fs/procfs: Switch to irq_get_nr_irqs()

Use the irq_get_nr_irqs() function instead of the global variable
'nr_irqs'. Prepare for changing 'nr_irqs' from an exported global
variable into a variable wi

fs/procfs: Switch to irq_get_nr_irqs()

Use the irq_get_nr_irqs() function instead of the global variable
'nr_irqs'. Prepare for changing 'nr_irqs' from an exported global
variable into a variable with file scope.

Signed-off-by: Bart Van Assche <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/all/[email protected]

show more ...

proc/stat: remove arch_idle_time()

The last (only) architecture specific arch_idle_time() implementation was
removed with commit be76ea614460 ("s390/idle: remove arch_cpu_idle_time()
and correspondi

proc/stat: remove arch_idle_time()

The last (only) architecture specific arch_idle_time() implementation was
removed with commit be76ea614460 ("s390/idle: remove arch_cpu_idle_time()
and corresponding code").

Therefore remove the now dead code in fs/proc/stat.c as well.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Heiko Carstens <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

fs/proc/uptime.c: Fix idle time reporting in /proc/uptime

/proc/uptime reports idle time by reading the CPUTIME_IDLE field from
the per-cpu kcpustats. However, on NO_HZ systems, idle time is not
con

fs/proc/uptime.c: Fix idle time reporting in /proc/uptime

/proc/uptime reports idle time by reading the CPUTIME_IDLE field from
the per-cpu kcpustats. However, on NO_HZ systems, idle time is not
continually updated on idle cpus, leading this value to appear
incorrectly small.

/proc/stat performs an accounting update when reading idle time; we
can use the same approach for uptime.

With this patch, /proc/stat and /proc/uptime now agree on idle time.
Additionally, the following shows idle time tick up consistently on an
idle machine:

(while true; do cat /proc/uptime; sleep 1; done) | awk '{print $2-prev; prev=$2}'

Reported-by: Luigi Rizzo <[email protected]>
Signed-off-by: Josh Don <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

sched: Make nr_iowait() return 32-bit value

Creating 2**32 tasks to wait in D-state is impossible and wasteful.

Return "unsigned int" and save on REX prefixes.

Signed-off-by: Alexey Dobriyan <adob

sched: Make nr_iowait() return 32-bit value

Creating 2**32 tasks to wait in D-state is impossible and wasteful.

Return "unsigned int" and save on REX prefixes.

Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

sched: Make nr_running() return 32-bit value

Creating 2**32 tasks is impossible due to futex pid limits and wasteful
anyway. Nobody has done it.

Bring nr_running() into 32-bit world to save on REX

sched: Make nr_running() return 32-bit value

Creating 2**32 tasks is impossible due to futex pid limits and wasteful
anyway. Nobody has done it.

Bring nr_running() into 32-bit world to save on REX prefixes.

Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

proc/stat: switch to ->read_iter

Implement ->read_iter so that splice can be used on this file.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Christoph Hellwig <hch@ls

proc/stat: switch to ->read_iter

Implement ->read_iter so that splice can be used on this file.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

fs/proc: apply the time namespace offset to /proc/stat btime

'/proc/stat' provides the field 'btime' which states the time stamp of
system boot in seconds. In case of time namespaces, the offset to

fs/proc: apply the time namespace offset to /proc/stat btime

'/proc/stat' provides the field 'btime' which states the time stamp of
system boot in seconds. In case of time namespaces, the offset to the
boot time stamp was not applied earlier.
This confuses tasks which are in another time universe, e.g., in a
container of a container runtime which utilize time namespaces to
virtualize boottime.

Therefore, we make procfs to virtualize also the btime field by
subtracting the offset of the timens boottime from 'btime' before
printing the stats.

Since start_boottime of processes are seconds since boottime and the
boottime stamp is now shifted according to the timens offset, the
offset of the time namespace also needs to be applied before the
process stats are given to userspace.

This avoids that processes shown, e.g., by 'ps' appear as time
travelers in the corresponding time namespace.

Signed-off-by: Michael Weiß <[email protected]>
Reviewed-by: Andrei Vagin <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Acked-by: Christian Brauner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

proc: faster open/read/close with "permanent" files

Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...

Most of fs/proc/inode.

proc: faster open/read/close with "permanent" files

Now that "struct proc_ops" exist we can start putting there stuff which
could not fly with VFS "struct file_operations"...

Most of fs/proc/inode.c file is dedicated to make open/read/.../close
reliable in the event of disappearing /proc entries which usually happens
if module is getting removed. Files like /proc/cpuinfo which never
disappear simply do not need such protection.

