages_node()

alloc_pages_exact_node() was introduced in commit 6484eb3e2a81 ("page
allocator: do not check NUMA node ID when the caller knows the node

mm: rename alloc_pages_exact_node() to __alloc_pages_node()

alloc_pages_exact_node() was introduced in commit 6484eb3e2a81 ("page
allocator: do not check NUMA node ID when the caller knows the node is
valid") as an optimized variant of alloc_pages_node(), that doesn't
fallback to current node for nid == NUMA_NO_NODE. Unfortunately the
name of the function can easily suggest that the allocation is
restricted to the given node and fails otherwise. In truth, the node is
only preferred, unless __GFP_THISNODE is passed among the gfp flags.

The misleading name has lead to mistakes in the past, see for example
commits 5265047ac301 ("mm, thp: really limit transparent hugepage
allocation to local node") and b360edb43f8e ("mm, mempolicy:
migrate_to_node should only migrate to node").

Another issue with the name is that there's a family of
alloc_pages_exact*() functions where 'exact' means exact size (instead
of page order), which leads to more confusion.

To prevent further mistakes, this patch effectively renames
alloc_pages_exact_node() to __alloc_pages_node() to better convey that
it's an optimized variant of alloc_pages_node() not intended for general
usage. Both functions get described in comments.

It has been also considered to really provide a convenience function for
allocations restricted to a node, but the major opinion seems to be that
__GFP_THISNODE already provides that functionality and we shouldn't
duplicate the API needlessly. The number of users would be small
anyway.

Existing callers of alloc_pages_exact_node() are simply converted to
call __alloc_pages_node(), with the exception of sba_alloc_coherent()
which open-codes the check for NUMA_NO_NODE, so it is converted to use
alloc_pages_node() instead. This means it no longer performs some
VM_BUG_ON checks, and since the current check for nid in
alloc_pages_node() uses a 'nid < 0' comparison (which includes
NUMA_NO_NODE), it may hide wrong values which would be previously
exposed.

Both differences will be rectified by the next patch.

To sum up, this patch makes no functional changes, except temporarily
hiding potentially buggy callers. Restricting the checks in
alloc_pages_node() is left for the next patch which can in turn expose
more existing buggy callers.

Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Acked-by: Robin Holt <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Christoph Lameter <[email protected]>
Acked-by: Michael Ellerman <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Greg Thelen <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Gleb Natapov <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Cliff Whickman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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profile: use %*pb[l] to print bitmaps including cpumasks and nodemasks

printk and friends can now format bitmaps using '%*pb[l]'. cpumask
and nodemask also provide cpumask_pr_args() and nodemask_pr

profile: use %*pb[l] to print bitmaps including cpumasks and nodemasks

printk and friends can now format bitmaps using '%*pb[l]'. cpumask
and nodemask also provide cpumask_pr_args() and nodemask_pr_args()
respectively which can be used to generate the two printf arguments
necessary to format the specified cpu/nodemask.

Signed-off-by: Tejun Heo <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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kernel/profile.c: use static const char instead of static char

schedstr, sleepstr and kvmstr are only used in strcmp & strlen

Signed-off-by: Fabian Frederick <[email protected]>
Cc: Paul Gortmaker <pa

kernel/profile.c: use static const char instead of static char

schedstr, sleepstr and kvmstr are only used in strcmp & strlen

Signed-off-by: Fabian Frederick <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

kernel/profile.c: convert printk to pr_foo()

Signed-off-by: Fabian Frederick <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Signed-off-by: Andrew Morton <[email protected]

kernel/profile.c: convert printk to pr_foo()

Signed-off-by: Fabian Frederick <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...