Save 2 atomic ops, 1 allocation, 1 free per open/read/close sequence for such
"permanent" files.

Enable "permanent" flag for

/proc/cpuinfo
/proc/kmsg
/proc/modules
/proc/slabinfo
/proc/stat
/proc/sysvipc/*
/proc/swaps

More will come once I figure out foolproof way to prevent out module
authors from marking their stuff "permanent" for performance reasons
when it is not.

This should help with scalability: benchmark is "read /proc/cpuinfo R times
by N threads scattered over the system".

N R t, s (before) t, s (after)
-----------------------------------------------------
64 4096 1.582458 1.530502 -3.2%
256 4096 6.371926 6.125168 -3.9%
1024 4096 25.64888 24.47528 -4.6%

Benchmark source:

#include <chrono>
#include <iostream>
#include <thread>
#include <vector>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

const int NR_CPUS = sysconf(_SC_NPROCESSORS_ONLN);
int N;
const char *filename;
int R;

int xxx = 0;

int glue(int n)
{
cpu_set_t m;
CPU_ZERO(&m);
CPU_SET(n, &m);
return sched_setaffinity(0, sizeof(cpu_set_t), &m);
}

void f(int n)
{
glue(n % NR_CPUS);

while (*(volatile int *)&xxx == 0) {
}

for (int i = 0; i < R; i++) {
int fd = open(filename, O_RDONLY);
char buf[4096];
ssize_t rv = read(fd, buf, sizeof(buf));
asm volatile ("" :: "g" (rv));
close(fd);
}
}

int main(int argc, char *argv[])
{
if (argc < 4) {
std::cerr << "usage: " << argv[0] << ' ' << "N /proc/filename R
";
return 1;
}

N = atoi(argv[1]);
filename = argv[2];
R = atoi(argv[3]);

for (int i = 0; i < NR_CPUS; i++) {
if (glue(i) == 0)
break;
}

std::vector<std::thread> T;
T.reserve(N);
for (int i = 0; i < N; i++) {
T.emplace_back(f, i);
}

auto t0 = std::chrono::system_clock::now();
{
*(volatile int *)&xxx = 1;
for (auto& t: T) {
t.join();
}
}
auto t1 = std::chrono::system_clock::now();
std::chrono::duration<double> dt = t1 - t0;
std::cout << dt.count() << '
';

return 0;
}

P.S.:
Explicit randomization marker is added because adding non-function pointer
will silently disable structure layout randomization.

[[email protected]: coding style fixes]
Reported-by: kbuild test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Joe Perches <[email protected]>
Link: http://lkml.kernel.org/r/20200222201539.GA22576@avx2
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

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 ...

sched/cputime, proc/stat: Fix incorrect guest nice cpustat value

The value being used for guest_nice should be CPUTIME_GUEST_NICE
and not CPUTIME_USER.

Fixes: 26dae145a76c ("procfs: Use all-in-one

sched/cputime, proc/stat: Fix incorrect guest nice cpustat value

The value being used for guest_nice should be CPUTIME_GUEST_NICE
and not CPUTIME_USER.

Fixes: 26dae145a76c ("procfs: Use all-in-one vtime aware kcpustat accessor")
Signed-off-by: Flavio Leitner <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

show more ...

procfs: Use all-in-one vtime aware kcpustat accessor

Now that we can read also user and guest time safely under vtime, use
the relevant accessor to fix frozen kcpustat values on nohz_full CPUs.

Rep

procfs: Use all-in-one vtime aware kcpustat accessor

Now that we can read also user and guest time safely under vtime, use
the relevant accessor to fix frozen kcpustat values on nohz_full CPUs.

Reported-by: Yauheni Kaliuta <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wanpeng Li <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

show more ...

procfs: Use vtime aware kcpustat accessor to fetch CPUTIME_SYSTEM

Now that we have a vtime safe kcpustat accessor for CPUTIME_SYSTEM, use
it to start fixing frozen kcpustat values on nohz_full CPUs.

procfs: Use vtime aware kcpustat accessor to fetch CPUTIME_SYSTEM

Now that we have a vtime safe kcpustat accessor for CPUTIME_SYSTEM, use
it to start fixing frozen kcpustat values on nohz_full CPUs.

Reported-by: Yauheni Kaliuta <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Jacek Anaszewski <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rafael J . Wysocki <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Viresh Kumar <[email protected]>
Cc: Wanpeng Li <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

show more ...

proc: read kernel cpu stat pointer once

Help gcc generate better code:

$ ./scripts/bloat-o-meter ../vmlinux-000 ../vmlinux-001
add/remove: 2/2 grow/shrink: 0/1 up/down: 92/-142 (-50)
Function

proc: read kernel cpu stat pointer once

Help gcc generate better code:

$ ./scripts/bloat-o-meter ../vmlinux-000 ../vmlinux-001
add/remove: 2/2 grow/shrink: 0/1 up/down: 92/-142 (-50)
Function old new delta
get_iowait_time.isra - 46 +46
get_idle_time.isra - 46 +46
show_stat 1489 1477 -12
get_iowait_time 65 - -65
get_idle_time 65 - -65

Link: http://lkml.kernel.org/r/20190114195907.GA9680@avx2
Signed-off-by: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

proc/stat: Make the interrupt statistics more efficient

Waiman reported that on large systems with a large amount of interrupts the
readout of /proc/stat takes a long time to sum up the interrupt
st

proc/stat: Make the interrupt statistics more efficient

Waiman reported that on large systems with a large amount of interrupts the
readout of /proc/stat takes a long time to sum up the interrupt
statistics. In principle this is not a problem. but for unknown reasons
some enterprise quality software reads /proc/stat with a high frequency.

The reason for this is that interrupt statistics are accounted per cpu. So
the /proc/stat logic has to sum up the interrupt stats for each interrupt.

The interrupt core provides now a per interrupt summary counter which can
be used to avoid the summation loops completely except for interrupts
marked PER_CPU which are only a small fraction of the interrupt space if at
all.

Another simplification is to iterate only over the active interrupts and
skip the potentially large gaps in the interrupt number space and just
print zeros for the gaps without going into the interrupt core in the first
place.

Waiman provided test results from a 4-socket IvyBridge-EX system (60-core
120-thread, 3016 irqs) excuting a test program which reads /proc/stat
50,000 times:

Before: 18.436s (sys 18.380s)
After: 3.769s (sys 3.742s)

Reported-by: Waiman Long <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Alexey Dobriyan <[email protected]>
Reviewed-by: Waiman Long <[email protected]>
Reviewed-by: Marc Zyngier <[email protected]>
Reviewed-by: Davidlohr Bueso <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: [email protected]
Cc: Davidlohr Bueso <[email protected]>
Cc: Miklos Szeredi <[email protected]>
Cc: Daniel Colascione <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Randy Dunlap <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

show more ...

proc: use "unsigned int" in /proc/stat hook

Number of CPUs is never high enough to force 64-bit arithmetic.
Save couple of bytes on x86_64.

Link: http://lkml.kernel.org/r/20180627200710.GC18434@avx

proc: use "unsigned int" in /proc/stat hook

Number of CPUs is never high enough to force 64-bit arithmetic.
Save couple of bytes on x86_64.

Link: http://lkml.kernel.org/r/20180627200710.GC18434@avx2
Signed-off-by: Alexey Dobriyan <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>

Introduce a trivial, mostly empty <linux/sched/cputime.h> header
to prepare for the moving of c

sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>

Introduce a trivial, mostly empty <linux/sched/cputime.h> header
to prepare for the moving of cputime functionality out of sched.h.

Update all code that relies on these facilities.

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]>

show more ...

sched/headers: Prepare for new header dependencies before moving code to <linux/sched/stat.h>

We are going to split <linux/sched/stat.h> out of <linux/sched.h>, which
will have to be picked up from

sched/headers: Prepare for new header dependencies before moving code to <linux/sched/stat.h>

We are going to split <linux/sched/stat.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/stat.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

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]>

show more ...

s390, sched/cputime: Make arch_cpu_idle_time() to return nsecs

This way we don't need to deal with cputime_t details from the core code.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc:

s390, sched/cputime: Make arch_cpu_idle_time() to return nsecs

This way we don't need to deal with cputime_t details from the core code.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Wanpeng Li <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

show more ...

sched/cputime: Convert kcpustat to nsecs

Kernel CPU stats are stored in cputime_t which is an architecture
defined type, and hence a bit opaque and requiring accessors and mutators
for any operation

sched/cputime: Convert kcpustat to nsecs

Kernel CPU stats are stored in cputime_t which is an architecture
defined type, and hence a bit opaque and requiring accessors and mutators
for any operation.

Converting them to nsecs simplifies the code and is one step toward
the removal of cputime_t in the core code.

Signed-off-by: Frederic Weisbecker <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Wanpeng Li <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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seq/proc: modify seq_put_decimal_[u]ll to take a const char *, not char

Allow some seq_puts removals by taking a string instead of a single
char.

[[email protected]: update vmstat_show(), p

seq/proc: modify seq_put_decimal_[u]ll to take a const char *, not char

Allow some seq_puts removals by taking a string instead of a single
char.

[[email protected]: update vmstat_show(), per Joe]
Link: http://lkml.kernel.org/r/667e1cf3d436de91a5698170a1e98d882905e956.1470704995.git.joe@perches.com
Signed-off-by: Joe Perches <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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procfs: avoid 32-bit time_t in /proc/*/stat

/proc/stat shows (among lots of other things) the current boottime (i.e.
number of seconds since boot). While a 32-bit number is sufficient for
this part

procfs: avoid 32-bit time_t in /proc/*/stat

/proc/stat shows (among lots of other things) the current boottime (i.e.
number of seconds since boot). While a 32-bit number is sufficient for
this particular case, we want to get rid of the 'struct timespec'
suffers from a 32-bit overflow in 2038.

This changes the code to use a struct timespec64, which is known to be
safe in all cases.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnd Bergmann <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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genirq: Prevent proc race against freeing of irq descriptors

Since the rework of the sparse interrupt code to actually free the
unused interrupt descriptors there exists a race between the /proc
int

genirq: Prevent proc race against freeing of irq descriptors

Since the rework of the sparse interrupt code to actually free the
unused interrupt descriptors there exists a race between the /proc
interfaces to the irq subsystem and the code which frees the interrupt
descriptor.

CPU0 CPU1
show_interrupts()
desc = irq_to_desc(X);
free_desc(desc)
remove_from_radix_tree();
kfree(desc);
raw_spinlock_irq(&desc->lock);

/proc/interrupts is the only interface which can actively corrupt
kernel memory via the lock access. /proc/stat can only read from freed
memory. Extremly hard to trigger, but possible.

The interfaces in /proc/irq/N/ are not affected by this because the
removal of the proc file is serialized in procfs against concurrent
readers/writers. The removal happens before the descriptor is freed.

For architectures which have CONFIG_SPARSE_IRQ=n this is a non issue
as the descriptor is never freed. It's merely cleared out with the irq
descriptor lock held. So any concurrent proc access will either see
the old correct value or the cleared out ones.

Protect the lookup and access to the irq descriptor in
show_interrupts() with the sparse_irq_lock.

Provide kstat_irqs_usr() which is protecting the lookup and access
with sparse_irq_lock and switch /proc/stat to use it.

Document the existing kstat_irqs interfaces so it's clear that the
caller needs to take care about protection. The users of these
interfaces are either not affected due to SPARSE_IRQ=n or already
protected against removal.

Fixes: 1f5a5b87f78f "genirq: Implement a sane sparse_irq allocator"
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]

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/proc/stat: convert to single_open_size()

These two patches are supposed to "fix" failed order-4 memory
allocations which have been observed when reading /proc/stat. The
problem has been observed o

/proc/stat: convert to single_open_size()

These two patches are supposed to "fix" failed order-4 memory
allocations which have been observed when reading /proc/stat. The
problem has been observed on s390 as well as on x86.

To address the problem change the seq_file memory allocations to
fallback to use vmalloc, so that allocations also work if memory is
fragmented.

This approach seems to be simpler and less intrusive than changing
/proc/stat to use an interator. Also it "fixes" other users as well,
which use seq_file's single_open() interface.

This patch (of 2):

Use seq_file's single_open_size() to preallocate a buffer that is large
enough to hold the whole output, instead of open coding it. Also
calculate the requested size using the number of online cpus instead of
possible cpus, since the size of the output only depends on the number
of online cpus.

Signed-off-by: Heiko Carstens <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Ian Kent <[email protected]>
Cc: Hendrik Brueckner <[email protected]>
Cc: Thorsten Diehl <[email protected]>
Cc: Andrea Righi <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Stefan Bader <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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cputime: Default implementation of nsecs -> cputime conversion

The architectures that override cputime_t (s390, ppc) don't provide
any version of nsecs_to_cputime(). Indeed this cputime_t implementa

cputime: Default implementation of nsecs -> cputime conversion

The architectures that override cputime_t (s390, ppc) don't provide
any version of nsecs_to_cputime(). Indeed this cputime_t implementation
by backend only happens when CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=y under
which the core code doesn't make any use of nsecs_to_cputime().

At least for now.

We are going to make a broader use of it so lets provide a default
version with a per usecs granularity. It should be good enough for most
usecases.

Cc: Ingo Molnar <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>

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